Design of a boron neutron capture enhanced fast neutron therapy assembly
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Zhonglu
The use of boron neutron capture to boost tumor dose in fast neutron therapy has been investigated at several fast neutron therapy centers worldwide. This treatment is termed boron neutron capture enhanced fast neutron therapy (BNCEFNT). It is a combination of boron neutron capture therapy (BNCT) and fast neutron therapy (FNT). It is believed that BNCEFNT may be useful in the treatment of some radioresistant brain tumors, such as glioblastoma multiform (GBM). A boron neutron capture enhanced fast neutron therapy assembly has been designed for the Fermilab Neutron Therapy Facility (NTF). This assembly uses a tungsten filter and collimator nearmore » the patient's head, with a graphite reflector surrounding the head to significantly increase the dose due to boron neutron capture reactions. The assembly was designed using Monte Carlo radiation transport code MCNP version 5 for a standard 20x20 cm 2 treatment beam. The calculated boron dose enhancement at 5.7-cm depth in a water-filled head phantom in the assembly with a 5x5 cm 2 collimation was 21.9% per 100-ppm 10B for a 5.0-cm tungsten filter and 29.8% for a 8.5-cm tungsten filter. The corresponding dose rate for the 5.0-cm and 8.5-cm thick filters were 0.221 and 0.127 Gy/min, respectively; about 48.5% and 27.9% of the dose rate of the standard 10x10 cm 2 fast neutron treatment beam. To validate the design calculations, a simplified BNCEFNT assembly was built using four lead bricks to form a 5x5 cm 2 collimator. Five 1.0-cm thick 20x20 cm 2 tungsten plates were used to obtain different filter thicknesses and graphite bricks/blocks were used to form a reflector. Measurements of the dose enhancement of the simplified assembly in a water-filled head phantom were performed using a pair of tissue-equivalent ion chambers. One of the ion chambers is loaded with 1000-ppm natural boron (184-ppm 10B) to measure dose due to boron neutron capture. The measured dose enhancement at 5.0-cm depth in the head phantom for the 5
Commissioning optically stimulated luminescence in vivo dosimeters for fast neutron therapy.
Young, Lori A; Yang, Fei; Woodworth, Davis; McCormick, Zephyr; Sandison, George
2016-01-01
Clinical in vivo dosimeters intended for use with photon and electron therapies have not been utilized for fast neutron therapy because they are highly susceptible to neutron damage. The objective of this work was to determine if a commercial optically stimulated luminescence (OSL) in vivo dosimetry system could be adapted for use in fast neutron therapy. A 50.5 MeV fast neutron beam generated by a clinical neutron therapy cyclotron was used to irradiate carbon doped aluminum oxide (Al2O3:C) optically simulated luminescence dosimeters (OSLDs) in a solid water phantom under standard calibration conditions, 150 cm SAD, 1.7 cm depth, and 10.3 × 10.0 cm field size. OSLD fading and electron trap depletion studies were performed with the OSLDs irradiated with 20 and 50 cGy and monitored over a 24-h period to determine the optimal time for reading the dosimeters during calibration. Four OSLDs per group were calibrated over a clinical dose range of 0-150 cGy. OSLD measurement uncertainties were lowered to within ±2%-3% of the expected dose by minimizing the effect of transient fading that occurs with neutron irradiation and maintaining individual calibration factors for each dosimeter. Dose dependent luminescence fading extended beyond the manufacturer's recommended 10 min period for irradiation with photon or electron beams. To minimize OSL variances caused by inconsistent fading among dosimeters, the observed optimal time for reading the OSLDs postirradiation was between 30 and 90 min. No field size, wedge factor, or gantry angle dependencies were observed in the OSLDs irradiated by the studied fast neutron beam. Measurements demonstrated that uncertainties less than ±3% were attainable in OSLDs irradiated with fast neutrons under clinical conditions. Accuracy and precision comparable to clinical OSL measurements observed with photons can be achieved by maintaining individual OSLD calibration factors and minimizing transient fading effects.
Commissioning optically stimulated luminescence in vivo dosimeters for fast neutron therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Young, Lori A., E-mail: layoung@uw.edu; Sandison, George; Yang, Fei
Purpose: Clinical in vivo dosimeters intended for use with photon and electron therapies have not been utilized for fast neutron therapy because they are highly susceptible to neutron damage. The objective of this work was to determine if a commercial optically stimulated luminescence (OSL) in vivo dosimetry system could be adapted for use in fast neutron therapy. Methods: A 50.5 MeV fast neutron beam generated by a clinical neutron therapy cyclotron was used to irradiate carbon doped aluminum oxide (Al{sub 2}O{sub 3}:C) optically simulated luminescence dosimeters (OSLDs) in a solid water phantom under standard calibration conditions, 150 cm SAD, 1.7more » cm depth, and 10.3 × 10.0 cm field size. OSLD fading and electron trap depletion studies were performed with the OSLDs irradiated with 20 and 50 cGy and monitored over a 24-h period to determine the optimal time for reading the dosimeters during calibration. Four OSLDs per group were calibrated over a clinical dose range of 0–150 cGy. Results: OSLD measurement uncertainties were lowered to within ±2%–3% of the expected dose by minimizing the effect of transient fading that occurs with neutron irradiation and maintaining individual calibration factors for each dosimeter. Dose dependent luminescence fading extended beyond the manufacturer’s recommended 10 min period for irradiation with photon or electron beams. To minimize OSL variances caused by inconsistent fading among dosimeters, the observed optimal time for reading the OSLDs postirradiation was between 30 and 90 min. No field size, wedge factor, or gantry angle dependencies were observed in the OSLDs irradiated by the studied fast neutron beam. Conclusions: Measurements demonstrated that uncertainties less than ±3% were attainable in OSLDs irradiated with fast neutrons under clinical conditions. Accuracy and precision comparable to clinical OSL measurements observed with photons can be achieved by maintaining individual OSLD calibration factors
NASA Technical Reports Server (NTRS)
Frigerio, N. A.; Nellans, H. N.; Shaw, M. J.
1969-01-01
Reports relate applications of neutrons to the problem of cancer therapy. The biochemical and biophysical aspects of fast-neutron therapy, neutron-capture and neutron-conversion therapy with intermediate-range neutrons are presented. Also included is a computer program for neutron-gamma radiobiology.
A study on the optimum fast neutron flux for boron neutron capture therapy of deep-seated tumors.
Rasouli, Fatemeh S; Masoudi, S Farhad
2015-02-01
High-energy neutrons, named fast neutrons which have a number of undesirable biological effects on tissue, are a challenging problem in beam designing for Boron Neutron Capture Therapy, BNCT. In spite of this fact, there is not a widely accepted criterion to guide the beam designer to determine the appropriate contribution of fast neutrons in the spectrum. Although a number of researchers have proposed a target value for the ratio of fast neutron flux to epithermal neutron flux, it can be shown that this criterion may not provide the optimum treatment condition. This simulation study deals with the determination of the optimum contribution of fast neutron flux in the beam for BNCT of deep-seated tumors. Since the dose due to these high-energy neutrons damages shallow tissues, delivered dose to skin is considered as a measure for determining the acceptability of the designed beam. To serve this purpose, various beam shaping assemblies that result in different contribution of fast neutron flux are designed. The performances of the neutron beams corresponding to such configurations are assessed in a simulated head phantom. It is shown that the previously used criterion, which suggests a limit value for the contribution of fast neutrons in beam, does not necessarily provide the optimum condition. Accordingly, it is important to specify other complementary limits considering the energy of fast neutrons. By analyzing various neutron spectra, two limits on fast neutron flux are proposed and their validity is investigated. The results show that considering these limits together with the widely accepted IAEA criteria makes it possible to have a more realistic assessment of sufficiency of the designed beam. Satisfying these criteria not only leads to reduction of delivered dose to skin, but also increases the advantage depth in tissue and delivered dose to tumor during the treatment time. The Monte Carlo Code, MCNP-X, is used to perform these simulations. Copyright © 2014
Feasibility of the Utilization of BNCT in the Fast Neutron Therapy Beam at Fermilab
DOE R&D Accomplishments Database
Langen, Katja; Lennox, Arlene J.; Kroc, Thomas K.; DeLuca, Jr., Paul M.
2000-06-01
The Neutron Therapy Facility at Fermilab has treated cancer patients since 1976. Since then more than 2,300 patients have been treated and a wealth of clinical information accumulated. The therapeutic neutron beam at Fermilab is produced by bombarding a beryllium target with 66 MeV protons. The resulting continuous neutron spectrum ranges from thermal to 66 MeV in neutron energy. It is clear that this spectrum is not well suited for the treatment of tumors with boron neutron capture therapy (BNCT) only However, since this spectrum contains thermal and epithermal components the authors are investigating whether BNCT can be used in this beam to boost the tumor dose. There are clinical scenarios in which a selective tumor dose boost of 10 - 15% could be clinically significant. For these cases the principal treatment would still be fast neutron therapy but a tumor boost could be used either to deliver a higher dose to the tumor tissue or to reduce the dose to the normal healthy tissue while maintaining the absorbed dose level in the tumor tissue.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Musabaeva, L. I., E-mail: musabaevaLI@oncology.tomsk.ru; Lisin, V. A., E-mail: Lisin@oncology.tomsk.ru; Startseva, Zh. A., E-mail: zhanna.alex@rambler.ru
The analysis of clinical use of neutron therapy with 6 MeV fast neutrons compared to conventional radiation therapy was carried out. The experience of using neutron and mixed neutron and photon therapy in patients with different radio-resistant malignant tumors shows the necessity of further studies and development of the novel approaches to densely-ionizing radiation. The results of dosimetry and radiobiological studies have been the basis for planning clinical programs for neutron therapy. Clinical trials over the past 30 years have shown that neutron therapy successfully destroys radio-resistant cancers, including salivary gland tumors, adenoidcystic carcinoma, inoperable sarcomas, locally advanced head andmore » neck tumors, and locally advanced prostate cancer. Radiation therapy with 6.3 MeV fast neutrons used alone and in combination with photon therapy resulted in improved long-term treatment outcomes in patients with radio-resistant malignant tumors.« less
NASA Astrophysics Data System (ADS)
Musabaeva, L. I.; Startseva, Zh. A.; Gribova, O. V.; Velikaya, V. V.; Lisin, V. A.
2016-08-01
The analysis of clinical use of neutron therapy with 6 MeV fast neutrons compared to conventional radiation therapy was carried out. The experience of using neutron and mixed neutron and photon therapy in patients with different radio-resistant malignant tumors shows the necessity of further studies and development of the novel approaches to densely-ionizing radiation. The results of dosimetry and radiobiological studies have been the basis for planning clinical programs for neutron therapy. Clinical trials over the past 30 years have shown that neutron therapy successfully destroys radio-resistant cancers, including salivary gland tumors, adenoidcystic carcinoma, inoperable sarcomas, locally advanced head and neck tumors, and locally advanced prostate cancer. Radiation therapy with 6.3 MeV fast neutrons used alone and in combination with photon therapy resulted in improved long-term treatment outcomes in patients with radio-resistant malignant tumors.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sakurai, Yoshinori, E-mail: yosakura@rri.kyoto-u.ac.jp; Tanaka, Hiroki; Kondo, Natsuko
2015-11-15
Purpose: Research and development of various accelerator-based irradiation systems for boron neutron capture therapy (BNCT) is underway throughout the world. Many of these systems are nearing or have started clinical trials. Before the start of treatment with BNCT, the relative biological effectiveness (RBE) for the fast neutrons (over 10 keV) incident to the irradiation field must be estimated. Measurements of RBE are typically performed by biological experiments with a phantom. Although the dose deposition due to secondary gamma rays is dominant, the relative contributions of thermal neutrons (below 0.5 eV) and fast neutrons are virtually equivalent under typical irradiation conditionsmore » in a water and/or acrylic phantom. Uniform contributions to the dose deposited from thermal and fast neutrons are based in part on relatively inaccurate dose information for fast neutrons. This study sought to improve the accuracy in the dose estimation for fast neutrons by using two phantoms made of different materials in which the dose components can be separated according to differences in the interaction cross sections. The development of a “dual phantom technique” for measuring the fast neutron component of dose is reported. Methods: One phantom was filled with pure water. The other phantom was filled with a water solution of lithium hydroxide (LiOH) capitalizing on the absorbing characteristics of lithium-6 (Li-6) for thermal neutrons. Monte Carlo simulations were used to determine the ideal mixing ratio of Li-6 in LiOH solution. Changes in the depth dose distributions for each respective dose component along the central beam axis were used to assess the LiOH concentration at the 0, 0.001, 0.01, 0.1, 1, and 10 wt. % levels. Simulations were also performed with the phantom filled with 10 wt. % {sup 6}LiOH solution for 95%-enriched Li-6. A phantom was constructed containing 10 wt. % {sup 6}LiOH solution based on the simulation results. Experimental characterization
Sakurai, Yoshinori; Tanaka, Hiroki; Kondo, Natsuko; Kinashi, Yuko; Suzuki, Minoru; Masunaga, Shinichiro; Ono, Koji; Maruhashi, Akira
2015-11-01
Research and development of various accelerator-based irradiation systems for boron neutron capture therapy (BNCT) is underway throughout the world. Many of these systems are nearing or have started clinical trials. Before the start of treatment with BNCT, the relative biological effectiveness (RBE) for the fast neutrons (over 10 keV) incident to the irradiation field must be estimated. Measurements of RBE are typically performed by biological experiments with a phantom. Although the dose deposition due to secondary gamma rays is dominant, the relative contributions of thermal neutrons (below 0.5 eV) and fast neutrons are virtually equivalent under typical irradiation conditions in a water and/or acrylic phantom. Uniform contributions to the dose deposited from thermal and fast neutrons are based in part on relatively inaccurate dose information for fast neutrons. This study sought to improve the accuracy in the dose estimation for fast neutrons by using two phantoms made of different materials in which the dose components can be separated according to differences in the interaction cross sections. The development of a "dual phantom technique" for measuring the fast neutron component of dose is reported. One phantom was filled with pure water. The other phantom was filled with a water solution of lithium hydroxide (LiOH) capitalizing on the absorbing characteristics of lithium-6 (Li-6) for thermal neutrons. Monte Carlo simulations were used to determine the ideal mixing ratio of Li-6 in LiOH solution. Changes in the depth dose distributions for each respective dose component along the central beam axis were used to assess the LiOH concentration at the 0, 0.001, 0.01, 0.1, 1, and 10 wt. % levels. Simulations were also performed with the phantom filled with 10 wt. % 6LiOH solution for 95%-enriched Li-6. A phantom was constructed containing 10 wt. % 6LiOH solution based on the simulation results. Experimental characterization of the depth dose distributions of the
NASA Astrophysics Data System (ADS)
Mirabelli, R.; Battistoni, G.; Giacometti, V.; Patera, V.; Pinci, D.; Sarti, A.; Sciubba, A.; Traini, G.; Marafini, M.
2018-01-01
In Particle Therapy (PT) accelerated charged particles and light ions are used for treating tumors. One of the main limitation to the precision of PT is the emission of secondary particles due to the beam interaction with the patient: secondary emitted neutrons can release a significant dose far from the tumor. Therefore, a precise characterization of their flux, production energy and angle distribution is eagerly needed in order to improve the Treatment Planning Systems (TPS) codes. The principal aim of the MONDO (MOnitor for Neutron Dose in hadrOntherapy) project is the development of a tracking device optimized for the detection of fast and ultra-fast secondary neutrons emitted in PT. The detector consists of a matrix of scintillating square fibres coupled with a CMOS-based readout. Here, we present the characterization of the detector tracker prototype and CMOS-based digital SPAD (Single Photon Avalanche Diode) array sensor tested with protons at the Beam Test Facility (Frascati, Italy) and at the Proton Therapy Centre (Trento, Italy), respectively.
Neutron therapy for salivary and thyroid gland cancer
NASA Astrophysics Data System (ADS)
Gribova, O. V.; Musabaeva, L. I.; Choynzonov, E. L.; Lisin, V. A.; Novikov, V. A.
2016-08-01
The purpose of this study was to analyze the results of the combined modality treatment and radiation therapy using 6.3 MeV fast neutrons for salivary gland cancer and prognostically unfavorable thyroid gland cancer. The study group comprised 127 patients with salivary gland cancer and 46 patients with thyroid gland cancer, who received neutron therapy alone and in combination with surgery. The results obtained demonstrated that the combined modality treatment including fast neutron therapy led to encouraging local control in patients with salivary and thyroid gland cancers.
Neutron therapy for salivary and thyroid gland cancer
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gribova, O. V., E-mail: gribova79@mail.ru; Choynzonov, E. L., E-mail: nii@oncology.tomsk.ru; National Research Tomsk Polytechnic University, Lenina Avenue 30, Tomsk, 634050
The purpose of this study was to analyze the results of the combined modality treatment and radiation therapy using 6.3 MeV fast neutrons for salivary gland cancer and prognostically unfavorable thyroid gland cancer. The study group comprised 127 patients with salivary gland cancer and 46 patients with thyroid gland cancer, who received neutron therapy alone and in combination with surgery. The results obtained demonstrated that the combined modality treatment including fast neutron therapy led to encouraging local control in patients with salivary and thyroid gland cancers.
SU-E-T-75: Commissioning Optically Stimulated Luminescence Dosimeters for Fast Neutron Therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Young, L; Yang, F; Sandison, G
Purpose: Fast neutrons therapy used at the University of Washington is clinically proven to be more effective than photon therapy in treating salivary gland and other cancers. A nanodot optically stimulated luminescence (OSL) system was chosen to be commissioned for patient in vivo dosimetry for neutron therapy. The OSL-based radiation detectors are not susceptible to radiation damage caused by neutrons compared to diodes or MOSFET systems. Methods: An In-Light microStar OSL system was commissioned for in vivo use by radiating Landauer nanodots with neutrons generated from 50.0 MeV protons accelerated onto a beryllium target. The OSLs were calibrated the depthmore » of maximum dose in solid water localized to 150 cm SAD isocenter in a 10.3 cm square field. Linearity was tested over a typical clinical dose fractionation range i.e. 0 to 150 neutron-cGy. Correction factors for transient signal fading, trap depletion, gantry angle, field size, and wedge factor dependencies were also evaluated. The OSLs were photo-bleached between radiations using a tungsten-halogen lamp. Results: Landauer sensitivity factors published for each nanodot are valid for measuring photon and electron doses but do not apply for neutron irradiation. Individually calculated nanodot calibration factors exhibited a 2–5% improvement over calibration factors computed by the microStar InLight software. Transient fading effects had a significant impact on neutron dose reading accuracy compared to photon and electron in vivo dosimetry. Greater accuracy can be achieved by calibrating and reading each dosimeter within 1–2 hours after irradiation. No additional OSL correction factors were needed for field size, gantry angle, or wedge factors in solid water phantom measurements. Conclusion: OSL detectors are a useful for neutron beam in vivo dosimetry verification. Dosimetric accuracy comparable to conventional diode systems can be achieved. Accounting for transient fading effects during the neutron
Neutron therapy of resistant thyroid gland cancer
NASA Astrophysics Data System (ADS)
Choynzonov, E. L.; Gribova, O. V.; Startseva, Zh. A.; Lisin, V. A.; Novikov, V. A.; Musabaeva, L. I.
2017-09-01
The purpose of this study was to analyze the results of the combined modality treatment and radiation therapy using 6.3 MeV fast neutrons c. The study included 45 patients with thyroid gland cancers who received the combined modality treatment and radiation therapy alone with the use of 6.3 MeV fast neutrons generated within U-120 cyclotron. The clinical trial of neutron-photon therapy used alone and in combination with the surgery for the patients with aggressive forms of thyroid cancer showed feasibility of increasing the effectiveness of treatment due to the reduction in the incidence of local recurrences. In addition, satisfactory treatment tolerance and absence of severe specific complications dictate the necessity of prospective studies to improve treatment outcomes.
System and method for delivery of neutron beams for medical therapy
Nigg, David W.; Wemple, Charles A.
1999-01-01
A neutron delivery system that provides improved capability for tumor control during medical therapy. The system creates a unique neutron beam that has a bimodal or multi-modal energy spectrum. This unique neutron beam can be used for fast-neutron therapy, boron neutron capture therapy (BNCT), or both. The invention includes both an apparatus and a method for accomplishing the purposes of the invention.
System and method for delivery of neutron beams for medical therapy
Nigg, D.W.; Wemple, C.A.
1999-07-06
A neutron delivery system that provides improved capability for tumor control during medical therapy is disclosed. The system creates a unique neutron beam that has a bimodal or multi-modal energy spectrum. This unique neutron beam can be used for fast-neutron therapy, boron neutron capture therapy (BNCT), or both. The invention includes both an apparatus and a method for accomplishing the purposes of the invention. 5 figs.
Specht, Hanno M; Neff, Teresa; Reuschel, Waltraud; Wagner, Franz M; Kampfer, Severin; Wilkens, Jan J; Petry, Winfried; Combs, Stephanie E
2015-01-01
While neutron therapy was a highly topical subject in the 70s and 80s, today there are only a few remaining facilities offering fast neutron therapy (FNT). Nevertheless, up to today more than 30,000 patients were treated with neutron therapy. For some indications like salivary gland tumors and malignant melanoma, there is clinical evidence that the addition of FNT leads to superior local control compared to photon treatment alone. FNT was available in Munich from 1985 until 2000 at the Reactor Neutron Therapy (RENT) facility. Patient treatment continued at the new research reactor FRM II in 2007 under improved treatment conditions, and today it can still be offered to selected patients as an individual treatment option. As there is a growing interest in high-linear energy transfer (LET) therapy with new hadron therapy centers emerging around the globe, the clinical data generated by neutron therapy might help to develop biologically driven treatment planning algorithms. Also FNT might experience its resurgence as a combinational partner of modern immunotherapies.
Specht, Hanno M.; Neff, Teresa; Reuschel, Waltraud; Wagner, Franz M.; Kampfer, Severin; Wilkens, Jan J.; Petry, Winfried; Combs, Stephanie E.
2015-01-01
While neutron therapy was a highly topical subject in the 70s and 80s, today there are only a few remaining facilities offering fast neutron therapy (FNT). Nevertheless, up to today more than 30,000 patients were treated with neutron therapy. For some indications like salivary gland tumors and malignant melanoma, there is clinical evidence that the addition of FNT leads to superior local control compared to photon treatment alone. FNT was available in Munich from 1985 until 2000 at the Reactor Neutron Therapy (RENT) facility. Patient treatment continued at the new research reactor FRM II in 2007 under improved treatment conditions, and today it can still be offered to selected patients as an individual treatment option. As there is a growing interest in high-linear energy transfer (LET) therapy with new hadron therapy centers emerging around the globe, the clinical data generated by neutron therapy might help to develop biologically driven treatment planning algorithms. Also FNT might experience its resurgence as a combinational partner of modern immunotherapies. PMID:26640777
Fast neutron imaging device and method
Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.
2014-02-11
A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.
Epithermal neutron beams from the 7 Li(p,n) reaction near the threshold for neutron capture therapy
NASA Astrophysics Data System (ADS)
Porras, I.; Praena, J.; Arias de Saavedra, F.; Pedrosa, M.; Esquinas, P.; L. Jiménez-Bonilla, P.
2016-11-01
Two applications for neutron capture therapy of epithermal neutron beams calculated from the 7Li ( p , n reaction are discussed. In particular, i) for a proton beam of 1920 keV of a 30 mA, a neutron beam of adequate features for BNCT is found at an angle of 80° from the forward direction; and ii) for a proton beam of 1910 keV, a neutron beam is obtained at the forward direction suitable for performing radiobiology experiments for the determination of the biological weighting factors of the fast dose component in neutron capture therapy.
Positron emission tomography-guided conformal fast neutron therapy for glioblastoma multiforme
Stelzer, Keith J.; Douglas, James G.; Mankoff, David A.; Silbergeld, Daniel L.; Krohn, Kenneth A.; Laramore, George E.; Spence, Alexander M.
2008-01-01
Glioblastoma multiforme (GBM) continues to be a difficult therapeutic challenge. Our study was conducted to determine whether improved survival and tumor control could be achieved with modern delivery of fast neutron radiation using three-dimensional treatment planning. Ten patients were enrolled. Eligibility criteria included pathologic diagnosis of GBM, age ≥ 18 years, and KPS ≥60. Patients underwent MRI and 18F-fluorodeoxyglucose PET (FDG PET) as part of initial three-dimensional treatment planning. Sequential targets were treated with noncoplanar fields to a total dose of 18 Gy in 16 fractions over 4 weeks. Median and 1-year overall survival were 55 weeks and 60%, respectively. One patient remains alive at last follow-up 255 weeks after diagnosis. Median progression-free survival was 16 weeks, and all patients had tumor progression by 39 weeks. Treatment was clinically well tolerated, but evidence of mild to moderate gliosis and microvascular sclerosis consistent with radiation injury was observed at autopsy in specimens taken from regions of contralateral brain that received approximately 6–10 Gy. Fast neutron radiation using modern imaging, treatment planning, and beam delivery was feasible to a total dose of 18 Gy, but tumor control probability was poor in comparison to that predicted from a dose-response model based on older studies. Steep dose-response curves for both tumor control and neurotoxicity continue to present a challenge to establishing a therapeutic window for fast neutron radiation in GBM, even with modern techniques. PMID:18055860
Auberger, T; Koester, L; Knopf, K; Weissfloch, L
1996-01-01
In 12 patients with recurrences and metastases of different primaries (head and neck cancer, breast cancer, malignant melanoma, and osteosarcoma) who were treated with reactor fission neutrons the photon emission of irradiated tissue was measured after each radiotherapy fraction. Spectral analyses of the decay rates resulted in data for the exchange of sodium (Na) and chlorine (Cl) between the irradiated tissue and the body. About 60% of Na and Cl exchanged rapidly with a turnover half-life of 13 +/- 2 min. New defined mass exchange rates for Na and Cl amount to an average of 0.8 mval/min/kg of soft tissue. At the beginning of radiotherapy the turnover of the electrolytes in tissues with large tumor volumes was about twice that in tissues with small tumor volumes. Depending on the dose, neutron therapy led in all cases to variation in the metabolism. A maximum of Cl exchange and a minimum of Na exchange occurred after 10 Gy of neutrons (group of six previously untreated patients) or after 85 Gy (photon equivalent dose) of combined photon-neutron therapy. A significant increase in non-exchangeable fraction of Na from about 40 to 80% was observed in three tumors after a neutron dose of 10 Gy administered in five fractions correlated with a rapid reduction of tissue within 4 weeks after end of therapy. These results demonstrate for the first time the local response of the electrolyte metabolism to radiotherapy.
Real-time detection of fast and thermal neutrons in radiotherapy with CMOS sensors.
Arbor, Nicolas; Higueret, Stephane; Elazhar, Halima; Combe, Rodolphe; Meyer, Philippe; Dehaynin, Nicolas; Taupin, Florence; Husson, Daniel
2017-03-07
The peripheral dose distribution is a growing concern for the improvement of new external radiation modalities. Secondary particles, especially photo-neutrons produced by the accelerator, irradiate the patient more than tens of centimeters away from the tumor volume. However the out-of-field dose is still not estimated accurately by the treatment planning softwares. This study demonstrates the possibility of using a specially designed CMOS sensor for fast and thermal neutron monitoring in radiotherapy. The 14 microns-thick sensitive layer and the integrated electronic chain of the CMOS are particularly suitable for real-time measurements in γ/n mixed fields. An experimental field size dependency of the fast neutron production rate, supported by Monte Carlo simulations and CR-39 data, has been observed. This dependency points out the potential benefits of a real-time monitoring of fast and thermal neutron during beam intensity modulated radiation therapies.
Smaller, Lower-Power Fast-Neutron Scintillation Detectors
NASA Technical Reports Server (NTRS)
Patel, Jagdish; Blaes, Brent
2008-01-01
Scintillation-based fast-neutron detectors that are smaller and less power-hungry than mainstream scintillation-based fast-neutron detectors are undergoing development. There are numerous applications for such detectors in monitoring fast-neutron fluxes from nuclear reactors, nuclear materials, and natural sources, both on Earth and in outer space. A particularly important terrestrial application for small, low-power, portable fast-neutron detectors lies in the requirement to scan for nuclear materials in cargo and baggage arriving at international transportation facilities. The present development of miniature, low-power scintillation-based fast-neutron detectors exploits recent advances in the fabrication of avalanche photodiodes (APDs). Basically, such a detector includes a plastic scintillator, typically between 300 and 400 m thick with very thin silver mirror coating on all its faces except the one bonded to an APD. All photons generated from scintillation are thus internally reflected and eventually directed to the APD. This design affords not only compactness but also tight optical coupling for utilization of a relatively large proportion of the scintillation light. The combination of this tight coupling and the avalanche-multiplication gain (typically between 750 and 1,000) of the APD is expected to have enough sensitivity to enable monitoring of a fast-neutron flux as small as 1,000 cm(exp -2)s(exp -1). Moreover, pulse-height analysis can be expected to provide information on the kinetic energies of incident neutrons. It has been estimated that a complete, fully developed fast-neutron detector of this type, would be characterized by linear dimensions of the order of 10 cm or less, a mass of no more than about 0.5 kg, and a power demand of no more than a few watts.
NASA Technical Reports Server (NTRS)
2002-01-01
Observations by NASA's 2001 Mars Odyssey spacecraft show a global view of Mars in high-energy, or fast, neutrons. These maps are based on data acquired by the high-energy neutron detector, one of the instruments in the gamma ray spectrometer suite. Fast neutrons, like epithermal neutrons, are sensitive to the presence of hydrogen. Unlike epithermal neutrons, however, they are not affected by the presence of carbon dioxide, which at the time of these observations covered the north polar area as 'dry ice' frost. The low flux of fast neutrons (blue and purple colors) in the north polar region suggests an abundance of hydrogen in the soil comparable to that determined in the south from the flux of epithermal neutrons. These observations were acquired during the first two months of mapping operations. Contours of topography are superimposed on these maps for geographic reference.
NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. Investigators at Arizona State University in Tempe, the University of Arizona in Tucson, and NASA's Johnson Space Center, Houston, operate the science instruments. The gamma-ray spectrometer was provided by the University of Arizona in collaboration with the Russian Aviation and Space Agency, which provided the high-energy neutron detector, and the Los Alamos National Laboratories, New Mexico, which provided the neutron spectrometer. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.Comparison of Fast Neutron Detector Technologies
DOE Office of Scientific and Technical Information (OSTI.GOV)
Stange, Sy; Mckigney, Edward Allen
2015-02-09
This report documents the work performed for the Department of Homeland Security Domestic Nuclear Detection O ce as the project Fast Neutron Detection Evaluation under contract HSHQDC-14-X-00022. This study was performed as a follow-on to the project Study of Fast Neutron Signatures and Measurement Techniques for SNM Detection - DNDO CFP11-100 STA-01. That work compared various detector technologies in a portal monitor con guration, focusing on a comparison between a number of fast neutron detection techniques and two standard thermal neutron detection technologies. The conclusions of the earlier work are contained in the report Comparison of Fast Neutron Detector Technologies.more » This work is designed to address questions raised about assumptions underlying the models built for the earlier project. To that end, liquid scintillators of two di erent sizes{ one a commercial, o -the-shelf (COTS) model of standard dimensions and the other a large, planer module{were characterized at Los Alamos National Laboratory. The results of those measurements were combined with the results of the earlier models to gain a more complete picture of the performance of liquid scintillator as a portal monitor technology.« less
Development of fast neutron radiography system based on portable neutron generator
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yi, Chia Jia, E-mail: gei-i-kani@hotmail.com; Nilsuwankosit, Sunchai, E-mail: sunchai.n@chula.ac.th
Due to the high installation cost, the safety concern and the immobility of the research reactors, the neutron radiography system based on portable neutron generator is proposed. Since the neutrons generated from a portable neutron generator are mostly the fast neutrons, the system is emphasized on using the fast neutrons for the purpose of conducting the radiography. In order to suppress the influence of X-ray produced by the neutron generator, a combination of a shielding material sandwiched between two identical imaging plates is used. A binary XOR operation is then applied for combining the information from the imaging plates. Themore » raw images obtained confirm that the X-ray really has a large effect and that XOR operation can help enhance the effect of the neutrons.« less
Snell, A.H.
1957-12-01
This patent relates to a reactor and process for carrying out a controlled fast neutron chain reaction. A cubical reactive mass, weighing at least 920 metric tons, of uranium metal containing predominantly U/sup 238/ and having a U/sup 235/ content of at least 7.63% is assembled and the maximum neutron reproduction ratio is limited to not substantially over 1.01 by insertion and removal of a varying amount of boron, the reactive mass being substantially freed of moderator.
Laser-based fast-neutron spectroscopy (Conference Presentation)
NASA Astrophysics Data System (ADS)
Pomerantz, Ishay; Kishon, Itay; Kleinschmidt, Annika; Schanz, Victor A.; Tebartz, Alexandra; Fernández, Juan Carlos; Gautier, Donald C.; Johnson, Randall Philip; Shimada, Tsutomu; Wurden, Glen Anthony; Roth, Markus
2017-05-01
Great progress has been made in recent years in realizing compact, laser-based neutron generators. These devices, however, are inapplicable for conducting energy-resolved fast-neutron radiography because of the electromagnetic noise produced by the interaction of a strong laser field with matter. To overcome this limitation, we developed a novel neutron time-of-flight detector, largely immune to electromagnetic noise. The detector is based on plastic scintillator, only a few mm in size, which is coupled to a silicon photo-multiplier by a long optical fiber. I will present results we obtained at the Trident Laser Facility at Los Alamos National Laboratory during the summer of 2016. Using this detector, we recorded high resolution, low-background fast neutron spectra generated by the interaction of laser accelerated deuterons with Beryllium. The quality of these spectra was sufficient to resolve the unique neutron absorption spectra of different elements and thus it is the first demonstration of laser-based fast neutron spectroscopy. I will discuss how this achievement paves the way to realizing compact neutron radiography systems for research, security, and commercial applications.
Fast neutron detection with a segmented spectrometer
NASA Astrophysics Data System (ADS)
Langford, T. J.; Bass, C. D.; Beise, E. J.; Breuer, H.; Erwin, D. K.; Heimbach, C. R.; Nico, J. S.
2015-01-01
A fast neutron spectrometer consisting of segmented plastic scintillator and 3He proportional counters was constructed for the measurement of neutrons in the energy range 1-200 MeV. We discuss its design, principles of operation, and the method of analysis. The detector is capable of observing very low neutron fluxes in the presence of ambient gamma background and does not require scintillator pulse-shape discrimination. The spectrometer was characterized for its energy response in fast neutron fields of 2.5 MeV and 14 MeV, and the results are compared with Monte Carlo simulations. Measurements of the fast neutron flux and energy response at 120 m above sea-level (39.130°N, 77.218°W) and at a depth of 560 m in a limestone mine are presented. Finally, the design of a spectrometer with improved sensitivity and energy resolution is discussed.
Fiber optic thermal/fast neutron and gamma ray scintillation detector
Neal, John S.; Mihalczo, John T.
2006-11-28
A detector system that combines a .sup.6Li loaded glass fiber scintillation thermal neutron detector with a fast scintillation detector in a single layered structure. Detection of thermal and fast neutrons and ionizing electromagnetic radiation is achieved in the unified detector structure. The fast scintillator replaces the polyethelene moderator layer adjacent the .sup.6Li loaded glass fiber panel of the neutron detector and acts as the moderator for the glass fibers. Fast neutrons, x-rays and gamma rays are detected in the fast scintillator. Thermal neutrons, x-rays and gamma rays are detected in the glass fiber scintillator.
Yanch, Jacquelyn C.; Shefer, Ruth E.; Klinkowstein, Robert E.
1999-01-01
In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.
Commentary: exciting new developments in fast neutron cross sections and dosimetry
NASA Astrophysics Data System (ADS)
Bielajew, A. F.; Chadwick, M. B.
1998-12-01
The field of fast neutron therapy, and to some extent the practice of radiation protection in the vicinity of medical linear accelerators, requires accurate physical data. The paucity of physical data for neutron cross sections above about 15 MeV in low- Z materials is best exemplified (and somewhat exaggerated!) in the late Herb Attix's standard textbook Introduction to Radiological Physics and Radiation Dosimetry (Attix 1986). On page 464, the contributions to kerma in tissue from neutrons stops abruptly shortly above about 15 MeV. Photon and electron dosimetry has benefited from a well established and highly cohesive relationship between measurement and theory due to the enormous success of quantum electrodynamics. In contrast, measurements in the field of neutron radiotherapy have benefited less from theory because of the complexity of the quantum mechanics of nuclear structure, especially for light elements. This is because the nuclear levels are widely spaced at low excitation energies unlike for heavy elements where the energy level spacing is more dense and statistical assumptions can be applied with success. This means that accurate measurements are crucial for guiding and testing theoretical development. Measurements contributing to the field of fast neutron dosimetry are few and far between. Amazingly, in this issue of Physics in Medicine and Biology there are two such contributions! The paper by Benck, Slypen, Meulders and Corcalciuc (1998) entitled `Experimental double differential cross sections and derived kerma factors for oxygen at incident neutron energies from reaction thresholds to 65 MeV' reports on a set of measurements of the doubly-differential cross sections (energy and angle) for fast neutrons on for 9 energies between 25 and 65 MeV. The reaction channels measured were (n, px), (n, dx), (n, tx) and (n, x). These cross sections were then integrated to produce partial and total kerma factors. There are several features of this paper that are
Fiber optic thermal/fast neutron and gamma ray scintillation detector
Neal, John S.; Mihalczo, John T
2007-10-30
A system for detecting fissile and fissionable material originating external to the system includes: a .sup.6Li loaded glass fiber scintillator for detecting thermal neutrons, x-rays and gamma rays; a fast scintillator for detecting fast neutrons, x-rays and gamma rays, the fast scintillator conjoined with the glass fiber scintillator such that the fast scintillator moderates fast neutrons prior to their detection as thermal neutrons by the glass fiber scintillator; and a coincidence detection system for processing the time distributions of arriving signals from the scintillators.
Superconducting High Resolution Fast-Neutron Spectrometers
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hau, Ionel Dragos
2006-01-01
Superconducting high resolution fast-neutron calorimetric spectrometers based on 6LiF and TiB{sub 2} absorbers have been developed. These novel cryogenic spectrometers measure the temperature rise produced in exothermal (n, α) reactions with fast neutrons in 6Li and 10B-loaded materials with heat capacity C operating at temperatures T close to 0.1 K. Temperature variations on the order of 0.5 mK are measured with a Mo/Cu thin film multilayer operated in the transition region between its superconducting and its normal state. The advantage of calorimetry for high resolution spectroscopy is due to the small phonon excitation energies k BT on the order ofmore » μeV that serve as signal carriers, resulting in an energy resolution ΔE ~ (k BT 2C) 1/2, which can be well below 10 keV. An energy resolution of 5.5 keV has been obtained with a Mo/Cu superconducting sensor and a TiB 2 absorber using thermal neutrons from a 252Cf neutron source. This resolution is sufficient to observe the effect of recoil nuclei broadening in neutron spectra, which has been related to the lifetime of the first excited state in 7Li. Fast-neutron spectra obtained with a 6Li-enriched LiF absorber show an energy resolution of 16 keV FWHM, and a response in agreement with the 6Li(n, α) 3H reaction cross section and Monte Carlo simulations for energies up to several MeV. The energy resolution of order of a few keV makes this novel instrument applicable to fast-neutron transmission spectroscopy based on the unique elemental signature provided by the neutron absorption and scattering resonances. The optimization of the energy resolution based on analytical and numerical models of the detector response is discussed in the context of these applications.« less
The Use of Fast Neutron Detection for Materials Accountability
NASA Astrophysics Data System (ADS)
Nakae, L. F.; Chapline, G. F.; Glenn, A. M.; Kerr, P. L.; Kim, K. S.; Ouedraogo, S. A.; Prasad, M. K.; Sheets, S. A.; Snyderman, N. J.; Verbeke, J. M.; Wurtz, R. E.
2014-02-01
For many years at LLNL, we have been developing time-correlated neutron detection techniques and algorithms for applications such as Arms Control, Threat Detection and Nuclear Material Assay. Many of our techniques have been developed specifically for the relatively low efficiency (a few percent) inherent in man-portable systems. Historically, thermal neutron detectors (mainly 3He) were used, taking advantage of the high thermal neutron interaction cross-sections, but more recently we have been investigating the use of fast neutron detection with liquid scintillators, inorganic crystals, and in the near future, pulse-shape discriminating plastics that respond over 1000 times faster (nanoseconds versus tens of microseconds) than thermal neutron detectors. Fast neutron detection offers considerable advantages, since the inherent nanosecond production timescales of fission and neutron-induced fission are preserved and measured instead of being lost in the thermalization of thermal neutron detectors. We are now applying fast neutron technology to the safeguards regime in the form of high efficiency counters. Faster detector response times and sensitivity to neutron momentum show promise in measuring, differentiating, and assaying samples that have modest to very high count rates, as well as mixed neutron sources (e.g., Pu oxide or Mixed Cm and Pu). Here we report on measured results with our existing liquid scintillator array and promote the design of a nuclear material assay system that incorporates fast neutron detection, including the surprising result that fast liquid scintillator becomes competitive and even surpasses the precision of 3He counters measuring correlated pairs in modest (kg) samples of plutonium.
Fast neutron dosemeter using pixelated detector Timepix.
Bulanek, Boris; Ekendahl, Daniela; Prouza, Zdenek
2014-10-01
A Timepix detector covered with polyethylene convertors of different thicknesses is presented as a fast neutron real-time dosemeter. The application of different weighting factors in connection with the position of a signal in a Timepix detector enables one to obtain an energy-dependent signal equal to neutron dose equivalents. A simulation of a Timepix detector covered with polyethylene convertors using monoenergetic neutrons is presented. The experimental set-up of a dosemeter was also produced. The first results of detector response using different fast neutron sources are presented. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Workshop on neutron capture therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fairchild, R.G.; Bond, V.P.
1986-01-01
Potentially optimal conditions for Neutron Capture Therapy (NCT) may soon be in hand due to the anticipated development of band-pass filtered beams relatively free of fast neutron contaminations, and of broadly applicable biomolecules for boron transport such as porphyrins and monoclonal antibodies. Consequently, a number of groups in the US are now devoting their efforts to exploring NCT for clinical application. The purpose of this Workshop was to bring these groups together to exchange views on significant problems of mutual interest, and to assure a unified and effective approach to the solutions. Several areas of preclinical investigation were deemed tomore » be necessary before it would be possible to initiate clinical studies. As neither the monomer nor the dimer of sulfhydryl boron hydride is unequivocally preferable at this time, studies on both compounds should be continued until one is proven superior.« less
C7LYC Scintillators and Fast Neutron Spectroscopy
NASA Astrophysics Data System (ADS)
Chowdhury, P.; Brown, T.; Doucet, E.; Lister, C. J.; Wilson, G. L.; D'Olympia, N.; Devlin, M.; Mosby, S.
2016-09-01
Cs2 LiYCl6 (CLYC) scintillators detect both gammas and neutrons with excellent pulse shape discrimination. At UML, fast neutron measurements with a 16-element 1''x1'' CLYC array show promise for low energy nuclear science. CLYC detects fast neutrons via the 35Cl (n,p) reaction (resolution < 10 % at < 8 MeV). In our 7Li-enriched C7LYC, the thermal neutron response from the 6Li(n, α)t reaction is virtually eliminated. The low intrinsic efficiency of CLYC for fast neutrons (< 1 %) is offset by increased solid angle with the array placed near the target, since TOF is not needed for energy resolution. The array was tested at LANL for measuring elastic and inelastic neutron scattering on 56Fe. The incident energy from the white neutron source was measured via TOF, and the scattered neutron energy via the pulse height in CLYC. The array was also tested at CARIBU for measuring beta-delayed neutrons. Larger CLYC crystals are now a reality. Measurements with the first 3'' x 3'' C7LYC crystal are in progress at UML. Results will be discussed in the context of constructing a C7LYC array at FRIB for reaction and decay spectroscopy of neutron-rich fragments. Supported by the NNSA Stewardship Science Academic Alliance Program under Grant DE-NA00013008.
Simplified fast neutron dosimeter
Sohrabi, Mehdi
1979-01-01
Direct fast-neutron-induced recoil and alpha particle tracks in polycarbonate films may be enlarged for direct visual observation and automated counting procedures employing electrochemical etching techniques. Electrochemical etching is, for example, carried out in a 28% KOH solution at room temperature by applying a 2000 V peak-to-peak voltage at 1 kHz frequency. Such recoil particle amplification can be used for the detection of wide neutron dose ranges from 1 mrad. to 1000 rads. or higher, if desired.
Fast Neutron Detection using Pixelated CdZnTe Spectrometers
Streicher, Michael; Goodman, David; Zhu, Yuefeng; ...
2017-05-29
One important important signature of special nuclear materials (SNM) are fast neutrons. Fast neutrons have a low natural background rate and readily penetrate high atomic number materials which easily shield gamma-ray signatures. Thus, fast neutrons provide a complementary signal to gamma rays for detecting shielded SNM. Scattering kinematics dictate that a large nucleus (such as Cd or Te) will recoil with small kinetic energy after an elastic collision with a fast neutron. Charge carrier recombination and quenching further reduce the recorded energy deposited. Thus, the energy threshold of CdZnTe detectors must be very low in order to sense the smallmore » signals from these recoils. Here, the threshold was reduced to less than 5 keVee to demonstrate that the 5.9 keV x-ray line from 55Fe could be separated from electronic noise. Elastic scattering neutron interactions were observed as small energy depositions (less than 20 keVee) using digitally-sampled pulse waveforms from pixelated CdZnTe detectors. Characteristic gamma-ray lines from inelastic neutron scattering were also observed.« less
Conception of a New Recoil Proton Telescope for Real-Time Neutron Spectrometry in Proton-Therapy
NASA Astrophysics Data System (ADS)
Combe, Rodolphe; Arbor, Nicolas; el Bitar, Ziad; Higueret, Stéphane; Husson, Daniel
2018-01-01
Neutrons are the main type of secondary particles emitted in proton-therapy. Because of the risk of secondary cancer and other late occurring effects, the neutron dose should be included in the out-of-field dose calculations. A neutron spectrometer has to be used to take into account the energy dependence of the neutron radiological weighting factor. Due to its high dependence on various parameters of the irradiation (beam, accelerator, patient), the neutron spectrum should be measured independently for each treatment. The current reference method for the measurement of the neutron energy, the Bonner Sphere System, consists of several homogeneous polyethylene spheres with increasing diameters equipped with a proportional counter. It provides a highresolution reconstruction of the neutron spectrum but requires a time-consuming work of signal deconvolution. New neutron spectrometers are being developed, but the main experimental limitation remains the high neutron flux in proton therapy treatment rooms. A new model of a real-time neutron spectrometer, based on a Recoil Proton Telescope technology, has been developed at the IPHC. It enables a real-time high-rate reconstruction of the neutron spectrum from the measurement of the recoil proton trajectory and energy. A new fast-readout microelectronic integrated sensor, called FastPixN, has been developed for this specific purpose. A first prototype, able to detect neutrons between 5 and 20 MeV, has already been validated for metrology with the AMANDE facility at Cadarache. The geometry of the new Recoil Proton Telescope has been optimized via extensive Geant4 Monte Carlo simulations. Uncertainty sources have been carefully studied in order to improve simultaneously efficiency and energy resolution, and solutions have been found to suppress the various expected backgrounds. We are currently upgrading the prototype for secondary neutron detection in proton therapy applications.
Osteogenic Sarcoma of the Maxilla: Neutron Therapy for Unresectable Disease
Smoron, Geoffrey L.; Lennox, Arlene J.; Mcgee, James L.
1999-01-01
Purpose. To present a case study involving the use of fast neutron therapy to treat an extensive unresectable osteogenic sarcoma arising from the left maxilla. Patient. A 14-year-old male presented with a massive tumor producing severe distortion of his facial structures. He had already received six courses of chemotherapy, which had reduced his pain, but had not measurably reduced the tumor. Methods. The patient was treated with 66 MeV fast neutrons to a dose of 20.4 Gy in 13 fractions over 35 days. Results. CT assessments indicate gradually increasing calcification and noticeable reduction of soft-tissue disease in the frontal sinus,more » orbit and maxillary antrum.There has been some recontouring of the facial structures.The boy conducts an active life, has no pain, and feels well. He was 17 years old at the last follow-up. Discussion. Fast neutrons have a greater biological effectiveness than conventional photon beams. Their use has been associated with improved chance for local control of unresectable disease.This case illustrates their effectiveness in controlling an unusual and aggressive osteogenic sarcoma of the facial bone and sinuses.« less
Fast-neutron, coded-aperture imager
NASA Astrophysics Data System (ADS)
Woolf, Richard S.; Phlips, Bernard F.; Hutcheson, Anthony L.; Wulf, Eric A.
2015-06-01
This work discusses a large-scale, coded-aperture imager for fast neutrons, building off a proof-of concept instrument developed at the U.S. Naval Research Laboratory (NRL). The Space Science Division at the NRL has a heritage of developing large-scale, mobile systems, using coded-aperture imaging, for long-range γ-ray detection and localization. The fast-neutron, coded-aperture imaging instrument, designed for a mobile unit (20 ft. ISO container), consists of a 32-element array of 15 cm×15 cm×15 cm liquid scintillation detectors (EJ-309) mounted behind a 12×12 pseudorandom coded aperture. The elements of the aperture are composed of 15 cm×15 cm×10 cm blocks of high-density polyethylene (HDPE). The arrangement of the aperture elements produces a shadow pattern on the detector array behind the mask. By measuring of the number of neutron counts per masked and unmasked detector, and with knowledge of the mask pattern, a source image can be deconvolved to obtain a 2-d location. The number of neutrons per detector was obtained by processing the fast signal from each PMT in flash digitizing electronics. Digital pulse shape discrimination (PSD) was performed to filter out the fast-neutron signal from the γ background. The prototype instrument was tested at an indoor facility at the NRL with a 1.8-μCi and 13-μCi 252Cf neutron/γ source at three standoff distances of 9, 15 and 26 m (maximum allowed in the facility) over a 15-min integration time. The imaging and detection capabilities of the instrument were tested by moving the source in half- and one-pixel increments across the image plane. We show a representative sample of the results obtained at one-pixel increments for a standoff distance of 9 m. The 1.8-μCi source was not detected at the 26-m standoff. In order to increase the sensitivity of the instrument, we reduced the fastneutron background by shielding the top, sides and back of the detector array with 10-cm-thick HDPE. This shielding configuration led
Response of six neutron survey meters in mixed fields of fast and thermal neutrons.
Kim, S I; Kim, B H; Chang, I; Lee, J I; Kim, J L; Pradhan, A S
2013-10-01
Calibration neutron fields have been developed at KAERI (Korea Atomic Energy Research Institute) to study the responses of commonly used neutron survey meters in the presence of fast neutrons of energy around 10 MeV. The neutron fields were produced by using neutrons from the (241)Am-Be sources held in a graphite pile and a DT neutron generator. The spectral details and the ambient dose equivalent rates of the calibration fields were established, and the responses of six neutron survey meters were evaluated. Four single-moderator-based survey meters exhibited an under-responses ranging from ∼9 to 55 %. DINEUTRUN, commonly used in fields around nuclear reactors, exhibited an over-response by a factor of three in the thermal neutron field and an under-response of ∼85 % in the mixed fields. REM-500 (tissue-equivalent proportional counter) exhibited a response close to 1.0 in the fast neutron fields and an under-response of ∼50 % in the thermal neutron field.
Fast neutron measurements with 7Li and 6Li enriched CLYC scintillators
NASA Astrophysics Data System (ADS)
Giaz, A.; Blasi, N.; Boiano, C.; Brambilla, S.; Camera, F.; Cattadori, C.; Ceruti, S.; Gramegna, F.; Marchi, T.; Mattei, I.; Mentana, A.; Million, B.; Pellegri, L.; Rebai, M.; Riboldi, S.; Salamida, F.; Tardocchi, M.
2016-07-01
The recently developed Cs2LiYCl6:Ce (CLYC) crystals are interesting scintillation detectors not only for their gamma energy resolution (<5% at 662 keV) but also for their capability to identify and measure the energy of both gamma rays and fast/thermal neutrons. The thermal neutrons were detected by the 6Li(n,α)t reaction while for the fast neutrons the 35Cl(n,p)35S and 35Cl(n,α)32P neutron-capture reactions were exploited. The energy of the outgoing proton or α particle scales linearly with the incident neutron energy. The kinetic energy of the fast neutrons can be measured using both the Time Of Flight (TOF) technique and using the CLYC energy signal. In this work, the response to monochromatic fast neutrons (1.9-3.8 MeV) of two CLYC 1″×1″ crystals was measured using both the TOF and the energy signal. The observables were combined to identify fast neutrons, to subtract the thermal neutron background and to identify different fast neutron-capture reactions on 35Cl, in other words to understand if the detected particle is an α or a proton. We performed a dedicated measurement at the CN accelerator facility of the INFN Legnaro National Laboratories (Italy), where the fast neutrons were produced by impinging a proton beam (4.5, 5.0 and 5.5 MeV) on a 7LiF target. We tested a CLYC detector 6Li-enriched at about 95%, which is ideal for thermal neutron measurements, in parallel with another CLYC detector 7Li-enriched at more than 99%, which is suitable for fast neutron measurements.
Lawrence, David J; Peplowski, Patrick N; Prettyman, Thomas H; Feldman, William C; Bazell, David; Mittlefehldt, David W; Reedy, Robert C; Yamashita, Naoyuki
2013-01-01
Surface composition information from Vesta is reported using fast neutron data collected by the gamma ray and neutron detector on the Dawn spacecraft. After correcting for variations due to hydrogen, fast neutrons show a compositional dynamic range and spatial variability that is consistent with variations in average atomic mass from howardite, eucrite, and diogenite (HED) meteorites. These data provide additional compositional evidence that Vesta is the parent body to HED meteorites. A subset of fast neutron data having lower statistical precision show spatial variations that are consistent with a 400 ppm variability in hydrogen concentrations across Vesta and supports the idea that Vesta's hydrogen is due to long-term delivery of carbonaceous chondrite material. PMID:26074718
Fission-neutrons source with fast neutron-emission timing
NASA Astrophysics Data System (ADS)
Rusev, G.; Baramsai, B.; Bond, E. M.; Jandel, M.
2016-05-01
A neutron source with fast timing has been built to help with detector-response measurements. The source is based on the neutron emission from the spontaneous fission of 252Cf. The time is provided by registering the fission fragments in a layer of a thin scintillation film with a signal rise time of 1 ns. The scintillation light output is measured by two silicon photomultipliers with rise time of 0.5 ns. Overall time resolution of the source is 0.3 ns. Design of the source and test measurements using it are described. An example application of the source for determining the neutron/gamma pulse-shape discrimination by a stilbene crystal is given.
Davis, F.J.; Hurst, G.S.; Reinhardt, P.W.
1959-08-18
An improved proton recoil spectrometer for determining the energy spectrum of a fast neutron beam is described. Instead of discriminating against and thereby"throwing away" the many recoil protons other than those traveling parallel to the neutron beam axis as do conventional spectrometers, this device utilizes protons scattered over a very wide solid angle. An ovoidal gas-filled recoil chamber is coated on the inside with a scintillator. The ovoidal shape of the sensitive portion of the wall defining the chamber conforms to the envelope of the range of the proton recoils from the radiator disposed within the chamber. A photomultiplier monitors the output of the scintillator, and a counter counts the pulses caused by protons of energy just sufficient to reach the scintillator.
Love, T.A.; Murray, R.B.
1964-04-14
A fast neutron spectrometer was designed, which utilizes a pair of opposed detectors having a layer of /sup 6/LiF between to produce alpha and T pair for each neutron captured to provide signals, which, when combined, constitute a measure of neutron energy. (AEC)
Takada, Kenta; Kumada, Hiroaki; Liem, Peng Hong; Sakurai, Hideyuki; Sakae, Takeji
2016-12-01
We simulated the effect of patient displacement on organ doses in boron neutron capture therapy (BNCT). In addition, we developed a faster calculation algorithm (NCT high-speed) to simulate irradiation more efficiently. We simulated dose evaluation for the standard irradiation position (reference position) using a head phantom. Cases were assumed where the patient body is shifted in lateral directions compared to the reference position, as well as in the direction away from the irradiation aperture. For three groups of neutron (thermal, epithermal, and fast), flux distribution using NCT high-speed with a voxelized homogeneous phantom was calculated. The three groups of neutron fluxes were calculated for the same conditions with Monte Carlo code. These calculated results were compared. In the evaluations of body movements, there were no significant differences even with shifting up to 9mm in the lateral directions. However, the dose decreased by about 10% with shifts of 9mm in a direction away from the irradiation aperture. When comparing both calculations in the phantom surface up to 3cm, the maximum differences between the fluxes calculated by NCT high-speed with those calculated by Monte Carlo code for thermal neutrons and epithermal neutrons were 10% and 18%, respectively. The time required for NCT high-speed code was about 1/10th compared to Monte Carlo calculation. In the evaluation, the longitudinal displacement has a considerable effect on the organ doses. We also achieved faster calculation of depth distribution of thermal neutron flux using NCT high-speed calculation code. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
Ionization signals from diamond detectors in fast-neutron fields
NASA Astrophysics Data System (ADS)
Weiss, C.; Frais-Kölbl, H.; Griesmayer, E.; Kavrigin, P.
2016-09-01
In this paper we introduce a novel analysis technique for measurements with single-crystal chemical vapor deposition (sCVD) diamond detectors in fast-neutron fields. This method exploits the unique electronic property of sCVD diamond sensors that the signal shape of the detector current is directly proportional to the initial ionization profile. In fast-neutron fields the diamond sensor acts simultaneously as target and sensor. The interaction of neutrons with the stable isotopes 12 C and 13 C is of interest for fast-neutron diagnostics. The measured signal shapes of detector current pulses are used to identify individual types of interactions in the diamond with the goal to select neutron-induced reactions in the diamond and to suppress neutron-induced background reactions as well as γ-background. The method is verified with experimental data from a measurement in a 14.3 MeV neutron beam at JRC-IRMM, Geel/Belgium, where the 13C(n, α)10Be reaction was successfully extracted from the dominating background of recoil protons and γ-rays and the energy resolution of the 12C(n, α)9Be reaction was substantially improved. The presented analysis technique is especially relevant for diagnostics in harsh radiation environments, like fission and fusion reactors. It allows to extract the neutron spectrum from the background, and is particularly applicable to neutron flux monitoring and neutron spectroscopy.
Calculation of fast neutron removal cross sections for different lunar soils
NASA Astrophysics Data System (ADS)
Tellili, B.; Elmahroug, Y.; Souga, C.
2014-01-01
The interaction of galactic cosmic rays (GCRs) and solar energetic particles (SEPs) with the lunar surface produces secondary radiations as neutrons. The study of the production and attenuation of these neutrons in the lunar soil is very important to estimate the annual ambient dose equivalent on the lunar surface and for lunar nuclear spectroscopy. Also, understanding the attenuation of fast neutrons in lunar soils can help in measuring of the lunar neutron density profile and to measure the neutron flux on the lunar surface. In this paper, the attenuation of fast neutrons in different lunar soils is investigated. The macroscopic effective removal cross section (ΣR) of fast neutrons was theoretically calculated from the mass removal cross-section values (ΣR/ρ) for various elements in soils. The obtained values of (ΣR) were discussed according to the density. The results show that the attenuation of fast neutrons is more important in the landing sites of Apollo 12 and Luna 16 than the other landing sites of Apollo and Luna missions.
The MONDO project: A secondary neutron tracker detector for particle therapy
NASA Astrophysics Data System (ADS)
Valle, S. M.; Battistoni, G.; Patera, V.; Pinci, D.; Sarti, A.; Sciubba, A.; Spiriti, E.; Marafini, M.
2017-02-01
During Particle Therapy treatments the patient irradiation produces, among different types of secondary radiation, an abundant flux of neutrons that can release a significant dose far away from the tumour region. A precise measurement of their flux, energy and angle distributions is eagerly needed in order to improve the Treatment Planning Systems software and to properly take into account the risk of late complications in the whole body. The technical challenges posed by a neutron detector aiming for high detection efficiency and good backtracking precision will be addressed within the MONDO project, whose main goal is to develop a tracking detector targeting fast and ultra-fast secondary neutrons. The neutron tracking principle is based on the reconstruction of two consequent elastic scattering interactions of a neutron with a target material. Reconstructing the recoiling protons it is hence possible to measure the energy and incoming direction of the neutron. Plastic scintillators will be used as scattering and detection media: the tracker is being developed as a matrix of squared scintillating fibres of 250 μm side. The light produced and collected in fibres will be amplified using a triple GEM-based image intensifier and acquired using CMOS Single Photon Avalanche Diode arrays. Using therapeutic beams, the principal detector goal will be the measurement of the neutron production yields, as a function of production angle and energy.
In-Pile Qualification of the Fast-Neutron-Detection-System
NASA Astrophysics Data System (ADS)
Fourmentel, D.; Villard, J.-F.; Destouches, C.; Geslot, B.; Vermeeren, L.; Schyns, M.
2018-01-01
In order to improve measurement techniques for neutron flux assessment, a unique system for online measurement of fast neutron flux has been developed and recently qualified in-pile by the French Alternative Energies and Atomic Energy Commission (CEA) in cooperation with the Belgian Nuclear Research Centre (SCK•ECEN). The Fast-Neutron-Detection-System (FNDS) has been designed to monitor accurately high-energy neutrons flux (E > 1 MeV) in typical Material Testing Reactor conditions, where overall neutron flux level can be as high as 1015 n.cm-2.s-1 and is generally dominated by thermal neutrons. Moreover, the neutron flux is coupled with a high gamma flux of typically a few 1015 γ.cm-2.s-1, which can be highly disturbing for the online measurement of neutron fluxes. The patented FNDS system is based on two detectors, including a miniature fission chamber with a special fissile material presenting an energy threshold near 1 MeV, which can be 242Pu for MTR conditions. Fission chambers are operated in Campbelling mode for an efficient gamma rejection. FNDS also includes a specific software that processes measurements to compensate online the fissile material depletion and to adjust the sensitivity of the detectors, in order to produce a precise evaluation of both thermal and fast neutron flux even after long term irradiation. FNDS has been validated through a two-step experimental program. A first set of tests was performed at BR2 reactor operated by SCK•CEN in Belgium. Then a second test was recently completed at ISIS reactor operated by CEA in France. FNDS proved its ability to measure online the fast neutron flux with an overall accuracy better than 5%.
Absolute measurements of fast neutrons using yttrium.
Roshan, M V; Springham, S V; Rawat, R S; Lee, P; Krishnan, M
2010-08-01
Yttrium is presented as an absolute neutron detector for pulsed neutron sources. It has high sensitivity for detecting fast neutrons. Yttrium has the property of generating a monoenergetic secondary radiation in the form of a 909 keV gamma-ray caused by inelastic neutron interaction. It was calibrated numerically using MCNPX and does not need periodic recalibration. The total yttrium efficiency for detecting 2.45 MeV neutrons was determined to be f(n) approximately 4.1x10(-4) with an uncertainty of about 0.27%. The yttrium detector was employed in the NX2 plasma focus experiments and showed the neutron yield of the order of 10(8) neutrons per discharge.
Fast Neutron Induced Autophagy Leads To Necrosis In Glioblastoma Multiforme Cells
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yasui, Linda; Gladden, Samantha; Andorf, Christine
Fast neutrons are highly effective at killing glioblastoma multiforme (GBM), U87 and U251 cells. The mode of cell death was investigated using transmission electron microscopy (TEM) to identify the fraction of irradiated U87 or U251 cells having morphological features of autophagy and/or necrosis. U87 or U251 cells were irradiated with 2 Gy fast neturons or 10 Gy {gamma} rays. A majority of U87 and U251 cells exhibit features of cell death with autophagy after irradiation with either 10 Gy {gamma} rays or 2 Gy fast neutrons. Very few {gamma} irradiated cells had features of necrosis (U87 or U251 cell samplesmore » processed for TEM 1 day after 10 Gy {gamma} irradiation). In contrast, a significant increase was observed in necrotic U87 and U251 cells irradiated with fast neutrons. These results show a greater percentage of cells exhibit morphological evidence of necrosis induced by a lower dose of fast neutron irradiation compared to {gamma} irradiation. Also, the evidence of necrosis in fast neutron irradiated U87 and U251 cells occurs in a background of autophagy. Since autophagy is observed before necrosis, autophagy may play a role in signaling programmed necrosis in fast neutron irradiated U87 and U251 cells.« less
Lithium-containing scintillators for thermal neutron, fast neutron, and gamma detection
Zaitseva, Natalia P.; Carman, M. Leslie; Faust, Michelle A.
2016-03-01
In one embodiment, a scintillator includes a scintillator material; a primary fluor, and a Li-containing compound, where the Li-containing compound is soluble in the primary fluor, and where the scintillator exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays.
The investigation of fast neutron Threshold Activation Detectors (TAD)
NASA Astrophysics Data System (ADS)
Gozani, T.; King, M. J.; Stevenson, J.
2012-02-01
The detection of fast neutrons is usually done by liquid hydrogenous organic scintillators, where the separation between the ever present gamma rays and neutrons is achieved by the pulse shape discrimination (PSD). In many practical situation the detection of fast neutrons has to be carried out while the intense source (be it neutrons, gamma rays or x-rays) that creates these neutrons, for example by the fission process, is present. This source, or ``flash'', usually blinds the neutron detectors and temporarily incapacitates them. By the time the detectors recover the prompt neutron signature does not exist. Thus to overcome the blinding background, one needs to search for processes whereby the desired signature, such as fission neutrons could in some way be measured long after the fission occurred and when the neutron detector is fully recovered from the overload. A new approach was proposed and demonstrated a good sensitivity for the detection of fast neutrons in adverse overload situations where normally it could not be done. A temporal separation of the fission event from the prompt neutrons detection is achieved via the activation process. The main idea, called Threshold Activation Detection (or detector)-TAD, is to find appropriate substances that can be selectively activated by the fission neutrons and not by the source radiation, and then measure the radioactively decaying activation products (typically beta and γ-rays) well after the source pulse has ended. The activation material should possess certain properties: a suitable half-life; an energy threshold below which the numerous source neutrons will not activate it (e.g. about 3 MeV); easily detectable activation products and has a usable cross section for the selected reaction. Ideally the substance would be part of the scintillator. There are several good candidates for TAD. The first one we have selected is based on fluorine. One of the major advantages of this element is the fact that it is a major
THERMAL NEUTRON INTENSITIES IN SOILS IRRADIATED BY FAST NEUTRONS FROM POINT SOURCES. (R825549C054)
Thermal-neutron fluences in soil are reported for selected fast-neutron sources, selected soil types, and selected irradiation geometries. Sources include 14 MeV neutrons from accelerators, neutrons from spontaneously fissioning 252Cf, and neutrons produced from alp...
Nodal weighting factor method for ex-core fast neutron fluence evaluation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chiang, R. T.
The nodal weighting factor method is developed for evaluating ex-core fast neutron flux in a nuclear reactor by utilizing adjoint neutron flux, a fictitious unit detector cross section for neutron energy above 1 or 0.1 MeV, the unit fission source, and relative assembly nodal powers. The method determines each nodal weighting factor for ex-core neutron fast flux evaluation by solving the steady-state adjoint neutron transport equation with a fictitious unit detector cross section for neutron energy above 1 or 0.1 MeV as the adjoint source, by integrating the unit fission source with a typical fission spectrum to the solved adjointmore » flux over all energies, all angles and given nodal volume, and by dividing it with the sum of all nodal weighting factors, which is a normalization factor. Then, the fast neutron flux can be obtained by summing the various relative nodal powers times the corresponding nodal weighting factors of the adjacent significantly contributed peripheral assembly nodes and times a proper fast neutron attenuation coefficient over an operating period. A generic set of nodal weighting factors can be used to evaluate neutron fluence at the same location for similar core design and fuel cycles, but the set of nodal weighting factors needs to be re-calibrated for a transition-fuel-cycle. This newly developed nodal weighting factor method should be a useful and simplified tool for evaluating fast neutron fluence at selected locations of interest in ex-core components of contemporary nuclear power reactors. (authors)« less
Sakamoto, S; Kiger, W S; Harling, O K
1999-09-01
Sensitivity studies of epithermal neutron beam performance in boron neutron capture therapy are presented for realistic neutron beams with varying filter/moderator and collimator/delimiter designs to examine the relative importance of neutron beam spectrum, directionality, and size. Figures of merit for in-air and in-phantom beam performance are calculated via the Monte Carlo technique for different well-optimized designs of a fission converter-based epithermal neutron beam with head phantoms as the irradiation target. It is shown that increasing J/phi, a measure of beam directionality, does not always lead to corresponding monotonic improvements in beam performance. Due to the relatively low significance, for most configurations, of its effect on in-phantom performance and the large intensity losses required to produce beams with very high J/phi, beam directionality should not be considered an important figure of merit in epithermal neutron beam design except in terms of its consequences on patient positioning and collateral dose. Hardening the epithermal beam spectrum, while maintaining the specific fast neutron dose well below the inherent hydrogen capture dose, improves beam penetration and advantage depth and, as a desirable by-product, significantly increases beam intensity. Beam figures of merit are shown to be strongly dependent on beam size relative to target size. Beam designs with J/phi approximately 0.65-0.7, specific fast neutron doses of 2-2.6x10(-13) Gy cm2/n and beam sizes equal to or larger than the size of the head target produced the deepest useful penetration, highest therapeutic ratios, and highest intensities.
Fast neutron sensitivity of neutron detectors based on Boron-10 converter layers
NASA Astrophysics Data System (ADS)
Mauri, G.; Messi, F.; Kanaki, K.; Hall-Wilton, R.; Karnickis, E.; Khaplanov, A.; Piscitelli, F.
2018-03-01
In the last few years many detector technologies for thermal neutron detection have been developed in order to face the shortage of 3He, which is now much less available and more expensive. Moreover the 3He-based detectors can not fulfil the requirements in performance, e.g. the spatial resolution and the counting rate capability needed for the new instruments. The Boron-10-based gaseous detectors have been proposed as a suitable choice. This and other alternative technologies are being developed at ESS. Higher intensities mean higher signals but higher background as well. The signal-to-background ratio is an important feature to study, in particular the γ-ray and the fast neutron contributions. This paper investigates, for the first time, the fast neutrons sensitivity of 10B-based thermal neutron detector. It presents the study of the detector response as a function of energy threshold and the underlying physical mechanisms. The latter are explained with the help of theoretical considerations and simulations.
NASA Astrophysics Data System (ADS)
Giannini, G.; Gribkov, V.; Longo, F.; Ramos Aruca, M.; Tuniz, C.
2012-11-01
The use of short and powerful neutron pulses for boron neutron capture therapy (BNCT) can potentially increase selectivity and reduce the total dose absorbed by the patient. The biological effects of radiation depend on the dose, the dose power and the spatial distribution of the microscopic energy deposition. A dense plasma focus (DPF) device emits very short (in the nanosecond range) and extremely intense pulses of fast neutrons (2.5 or 14 MeV neutrons—from D-D or D-T nuclear reactions) and x-rays. Optimal spectra of neutrons formed for use in BNCT must contain an epithermal part to ensure a reasonable penetration depth into tissues at high enough cross-section on boron. So the powerful nanosecond pulses of fast neutrons generated by DPF must be moderated. After this moderation, the pulse duration must be shorter compared with the duration of the reaction with free radicals, that is, ⩾1 μs. In this work we focus on the development of a detailed simulation of interaction of short-pulse radiation from a DPF with the device's materials and with different types of moderators to estimate the dose power at the cells for this dynamic case. The simulation was carried out by means of the Geant4 toolkit in two main steps: the modeling of the pulsed neutron source device itself; the study of the interaction of fast mono-energetic neutrons with a moderator specific for BNCT.
A high yield neutron target for cancer therapy
NASA Technical Reports Server (NTRS)
Alger, D. L.; Steinberg, R.
1972-01-01
A rotating target was developed that has the potential for providing an initial yield of 10 to the 13th power neutrons per second by the T(d,n)He-4 reaction, and a useable lifetime in excess of 600 hours. This yield and lifetime are indicated for a 300 Kv and 30 mA deuteron accelerator and a 30 microns thick titanium tritide film formed of the stoichiometric compound TiT2. The potential for extended lifetime is made possible by incorporating a sputtering electrode that permits use of titanium tritide thicknesses much greater than the deuteron range. The electrode is used to remove in situ depleted titanium layers to expose fresh tritide beneath. The utilization of the rotating target as a source of fast neutrons for cancer therapy is discussed.
Geochemistry at 4 Vesta: Observations Using Fast Neutrons
NASA Technical Reports Server (NTRS)
Lawrence, David J.; Prettyman, Thomas H.; Feldman, William C.; Bazell, David; Mittlefehldt, David W.; Peplowski, Patrick N.; Reedy, Robert C.
2012-01-01
Dawn is currently in orbit around the asteroid 4 Vesta, and one of the major objectives of the mission is to probe the relationship of Vesta to the Howardite, Eucrite, and Diogenite (HED) meteorites. As Vesta is an example of a differentiated planetary embryo, Dawn will also provide fundamental information about planetary evolution in the early solar system [1]. To help accomplish this overall goal, the Dawn spacecraft carries the Gamma-Ray and Neutron Detector (GRaND). GRaND uses planetary gamma-ray and neutron spectroscopy to measure the surface elemental composition of Vesta and will provide information that is unique and complementary to that provided by the other Dawn instruments and investigations. Gamma-ray and neutron spectroscopy is a standard technique for measuring planetary compositions [2], having successfully made measurements at near-Earth asteroids, the Moon, Mars, Mercury and now Vesta. GRaND has made the first measurements of the neutron spectrum from any asteroid (previous asteroid measurements were only made with gamma-rays). Dawn has been collecting data at Vesta since July 2011. The prime data collection period for GRaND is the Low-Altitude Mapping Orbit (LAMO), which started on 12 December 2011 and will last through spring 2012. During LAMO, the Dawn spacecraft orbits at an average altitude of 210 km above the surface of Vesta, which allows good neutron and gamma-ray signals to be detected from Vesta. A description of the overall goals of GRaND and a summary of the initial findings are given elsewhere [3,4]. The subject of this study is to present the information that will be returned from GRaND using fast neutron measurements. Here, we discuss what fast neutrons can reveal about Vesta s surface composition, how such data can address Dawn science goals, and describe fast neutron measurements made in the early portion of the Vesta LAMO phase.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Iliescu, Elena; Bercea, Sorin; Dudu, Dorin
2013-12-16
The use of the U-120 Cyclotron of the IFIN-HH allowed to perform a testing bench with fast neutrons in order to determine the correction factors of the doseratemeters dedicated to neutron measurement. This paper deals with researchers performed in order to develop the irradiation facility testing the fast neutrons flux generated at the Cyclotron. This facility is presented, together with the results obtain in determining the correction factor for a doseratemeter dedicated to the neutron dose equivalent rate measurement.
High-Resolution Fast-Neutron Spectrometry for Arms Control and Treaty Verification
DOE Office of Scientific and Technical Information (OSTI.GOV)
David L. Chichester; James T. Johnson; Edward H. Seabury
2012-07-01
Many nondestructive nuclear analysis techniques have been developed to support the measurement needs of arms control and treaty verification, including gross photon and neutron counting, low- and high-resolution gamma spectrometry, time-correlated neutron measurements, and photon and neutron imaging. One notable measurement technique that has not been extensively studied to date for these applications is high-resolution fast-neutron spectrometry (HRFNS). Applied for arms control and treaty verification, HRFNS has the potential to serve as a complimentary measurement approach to these other techniques by providing a means to either qualitatively or quantitatively determine the composition and thickness of non-nuclear materials surrounding neutron-emitting materials.more » The technique uses the normally-occurring neutrons present in arms control and treaty verification objects of interest as an internal source of neutrons for performing active-interrogation transmission measurements. Most low-Z nuclei of interest for arms control and treaty verification, including 9Be, 12C, 14N, and 16O, possess fast-neutron resonance features in their absorption cross sections in the 0.5- to 5-MeV energy range. Measuring the selective removal of source neutrons over this energy range, assuming for example a fission-spectrum starting distribution, may be used to estimate the stoichiometric composition of intervening materials between the neutron source and detector. At a simpler level, determination of the emitted fast-neutron spectrum may be used for fingerprinting 'known' assemblies for later use in template-matching tests. As with photon spectrometry, automated analysis of fast-neutron spectra may be performed to support decision making and reporting systems protected behind information barriers. This paper will report recent work at Idaho National Laboratory to explore the feasibility of using HRFNS for arms control and treaty verification applications, including simulations
Zaitseva, Natalia P.; Carman, M. Leslie; Faust, Michelle A.; Glenn, Andrew M.; Martinez, H. Paul; Pawelczak, Iwona A.; Payne, Stephen A.
2017-05-16
A scintillator material according to one embodiment includes a polymer matrix; a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount of 3 wt % or more; and at least one component in the polymer matrix, the component being selected from a group consisting of B, Li, Gd, a B-containing compound, a Li-containing compound and a Gd-containing compound, wherein the scintillator material exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays. A system according to one embodiment includes a scintillator material as disclosed herein and a photodetector for detecting the response of the material to fast neutron, thermal neutron and gamma ray irradiation.
NASA Astrophysics Data System (ADS)
Arbor, Nicolas; Higueret, Stephane; Husson, Daniel
2018-04-01
The CMOS sensor AlphaRad has been designed at the IPHC Strasbourg for real-time monitoring of fast and thermal neutrons over a full energy spectrum. Completely integrated, highly transparent to photons and optimized for low power consumption, this sensor offers very interesting characteristics for the study of internal neutrons in radiation therapy with anthropomorphic phantoms. However, specific effects related to the CMOS metal substructure and to the charge collection process of low energy particles must be carefully estimated before being used for medical applications. We present a detailed characterization of the AlphaRad chip in the MeV energy range using proton and alpha micro-beam experiments performed at the AIFIRA facility (CENBG, Bordeaux). Two-dimensional maps of the charge collection were carried out on a micro-metric scale to be integrated into a Geant4 Monte Carlo simulation of the system. The gamma rejection, as well as the fast and thermal neutrons separation, were studied using both simulation and experimental data. The results highlight the potential of a future system based on CMOS sensor for in-phantom neutron detection in radiation therapies.
How resilient is the soybean genome? Insights from fast neutron mutagenesis
USDA-ARS?s Scientific Manuscript database
Previously, we described the development of a fast neutron mutant population resource in soybean and identified mutations of interest through phenotypic screening. Here, we consider the resiliency of the soybean genome by examining genomic rearrangements and mutations that arise from fast neutron ra...
Indoor Fast Neutron Generator for Biophysical and Electronic Applications
NASA Astrophysics Data System (ADS)
Cannuli, A.; Caccamo, M. T.; Marchese, N.; Tomarchio, E. A.; Pace, C.; Magazù, S.
2018-05-01
This study focuses the attention on an indoor fast neutron generator for biophysical and electronic applications. More specifically, the findings obtained by several simulations with the MCNP Monte Carlo code, necessary for the realization of a shield for indoor measurements, are presented. Furthermore, an evaluation of the neutron spectrum modification caused by the shielding is reported. Fast neutron generators are a valid and interesting available source of neutrons, increasingly employed in a wide range of research fields, such as science and engineering. The employed portable pulsed neutron source is a MP320 Thermo Scientific neutron generator, able to generate 2.5 MeV neutrons with a neutron yield of 2.0 x 106 n/s, a pulse rate of 250 Hz to 20 KHz and a duty factor varying from 5% to 100%. The neutron generator, based on Deuterium-Deuterium nuclear fusion reactions, is employed in conjunction with a solid-state photon detector, made of n-type high-purity germanium (PINS-GMX by ORTEC) and it is mainly addressed to biophysical and electronic studies. The present study showed a proposal for the realization of a shield necessary for indoor applications for MP320 neutron generator, with a particular analysis of the transport of neutrons simulated with Monte Carlo code and described the two main lines of research in which the source will be used.
Transportable, Low-Dose Active Fast-Neutron Imaging
DOE Office of Scientific and Technical Information (OSTI.GOV)
Mihalczo, John T.; Wright, Michael C.; McConchie, Seth M.
2017-08-01
This document contains a description of the method of transportable, low-dose active fast-neutron imaging as developed by ORNL. The discussion begins with the technique and instrumentation and continues with the image reconstruction and analysis. The analysis discussion includes an example of how a gap smaller than the neutron production spot size and detector size can be detected and characterized depending upon the measurement time.
A scintillator-based approach to monitor secondary neutron production during proton therapy.
Clarke, S D; Pryser, E; Wieger, B M; Pozzi, S A; Haelg, R A; Bashkirov, V A; Schulte, R W
2016-11-01
The primary objective of this work is to measure the secondary neutron field produced by an uncollimated proton pencil beam impinging on different tissue-equivalent phantom materials using organic scintillation detectors. Additionally, the Monte Carlo code mcnpx-PoliMi was used to simulate the detector response for comparison to the measured data. Comparison of the measured and simulated data will validate this approach for monitoring secondary neutron dose during proton therapy. Proton beams of 155- and 200-MeV were used to irradiate a variety of phantom materials and secondary particles were detected using organic liquid scintillators. These detectors are sensitive to fast neutrons and gamma rays: pulse shape discrimination was used to classify each detected pulse as either a neutron or a gamma ray. The mcnpx-PoliMi code was used to simulate the secondary neutron field produced during proton irradiation of the same tissue-equivalent phantom materials. An experiment was performed at the Loma Linda University Medical Center proton therapy research beam line and corresponding models were created using the mcnpx-PoliMi code. The authors' analysis showed agreement between the simulations and the measurements. The simulated detector response can be used to validate the simulations of neutron and gamma doses on a particular beam line with or without a phantom. The authors have demonstrated a method of monitoring the neutron component of the secondary radiation field produced by therapeutic protons. The method relies on direct detection of secondary neutrons and gamma rays using organic scintillation detectors. These detectors are sensitive over the full range of biologically relevant neutron energies above 0.5 MeV and allow effective discrimination between neutron and photon dose. Because the detector system is portable, the described system could be used in the future to evaluate secondary neutron and gamma doses on various clinical beam lines for commissioning and
Next Generation Fast Neutron Detector for Space Exploration (Mini-FND)
NASA Astrophysics Data System (ADS)
Hassler, D. M.; Ehresmann, B.
2018-02-01
SwRI has developed a miniature Fast Neutron Detector (mini-FND), for use in the Deep Space Gateway, to characterize the neutron albedo radiation. Mini-FND will provide coverage of the biologically relevant neutrons at energies of 500 keV and greater.
SU-E-J-115: Graticule for Verification of Treatment Position in Neutron Therapy.
Halford, R; Snyder, M
2012-06-01
Until recently the treatment verification for patients undergoing fast neutron therapy at our facility was accomplished through a combination of neutron beam portal films aligned with a graticule mounted on an orthronormal x-ray tube. To eliminate uncertainty with respect to the relative positions of the x-ray graticule and the therapy beam, we have developed a graticule which is placed in the neutron beam itself. For a graticule to be visible on the portal film, the attenuation of the neutron beam by the graticule landmarks must be significantly greater than that of the material in which the landmarks are mounted. Various materials, thicknesses, and mounting points were tried to gain the largest contrast between the graticule landmarks and the mounting material. The final design involved 2 inch steel pins of 0.125 inch diameter captured between two parallel plates of 0.25 inch thick clear acrylic plastic. The distance between the two acrylic plates was 1.625 inches, held together at the perimeter with acrylic sidewall spacers. This allowed the majority of length of the steel pins to be surrounded by air. The pins were set 1 cm apart and mounted at angles parallel to the divergence of the beam dependent on their position within the array. The entire steel pin and acrylic plate assembly was mounted on an acrylic accessory tray to allow for graticule alignment. Despite the inherent difficulties in attenuating fast neutrons, our simple graticule design produces the required difference of attenuation between the arrays of landmarks and the mounting material. The graticule successfully provides an in-beam frame of reference for patient portal verification. © 2012 American Association of Physicists in Medicine.
Neutron-beam-shaping assembly for boron neutron-capture therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zaidi, L.; Kashaeva, E. A.; Lezhnin, S. I.
A neutron-beam-shaping assembly consisting of a moderator, a reflector, and an absorber is used to form a therapeutic neutron beam for the boron neutron-capture therapy of malignant tumors at accelerator neutron sources. A new structure of the moderator and reflector is proposed in the present article, and the results of a numerical simulation of the neutron spectrum and of the absorbed dose in a modified Snyder head phantom are presented. The application of a composite moderator and of a composite reflector and the implementation of neutron production at the proton energy of 2.3MeV are shown to permit obtaining a high-qualitymore » therapeutic neutron beam.« less
Neutronic calculation of fast reactors by the EUCLID/V1 integrated code
NASA Astrophysics Data System (ADS)
Koltashev, D. A.; Stakhanova, A. A.
2017-01-01
This article considers neutronic calculation of a fast-neutron lead-cooled reactor BREST-OD-300 by the EUCLID/V1 integrated code. The main goal of development and application of integrated codes is a nuclear power plant safety justification. EUCLID/V1 is integrated code designed for coupled neutronics, thermomechanical and thermohydraulic fast reactor calculations under normal and abnormal operating conditions. EUCLID/V1 code is being developed in the Nuclear Safety Institute of the Russian Academy of Sciences. The integrated code has a modular structure and consists of three main modules: thermohydraulic module HYDRA-IBRAE/LM/V1, thermomechanical module BERKUT and neutronic module DN3D. In addition, the integrated code includes databases with fuel, coolant and structural materials properties. Neutronic module DN3D provides full-scale simulation of neutronic processes in fast reactors. Heat sources distribution, control rods movement, reactivity level changes and other processes can be simulated. Neutron transport equation in multigroup diffusion approximation is solved. This paper contains some calculations implemented as a part of EUCLID/V1 code validation. A fast-neutron lead-cooled reactor BREST-OD-300 transient simulation (fuel assembly floating, decompression of passive feedback system channel) and cross-validation with MCU-FR code results are presented in this paper. The calculations demonstrate EUCLID/V1 code application for BREST-OD-300 simulating and safety justification.
Cross-Section Measurements in the Fast Neutron Energy Range
NASA Astrophysics Data System (ADS)
Plompen, Arjan
2006-04-01
Generation IV focuses research for advanced nuclear reactors on six concepts. Three of these concepts, the lead, gas and sodium fast reactors (LFR, GFR and SFR) have fast neutron spectra, whereas a fourth, the super-critical water reactor (SCWR), can be configured to have a fast spectrum. Such fast neutron spectra are essential to meet the sustainability objective of GenIV. Nuclear data requirements for GenIV concepts will therefore emphasize the energy region from about 1 keV to 10 MeV. Here, the potential is illustrated of the GELINA neutron time-of-flight facility and the Van de Graaff laboratory at IRMM to measure the relevant nuclear data in this energy range: the total, capture, fission and inelastic-scattering cross sections. In particular, measurement results will be shown for lead and bismuth inelastic scattering for which the need was recently expressed in a quantitative way by Aliberti et al. for Accelerator Driven Systems. Even without completion of the quantitative assessment of the data needs for GenIV concepts at ANL it is clear that this particular effort is of relevance to LFR system studies.
Fast neutron measurements using Cs2LiYCl6:Ce (CLYC) scintillator
NASA Astrophysics Data System (ADS)
Smith, M. B.; Achtzehn, T.; Andrews, H. R.; Clifford, E. T. H.; Forget, P.; Glodo, J.; Hawrami, R.; Ing, H.; O'Dougherty, P.; Shah, K. S.; Shirwadkar, U.; Soundara-Pandian, L.; Tower, J.
2015-06-01
Samples of Cs2LiYCl6:Ce (CLYC) scintillator have been characterized using monoenergetic neutron beams in the energy range 4.1-5.5 MeV. Four crystals with dimensions (thickness×diameter) of 1″×1″, 1″×2″, and 2″×2″ were evaluated, including one crystal with natural concentrations of Li isotopes and three that were enriched in 6Li. The intrinsic efficiency of CLYC for fast-neutron detection has been determined for the natural-Li crystal. These measurements were translated into reaction cross-sections, and show good agreement with available cross-section data for neutron interactions with the 35Cl component of CLYC. Furthermore, it is shown that the charged-particle energy released in the fast-neutron reactions on 35Cl varies linearly with the energy of the incoming neutron. These results verify the efficacy of CLYC for fast-neutron spectroscopy in a range of applications.
Acute Lethality after Fast-Neutron and X-Irradiation of Tribolium confusum
DOE Office of Scientific and Technical Information (OSTI.GOV)
Glenn, Norman D.; Ducoff, Howard S.
1976-01-01
The acute lethal effects of fast neutrons and of X-rays on adults and larvae of T. confusum are compared. The time course of mortality of adults of the Oklahoma strain was the same after midlethal doses of neutrons and X-rays, although the neutrons were about twice as effective as X-rays in producing lethality, based on LD 50(35). The neutron RBE for adults of the Ebony mutant strain was also about 2, but that for Oklahoma larvae was about 3.85. Larvae surviving midlethal doses of neutrons showed a tendency toward wing abnormalities and delayed pupation. Dose-fractionation recovery with neutron doses inmore » the midlethal range was not detectable in the adults or in the larvae. A considerable sparing effect of dose fractionation was found in X-irradiated adults. Finally, also presented are techniques for using a beam port of a Triga research reactor for fast-neutron irradiation and a method of neutron and gamma dosimetry.« less
Two detector arrays for fast neutrons at LANSCE
NASA Astrophysics Data System (ADS)
Haight, R. C.; Lee, H. Y.; Taddeucci, T. N.; O'Donnell, J. M.; Perdue, B. A.; Fotiades, N.; Devlin, M.; Ullmann, J. L.; Laptev, A.; Bredeweg, T.; Jandel, M.; Nelson, R. O.; Wender, S. A.; White, M. C.; Wu, C. Y.; Kwan, E.; Chyzh, A.; Henderson, R.; Gostic, J.
2012-03-01
The neutron spectrum from neutron-induced fission needs to be known in designing new fast reactors, predicting criticality for safety analyses, and developing techniques for global security application. The experimental data base of fission neutron spectra is very incomplete and most present evaluated libraries are based on the approach of the Los Alamos Model. To validate these models and to provide improved data for applications, a program is underway to measure the fission neutron spectrum for a wide range of incident neutron energies using the spallation source of fast neutrons at the Weapons Neutron Research (WNR) facility at the Los Alamos Neutron Science Center (LANSCE). In a double time-of-flight experiment, fission neutrons are detected by arrays of neutron detectors to increase the solid angle and also to investigate possible angular dependence of the fission neutrons. The challenge is to measure the spectrum from low energies, down to 100 keV or so, to energies over 10 MeV, where the evaporation-like spectrum decreases by 3 orders of magnitude from its peak around 1 MeV. For these measurements, we are developing two arrays of neutron detectors, one based on liquid organic scintillators and the other on 6Li-glass detectors. The range of fission neutrons detected by organic liquid scintillators extends from about 600 keV to well over 10 MeV, with the lower limit being defined by the limit of pulse-shape discrimination. The 6Li-glass detectors have a range from very low energies to about 1 MeV, where their efficiency then becomes small. Various considerations and tests are in progress to understand important contributing factors in designing these two arrays and they include selection and characterization of photomultiplier tubes (PM), the performance of relatively thin (1.8 cm) 6Li-glass scintillators on 12.5 cm diameter PM tubes, use of 17.5 cm diameter liquid scintillators with 12.5 cm PM tubes, measurements of detector efficiencies with tagged neutrons
Tagged fast neutron beams En > 6 MeV
NASA Astrophysics Data System (ADS)
Favela, F.; Huerta, A.; Santa Rita, P.; Ramos, A. T.; de Lucio, O.; Andrade, E.; Acosta, L.; Ortiz, M. E.; Araujo, V.; Murillo, G.; Policroniades, R.; Varela, A.; Chávez, E.
2015-07-01
Controlled flux of neutrons are produced through the 14N(d,n)15O nuclear reaction. Deuteron beams (2-4 MeV) are delivered by the CN-Van de Graaff accelerator and directed with full intensity to our Nitrogen target at SUGAR (SUpersonic GAs jet taRget). Each neutron is electronically tagged by the detection of the associated15O. Its energy and direction are known and "beams" of fast monochromatic tagged neutrons (En> 6 MeV) are available for basic research and applied work. MONDE is a large area (158 × 63 cm2) plastic scintillating slab (5 cm thick), viewed by 16 PMTs from the sides. Fast neutrons (MeV) entering the detector will produce a recoiling proton that induces a light spark at the spot. Signals from the 16 detectors are processed to deduce the position of the spark. Time logic signals from both the 15O detector and MONDE are combined to deduce a time of flight (TOF) signal. Finally, the position information together with the TOF yields the full momentum vector of each detected neutron.
Towards radiation hard converter material for SiC-based fast neutron detectors
NASA Astrophysics Data System (ADS)
Tripathi, S.; Upadhyay, C.; Nagaraj, C. P.; Venkatesan, A.; Devan, K.
2018-05-01
In the present work, Geant4 Monte-Carlo simulations have been carried out to study the neutron detection efficiency of the various neutron to other charge particle (recoil proton) converter materials. The converter material is placed over Silicon Carbide (SiC) in Fast Neutron detectors (FNDs) to achieve higher neutron detection efficiency as compared to bare SiC FNDs. Hydrogenous converter material such as High-Density Polyethylene (HDPE) is preferred over other converter materials due to the virtue of its high elastic scattering reaction cross-section for fast neutron detection at room temperature. Upon interaction with fast neutrons, hydrogenous converter material generates recoil protons which liberate e-hole pairs in the active region of SiC detector to provide a detector signal. The neutron detection efficiency offered by HDPE converter is compared with several other hydrogenous materials viz., 1) Lithium Hydride (LiH), 2) Perylene, 3) PTCDA . It is found that, HDPE, though providing highest efficiency among various studied materials, cannot withstand high temperature and harsh radiation environment. On the other hand, perylene and PTCDA can sustain harsh environments, but yields low efficiency. The analysis carried out reveals that LiH is a better material for neutron to other charge particle conversion with competent efficiency and desired radiation hardness. Further, the thickness of LiH has also been optimized for various mono-energetic neutron beams and Am-Be neutron source generating a neutron fluence of 109 neutrons/cm2. The optimized thickness of LiH converter for fast neutron detection is found to be ~ 500 μm. However, the estimated efficiency for fast neutron detection is only 0.1%, which is deemed to be inadequate for reliable detection of neutrons. A sensitivity study has also been done investigating the gamma background effect on the neutron detection efficiency for various energy threshold of Low-Level Discriminator (LLD). The detection
NASA Astrophysics Data System (ADS)
Tanaka, H.; Sakurai, Y.; Suzuki, M.; Masunaga, S.; Kinashi, Y.; Kashino, G.; Liu, Y.; Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Maruhashi, A.; Ono, K.
2009-06-01
At Kyoto University Research Reactor Institute (KURRI), 275 clinical trials of boron neutron capture therapy (BNCT) have been performed as of March 2006, and the effectiveness of BNCT has been revealed. In order to further develop BNCT, it is desirable to supply accelerator-based epithermal-neutron sources that can be installed near the hospital. We proposed the method of filtering and moderating fast neutrons, which are emitted from the reaction between a beryllium target and 30-MeV protons accelerated by a cyclotron accelerator, using an optimum moderator system composed of iron, lead, aluminum and calcium fluoride. At present, an epithermal-neutron source is under construction from June 2008. This system consists of a cyclotron accelerator, beam transport system, neutron-yielding target, filter, moderator and irradiation bed. In this article, an overview of this system and the properties of the treatment neutron beam optimized by the MCNPX Monte Carlo neutron transport code are presented. The distribution of biological effect weighted dose in a head phantom compared with that of Kyoto University Research Reactor (KUR) is shown. It is confirmed that for the accelerator, the biological effect weighted dose for a deeply situated tumor in the phantom is 18% larger than that for KUR, when the limit dose of the normal brain is 10 Gy-eq. The therapeutic time of the cyclotron-based neutron sources are nearly one-quarter of that of KUR. The cyclotron-based epithermal-neutron source is a promising alternative to reactor-based neutron sources for treatments by BNCT.
Fast neutron flux analyzer with real-time digital pulse shape discrimination
NASA Astrophysics Data System (ADS)
Ivanova, A. A.; Zubarev, P. V.; Ivanenko, S. V.; Khilchenko, A. D.; Kotelnikov, A. I.; Polosatkin, S. V.; Puryga, E. A.; Shvyrev, V. G.; Sulyaev, Yu. S.
2016-08-01
Investigation of subthermonuclear plasma confinement and heating in magnetic fusion devices such as GOL-3 and GDT at the Budker Institute (Novosibirsk, Russia) requires sophisticated equipment for neutron-, gamma- diagnostics and upgrading data acquisition systems with online data processing. Measurement of fast neutron flux with stilbene scintillation detectors raised the problem of discrimination of the neutrons (n) from background cosmic particles (muons) and neutron-induced gamma rays (γ). This paper describes a fast neutron flux analyzer with real-time digital pulse-shape discrimination (DPSD) algorithm FPGA-implemented for the GOL-3 and GDT devices. This analyzer was tested and calibrated with the help of 137Cs and 252Cf radiation sources. The Figures of Merit (FOM) calculated for different energy cuts are presented.
Gadolinium as a Neutron Capture Therapy Agent
NASA Astrophysics Data System (ADS)
Shih, Jing-Luen Allen
The clinical results of treating brain tumors with boron neutron capture therapy are very encouraging and researchers around the world are once again making efforts to develop this therapeutic modality. Boron-10 is the agent receiving the most attention for neutron capture therapy but ^{157}Gd is a nuclide that also holds interesting properties of being a neutron capture therapy agent. The objective of this study is to evaluate ^{157}Gd as a neutron capture therapy agent. In this study it is determined that tumor concentrations of about 300 mug ^{157}Gd/g tumor can be achieved in brain tumors with some FDA approved MRI contrast agents such as Gd-DTPA and Gd-DOTA, and up to 628 mug ^{157 }Gd/g tumor can be established in bone tumors with Gd-EDTMP. Monte Carlo calculations show that with only 250 ppm of ^{157}Gd in tumor, neutron capture therapy can deliver 2,000 cGy to a tumor of 2 cm diameter or larger with 5 times 10^{12} n/cm ^2 fluence at the tumor. Dose measurements which were made with films and TLD's in phantoms verified these calculations. More extended Monte Carlo calculations demonstrate that neutron capture therapy with Gd possesses comparable dose distribution to B neutron capture therapy. With 5 times 10^{12 } n/cm^2 thermal neutrons at the tumor, Auger electrons from the Gd produced an optical density enhancement on the films that is similar to the effect caused by about 300 cGy of Gd prompt gamma dose which will further enhance the therapeutic effects. A technique that combines brachytherapy with Gd neutron capture therapy has been evaluated. Monte Carlo calculations show that 5,000 cGy of prompt gamma dose can be delivered to a treatment volume of 40 cm^3 with a 3-plane implant of a total of 9 Gd needles. The tumor to normal tissue advantage of this method is as good as ^{60} Co brachytherapy. Measurements of prompt gamma dose with films and TLD-700's in a lucite phantom verify the Monte Carlo evaluation. A technique which displays the Gd
Packed rod neutron shield for fast nuclear reactors
Eck, John E.; Kasberg, Alvin H.
1978-01-01
A fast neutron nuclear reactor including a core and a plurality of vertically oriented neutron shield assemblies surrounding the core. Each assembly includes closely packed cylindrical rods within a polygonal metallic duct. The shield assemblies are less susceptible to thermal stresses and are less massive than solid shield assemblies, and are cooled by liquid coolant flow through interstices among the rods and duct.
Feasibility of the Precise Energy Calibration for Fast Neutron Spectrometers
NASA Astrophysics Data System (ADS)
Gaganov, V. V.; Usenko, P. L.; Kryzhanovskaja, M. A.
2017-12-01
Computational studies aimed at improving the accuracy of measurements performed using neutron generators with a tritium target were performed. A measurement design yielding an extremely narrow peak in the energy spectrum of DT neutrons was found. The presence of such a peak establishes the conditions for precise energy calibration of fast-neutron spectrometers.
Design of a transportable high efficiency fast neutron spectrometer
Roecker, C.; Bernstein, A.; Bowden, N. S.; ...
2016-04-12
A transportable fast neutron detection system has been designed and constructed for measuring neutron energy spectra and flux ranging from tens to hundreds of MeV. The transportability of the spectrometer reduces the detector-related systematic bias between different neutron spectra and flux measurements, which allows for the comparison of measurements above or below ground. The spectrometer will measure neutron fluxes that are of prohibitively low intensity compared to the site-specific background rates targeted by other transportable fast neutron detection systems. To measure low intensity high-energy neutron fluxes, a conventional capture-gating technique is used for measuring neutron energies above 20 MeV andmore » a novel multiplicity technique is used for measuring neutron energies above 100 MeV. The spectrometer is composed of two Gd containing plastic scintillator detectors arranged around a lead spallation target. To calibrate and characterize the position dependent response of the spectrometer, a Monte Carlo model was developed and used in conjunction with experimental data from gamma ray sources. Multiplicity event identification algorithms were developed and used with a Cf-252 neutron multiplicity source to validate the Monte Carlo model Gd concentration and secondary neutron capture efficiency. The validated Monte Carlo model was used to predict an effective area for the multiplicity and capture gating analyses. For incident neutron energies between 100 MeV and 1000 MeV with an isotropic angular distribution, the multiplicity analysis predicted an effective area of 500 cm 2 rising to 5000 cm 2. For neutron energies above 20 MeV, the capture-gating analysis predicted an effective area between 1800 cm 2 and 2500 cm 2. As a result, the multiplicity mode was found to be sensitive to the incident neutron angular distribution.« less
Approach to magnetic neutron capture therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kuznetsov, Anatoly A.; Podoynitsyn, Sergey N.; Filippov, Victor I.
2005-11-01
Purpose: The method of magnetic neutron capture therapy can be described as a combination of two methods: magnetic localization of drugs using magnetically targeted carriers and neutron capture therapy itself. Methods and Materials: In this work, we produced and tested two types of particles for such therapy. Composite ultradispersed ferro-carbon (Fe-C) and iron-boron (Fe-B) particles were formed from vapors of respective materials. Results: Two-component ultradispersed particles, containing Fe and C, were tested as magnetic adsorbent of L-boronophenylalanine and borax and were shown that borax sorption could be effective for creation of high concentration of boron atoms in the area ofmore » tumor. Kinetics of boron release into the physiologic solution demonstrate that ultradispersed Fe-B (10%) could be applied for an effective magnetic neutron capture therapy. Conclusion: Both types of the particles have high magnetization and magnetic homogeneity, allow to form stable magnetic suspensions, and have low toxicity.« less
Dosimetric characteristics of the University of Washington Clinical Neutron Therapy System
NASA Astrophysics Data System (ADS)
Moffitt, Gregory B.; Stewart, Robert D.; Sandison, George A.; Goorley, John T.; Argento, David C.; Jevremovic, Tatjana; Emery, Robert; Wootton, Landon S.; Parvathaneni, Upendra; Laramore, George E.
2018-05-01
The University of Washington (UW) Clinical Neutron Therapy System (CNTS), which generates high linear energy transfer fast neutrons through interactions of 50.5 MeV protons incident on a Be target, has depth-dose characteristics similar to 6 MV x-rays. In contrast to the fixed beam angles and primitive blocking used in early clinical trials of neutron therapy, the CNTS has a gantry with a full 360° of rotation, internal wedges, and a multi-leaf collimator (MLC). Since October of 1984, over 3178 patients have received conformal neutron therapy treatments using the UW CNTS. In this work, the physical and dosimetric characteristics of the CNTS are documented through comparisons of measurements and Monte Carlo simulations. A high resolution computed tomography scan of the model 17 ionization chamber (IC-17) has also been used to improve the accuracy of simulations of the absolute calibration geometry. The response of the IC-17 approximates well the kinetic energy released per unit mass (KERMA) in water for neutrons and photons for energies from a few tens of keV up to about 20 MeV. Above 20 MeV, the simulated model 17 ion chamber response is 20%–30% higher than the neutron KERMA in water. For CNTS neutrons, simulated on- and off-axis output factors in water match measured values within ~2% ± 2% for rectangular and irregularly shaped field with equivalent square areas ranging in a side dimension from 2.8 cm to 30.7 cm. Wedge factors vary by less than 1.9% of the measured dose in water for clinically relevant field sizes. Simulated tissue maximum ratios in water match measured values within 3.3% at depths up to 20 cm. Although the absorbed dose for water and adipose tissue are within 2% at a depth of 1.7 cm, the absorbed dose in muscle and bone can be as much as 12 to 40% lower than the absorbed dose in water. The reported studies are significant from a historical perspective and as additional validation of a new tool for patient quality assurance
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhang, L.; Lanza, R.C.
1999-12-01
The authors have developed a near field coded aperture imaging system for use with fast neutron techniques as a tool for the detection of contraband and hidden explosives through nuclear elemental analysis. The technique relies on the prompt gamma rays produced by fast neutron interactions with the object being examined. The position of the nuclear elements is determined by the location of the gamma emitters. For existing fast neutron techniques, in Pulsed Fast Neutron Analysis (PFNA), neutrons are used with very low efficiency; in Fast Neutron Analysis (FNS), the sensitivity for detection of the signature gamma rays is very low.more » For the Coded Aperture Fast Neutron Analysis (CAFNA{reg{underscore}sign}) the authors have developed, the efficiency for both using the probing fast neutrons and detecting the prompt gamma rays is high. For a probed volume of n{sup 3} volume elements (voxels) in a cube of n resolution elements on a side, they can compare the sensitivity with other neutron probing techniques. As compared to PFNA, the improvement for neutron utilization is n{sup 2}, where the total number of voxels in the object being examined is n{sup 3}. Compared to FNA, the improvement for gamma-ray imaging is proportional to the total open area of the coded aperture plane; a typical value is n{sup 2}/2, where n{sup 2} is the number of total detector resolution elements or the number of pixels in an object layer. It should be noted that the actual signal to noise ratio of a system depends also on the nature and distribution of background events and this comparison may reduce somewhat the effective sensitivity of CAFNA. They have performed analysis, Monte Carlo simulations, and preliminary experiments using low and high energy gamma-ray sources. The results show that a high sensitivity 3-D contraband imaging and detection system can be realized by using CAFNA.« less
Energy-resolved fast neutron resonance radiography at CSNS
NASA Astrophysics Data System (ADS)
Tan, Zhixin; Tang, Jingyu; Jing, Hantao; Fan, Ruirui; Li, Qiang; Ning, Changjun; Bao, Jie; Ruan, Xichao; Luan, Guangyuan; Feng, Changqin; Zhang, Xianpeng
2018-05-01
The white neutron beamline at the China Spallation Neutron Source will be used mainly for nuclear data measurements. It will be characterized by high flux and broad energy spectra. To exploit the beamline as a neutron imaging source, we propose a liquid scintillator fiber array for fast neutron resonance radiography. The fiber detector unit has a small exposed area, which will limit the event counts and separate the events in time, thus satisfying the requirements for single-event time-of-flight (SEToF) measurement. The current study addresses the physical design criteria for ToF measurement, including flux estimation and detector response. Future development and potential application of the technology are also discussed.
Fast Neutron Detection Using Pixelated CdZnTe Spectrometers
NASA Astrophysics Data System (ADS)
Streicher, Michael; Goodman, David; Zhu, Yuefeng; Brown, Steven; Kiff, Scott; He, Zhong
2017-07-01
Fast neutrons are an important signature of special nuclear materials (SNMs). They have a low natural background rate and readily penetrate high atomic number materials that easily shield gamma-ray signatures. Therefore, they provide a complementary signal to gamma rays for detecting shielded SNM. Scattering kinematics dictate that a large nucleus (such as Cd or Te) will recoil with small kinetic energy after an elastic collision with a fast neutron. Charge carrier recombination and quenching further reduce the recorded energy deposited. Thus, the energy threshold of CdZnTe detectors must be very low in order to sense the small signals from these recoils. In this paper, the threshold was reduced to less than 5 keVee to demonstrate that the 5.9-keV X-ray line from 55Fe could be separated from electronic noise. Elastic scattering neutron interactions were observed as small energy depositions (less than 20 keVee) using digitally sampled pulse waveforms from pixelated CdZnTe detectors. Characteristic gamma-ray lines from inelastic neutron scattering were also observed.
Fast neutron detection at near-core location of a research reactor with a SiC detector
NASA Astrophysics Data System (ADS)
Wang, Lei; Jarrell, Josh; Xue, Sha; Tan, Chuting; Blue, Thomas; Cao, Lei R.
2018-04-01
The measurable charged-particle produced from the fast neutron interactions with the Si and C nucleuses can make a wide bandgap silicon carbide (SiC) sensor intrinsically sensitive to neutrons. The 4H-SiC Schottky detectors have been fabricated and tested at up to 500 °C, presenting only a slightly degraded energy resolution. The response spectrum of the SiC detectors were also obtained by exposing the detectors to external neutron beam irradiation and at a near-core location where gamma-ray field is intense. The fast neutron flux of these two locations are ∼ 4 . 8 × 104cm-2 ṡs-1 and ∼ 2 . 2 × 107cm-2 ṡs-1, respectively. At the external beam location, a Si detector was irradiated side-by-side with SiC detector to disjoin the neutron response from Si atoms. The contribution of gamma ray, neutron scattering, and charged-particles producing reactions in the SiC was discussed. The fast neutron detection efficiencies were determined to be 6 . 43 × 10-4 for the external fast neutron beam irradiation and 6 . 13 × 10-6 for the near-core fast neutron irradiation.
USDA-ARS?s Scientific Manuscript database
Fast neutron radiation has been used as a mutagen to develop extensive mutant collections. However, the genome-wide structural consequences of fast neutron radiation are not well understood. Here, we examine the genome-wide structural variants observed among 264 soybean (Glycine max (L.) Merrill) pl...
Culbertson, C N; Wangerin, K; Ghandourah, E; Jevremovic, T
2005-08-01
The goal of this study was to evaluate the COG Monte Carlo radiation transport code, developed and tested by Lawrence Livermore National Laboratory, for neutron capture therapy related modeling. A boron neutron capture therapy model was analyzed comparing COG calculational results to results from the widely used MCNP4B (Monte Carlo N-Particle) transport code. The approach for computing neutron fluence rate and each dose component relevant in boron neutron capture therapy is described, and calculated values are shown in detail. The differences between the COG and MCNP predictions are qualified and quantified. The differences are generally small and suggest that the COG code can be applied for BNCT research related problems.
Advanced plastic scintillators for fast neutron discrimination
DOE Office of Scientific and Technical Information (OSTI.GOV)
Feng, Patrick L; Anstey, Mitchell; Doty, F. Patrick
2014-09-01
The present work addresses the need for solid-state, fast neutron discriminating scintillators that possess higher light yields and faster decay kinetics than existing organic scintillators. These respective attributes are of critical importance for improving the gamma-rejection capabilities and increasing the neutron discrimination performance under high-rate conditions. Two key applications that will benefit from these improvements include large-volume passive detection scenarios as well as active interrogation search for special nuclear materials. Molecular design principles were employed throughout this work, resulting in synthetically tailored materials that possess the targeted scintillation properties.
Fast neutron irradiation deteriorates hippocampus-related memory ability in adult mice.
Yang, Miyoung; Kim, Hwanseong; Kim, Juhwan; Kim, Sung-Ho; Kim, Jong-Choon; Bae, Chun-Sik; Kim, Joong-Sun; Shin, Taekyun; Moon, Changjong
2012-03-01
Object recognition memory and contextual fear conditioning task performance in adult C57BL/6 mice exposed to cranial fast neutron irradiation (0.8 Gy) were examined to evaluate hippocampus-related behavioral dysfunction following acute exposure to relatively low doses of fast neutrons. In addition, hippocampal neurogenesis changes in adult murine brain after cranial irradiation were analyzed using the neurogenesis immunohistochemical markers Ki-67 and doublecortin (DCX). In the object recognition memory test and contextual fear conditioning, mice trained 1 and 7 days after irradiation displayed significant memory deficits compared to the sham-irradiated controls. The number of Ki-67- and DCX-positive cells decreased significantly 24 h post-irradiation. These results indicate that acute exposure of the adult mouse brain to a relatively low dose of fast neutrons interrupts hippocampal functions, including learning and memory, possibly by inhibiting neurogenesis.
A cargo inspection system based on pulsed fast neutron analysis (PFNA).
Ipe, N E; Olsher, R; Ryge, P; Mrozack, J; Thieu, J
2005-01-01
A cargo inspection system based on pulsed fast neutron analysis (PFNA) is to be used at a border crossing to detect explosives and contraband hidden in trucks and cargo containers. Neutrons are produced by the interaction of deuterons in a deuterium target mounted on a moveable scan arm. The collimated pulsed fast neutron beam is used to determine the location and composition of objects in a cargo container. The neutrons produce secondary gamma rays that are characteristic of the object's elemental composition. The cargo inspection system building consists of an accelerator room and an inspection tunnel. The accelerator room is shielded and houses the injector, accelerator and the neutron production gas target. The inspection tunnel is partially shielded. The truck or container to be inspected will be moved through the inspection tunnel by a conveyor system. The facility and radiation source terms considered in the shielding design are described.
Fast-Neutron Survey With Compact Plastic Scintillation Detectors.
Preston, Rhys M; Tickner, James R
2017-07-01
With the rise of the Silicon Photomultiplier (SiPM), it is now practical to build compact scintillation detectors well suited to portable use. A prototype survey meter for fast-neutrons and gamma-rays, based around an EJ-299-34 plastic scintillator with SiPM readout, has been developed and tested. A custom digital pulse processor was used to perform pulse shape discrimination on-the-fly. Ambient dose equivalent H*(10) was calculated by means of two energy-dependent 'G-functions'. The sensitivity was calculated to be between 0.10 and 0.22 cps/(µSv/hr) for fast-neutrons with energies above 2.5 MeV. The prototype was used to survey various laboratory radiation fields, with the readings compared with commercial survey meters. The high sensitivity and lightweight nature of this detector makes it promising for rapid survey of the mixed neutron/gamma-ray fields encountered in industry and homeland security. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Treatment of salivary gland neoplasms with fast neutron radiotherapy.
Douglas, James G; Koh, Wui-jin; Austin-Seymour, Mary; Laramore, George E
2003-09-01
To evaluate the efficacy of fast neutron radiotherapy for the treatment of salivary gland neoplasms. Retrospective analysis. University of Washington Cancer Center, Neutron Facility, Seattle. The medical records of 279 patients treated with curative intent using fast neutron radiotherapy at the University of Washington Cancer Center were reviewed. Of the 279 patients, 263 had evidence of gross residual disease at the time of treatment (16 had no evidence of gross residual disease), 141 had tumors of a major salivary gland, and 138 had tumors of minor salivary glands. The median follow-up period was 36 months (range, 1-142 months). Local-regional control, cause-specific survival, and freedom from metastasis. The 6-year actuarial cause-specific survival rate was 67%. Multivariate analysis revealed that low group stage (I-II) disease, minor salivary sites, lack of skull base invasion, and primary disease were associated with a statistically significant improvement in cause-specific survival. The 6-year actuarial local-regional control rate was 59%. Multivariate analysis revealed size 4 cm or smaller, lack of base of skull invasion, prior surgical resection, and no previous radiotherapy to have a statistically significant improved local-regional control. Sixteen patients without evidence of gross residual disease had a 100% 6-year actuarial local-regional control. The 6-year actuarial freedom from metastasis rate was 64%. Factors associated with decreased development of systemic metastases included negative lymph nodes at the time of treatment and lack of base of skull involvement. The 6-year actuarial rate of development of grade 3 or 4 long-term toxicity (using the Radiation Therapy Oncology Group and European Organization for Research on the Treatment of Cancer criteria) was 10%. No patient experienced grade 5 toxic effects. Neuron radiotherapy is an effective treatment for patients with salivary gland neoplasms who have gross residual disease and achieves excellent
A laser-induced repetitive fast neutron source applied for gold activation analysis
NASA Astrophysics Data System (ADS)
Lee, Sungman; Park, Sangsoon; Lee, Kitae; Cha, Hyungki
2012-12-01
A laser-induced repetitively operated fast neutron source was developed for applications in laser-driven nuclear physics research. The developed neutron source, which has a neutron yield of approximately 4 × 105 n/pulse and can be operated up to a pulse repetition rate of 10 Hz, was applied for a gold activation analysis. Relatively strong delayed gamma spectra of the activated gold were measured at 333 keV and 355 keV, and proved the possibility of the neutron source for activation analyses. In addition, the nuclear reactions responsible for the measured gamma spectra of gold were elucidated by the 14 MeV fast neutrons resulting from the D(t,n)He4 nuclear reaction, for which the required tritium originated from the primary fusion reaction, D(d,p)T3.
A laser-induced repetitive fast neutron source applied for gold activation analysis.
Lee, Sungman; Park, Sangsoon; Lee, Kitae; Cha, Hyungki
2012-12-01
A laser-induced repetitively operated fast neutron source was developed for applications in laser-driven nuclear physics research. The developed neutron source, which has a neutron yield of approximately 4 × 10(5) n/pulse and can be operated up to a pulse repetition rate of 10 Hz, was applied for a gold activation analysis. Relatively strong delayed gamma spectra of the activated gold were measured at 333 keV and 355 keV, and proved the possibility of the neutron source for activation analyses. In addition, the nuclear reactions responsible for the measured gamma spectra of gold were elucidated by the 14 MeV fast neutrons resulting from the D(t,n)He(4) nuclear reaction, for which the required tritium originated from the primary fusion reaction, D(d,p)T(3).
Digital fast neutron radiography of steel reinforcing bar in concrete
NASA Astrophysics Data System (ADS)
Mitton, K.; Jones, A.; Joyce, M. J.
2014-12-01
Neutron imaging has previously been used in order to test for cracks, degradation and water content in concrete. However, these techniques often fall short of alternative non-destructive testing methods, such as γ-ray and X-ray imaging, particularly in terms of resolution. Further, thermal neutron techniques can be compromised by the significant expense associated with thermal neutron sources of sufficient intensity to yield satisfactory results that can often precipitate the need for a reactor. Such embodiments are clearly not portable in the context of the needs of field applications. This paper summarises the results of a study to investigate the potential for transmission radiography based on fast neutrons. The objective of this study was to determine whether the presence of heterogeneities in concrete, such as reinforcement structures, could be identified on the basis of variation in transmitted fast-neutron flux. Monte-Carlo simulations have been performed and the results from these are compared to those arising from practical tests using a 252Cf source. The experimental data have been acquired using a digital pulse-shape discrimination system that enables fast neutron transmission to be studied across an array of liquid scintillators placed in close proximity to samples under test, and read out in real time. Whilst this study does not yield sufficient spatial resolution, a comparison of overall flux ratios does provide a basis for the discrimination between samples with contrasting rebar content. This approach offers the potential for non-destructive testing that gives less dose, better transportability and better accessibility than competing approaches. It is also suitable for thick samples where γ-ray and X-ray methods can be limited.
Fast Neutron Emission Tomography of Used Nuclear Fuel Assemblies
NASA Astrophysics Data System (ADS)
Hausladen, Paul; Iyengar, Anagha; Fabris, Lorenzo; Yang, Jinan; Hu, Jianwei; Blackston, Matthew
2017-09-01
Oak Ridge National Laboratory is developing a new capability to perform passive fast neutron emission tomography of spent nuclear fuel assemblies for the purpose of verifying their integrity for international safeguards applications. Most of the world's plutonium is contained in spent nuclear fuel, so it is desirable to detect the diversion of irradiated fuel rods from an assembly prior to its transfer to ``difficult to access'' storage, such as a dry cask or permanent repository, where re-verification is practically impossible. Nuclear fuel assemblies typically consist of an array of fuel rods that, depending on exposure in the reactor and consequent ingrowth of 244Cm, are spontaneous sources of as many as 109 neutrons s-1. Neutron emission tomography uses collimation to isolate neutron activity along ``lines of response'' through the assembly and, by combining many collimated views through the object, mathematically extracts the neutron emission from each fuel rod. This technique, by combining the use of fast neutrons -which can penetrate the entire fuel assembly -and computed tomography, is capable of detecting vacancies or substitutions of individual fuel rods. This paper will report on the physics design and component testing of the imaging system. This material is based upon work supported by the U.S. Department of Energy, Office of Defense Nuclear Nonproliferation Research and Development within the National Nuclear Security Administration, under Contract Number DE-AC05-00OR22725.
Corrections on energy spectrum and scatterings for fast neutron radiography at NECTAR facility
NASA Astrophysics Data System (ADS)
Liu, Shu-Quan; Bücherl, Thomas; Li, Hang; Zou, Yu-Bin; Lu, Yuan-Rong; Guo, Zhi-Yu
2013-11-01
Distortions caused by the neutron spectrum and scattered neutrons are major problems in fast neutron radiography and should be considered for improving the image quality. This paper puts emphasis on the removal of these image distortions and deviations for fast neutron radiography performed at the NECTAR facility of the research reactor FRM- II in Technische Universität München (TUM), Germany. The NECTAR energy spectrum is analyzed and established to modify the influence caused by the neutron spectrum, and the Point Scattered Function (PScF) simulated by the Monte-Carlo program MCNPX is used to evaluate scattering effects from the object and improve image quality. Good analysis results prove the sound effects of the above two corrections.
Detection of fast neutrons from shielded nuclear materials using a semiconductor alpha detector.
Pöllänen, R; Siiskonen, T
2014-08-01
The response of a semiconductor alpha detector to fast (>1 MeV) neutrons was investigated by using measurements and simulations. A polyethylene converter was placed in front of the detector to register recoil protons generated by elastic collisions between neutrons and hydrogen nuclei of the converter. The developed prototype equipment was tested with shielded radiation sources. The low background of the detector and insensitivity to high-energy gamma rays above 1 MeV are advantages when the detection of neutron-emitting nuclear materials is of importance. In the case of a (252)Cf neutron spectrum, the intrinsic efficiency of fast neutron detection was determined to be 2.5×10(-4), whereas three-fold greater efficiency was obtained for a (241)AmBe neutron spectrum. Copyright © 2014 Elsevier Ltd. All rights reserved.
Abe, Y; Hosoda, H; Arikawa, Y; Nagai, T; Kojima, S; Sakata, S; Inoue, H; Iwasa, Y; Iwano, K; Yamanoi, K; Fujioka, S; Nakai, M; Sarukura, N; Shiraga, H; Norimatsu, T; Azechi, H
2014-11-01
The characteristics of oxygen-enriched liquid scintillators with very low afterglow are investigated and optimized for application to a single-hit neutron spectrometer for fast ignition experiments. It is found that 1,2,4-trimethylbenzene has better characteristics as a liquid scintillator solvent than the conventional solvent, p-xylene. In addition, a benzophenon-doped BBQ liquid scintillator is shown to demonstrate very rapid time response, and therefore has potential for further use in neutron diagnostics with fast time resolution.
The accelerator neutron source for boron neutron capture therapy
NASA Astrophysics Data System (ADS)
Kasatov, D.; Koshkarev, A.; Kuznetsov, A.; Makarov, A.; Ostreinov, Yu; Shchudlo, I.; Sorokin, I.; Sycheva, T.; Taskaev, S.; Zaidi, L.
2016-11-01
The accelerator based epithermal neutron source for Boron Neutron Capture Therapy (BNCT) is proposed, created and used in the Budker Institute of Nuclear Physics. In 2014, with the support of the Russian Science Foundation created the BNCT laboratory for the purpose to the end of 2016 get the neutron flux, suitable for BNCT. For getting 3 mA 2.3 MeV proton beam, was created a new type accelerator - tandem accelerator with vacuum isolation. On this moment, we have a stationary proton beam with 2.3 MeV and current 1.75 mA. Generation of neutrons is carried out by dropping proton beam on to lithium target as a result of threshold reaction 7Li(p,n)7Be. Established facility is a unique scientific installation. It provides a generating of neutron flux, including a monochromatic energy neutrons, gamma radiation, alpha-particles and positrons, and may be used by other research groups for carrying out scientific researches. The article describes an accelerator neutron source, presents and discusses the result of experiments and declares future plans.
MTR FAST NEUTRON FLUX MEASUREMENTS FOR CYCLE 146
DOE Office of Scientific and Technical Information (OSTI.GOV)
Weber, L D; Hogg, C H
1962-03-20
The fast neutron fluxes in selected positions of the MTR were measured for Cycle 146. The measurements were made at the beginning, throughout, and at the end of the cycle (564 Mwd). Vertical traverses for each position monitors are shown. (auth)
Time Evolving Fission Chain Theory and Fast Neutron and Gamma-Ray Counting Distributions
Kim, K. S.; Nakae, L. F.; Prasad, M. K.; ...
2015-11-01
Here, we solve a simple theoretical model of time evolving fission chains due to Feynman that generalizes and asymptotically approaches the point model theory. The point model theory has been used to analyze thermal neutron counting data. This extension of the theory underlies fast counting data for both neutrons and gamma rays from metal systems. Fast neutron and gamma-ray counting is now possible using liquid scintillator arrays with nanosecond time resolution. For individual fission chains, the differential equations describing three correlated probability distributions are solved: the time-dependent internal neutron population, accumulation of fissions in time, and accumulation of leaked neutronsmore » in time. Explicit analytic formulas are given for correlated moments of the time evolving chain populations. The equations for random time gate fast neutron and gamma-ray counting distributions, due to randomly initiated chains, are presented. Correlated moment equations are given for both random time gate and triggered time gate counting. There are explicit formulas for all correlated moments are given up to triple order, for all combinations of correlated fast neutrons and gamma rays. The nonlinear differential equations for probabilities for time dependent fission chain populations have a remarkably simple Monte Carlo realization. A Monte Carlo code was developed for this theory and is shown to statistically realize the solutions to the fission chain theory probability distributions. Combined with random initiation of chains and detection of external quanta, the Monte Carlo code generates time tagged data for neutron and gamma-ray counting and from these data the counting distributions.« less
SWAN - Detection of explosives by means of fast neutron activation analysis
NASA Astrophysics Data System (ADS)
Gierlik, M.; Borsuk, S.; Guzik, Z.; Iwanowska, J.; Kaźmierczak, Ł.; Korolczuk, S.; Kozłowski, T.; Krakowski, T.; Marcinkowski, R.; Swiderski, L.; Szeptycka, M.; Szewiński, J.; Urban, A.
2016-10-01
In this work we report on SWAN, the experimental, portable device for explosives detection. The device was created as part of the EU Structural Funds Project "Accelerators & Detectors" (POIG.01.01.02-14-012/08-00), with the goal to increase beneficiary's expertise and competencies in the field of neutron activation analysis. Previous experiences and budged limitations lead toward a less advanced design based on fast neutron interactions and unsophisticated data analysis with the emphasis on the latest gamma detection and spectrometry solutions. The final device has been designed as a portable, fast neutron activation analyzer, with the software optimized for detection of carbon, nitrogen and oxygen. SWAN's performance in the role of explosives detector is elaborated in this paper. We demonstrate that the unique features offered by neutron activation analysis might not be impressive enough when confronted with practical demands and expectations of a generic homeland security customer.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hsieh, M; Liu, Y; Nie, L
Purpose: To design a beam shaping assembly (BSA) to shape the 2.45-MeV neutrons produced by a deuterium-deuterium (DD) neutron generator and to optimize the beam output for boron neutron capture therapy of brain tumors Methods: MCNP is used for this simulation study. The simulation model consists of a neutron surface source that resembles an actual DD source and is surrounded by a BSA. The neutron source emits 2.45-MeV neutrons isotropically. The BSA is composed of a moderator, reflector, collimator and filter. Various types of materials and geometries are tested for each component to optimize the neutron output. Neutron characteristics aremore » measured with an 2×2×2-cm{sup 3} air-equivalent cylinder at the beam exit. The ideal BSA is determined by evaluating the in-air parameters, which include epithermal neutron per source neutron, fast neutron dose per epithermal neutron, and photon dose per epithermal neutron. The parameter values are compared to those recommended by the IAEA. Results: The ideal materials for reflector and thermal neutron filter were lead and cadmium, respectively. The thickness for reflector was 43 cm and for filter was 0.5 mm. At present, the best-performing moderator has 25 cm of AlF{sub 3} and 5 cm of MgF{sub 2}. This layout creates a neutron spectrum that has a peak at approximately 10 keV and produces 1.35E-4 epithermal neutrons per source neutron per cm{sup 2}. Additional neutron characteristics, fast neutrons per epithermal neutron and photon per epithermal neutron, are still under investigation. Conclusion: Working is ongoing to optimize the final layout of the BSA. The neutron spectrum at the beam exit window of the final configuration will have the maximum number of epithermal neutrons and limited photon and fast neutron contaminations within the recommended values by IAEA. Future studies will also include phantom experiments to validate the simulation results.« less
MONDO: a neutron tracker for particle therapy secondary emission characterisation
NASA Astrophysics Data System (ADS)
Marafini, M.; Gasparini, L.; Mirabelli, R.; Pinci, D.; Patera, V.; Sciubba, A.; Spiriti, E.; Stoppa, D.; Traini, G.; Sarti, A.
2017-04-01
Tumour control is performed in particle therapy using particles and ions, whose high irradiation precision enhances the effectiveness of the treatment, while sparing the healthy tissue surrounding the target volume. Dose range monitoring devices using photons and charged particles produced by the beam interacting with the patient’s body have already been proposed, but no attempt has been made yet to exploit the detection of the abundant neutron component. Since neutrons can release a significant dose far away from the tumour region, precise measurements of their flux, production energy and angle distributions are eagerly sought in order to improve the treatment planning system (TPS) software. It will thus be possible to predict not only the normal tissue toxicity in the target region, but also the risk of late complications in the whole body. The aforementioned issues underline the importance of an experimental effort devoted to the precise characterisation of neutron production, aimed at the measurement of their abundance, emission point and production energy. The technical challenges posed by a neutron detector aimed at high detection efficiency and good backtracking precision are addressed within the MONDO (monitor for neutron dose in hadrontherapy) project, whose main goal is to develop a tracking detector that can target fast and ultrafast neutrons. A full reconstruction of two consecutive elastic scattering interactions undergone by the neutrons inside the detector material will be used to measure their energy and direction. The preliminary results of an MC simulation performed using the FLUKA software are presented here, together with the DSiPM (digital SiPM) readout implementation. New detector readout implementations specifically tailored to the MONDO tracker are also discussed, and the neutron detection efficiency attainable with the proposed neutron tracking strategy are reported.
MONDO: a neutron tracker for particle therapy secondary emission characterisation.
Marafini, M; Gasparini, L; Mirabelli, R; Pinci, D; Patera, V; Sciubba, A; Spiriti, E; Stoppa, D; Traini, G; Sarti, A
2017-04-21
Tumour control is performed in particle therapy using particles and ions, whose high irradiation precision enhances the effectiveness of the treatment, while sparing the healthy tissue surrounding the target volume. Dose range monitoring devices using photons and charged particles produced by the beam interacting with the patient's body have already been proposed, but no attempt has been made yet to exploit the detection of the abundant neutron component. Since neutrons can release a significant dose far away from the tumour region, precise measurements of their flux, production energy and angle distributions are eagerly sought in order to improve the treatment planning system (TPS) software. It will thus be possible to predict not only the normal tissue toxicity in the target region, but also the risk of late complications in the whole body. The aforementioned issues underline the importance of an experimental effort devoted to the precise characterisation of neutron production, aimed at the measurement of their abundance, emission point and production energy. The technical challenges posed by a neutron detector aimed at high detection efficiency and good backtracking precision are addressed within the MONDO (monitor for neutron dose in hadrontherapy) project, whose main goal is to develop a tracking detector that can target fast and ultrafast neutrons. A full reconstruction of two consecutive elastic scattering interactions undergone by the neutrons inside the detector material will be used to measure their energy and direction. The preliminary results of an MC simulation performed using the FLUKA software are presented here, together with the DSiPM (digital SiPM) readout implementation. New detector readout implementations specifically tailored to the MONDO tracker are also discussed, and the neutron detection efficiency attainable with the proposed neutron tracking strategy are reported.
2016-06-01
of these three pillars, yet current detectors for fast neutrons from nuclear weapons materials are bulky, expensive, and have low efficiencies, well...passive fast neutron emissions. Similarly, isotopes present in weapons grade Plutonium (which is predominantly Pu-239), especially Pu-240, are... weapons material, and the propensity of the neutrons resulting from their fission to inelastically scatter, defines the interactions of interest
2015-03-01
HEAVY OXIDE INORGANIC SCINTILLATOR CRYSTALS FOR DIRECT DETECTION OF FAST NEUTRONS BASED ON INELASTIC SCATTERING by Philip R. Rusiecki...HEAVY OXIDE INORGANIC SCINTILLATOR CRYSTALS FOR DIRECT DETECTION OF FAST NEUTRONS BASED ON INELASTIC SCATTERING 6. AUTHOR(S) Philip R. Rusiecki 7...ABSTRACT (maximum 200 words) Heavy oxide inorganic scintillators may prove viable in the detection of fast neutrons based on the mechanism of
NASA Technical Reports Server (NTRS)
Semones, Edward; Leitgab, Martin
2016-01-01
The ISS-RAD instrument was activated on ISS on February 1st, 2016. Integrated in ISS-RAD, the Fast Neutron Detector (FND) performs, for the first time on ISS, routine and precise direct neutron measurements between 0.5 and 8 MeV. Preliminary results for neutron dose equivalent and neutron flux energy distributions from online/on-board algorithms and offline ground analyses will be shown, along with comparisons to simulated data and previously measured neutron spectral data. On-orbit data quality and pre-launch analysis validation results will be discussed as well.
Measurement of the fast neutron background at the China Jinping Underground Laboratory
NASA Astrophysics Data System (ADS)
Du, Q.; Lin, S. T.; Liu, S. K.; Tang, C. J.; Wang, L.; Wei, W. W.; Wong, H. T.; Xing, H. Y.; Yue, Q.; Zhu, J. J.
2018-05-01
We report on the measurements of the fluxes and spectra of the environmental fast neutron background at the China Jinping Underground Laboratory (CJPL) with a rock overburden of about 6700 meters water equivalent, using a liquid scintillator detector doped with 0.5% gadolinium. The signature of a prompt nuclear recoil followed by a delayed high energy γ-ray cascade is used to identify neutron events. The large energy deposition of the delayed γ-rays from the (n , γ) reaction on gadolinium, together with the excellent n- γ discrimination capability provides a powerful background suppression which allows the measurement of a low intensity neutron flux. The neutron flux of (1 . 51 ± 0 . 03(stat .) ± 0 . 10(syst .)) × 10-7cm-2s-1 in the energy range of 1-10 MeV in the Hall A of CJPL was measured based on 356 days of data. In the same energy region, measurement with the same detector placed in a room surrounding with one meter thick polyethylene shielding gives a significantly lower flux of (4 . 9 ± 0 . 9(stat .) ± 0 . 5(syst .)) × 10-9cm-2s-1 with 174 days of data. This represents a measurement of the lowest environmental fast neutron background among the underground laboratories in the world, prior to additional experiment-specific attenuation. Additionally, the fast neutron spectra both in the Hall A and the polyethylene room were reconstructed with the help of GEANT4 simulations.
Superconducting gamma and fast-neutron spectrometers with high energy resolution
Friedrich, Stephan; , Niedermayr, Thomas R.; Labov, Simon E.
2008-11-04
Superconducting Gamma-ray and fast-neutron spectrometers with very high energy resolution operated at very low temperatures are provided. The sensor consists of a bulk absorber and a superconducting thermometer weakly coupled to a cold reservoir, and determines the energy of the incident particle from the rise in temperature upon absorption. A superconducting film operated at the transition between its superconducting and its normal state is used as the thermometer, and sensor operation at reservoir temperatures around 0.1 K reduces thermal fluctuations and thus enables very high energy resolution. Depending on the choice of absorber material, the spectrometer can be configured either as a Gamma-spectrometer or as a fast-neutron spectrometer.
Adams, Robert; Zboray, Robert; Prasser, Horst-Michael
2016-01-01
Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D-T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D-D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a discussion
Bass, C D; Beise, E J; Breuer, H; Heimbach, C R; Langford, T J; Nico, J S
2013-07-01
The characterization of a liquid scintillator incorporating an aqueous solution of enriched lithium chloride to produce a scintillator with 0.40% (6)Li is presented, including the performance of the scintillator in terms of its optical properties and neutron response. The scintillator was incorporated into a fast neutron spectrometer, and the light output spectra from 2.5 MeV, 14.1 MeV, and (252)Cf neutrons were measured using capture-gated coincidence techniques. The spectrometer was operated without coincidence to perform thermal neutron measurements. Possible improvements in spectrometer performance are discussed. Published by Elsevier Ltd.
NASA Astrophysics Data System (ADS)
Longo, A.; Collura, G.; Gallo, S.; Bartolotta, A.; Marrale, M.
2017-11-01
In this work analyses of the energy released per unit mass in phenolic compound exposed to neutron beams were performed with the aim of predicting the increase in dose achievable by addition of gadolinium (Gd) inside the pellets. In particular, Monte Carlo (MC) simulations were carried out for IRGANOX® 1076 phenolic compound irradiated with neutron beams with different energy spectra at various depths inside a water phantom. The addition of gadolinium increases sensitivity of phenolic ESR (electron spin resonance) dosimeters to neutrons thanks to the high gadolinium cross section for neutron capture and to the large number of secondary particles (mainly Auger and internal conversion electrons) which are able to release energy inside the sensitive material layers. For small depths in water phantom and low energy neutron spectra the increase in dose due to gadolinium is large (more than a factor 50). The enhancement is smaller in case of epithermal neutron beam, whereas the increase in dose for fast neutrons is less than 50%. In order to have a comparison with other ESR dosimeters the energy released per unit mass in phenolic compound was compared with that calculated in alanine pellets. For thermal neutron beams the energy released in phenolic compound with gadolinium is comparable to that released in alanine for small depths in phantom, whereas it is larger than in alanine for large depths. In case of epithermal and fast neutron beams the energy released in phenolic compound is larger than in alanine samples because the elastic scattering with hydrogen nuclei is more probable for high neutron energies and this phenolic compound is characterized by an higher number of 1H nuclei than alanine. All results here found suggest that these phenolic pellets could be fruitfully used for dosimetric applications in Neutron Capture Therapy.
Accelerator based epithermal neutron source
NASA Astrophysics Data System (ADS)
Taskaev, S. Yu.
2015-11-01
We review the current status of the development of accelerator sources of epithermal neutrons for boron neutron capture therapy (BNCT), a promising method of malignant tumor treatment. Particular attention is given to the source of epithermal neutrons on the basis of a new type of charged particle accelerator: tandem accelerator with vacuum insulation and lithium neutron-producing target. It is also shown that the accelerator with specialized targets makes it possible to generate fast and monoenergetic neutrons, resonance and monoenergetic gamma-rays, alpha-particles, and positrons.
MCNP6 model of the University of Washington clinical neutron therapy system (CNTS).
Moffitt, Gregory B; Stewart, Robert D; Sandison, George A; Goorley, John T; Argento, David C; Jevremovic, Tatjana
2016-01-21
A MCNP6 dosimetry model is presented for the Clinical Neutron Therapy System (CNTS) at the University of Washington. In the CNTS, fast neutrons are generated by a 50.5 MeV proton beam incident on a 10.5 mm thick Be target. The production, scattering and absorption of neutrons, photons, and other particles are explicitly tracked throughout the key components of the CNTS, including the target, primary collimator, flattening filter, monitor unit ionization chamber, and multi-leaf collimator. Simulations of the open field tissue maximum ratio (TMR), percentage depth dose profiles, and lateral dose profiles in a 40 cm × 40 cm × 40 cm water phantom are in good agreement with ionization chamber measurements. For a nominal 10 × 10 field, the measured and calculated TMR values for depths of 1.5 cm, 5 cm, 10 cm, and 20 cm (compared to the dose at 1.7 cm) are within 0.22%, 2.23%, 4.30%, and 6.27%, respectively. For the three field sizes studied, 2.8 cm × 2.8 cm, 10.4 cm × 10.3 cm, and 28.8 cm × 28.8 cm, a gamma test comparing the measured and simulated percent depth dose curves have pass rates of 96.4%, 100.0%, and 78.6% (depth from 1.5 to 15 cm), respectively, using a 3% or 3 mm agreement criterion. At a representative depth of 10 cm, simulated lateral dose profiles have in-field (⩾ 10% of central axis dose) pass rates of 89.7% (2.8 cm × 2.8 cm), 89.6% (10.4 cm × 10.3 cm), and 100.0% (28.8 cm × 28.8 cm) using a 3% and 3 mm criterion. The MCNP6 model of the CNTS meets the minimum requirements for use as a quality assurance tool for treatment planning and provides useful insights and information to aid in the advancement of fast neutron therapy.
NASA Astrophysics Data System (ADS)
Ryzhikov, Vladimir D.; Naydenov, Sergei V.; Pochet, Thierry; Onyshchenko, Gennadiy M.; Piven, Leonid A.; Smith, Craig F.
2018-01-01
We have developed and evaluated a new approach to fast neutron and neutron-gamma detection based on large-area multilayer composite heterogeneous detection media consisting of dispersed granules of small-crystalline scintillators contained in a transparent organic (plastic) matrix. Layers of the composite material are alternated with layers of transparent plastic scintillator material serving as light guides. The resulting detection medium - designated as ZEBRA - serves as both an active neutron converter and a detection scintillator which is designed to detect both neutrons and gamma-quanta. The composite layers of the ZEBRA detector consist of small heavy-oxide scintillators in the form of granules of crystalline BGO, GSO, ZWO, PWO and other materials. We have produced and tested the ZEBRA detector of sizes 100x100x41 mm and greater, and determined that they have very high efficiency of fast neutron detection (up to 49% or greater), comparable to that which can be achieved by large sized heavy-oxide single crystals of about Ø40x80 cm3 volume. We have also studied the sensitivity variation to fast neutron detection by using different types of multilayer ZEBRA detectors of 100 cm2 surface area and 41 mm thickness (with a detector weight of about 1 kg) and found it to be comparable to the sensitivity of a 3He-detector representing a total cross-section of about 2000 cm2 (with a weight of detector, including its plastic moderator, of about 120 kg). The measured count rate in response to a fast neutron source of 252Cf at 2 m for the ZEBRA-GSO detector of size 100x100x41 mm3 was 2.84 cps/ng, and this count rate can be doubled by increasing the detector height (and area) up to 200x100 mm2. In summary, the ZEBRA detectors represent a new type of high efficiency and low cost solid-state neutron detector that can be used for stationary neutron/gamma portals. They may represent an interesting alternative to expensive, bulky gas counters based on 3He or 10B neutron
High-Sensitivity Fast Neutron Detector KNK-2-8M
NASA Astrophysics Data System (ADS)
Koshelev, A. S.; Dovbysh, L. Ye.; Ovchinnikov, M. A.; Pikulina, G. N.; Drozdov, Yu. M.; Chuklyaev, S. V.; Pepyolyshev, Yu. N.
2017-12-01
The design of the fast neutron detector KNK-2-8M is outlined. The results of he detector study in the pulse counting mode with pulses from 238U nuclei fission in the radiator of the neutron-sensitive section and in the current mode with separation of functional section currents are presented. The possibilities of determination of the effective number of 238U nuclei in the radiator of the neutron-sensitive section are considered. The diagnostic capabilities of the detector in the counting mode are demonstrated, as exemplified by the analysis of reference data on characteristics of neutron fields in the BR-1 reactor hall. The diagnostic capabilities of the detector in the current mode are demonstrated, as exemplified by the results of measurements of 238U fission intensity in the power startup of the BR-K1 reactor in the fission pulse generation mode with delayed neutrons and the detector placed in the reactor cavity in conditions of large-scale variation of the reactor radiation fields.
Time-resolved Fast Neutron Radiography of Air-water Two-phase Flows
NASA Astrophysics Data System (ADS)
Zboray, Robert; Dangendorf, Volker; Mor, Ilan; Tittelmeier, Kai; Bromberger, Benjamin; Prasser, Horst-Michael
Neutron imaging, in general, is a useful technique for visualizing low-Z materials (such as water or plastics) obscured by high-Z materials. However, when significant amounts of both materials are present and full-bodied samples have to be examined, cold and thermal neutrons rapidly reach their applicability limit as the samples become opaque. In such cases one can benefit from the high penetrating power of fast neutrons. In this work we demonstrate the feasibility of time-resolved, fast neutron radiography of generic air-water two-phase flows in a 1.5 cm thick flow channel with Aluminum walls and rectangular cross section. The experiments have been carried out at the high-intensity, white-beam facility of the Physikalisch-Technische Bundesanstalt, Germany. Exposure times down to 3.33 ms have been achieved at reasonable image quality and acceptable motion artifacts. Different two-phase flow regimes such as bubbly slug and churn flows have been examined. Two-phase flow parameters like the volumetric gas fraction, bubble size and bubble velocities have been measured.
Measurement of fast neutron detection efficiency with 6Li and 7Li enriched CLYC scintillators
NASA Astrophysics Data System (ADS)
Mentana, A.; Camera, F.; Giaz, A.; Blasi, N.; Brambilla, S.; Ceruti, S.; Gini, L.; Groppi, F.; Manenti, S.; Million, B.; Riboldi, S.
2016-10-01
The CLYC (Cs2LiYC6:Ce) crystal belongs to the elpasolite scintillator family, discovered about 15 years ago. It is a very interesting material because of its good energy resolution and its capability to identify and measure gamma rays and fast/thermal neutrons. In the present work, the fast neutron detection efficiency for two different CLYC cylindrical samples has been measured. These two crystals, both with dimension (thickness x diameter) 1”×1”, were respectively enriched with more than 99% of 7Li (CLYC-7) and with ∼ 95% of 6Li (CLYC-6). The presence of the 6Li isotope makes the CLYC-6 ideal to detect thermal neutrons. In order to compare the two scintillators, only the detection efficiency for fast neutrons was considered, neglecting the energy region associated to thermal neutrons in both the crystals. The measurement was performed at the L.A.S.A. Laboratory of INFN and University of Milano (Italy), using a 241Am-Be source.
Boron neutron capture therapy: Moving toward targeted cancer therapy.
Mirzaei, Hamid Reza; Sahebkar, Amirhossein; Salehi, Rasoul; Nahand, Javid Sadri; Karimi, Ehsan; Jaafari, Mahmoud Reza; Mirzaei, Hamed
2016-01-01
Boron neutron capture therapy (BNCT) occurs when a stable isotope, boton-10, is irradiated with low-energy thermal neutrons to yield stripped down helium-4 nuclei and lithium-7 nuclei. It is a binary therapy in the treatment of cancer in which a cytotoxic event is triggered when an atom placed in a cancer cell. Here, we provide an overview on the application of BNCT in cancer therapy as well as current preclinical and clinical evidence on the efficacy of BNCT in the treatment of melanoma, brain tumors, head and neck cancer, and thyroid cancer. Several studies have shown that BNCT is effective in patients who had been treated with a full dose of conventional radiotherapy, because of its selectivity. In addition, BNCT is dependent on the normal/tumor tissue ratio of boron distribution. Increasing evidence has shown that BNCT can be combined with different drug delivery systems to enhance the delivery of boron to cancer cells. The flexibility of BNCT to be used in combination with different tumor-targeting approaches has made this strategy a promising option for cancer therapy. This review aims to provide a state-of-the-art overview of the recent advances in the use of BNCT for targeted therapy of cancer.
NASA Astrophysics Data System (ADS)
Liu, Linyue; Liu, Jinliang; Zhang, Jianfu; Chen, Liang; Zhang, Xianpeng; Zhang, Zhongbing; Ruan, Jinlu; Jin, Peng; Bai, Song; Ouyang, Xiaoping
2017-12-01
Silicon carbide radiation detectors are attractive in the measurement of the total numbers of pulsed fast neutrons emitted from nuclear fusion and fission devices because of high neutron-gamma discrimination and good radiation resistance. A fast-neutron detection system was developed based on a large-area 4H-SiC Schottky diode detector and a 235U fission target. Excellent pulse-height spectra of fission fragments induced by mono-energy deuterium-tritium (D-T) fusion neutrons and continuous energy fission neutrons were obtained. The detector is proven to be a good candidate for pulsed fast neutron detection in a complex radiation field.
Davis, John R.; Brubaker, Erik; Vetter, Kai
2017-03-29
In an effort to characterize the fast neutron radiation background, 16 EJ-309 liquid scintillator cells were installed in the Radiological Multi-sensor Analysis Platform (RadMAP) to collect data in the San Francisco Bay Area. Each fast neutron event was associated with specific weather metrics (pressure, temperature, absolute humidity) and GPS coordinates. Furthermore, the expected exponential dependence of the fast neutron count rate on atmospheric pressure was demonstrated and event rates were subsequently adjusted given the measured pressure at the time of detection. Pressure adjusted data was also used to investigate the influence of other environmental conditions on the neutron background rate.more » Using National Oceanic and Atmospheric Administration (NOAA) coastal area lidar data, an algorithm was implemented to approximate sky-view factors (the total fraction of visible sky) for points along RadMAPs route. In the three areas we analyzed, San Francisco, Downtown Oakland, and Berkeley, all demonstrated a suppression in the background rate of over 50% for the range of sky-view factors measured. This effect, which is due to the shielding of cosmic-ray produced neutrons by surrounding buildings, was comparable to the pressure influence which yielded a 32% suppression in the count rate over the range of pressures measured.« less
Dionet, Claude; Müller-Barthélémy, Melanie; Marceau, Geoffroy; Denis, Jean-Marc; Averbeck, Dietrich; Gueulette, John; Sapin, Vincent; Pereira, Bruno; Tchirkov, Andrei; Chautard, Emmanuel; Verrelle, Pierre
2016-09-01
To analyze the dose rate influence in hyper-radiosensitivity (HRS) of human melanoma cells to very low doses of fast neutrons and to compare to the behaviour of normal human skin fibroblasts. We explored different neutron dose rates as well as possible implication of DNA double-strand breaks (DSB), apoptosis, and energy-provider adenosine-triphosphate (ATP) levels during HRS. HRS in melanoma cells appears only at a very low dose rate (VLDR), while a high dose rate (HDR) induces an initial cell-radioresistance (ICRR). HRS does not seem to be due either to DSB or to apoptosis. Both phenomena (HRS and ICRR) appear to be related to ATP availability for triggering cell repair. Fibroblast survival after neutron irradiation is also dose rate-dependent but without HRS. Melanoma cells or fibroblasts exert their own survival behaviour at very low doses of neutrons, suggesting that in some cases there is a differential between cancer and normal cells radiation responses. Only the survival of fibroblasts at HDR fits the linear no-threshold model. This new insight into human cell responses to very low doses of neutrons, concerns natural radiations, surroundings of accelerators, proton-therapy devices, flights at high altitude. Furthermore, ATP inhibitors could increase HRS during high-linear energy transfer (high-LET) irradiation.
Development and Characterization of a High Sensitivity Segmented Fast Neutron Spectrometer (FaNS-2)
Langford, T.J.; Beise, E.J.; Breuer, H.; Heimbach, C.R.; Ji, G.; Nico, J.S.
2016-01-01
We present the development of a segmented fast neutron spectrometer (FaNS-2) based upon plastic scintillator and 3He proportional counters. It was designed to measure both the flux and spectrum of fast neutrons in the energy range of few MeV to 1 GeV. FaNS-2 utilizes capture-gated spectroscopy to identify neutron events and reject backgrounds. Neutrons deposit energy in the plastic scintillator before capturing on a 3He nucleus in the proportional counters. Segmentation improves neutron energy reconstruction while the large volume of scintillator increases sensitivity to low neutron fluxes. A main goal of its design is to study comparatively low neutron fluxes, such as cosmogenic neutrons at the Earth's surface, in an underground environment, or from low-activity neutron sources. In this paper, we present details of its design and construction as well as its characterization with a calibrated 252Cf source and monoenergetic neutron fields of 2.5 MeV and 14 MeV. Detected monoenergetic neutron spectra are unfolded using a Singular Value Decomposition method, demonstrating a 5% energy resolution at 14 MeV. Finally, we discuss plans for measuring the surface and underground cosmogenic neutron spectra with FaNS-2. PMID:27226807
Fast neutron irradiation for locally advanced pancreatic cancer
DOE Office of Scientific and Technical Information (OSTI.GOV)
Smith, F.P.; Schein, P.S.; MacDonald, J.S.
1981-11-01
Nineteen patients with locally advanced pancreatic cancer and one patient with islet cell cancer were treated with 1700-1500 neutron rad alone or in combination with 5-fluorouracil to exploit the theoretic advantages of higher linear energy of transfer, and lower oxygen enhancement ratio of neutrons. Only 5 of 14 (36%) obtained partial tumor regression. The median survival for all patients with pancreatic cancer was 6 months, which is less than that reported with 5-fluorouracil and conventional photon irradiation. Gastrointestinal toxicity was considerable; hemorhagic gastritis in five patients, colitis in two and esophagitis in one. One patient developed radiation myelitis. We therefore,more » caution any enthusiasm for this modality of therapy until clear evidence of a therapeutic advantage over photon therapy is demonstrated in controlled clinical trials.« less
COMBINED ANALYSIS OF THORIUM AND FAST NEUTRON DATA AT THE LUNAR SURFACE
DOE Office of Scientific and Technical Information (OSTI.GOV)
O. GASNAULT; W. FELDMAN; ET AL
2001-01-01
The global distribution of the radioactive elements (U, K, Th) at the lunar surface is an important parameter for an understanding of lunar evolution, because they have provided continuous heat over the lifetime of the Moon. Today, only the thorium distribution is available for the whole lunar surface [1]. Another key parameter that characterize the surface of the Moon is the presence of mare basalts. These basalts are concentrated on the nearside and are represented by materials with high-Fe content, sometimes associated with high-Ti. We demonstrated elsewhere that the fast neutron measurement made by Lunar Prospector is representative of themore » average soil atomic mass [2]. is primarily dominated by Fe and Ti in basaltic terranes, and therefore the map of the fast neutrons provides a good delineation of mare basalts. We focus here on the correlated variations of thorium abundances and fast neutron fluxes averaged over areas of 360 km in diameter, in an attempt to provide a better understanding of the thorium emplacement on the surface of the Moon.« less
Preliminary study of MAGAT polymer gel dosimetry for boron-neutron capture therapy
NASA Astrophysics Data System (ADS)
Hayashi, Shin-ichiro; Sakurai, Yoshinori; Uchida, Ryohei; Suzuki, Minoru; Usui, Shuji; Tominaga, Takahiro
2015-01-01
MAGAT gel dosimeter with boron is irradiated in Heavy Water Neutron Irradiation Facility (HWNIF) of Kyoto University Research Reactor (KUR). The cylindrical gel phantoms are exposed to neutron beams of three different energy spectra (thermal neutron rich, epithermal and fast neutron rich and the mixed modes) in air. Preliminary results corresponding to depth-dose responses are obtained as the transverse relaxation rate (R2=1/T2) from magnetic resonance imaging data. As the results MAGAT gel dosimeter has the higher sensitivity on thermal neutron than on epi-thermal and fast neutron, and the gel with boron showed an enhancement and a change in the depth-R2 response explicitly. From these results, it is suggested that MAGAT gel dosimeter can be an effective tool in BNCT dosimetry.
Fast-neutron solid-state dosimeter
Kecker, K.H.; Haywood, F.F.; Perdue, P.T.; Thorngate, J.H.
1975-07-22
This patent relates to an improved fast-neutron solid-state dosimeter that does not require separation of materials before it can be read out, that utilizes materials that do not melt or otherwise degrade at about 300$sup 0$C readout temperature, that provides a more efficient dosimeter, and that can be reused. The dosimeters are fabricated by intimately mixing a TL material, such as CaSO$sub 4$:Dy, with a powdered polyphenyl, such as p-sexiphenyl, and hot- pressing the mixture to form pellets, followed by out-gassing in a vacuum furnace at 150$sup 0$C prior to first use dosimeters. (auth)
MONDO: A neutron tracker for particle therapy secondary emission fluxes measurements
NASA Astrophysics Data System (ADS)
Marafini, M.; Patera, V.; Pinci, D.; Sarti, A.; Sciubba, A.; Spiriti, E.
2016-07-01
Cancer treatment is performed, in Particle Therapy, using accelerated charged particles whose high irradiation precision and conformity allows the tumor destruction while sparing the surrounding healthy tissues. Dose release monitoring devices using photons and charged particles produced by the beam interaction with the patient body have already been proposed, but no attempt based on the detection of the abundant secondary radiation neutron component has been made yet. The reduced attenuation length of neutrons yields a secondary particle sample that is larger in number when compared to photons and charged particles. Furthermore, neutrons allow for a backtracking of the emission point that is not affected by multiple scattering. Since neutrons can release a significant dose far away from the tumor region, a precise measurement of their flux, production energy and angle distributions is eagerly needed in order to improve the Treatment Planning Systems (TPS) software, so to predict not only the normal tissue toxicity in the target region but also the risk of late complications in the whole body. All the aforementioned issues underline the importance for an experimental effort devoted to the precise characterization of the neutron production gaining experimental access both to the emission point and production energy. The technical challenges posed by a neutron detector aiming for a high detection efficiency and good backtracking precision will be addressed within the MONDO (MOnitor for Neutron Dose in hadrOntherapy) project. The MONDO's main goal is to develop a tracking detector targeting fast and ultrafast secondary neutrons. The tracker is composed by a scintillating fiber matrix (4 × 4 × 8cm3). The full reconstruction of protons, produced in elastic interactions, will be used to measure energy and direction of the impinging neutron. The neutron tracker will measure the neutron production yields, as a function of production angle and energy, using different
Fast-ion distributions from third harmonic ICRF heating studied with neutron emission spectroscopy
NASA Astrophysics Data System (ADS)
Hellesen, C.; Gatu Johnson, M.; Andersson Sundén, E.; Conroy, S.; Ericsson, G.; Eriksson, J.; Sjöstrand, H.; Weiszflog, M.; Johnson, T.; Gorini, G.; Nocente, M.; Tardocchi, M.; Kiptily, V. G.; Pinches, S. D.; Sharapov, S. E.; EFDA Contributors, JET
2013-11-01
The fast-ion distribution from third harmonic ion cyclotron resonance frequency (ICRF) heating on the Joint European Torus is studied using neutron emission spectroscopy with the time-of-flight spectrometer TOFOR. The energy dependence of the fast deuteron distribution function is inferred from the measured spectrum of neutrons born in DD fusion reactions, and the inferred distribution is compared with theoretical models for ICRF heating. Good agreements between modelling and measurements are seen with clear features in the fast-ion distribution function, that are due to the finite Larmor radius of the resonating ions, replicated. Strong synergetic effects between ICRF and neutral beam injection heating were also seen. The total energy content of the fast-ion population derived from TOFOR data was in good agreement with magnetic measurements for values below 350 kJ.
Test of a prototype neutron spectrometer based on diamond detectors in a fast reactor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Osipenko, M.; Ripani, M.; Ricco, G.
2015-07-01
A prototype of neutron spectrometer based on diamond detectors has been developed. This prototype consists of a {sup 6}Li neutron converter sandwiched between two CVD diamond crystals. The radiation hardness of the diamond crystals makes it suitable for applications in low power research reactors, while a low sensitivity to gamma rays and low leakage current of the detector permit to reach good energy resolution. A fast coincidence between two crystals is used to reject background. The detector was read out using two different electronic chains connected to it by a few meters of cable. The first chain was based onmore » conventional charge-sensitive amplifiers, the other used a custom fast charge amplifier developed for this purpose. The prototype has been tested at various neutron sources and showed its practicability. In particular, the detector was calibrated in a TRIGA thermal reactor (LENA laboratory, University of Pavia) with neutron fluxes of 10{sup 8} n/cm{sup 2}s and at the 3 MeV D-D monochromatic neutron source named FNG (ENEA, Rome) with neutron fluxes of 10{sup 6} n/cm{sup 2}s. The neutron spectrum measurement was performed at the TAPIRO fast research reactor (ENEA, Casaccia) with fluxes of 10{sup 9} n/cm{sup 2}s. The obtained spectra were compared to Monte Carlo simulations, modeling detector response with MCNP and Geant4. (authors)« less
Simulation of Fast Neutronics in an Accelerator-Driven Sub-Critical Core
NASA Astrophysics Data System (ADS)
Gwyn Rosaire, C.; Sattarov, Akhdiyor; McIntyre, Peter; Tsvetkov, Pavel
2011-10-01
Accelerator-driven subcritical fission in a molten salt core (ADSMS) is being developed as a technology for green nuclear power. ADSMS burns its fertile fuel to completion, it cannot melt down, and it destroys long-lived minor actinides. The ADSMS core consists of a vessel filled with a molten salt eutectic of UCl3 and NaCl. The fast neutronics of ADSMS makes possible two unique benefits: isobreeding, a steady-state equilibrium in which ^238U is bred to ^239Pu and the ^239Pu fissions, and destruction of minor actinides, in which fission of the intermediary nuclides dominates of breeding. Results of simulations of the fast neutronics in the ADSMS core will be presented.
Analysis of the propagation of neutrons and gamma-rays from the fast neutron source reactor YAYOI
NASA Astrophysics Data System (ADS)
Yoshida, Shigeo; Murata, Isao; Nakagawa, Tsutomu; Saito, Isao
2011-10-01
The skyshine effect is crucial for designing appropriate shielding. To investigate the skyshine effect, the propagation of neutrons was measured and analyzed at the fast neutron source reactor YAYOI. Pulse height spectra and dose distributions of neutron and secondary gamma-ray were measured outside YAYOI, and analyzed with MCNP-5 and JENDL-3.3. Comparison with the experimental results showed good agreement. Also, a semi-empirical formula was successfully derived to describe the dose distribution. The formulae can be used to predict the skyshine effect at YAYOI, and will be useful for estimating the skyshine effect and designing the shield structure for fusion facilities.
Neutron capture therapy: Years of experimentation---Years of reflection
DOE Office of Scientific and Technical Information (OSTI.GOV)
Farr, L.E.
1991-12-16
This report describes early research on neutron capture therapy over a number of years, beginning in 1950, speaking briefly of patient treatments but dwelling mostly on interpretations of our animal experiments. This work carried out over eighteen years, beginning over forty years ago. Yet, it is only fitting to start by relating how neutron capture therapy became part of Brookhaven`s Medical Research Center program.
Neutron capture therapy: Years of experimentation---Years of reflection
DOE Office of Scientific and Technical Information (OSTI.GOV)
Farr, L.E.
1991-12-16
This report describes early research on neutron capture therapy over a number of years, beginning in 1950, speaking briefly of patient treatments but dwelling mostly on interpretations of our animal experiments. This work carried out over eighteen years, beginning over forty years ago. Yet, it is only fitting to start by relating how neutron capture therapy became part of Brookhaven's Medical Research Center program.
α and 2 p 2 n emission in fast neutron-induced reactions on 60Ni
NASA Astrophysics Data System (ADS)
Fotiades, N.; Devlin, M.; Haight, R. C.; Nelson, R. O.; Kunieda, S.; Kawano, T.
2015-06-01
Background: The cross sections for populating the residual nucleus in the reaction ZAX(n,x) Z -2 A -4Y exhibit peaks as a function of incident neutron energy corresponding to the (n ,n'α ) reaction and, at higher energy, to the (n ,2 p 3 n ) reaction. The relative magnitudes of these peaks vary with the Z of the target nucleus. Purpose: Study fast neutron-induced reactions on 60Ni. Locate experimentally the nuclear charge region along the line of stability where the cross sections for α emission and for 2 p 2 n emission in fast neutron-induced reactions are comparable as a further test of reaction models. Methods: Data were taken by using the Germanium Array for Neutron-Induced Excitations. The broad-spectrum pulsed neutron beam of the Los Alamos Neutron Science Center's Weapons Neutron Research facility provided neutrons in the energy range from 1 to 250 MeV. The time-of-flight technique was used to determine the incident-neutron energies. Results: Absolute partial cross sections for production of seven discrete Fe γ rays populated in 60Ni (n ,α /2 p x n γ ) reactions with 2 ≤x ≤5 were measured for neutron energies 1 MeV
Theoretical and experimental physical methods of neutron-capture therapy
NASA Astrophysics Data System (ADS)
Borisov, G. I.
2011-09-01
This review is based to a substantial degree on our priority developments and research at the IR-8 reactor of the Russian Research Centre Kurchatov Institute. New theoretical and experimental methods of neutron-capture therapy are developed and applied in practice; these are: A general analytical and semi-empiric theory of neutron-capture therapy (NCT) based on classical neutron physics and its main sections (elementary theories of moderation, diffuse, reflection, and absorption of neutrons) rather than on methods of mathematical simulation. The theory is, first of all, intended for practical application by physicists, engineers, biologists, and physicians. This theory can be mastered by anyone with a higher education of almost any kind and minimal experience in operating a personal computer.
Study of the effect of sawteeth on fast ions and neutron emission in MAST using a neutron camera
NASA Astrophysics Data System (ADS)
Cecconello, M.; Sperduti, A.; the MAST team
2018-05-01
The effect of the sawtooth instability on the confinement of fast ions on MAST, and the impact it has on the neutron emission, has been studied in detail using the TRANSP/NUBEAM codes coupled to a full orbit following code. The sawtooth models in TRANSP/NUBEAM indicate that, on MAST, passing and trapped fast ions are redistributed in approximately equal number and on a level that is consistent with the observations. It has not been possible to discriminate between the different sawtooth models since their predictions are all compatible with the neutron camera observations. Full orbit calculations of the fast ion motion have been used to estimate the characteristic time scales and energy thresholds that according to theoretical predictions govern the fast ions redistribution: no energy threshold for the redistribution for either passing and trapped fast ions was found. The characteristic times have, however, frequencies that are comparable with the frequencies of a m = 1, n = 1 perturbation and its harmonics with toroidal mode numbers n=2, \\ldots , 4, suggesting that on spherical tokamaks, in addition to the classical sawtooth-induced transport mechanisms of fast ions by attachment to the evolving perturbation and the associated E × B drift, a resonance mechanism between the m = 1 perturbation and the fast ions orbits might be at play.
RBE OF MONOENERGETIC FAST NEUTRONS: CYTOGENETIC EFFECTS IN MAIZE
DOE Office of Scientific and Technical Information (OSTI.GOV)
Smith, H.H.; Bateman, J.L.; Quastler, H.
1963-01-01
>The relative biological effectiveness (RBE) of neutrons of 5 energies and x radiation at 3 exposure levels were compared in maize seeds. The maize material used in these experiments had the advantsge for RBE studies of yielding a basically first order dose-response curve (Y = alpha plus or minus BETA D) with low (x rays) as well as with high (fast neutron) LET radiations. The frequency of yellow-green (yg/sub 2/ sectors in leaves, 3, 4, and 5 of young plants grown from irradiated Yg/sub 2//Yg/syb 2/ seeds served as a quantitative measure of response. The mutant sectors are believed tomore » be due mostly to simple chromosome breakage and deletion. An exposure apparatus was used which produced essentially equal dose rates in five rings of seeds placed so as to intercept neutrons of 0.43, 0.65, 1.00, 1.50, and 1.80 Mev. Dose average LET values for these energies are 72, ments were performed at dosages that gave responses which were linear, below saturation levels, and overlapping in range for x rays andd neutrons. These ranges in dosages were 32.8 to 126.4 rads of neutrons and 1500 to 15,600 rads of 250 kvp x rays. RBE values, calculated from relative slopes of linear regression lines for N and X, randged from 42 to 135. Monoenergetic fast neutrons of 0.43 Mev were the most efficient in producing yg/sub 2/sectors as shown by the yield of sectors per krad andd highest RBE values. The RBE values obtained in these experiments are higher than commonly reported. With regard to minimum permissible levels of radiation, these results suggest the alternatives that either chromosome breaks in plants have a much higher RBE than comparable reactions in mand and need not be considered; or that the problem of chromosome damage per se in human tissues be reexamined after exposure to high LET radiations andd/or low LET radiations at low doses or dose rates. (auth)« less
Fast neutron tomography with real-time pulse-shape discrimination in organic scintillation detectors
NASA Astrophysics Data System (ADS)
Joyce, Malcolm J.; Agar, Stewart; Aspinall, Michael D.; Beaumont, Jonathan S.; Colley, Edmund; Colling, Miriam; Dykes, Joseph; Kardasopoulos, Phoevos; Mitton, Katie
2016-10-01
A fast neutron tomography system based on the use of real-time pulse-shape discrimination in 7 organic liquid scintillation detectors is described. The system has been tested with a californium-252 source of dose rate 163 μSv/h at 1 m and neutron emission rate of 1.5×107 per second into 4π and a maximum acquisition time of 2 h, to characterize two 100×100×100 mm3 concrete samples. The first of these was a solid sample and the second has a vertical, cylindrical void. The experimental data, supported by simulations with both Monte Carlo methods and MATLAB®, indicate that the presence of the internal cylindrical void, corners and inhomogeneities in the samples can be discerned. The potential for fast neutron assay of this type with the capability to probe hydrogenous features in large low-Z samples is discussed. Neutron tomography of bulk porous samples is achieved that combines effective penetration not possible with thermal neutrons in the absence of beam hardening.
Adjuvant neutron therapy in complex treatment of patients with locally advanced breast cancer
NASA Astrophysics Data System (ADS)
Lisin, V. A.; Velikaya, V. V.; Startseva, Zh. A.; Popova, N. O.; Goldberg, V. E.
2017-09-01
The study included 128 patients with stage T2-4N0-3M0 locally advanced breast cancer. All patients were divided into two groups. Group I (study group) consisted of 68 patients, who received neutron therapy, and group II (control group) comprised 60 patients, who received electron beam therapy. Neutron therapy was well tolerated by the patients and 1-2 grade radiation skin reactions were the most common. Neutron therapy was shown to be effective in multimodality treatment of the patients with locally advanced breast cancer. The 8-year recurrence-free survival rate in the patients with locally advanced breast cancer was 94.5 ± 4.1% after neutron therapy and 81.4 ± 5.9% after electron beam therapy (p = 0.05).
Age Modifies the Effect of 2-MeV Fast Neutrons on Rat Mammary Carcinogenesis.
Imaoka, Tatsuhiko; Nishimura, Mayumi; Daino, Kazuhiro; Hosoki, Ayaka; Takabatake, Masaru; Kokubo, Toshiaki; Doi, Kazutaka; Showler, Kaye; Nishimura, Yukiko; Moriyama, Hitomi; Morioka, Takamitsu; Shimada, Yoshiya; Kakinuma, Shizuko
2017-10-01
The relative biological effectiveness (RBE) of neutrons depends on their physical nature (e.g., energy) and the biological context (e.g., end points, materials). From the perspective of radiological protection, age is an important biological context that influences radiation-related cancer risk, but very few studies have addressed its potential impact on neutron effects. We therefore investigated the influence of age on the effect of accelerator-generated fast neutrons (mean energy, ∼2 MeV) in an animal model of breast carcinogenesis. Female Sprague-Dawley rats at 1, 3 and 7 weeks of age were irradiated with fast neutrons at absorbed doses of 0.0485-0.97 Gy. All animals were kept under specific pathogen-free conditions and screened weekly for mammary tumors by palpation until they were 90 weeks old. Tumors were diagnosed based on histology. Mathematical modeling was used to analyze mammary cancer incidence, collectively using data from this study and a previously reported experiment on 137 Cs gamma rays. The results indicate that neutron irradiation elevated the risk of palpable mammary carcinoma with a linear dose response, the slope of which depended on age at time of irradiation. The RBE of neutron radiation was 7.5 ± 3.4, 9.3 ± 3.5 and 26.1 ± 8.9 (mean ± SE) for animals exposed at 1, 3 and 7 weeks of age, respectively. Our results indicate that age of the animal is an important factor influencing the effect of fast neutrons on breast cancer risk.
Neutron Detection With Ultra-Fast Digitizer and Pulse Identification Techniques on DIII-D
NASA Astrophysics Data System (ADS)
Zhu, Y. B.; Heidbrink, W. W.; Piglowski, D. A.
2013-10-01
A prototype system for neutron detection with an ultra-fast digitizer and pulse identification techniques has been implemented on the DIII-D tokamak. The system consists of a cylindrical neutron fission chamber, a charge sensitive amplifier, and a GaGe Octopus 12-bit CompuScope digitizer card installed in a Linux computer. Digital pulse identification techniques have been successfully performed at maximum data acquisition rate of 50 MSPS with on-board memory of 2 GS. Compared to the traditional approach with fast nuclear electronics for pulse counting, this straightforward digital solution has many advantages, including reduced expense, improved accuracy, higher counting rate, and easier maintenance. The system also provides the capability of neutron-gamma pulse shape discrimination and pulse height analysis. Plans for the upgrade of the old DIII-D neutron counting system with these techniques will be presented. Work supported by the US Department of Energy under SC-G903402, and DE-FC02-04ER54698.
A comprehensive spectrometry study of a stray neutron radiation field in scanning proton therapy.
Mares, Vladimir; Romero-Expósito, Maite; Farah, Jad; Trinkl, Sebastian; Domingo, Carles; Dommert, Martin; Stolarczyk, Liliana; Van Ryckeghem, Laurent; Wielunski, Marek; Olko, Pawel; Harrison, Roger M
2016-06-07
The purpose of this study is to characterize the stray neutron radiation field in scanning proton therapy considering a pediatric anthropomorphic phantom and a clinically-relevant beam condition. Using two extended-range Bonner sphere spectrometry systems (ERBSS), Working Group 9 of the European Radiation Dosimetry Group measured neutron spectra at ten different positions around a pediatric anthropomorphic phantom irradiated for a brain tumor with a scanning proton beam. This study compares the different systems and unfolding codes as well as neutron spectra measured in similar conditions around a water tank phantom. The ten spectra measured with two ERBSS systems show a generally similar thermal component regardless of the position around the phantom while high energy neutrons (above 20 MeV) were only registered at positions near the beam axis (at 0°, 329° and 355°). Neutron spectra, fluence and ambient dose equivalent, H (*)(10), values of both systems were in good agreement (<15%) while the unfolding code proved to have a limited effect. The highest H (*)(10) value of 2.7 μSv Gy(-1) was measured at 329° to the beam axis and 1.63 m from the isocenter where high-energy neutrons (E ⩾ 20 MeV) contribute with about 53%. The neutron mapping within the gantry room showed that H (*)(10) values significantly decreased with distance and angular position with respect to the beam axis dropping to 0.52 μSv Gy(-1) at 90° and 3.35 m. Spectra at angles of 45° and 135° with respect to the beam axis measured here with an anthropomorphic phantom showed a similar peak structure at the thermal, fast and high energy range as in the previous water-tank experiments. Meanwhile, at 90°, small differences at the high-energy range were observed. Using ERBSS systems, neutron spectra mapping was performed to characterize the exposure of scanning proton therapy patients. The ten measured spectra provide precise information about the exposure of healthy organs to
NASA Technical Reports Server (NTRS)
Herley, P. J.; Wang, C. S.; Varsi, G.; Levy, P. W.
1974-01-01
The thermal decomposition kinetics have been determined for ammonium perchlorate crystals subjected to a fast neutron irradiation or to a fast neutron irradiation followed by a gamma-ray irradiation. Qualitatively, the radiation induced changes are similar to those obtained in this and in previous studies, with samples exposed only to gamma rays. The induction period is shortened and the rate constants, obtained from an Avrami-Erofeyev kinetic analysis, are modified. The acceleratory period constant increases and the decay period constant decreases. When compared on an equal deposited energy basis, the fast neutron induced changes are appreciably larger than the gamma-ray induced changes. Some, or all, of the fast neutron induced effects might be attributable to the introduction of localized regions of concentrated radiation damage ('spikes') by lattice atom recoils which become thermal decomposition sites when the crystals are heated.
Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method
Yoon, W.Y.; Jones, J.L.; Nigg, D.W.; Harker, Y.D.
1999-05-11
A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0{times}10{sup 9} neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use. 3 figs.
Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method
Yoon, Woo Y.; Jones, James L.; Nigg, David W.; Harker, Yale D.
1999-01-01
A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0.times.10.sup.9 neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use.
NASA Astrophysics Data System (ADS)
Guo, J.; Bücherl, T.; Zou, Y.; Guo, Z.
2011-09-01
Investigations on the fast neutron beam geometry for the NECTAR facility are presented. The results of MCNP simulations and experimental measurements of the beam distributions at NECTAR are compared. Boltzmann functions are used to describe the beam profile in the detection plane assuming the area source to be set up of large number of single neutron point sources. An iterative algebraic reconstruction algorithm is developed, realized and verified by both simulated and measured projection data. The feasibility for improved reconstruction in fast neutron computerized tomography at the NECTAR facility is demonstrated.
SU-E-T-484: In Vivo Dosimetry Tolerances in External Beam Fast Neutron Therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Young, L; Gopan, O
Purpose: Optical stimulated luminescence (OSL) dosimetry with Landauer Al2O3:C nanodots was developed at our institution as a passive in vivo dosimetry (IVD) system for patients treated with fast neutron therapy. The purpose of this study was to establish clinically relevant tolerance limits for detecting treatment errors requiring further investigation. Methods: Tolerance levels were estimated by conducting a series of IVD expected dose calculations for square field sizes ranging between 2.8 and 28.8 cm. For each field size evaluated, doses were calculated for open and internal wedged fields with angles of 30°, 45°, or 60°. Theoretical errors were computed for variationsmore » of incorrect beam configurations. Dose errors, defined as the percent difference from the expected dose calculation, were measured with groups of three nanodots placed in a 30 x 30 cm solid water phantom, at beam isocenter (150 cm SAD, 1.7 cm Dmax). The tolerances were applied to IVD patient measurements. Results: The overall accuracy of the nanodot measurements is 2–3% for open fields. Measurement errors agreed with calculated errors to within 3%. Theoretical estimates of dosimetric errors showed that IVD measurements with OSL nanodots will detect the absence of an internal wedge or a wrong wedge angle. Incorrect nanodot placement on a wedged field is more likely to be caught if the offset is in the direction of the “toe” of the wedge where the dose difference in percentage is about 12%. Errors caused by an incorrect flattening filter size produced a 2% measurement error that is not detectable by IVD measurement alone. Conclusion: IVD with nanodots will detect treatment errors associated with the incorrect implementation of the internal wedge. The results of this study will streamline the physicists’ investigations in determining the root cause of an IVD reading that is out of normally accepted tolerances.« less
A high gain energy amplifier operated with fast neutrons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Rubbia, C.
1995-10-01
The basic concept and the main practical considerations of an Energy Amplifier (EA) have been exhaustively described elsewhere. Here the concept of the EA is further explored and additional schemes are described which offer a higher gain, a larger maximum power density and an extended burn-up. All these benefits stem from the use of fast neutrons, instead of thermal or epithermal ones, which was the case in the original study. The higher gain is due both to a more efficient high energy target configuration and to a larger, practical value of the multiplication factor. The higher power density results frommore » the higher permissible neutron flux, which in turn is related to the reduced rate of {sup 233}Pa neutron captures (which, as is well known, suppress the formation of the fissile {sup 233}U fuel) and the much smaller k variations after switch-off due to {sup 233}Pa decays for a given burn-up rate. Finally a longer integrated burn-up is made possible by reduced capture rate by fission fragments of fast neutrons. In practice a 20 MW proton beam (20 mA @ 1 GeV) accelerated by a cyclotron will suffice to operate a compact EA at the level of {approx} 1 GW{sub e}. The integrated fuel burn-up can be extended in excess of 100 GW d/ton, limited by the mechanical survival of the fuel elements. Radio-Toxicity accumulated at the end of the cycle is found to be largely inferior to the one of an ordinary Reactor for the same energy produced. Schemes are proposed which make a {open_quotes}melt-down{close_quotes} virtually impossible. The conversion ratio, namely the rate of production of {sup 233}U relative to consumption is generally larger than unity, which permits production of fuel for other uses. Alternatively the neutron excess can be used to transform unwanted {open_quotes}ashes{close_quotes} into more acceptable elements.« less
McCune, D.A.
1964-03-17
A method and device for measurement of integrated fast neutron flux in the presence of a large thermal neutron field are described. The device comprises a thorium wire surrounded by a thermal neutron attenuator that is, in turn, enclosed by heat-resistant material. The method consists of irradiating the device in a neutron field whereby neutrons with energies in excess of 1.1 Mev cause fast fissions in the thorium, then removing the thorium wire, separating the cesium-137 fission product by chemical means from the thorium, and finally counting the radioactivity of the cesium to determine the number of fissions which have occurred so that the integrated fast flux may be obtained. (AEC)
Monte Carlo based dosimetry for neutron capture therapy of brain tumors
NASA Astrophysics Data System (ADS)
Zaidi, Lilia; Belgaid, Mohamed; Khelifi, Rachid
2016-11-01
Boron Neutron Capture Therapy (BNCT) is a biologically targeted, radiation therapy for cancer which combines neutron irradiation with a tumor targeting agent labeled with a boron10 having a high thermal neutron capture cross section. The tumor area is subjected to the neutron irradiation. After a thermal neutron capture, the excited 11B nucleus fissions into an alpha particle and lithium recoil nucleus. The high Linear Energy Transfer (LET) emitted particles deposit their energy in a range of about 10μm, which is of the same order of cell diameter [1], at the same time other reactions due to neutron activation with body component are produced. In-phantom measurement of physical dose distribution is very important for BNCT planning validation. Determination of total absorbed dose requires complex calculations which were carried out using the Monte Carlo MCNP code [2].
Yu, Haiyan; Tang, Xiaobin; Shu, Diyun; Liu, Yuanhao; Geng, Changran; Gong, Chunhui; Hang, Shuang; Chen, Da
2017-03-01
Boron Neutron Capture Therapy (BNCT) is a radiotherapy that combines biological targeting and high Linear Energy Transfer (LET). It is considered a potential therapeutic approach for non-small cell lung cancer (NSCLC). It could avoid the inaccurate treatment caused by the lung motion during radiotherapy, because the dose deposition mainly depends on the boron localization and neutron source. Thus, B concentration and neutron sources are both principal factors of BNCT, and they play significant roles in the curative effect of BNCT for different cases. The purpose was to explore the feasibility of BNCT treatment for NSCLC with either of two neutron sources (the epithermal reactor at the Massachusetts Institute of Technology named "MIT source" and the accelerator neutron source designed in Argentina named "MEC source") and various boron concentrations. Shallow and deeper lung tumors were defined in the Chinese hybrid radiation phantom, and the Monte Carlo method was used to calculate the dose to tumors and healthy organs. The MEC source was more appropriate to treat the shallow tumor (depth of 6 cm) with a shorter treatment time. However, the MIT source was more suitable for deep lung tumor (depth of 9 cm) treatment, as the MEC source is more likely to exceed the skin dose limit. Thus, a neutron source consisting of more fast neutrons is not necessarily suitable for deep treatment of lung tumors. Theoretical distribution of B in tumors and organs at risk (especially skin) was obtained to meet the treatable requirement of BNCT, which may provide the references to identify the feasibility of BNCT for the treatment of lung cancer using these two neutron sources in future clinical applications.
USDA-ARS?s Scientific Manuscript database
A small fast neutron mutant population has been established from Phaseolus vulgaris cv. Red Hawk. We leveraged the available P. vulgaris genome sequence and high throughput next generation DNA sequencing to examine the genomic structure of five Phaseolus vulgaris cv. Red Hawk fast neutron mutants wi...
Fast neutron counting in a mobile, trailer-based search platform
NASA Astrophysics Data System (ADS)
Hayward, Jason P.; Sparger, John; Fabris, Lorenzo; Newby, Robert J.
2017-12-01
Trailer-based search platforms for detection of radiological and nuclear threats are often based upon coded aperture gamma-ray imaging, because this method can be rendered insensitive to local variations in gamma background while still localizing the source well. Since gamma source emissions are rather easily shielded, in this work we consider the addition of fast neutron counting to a mobile platform for detection of sources containing Pu. A proof-of-concept system capable of combined gamma and neutron coded-aperture imaging was built inside of a trailer and used to detect a 252Cf source while driving along a roadway. Neutron detector types employed included EJ-309 in a detector plane and EJ-299-33 in a front mask plane. While the 252Cf gamma emissions were not readily detectable while driving by at 16.9 m standoff, the neutron emissions can be detected while moving. Mobile detection performance for this system and a scaled-up system design are presented, along with implications for threat sensing.
Fast neutrons measured in copper from the Hiroshima atomic bomb dome.
Marchetti, A A; McAninch, J E; Rugel, G; Rühm, W; Korschinek, G; Martinelli, R E; Faestermann, T; Knie, K; Egbert, S D; Wallner, A; Wallner, C; Tanaka, K; Endo, S; Hoshi, M; Shizuma, K; Fujita, S; Hasai, H; Imanaka, T; Straume, T
2009-01-01
The first measurements of (63)Ni produced by A-bomb fast neutrons (above approximately 1 MeV) in copper samples from Hiroshima encompassed distances from approximately 380 to 5062 m from the hypocenter (the point on the ground directly under the bomb). They included the region of interest to survivor studies (approximately 900 to 1500 m) and provided the first direct validation of fast neutrons in that range. However, a significant measurement gap remained between the hypocenter and 380 m. Measurements close to the hypocenter are important as a high-value anchor for the slope of the curve for neutron activation as a function of distance. Here we report measurements of (63)Ni in copper samples from the historic Hiroshima Atomic Bomb Dome, which is located approximately 150 m from the hypocenter. These measurements extend the range of our previously published data for (63)Ni providing a more comprehensive and consistent A-bomb activation curve. The results are also in good agreement with calculations based on the current dosimetry system (DS02) and give further experimental support to the accuracy of this system that forms the basis for radiation risk estimates worldwide.
Capabilities, Calibration, and Impact of the ISS-RAD Fast Neutron Detector
NASA Technical Reports Server (NTRS)
Leitgab, Martin
2015-01-01
In the current NASA crew radiation health risk assessment framework, estimates for the neutron contributions to crew radiation exposure largely rely on simulated data with sizeable uncertainties due to the lack of experimental measurements inside the ISS. Integrated in the ISS-RAD instrument, the ISS-RAD Fast Neutron Detector (FND) will deploy to the ISS on one of the next cargo supply missions. Together with the ISS-RAD Charged Particle Detector, the FND will perform, for the first time, routine and precise direct neutron measurements inside the ISS between 0.5 and 80 MeV. The measurements will close the NASA Medical Operations Requirement to monitor neutrons inside the ISS and impact crew radiation health risk assessments by reducing uncertainties on the neutron contribution to crew exposure, enabling more efficient mission planning. The presentation will focus on the FND detection mechanism, calibration results and expectations about the FND's interaction with the mixed radiation field inside the ISS.
Microstructural evolution in fast-neutron-irradiated austenitic stainless steels
DOE Office of Scientific and Technical Information (OSTI.GOV)
Stoller, R.E.
1987-12-01
The present work has focused on the specific problem of fast-neutron-induced radiation damage to austenitic stainless steels. These steels are used as structural materials in current fast fission reactors and are proposed for use in future fusion reactors. Two primary components of the radiation damage are atomic displacements (in units of displacements per atom, or dpa) and the generation of helium by nuclear transmutation reactions. The radiation environment can be characterized by the ratio of helium to displacement production, the so-called He/dpa ratio. Radiation damage is evidenced microscopically by a complex microstructural evolution and macroscopically by density changes and alteredmore » mechanical properties. The purpose of this work was to provide additional understanding about mechanisms that determine microstructural evolution in current fast reactor environments and to identify the sensitivity of this evolution to changes in the He/dpa ratio. This latter sensitivity is of interest because the He/dpa ratio in a fusion reactor first wall will be about 30 times that in fast reactor fuel cladding. The approach followed in the present work was to use a combination of theoretical and experimental analysis. The experimental component of the work primarily involved the examination by transmission electron microscopy of specimens of a model austenitic alloy that had been irradiated in the Oak Ridge Research Reactor. A major aspect of the theoretical work was the development of a comprehensive model of microstructural evolution. This included explicit models for the evolution of the major extended defects observed in neutron irradiated steels: cavities, Frank faulted loops and the dislocation network. 340 refs., 95 figs., 18 tabs.« less
NASA Astrophysics Data System (ADS)
Osawa, Yuta; Imoto, Shoichi; Kusaka, Sachie; Sato, Fuminobu; Tanoshita, Masahiro; Murata, Isao
2017-09-01
Boron Neutron Capture Therapy (BNCT) is known to be a new promising cancer therapy suppressing influence against normal cells. In Japan, Accelerator Based Neutron Sources (ABNS) are being developed for BNCT. For the spread of ABNS based BNCT, we should characterize the neutron field beforehand. For this purpose, we have been developing a low-energy neutron spectrometer based on 3He position sensitive proportional counter. In this study, a new intense epi-thermal neutron field was developed with a DT neutron source for verification of validity of the spectrometer. After the development, the neutron field characteristics were experimentally evaluated by using activation foils. As a result, we confirmed that an epi-thermal neutron field was successfully developed suppressing fast neutrons substantially. Thereafter, the neutron spectrometer was verified experimentally. In the verification, although a measured detection depth distribution agreed well with the calculated distribution by MCNP, the unfolded spectrum was significantly different from the calculated neutron spectrum due to contribution of the side neutron incidence. Therefore, we designed a new neutron collimator consisting of a polyethylene pre-collimator and boron carbide neutron absorber and confirmed numerically that it could suppress the side incident neutrons and shape the neutron flux to be like a pencil beam.
Ishikawa, Masayori; Tanaka, Kenichi; Endo, Satrou; Hoshi, Masaharu
2015-01-01
Abstract Phantom experiments to evaluate thermal neutron flux distribution were performed using the Scintillator with Optical Fiber (SOF) detector, which was developed as a thermal neutron monitor during boron neutron capture therapy (BNCT) irradiation. Compared with the gold wire activation method and Monte Carlo N-particle (MCNP) calculations, it was confirmed that the SOF detector is capable of measuring thermal neutron flux as low as 105 n/cm2/s with sufficient accuracy. The SOF detector will be useful for phantom experiments with BNCT neutron fields from low-current accelerator-based neutron sources. PMID:25589504
Fast neutron mutants database and web displays at SoyBase
USDA-ARS?s Scientific Manuscript database
SoyBase, the USDA-ARS soybean genetics and genomics database, has been expanded to include data for the fast neutron mutants produced by Bolon, Vance, et al. In addition to the expected text and sequence homology searches and visualization of the indels in the context of the genome sequence viewer, ...
Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy
Miura, Michiko; Slatkin, Daniel N.
1997-03-18
A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.
Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy
Miura, Michiko; Slatkin, Daniel N.
1995-10-03
A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.
Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy
Miura, Michiko; Slatkin, Daniel N.
1997-08-05
A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized. by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.
Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy
Miura, M.; Slatkin, D.N.
1995-10-03
A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.
Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy
Miura, M.; Slatkin, D.N.
1997-03-18
A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.
Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy
Miura, M.; Slatkin, D.N.
1997-08-05
A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.
Positron annihilation study of vacancy-type defects in fast-neutron-irradiated MgO·nAl2O3
NASA Astrophysics Data System (ADS)
Rahman, Abu Zayed Mohammad Saliqur; Li, Zhuoxin; Cao, Xingzhong; Wang, Baoyi; Wei, Long; Xu, Qiu; Atobe, Kozo
2014-09-01
The positron lifetimes of fast-neutron-irradiated MgO·nAl2O3 single crystals were measured to investigate the formation of cation vacancies. Al monovacancy was possibly observed in samples irradiated by fast neutrons at ultra-low temperatures. Additionally, vacancy-oxygen complex centers were possibly observed in samples irradiated at higher temperatures and fast neutron fluences. Coincidence Doppler broadening (CDB) spectra were measured to obtain information regarding the vicinity of vacancy-type defects. A peak at approximately 11 × 10-3 m0c was observed, which may be due to the presence of oxygen atoms in the neighborhood of the vacancies.
High-sensitivity fast neutron detector KNK-2-7M
DOE Office of Scientific and Technical Information (OSTI.GOV)
Koshelev, A. S., E-mail: alexsander.coshelev@yandex.ru; Dovbysh, L. Ye.; Ovchinnikov, M. A.
2015-12-15
The construction of the fast neutron detector KNK-2-7M is briefly described. The results of the study of the detector in the pulse-counting mode are given for the fissions of {sup 237}Np nuclei in the radiator of the neutron-sensitive section and in the current mode with the separation of sectional currents of functional sections. The possibilities of determining the effective number of {sup 237}Np nuclei in the radiator of the neutronsensitive section are considered. The diagnostic possibilities of the detector in the counting mode are shown by example of the analysis of the reference data from the neutron-field characteristics in themore » working hall of the BR-K1 reactor. The diagnostic possibilities of the detector in the current operating mode are shown by example of the results of measuring the {sup 237}Np-fission intensity in the BR-K1 reactor power start-ups implemented in the mode of fission-pulse generation on delayed neutrons at the detector arrangement inside the reactor core cavity under conditions of a wide variation of the reactor radiation field.« less
Measured Thermal and Fast Neutron Fluence Rates for ATF-1 Holders During ATR Cycle 157D
DOE Office of Scientific and Technical Information (OSTI.GOV)
Smith, Larry Don; Miller, David Torbet
This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 157D which were measured by the Radiation Measurements Laboratory (RML) as requested by the Power Reactor Programs (ATR Experiments) Radiation Measurements Work Order. This report contains measurements of the fluence rates corresponding to the particular elevations relative to the 80-ft. core elevation. The data in this report consist of (1) a table of the ATR power history and distribution, (2) a hard copy listing of all thermal and fast neutron fluence rates, and (3) plots ofmore » both the thermal and fast neutron fluence rates. The fluence rates reported are for the average power levels given in the table of power history and distribution.« less
Fast fission neutron detection using the Cherenkov effect
NASA Astrophysics Data System (ADS)
Millard, Matthew James
The Cherenkov effect in optically clear media of varying indices of refraction and composition was investigated for quantification of fast neutrons. The ultimate application of the proposed detection system is criticality monitoring. The optically clear medium, composed of select target nuclei, was coupled to a photomultiplier tube. Neutron reaction products of the target nuclei contained within the optical medium emit beta particles and gamma rays that produce Cherenkov photons within the medium which can be detected. Assessed media include quartz (SiO2), sapphire (Al2O3), spinel (MgAl2O4), and zinc sulfide (ZnS), which were irradiated with un-moderated 252Cf. Monte Carlo N-Particle (MCNP) code simulations were conducted to quantify the neutron flux incident on the media. High resolution gamma-ray spectroscopic measurements of the samples were conducted to verify the MCNP estimate. The threshold reactions of interest were 28Si (n, p) 28Al, 27 Al (n, p) 27Mg, 24Mg(n, p)24 Na, and 64Zn(n, p)64Cu which have neutron reaction cross sections in the 1 to 10 MeV range on the order of 0.1 barn. The detection system offers a unique way to measure a criticality event; it can count in place, making retrieval by emergency personnel unnecessary.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Velikaya, V. V., E-mail: viktoria.v.v@inbox.ru; Startseva, Zh. A., E-mail: zhanna.alex@rambler.ru; National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk, 634050
The study included 135 breast cancer patients (70 patients with locally recurrent breast cancer and 65 patients with locally advanced breast cancer with unfavorable prognostic factors) who received the neutron therapy alone or in combination with the photon therapy. The neutron therapy was shown to be effective in multimodality treatment of patients with locally advanced and locally recurrent breast cancer. The 8-year survival rate in patients without repeated breast cancer recurrence was 87.6 ± 8.7% after the neutron and neutron-photon therapy and 54.3 ± 9.2% after the electron beam therapy.
High conduction neutron absorber to simulate fast reactor environment in an existing test reactor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Donna Post Guillen; Larry R. Greenwood; James R. Parry
2014-06-22
A new metal matrix composite material has been developed to serve as a thermal neutron absorber for testing fast reactor fuels and materials in an existing pressurized water reactor. The performance of this material was evaluated by placing neutron fluence monitors within shrouded and unshrouded holders and irradiating for up to four cycles. The monitor wires were analyzed by gamma and X-ray spectrometry to determine the activities of the activation products. Adjusted neutron fluences were calculated and grouped into three bins—thermal, epithermal, and fast—to evaluate the spectral shift created by the new material. A comparison of shrouded and unshrouded fluencemore » monitors shows a thermal fluence decrease of ~11 % for the shielded monitors. Radioisotope activity and mass for each of the major activation products is given to provide insight into the evolution of thermal absorption cross-section during irradiation. The thermal neutron absorption capability of the composite material appears to diminish at total neutron fluence levels of ~8 × 1025 n/m2. Calculated values for dpa in excess of 2.0 were obtained for two common structural materials (iron and nickel) of interest for future fast flux experiments.« less
Accelerator-driven boron neutron capture therapy
NASA Astrophysics Data System (ADS)
Edgecock, Rob
2014-05-01
Boron Neutron Capture Therapy is a binary treatment for certain types of cancer. It works by loading the cancerous cells with a boron-10 carrying compound. This isotope has a large cross-section for thermal neutrons, the reaction producing a lithium nucleus and alpha particle that kill the cell in which they are produced. Recent studies of the boron carrier compound indicate that the uptake process works best in particularly aggressive cancers. Most studied is glioblastoma multiforme and a trial using a combination of BNCT and X-ray radiotherapy has shown an increase of nearly a factor of two in mean survival over the state of the art. However, the main technical problem with BNCT remains producing a sufficient flux of neutrons for a reasonable treatment duration in a hospital environment. This paper discusses this issue.
Neutron-induced reaction cross-sections of 93Nb with fast neutron based on 9Be(p,n) reaction
NASA Astrophysics Data System (ADS)
Naik, H.; Kim, G. N.; Kim, K.; Zaman, M.; Nadeem, M.; Sahid, M.
2018-02-01
The cross-sections of the 93Nb (n , 2 n)92mNb, 93Nb (n , 3 n)91mNb and 93Nb (n , 4 n)90Nb reactions with the average neutron energies of 14.4 to 34.0 MeV have been determined by using an activation and off-line γ-ray spectrometric technique. The fast neutrons were produced using the 9Be (p , n) reaction with the proton energies of 25-, 35- and 45-MeV from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron flux-weighted average cross-sections of the 93Nb(n , xn ; x = 2- 4) reactions were also obtained from the mono-energetic neutron-induced reaction cross-sections of 93Nb calculated using the TALYS 1.8 code, and the neutron flux spectrum based on the MCNPX 2.6.0 code. The present results for the 93Nb(n , xn ; x = 2- 4) reactions are compared with the calculated neutron flux-weighted average values and found to be in good agreement.
The changing role of accelerators in radiation therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hanson, W.F.
Conventional low energy x-rays have been used in radiation therapy since the turn of the century. Van de Graaff and Betatron accelerators changed the complexion of radiation therapy in the mid 1940's by providing significantly deeper penetrating photon beams and also providing therapeutic quality electron beams. The development of Cobalt-60 teletherapy in the mid 1950's suppressed the role of accelerators in radiation therapy for nearly 20 years. However, with the development of reliable isocentric rotating linear accelerators, accelerators are rapidly becoming the most popular conventional therapy devices. Following unfavorable clinical results with fast neutron therapy in the late 1930's andmore » early 1940's, the role of cyclotron produced fast neutrons is presently experiencing a renewal in radiation therapy. Several facilities are also experimenting with heavy charged particle beams for therapy.« less
A Fast Pulse, High Intensity Neutron Source Based Upon The Dense Plasma Focus
NASA Astrophysics Data System (ADS)
Krishnan, M.; Bures, B.; Madden, R.; Blobner, F.; Elliott, K. Wilson
2009-12-01
Alameda Applied Sciences Corporation (AASC) has built a bench-top source of fast neutrons (˜10-30 ns, 2.45 MeV), that is portable and can be scaled to operate at ˜100 Hz. The source is a Dense Plasma Focus driven by three different capacitor banks: a 40 J/30 kA/100 Hz driver; a 500 J/130 kA/2 Hz driver and a 3 kJ/350 kA/0.5 Hz driver. At currents of ˜130 kA, this source produces ˜1×107 (DD) n/pulse. The neutron pulse widths are ˜10-30 ns and may be controlled by adjusting the DPF electrode geometry and operating parameters. This paper describes the scaling of the fast neutron output with current from such a Dense Plasma Focus source. For each current and driver, different DPF head designs are required to match to the current rise-time, as the operating pressure and anode radius/shape are varied. Doping of the pure D2 gas fill with Ar or Kr was shown earlier to increase the neutron output. Results are discussed in the light of scaling laws suggested by prior literature.
Porphyrins for boron neutron capture therapy
Miura, Michiko; Gabel, Detlef
1990-01-01
Novel compounds for treatment of brain tumors in Boron Neutron Capture Therapy are disclosed. A method for preparing the compounds as well as pharmaceutical compositions containing said compounds are also disclosed. The compounds are water soluble, non-toxic and non-labile boronated porphyrins which show significant uptake and retention in tumors.
NASA Astrophysics Data System (ADS)
Licata, M.; Joyce, M. J.
2018-02-01
The potential of a combined and simultaneous fast-neutron/γ-ray computed tomography technique using Monte Carlo simulations is described. This technique is applied on the basis of a hypothetical tomography system comprising an isotopic radiation source (americium-beryllium) and a number (13) of organic scintillation detectors for the production and detection of both fast neutrons and γ rays, respectively. Via a combination of γ-ray and fast neutron tomography the potential is demonstrated to discern nuclear materials, such as compounds comprising plutonium and uranium, from substances that are used widely for neutron moderation and shielding. This discrimination is achieved on the basis of the difference in the attenuation characteristics of these substances. Discrimination of a variety of nuclear material compounds from shielding/moderating substances (the latter comprising lead or polyethylene for example) is shown to be challenging when using either γ-ray or neutron tomography in isolation of one another. Much-improved contrast is obtained for a combination of these tomographic modalities. This method has potential applications for in-situ, non-destructive assessments in nuclear security, safeguards, waste management and related requirements in the nuclear industry.
A novel fast-neutron detector concept for energy-selective imaging and imaging spectroscopy.
Cortesi, M; Dangendorf, V; Zboray, R; Prasser, H-M
2014-07-01
We present and discuss the operational principle of a new fast-neutron detector concept suitable for either energy-selective imaging or for imaging spectroscopy. The detector is comprised of a series of energy-selective stacks of converter foils immersed in a noble-gas based mixture, coupled to a position-sensitive charge readout. Each foil in the various stacks is made of two layers of different thicknesses, fastened together: a hydrogen-rich (plastic) layer for neutron-to-proton conversion, and a hydrogen-free coating to selectively stop/absorb the recoil protons below a certain energy cut-off. The neutron-induced recoil protons, that escape the converter foils, release ionization electrons in the gas gaps between consecutive foils. The electrons are then drifted towards and localized by a position-sensitive charge amplification and readout stage. Comparison of the images detected by stacks with different energy cut-offs allows energy-selective imaging. Neutron energy spectrometry is realized by analyzing the responses of a sufficient large number of stacks of different energy response and unfolding techniques. In this paper, we present the results of computer simulation studies and discuss the expected performance of the new detector concept. Potential applications in various fields are also briefly discussed, in particularly, the application of energy-selective fast-neutron imaging for nuclear safeguards application, with the aim of determining the plutonium content in Mixed Oxide (MOX) fuels.
Comparison between Silicon-Carbide and diamond for fast neutron detection at room temperature
NASA Astrophysics Data System (ADS)
Obraztsova, O.; Ottaviani, L.; Klix, A.; Döring, T.; Palais, O.; Lyoussi, A.
2018-01-01
Neutron radiation detector for nuclear reactor applications plays an important role in getting information about the actual neutron yield and reactor environment. Such detector must be able to operate at high temperature (up to 600° C) and high neutron flux levels. It is worth nothing that a detector for industrial environment applications must have fast and stable response over considerable long period of use as well as high energy resolution. Silicon Carbide is one of the most attractive materials for neutron detection. Thanks to its outstanding properties, such as high displacement threshold energy (20-35 eV), wide band gap energy (3.27 eV) and high thermal conductivity (4.9 W/cm·K), SiC can operate in harsh environment (high temperature, high pressure and high radiation level) without additional cooling system. Our previous analyses reveal that SiC detectors, under irradiation and at elevated temperature, respond to neutrons showing consistent counting rates as function of external reverse bias voltages and radiation intensity. The counting-rate of the thermal neutron-induced peak increases with the area of the detector, and appears to be linear with respect to the reactor power. Diamond is another semi-conductor considered as one of most promising materials for radiation detection. Diamond possesses several advantages in comparison to other semiconductors such as a wider band gap (5.5 eV), higher threshold displacement energy (40-50 eV) and thermal conductivity (22 W/cm·K), which leads to low leakage current values and make it more radiation resistant that its competitors. A comparison is proposed between these two semiconductors for the ability and efficiency to detect fast neutrons. For this purpose the deuterium-tritium neutron generator of Technical University of Dresden with 14 MeV neutron output of 1010 n·s-1 is used. In the present work, we interpret the first measurements and results with both 4H-SiC and chemical vapor deposition (CVD) diamond
Perspectives of boron-neutron capture therapy of malignant brain tumors
NASA Astrophysics Data System (ADS)
Kanygin, V. V.; Kichigin, A. I.; Krivoshapkin, A. L.; Taskaev, S. Yu.
2017-09-01
Boron neutron capture therapy (BNCT) is characterized by a selective effect directly on the cells of malignant tumors. The carried out research showed the perspective of the given kind of therapy concerning malignant tumors of the brain. However, the introduction of BNCT into clinical practice is hampered by the lack of a single protocol for the treatment of patients and the difficulty in using nuclear reactors to produce a neutron beam. This problem can be solved by using a compact accelerator as a source of neutrons, with the possibility of installation in a medical institution. Such a neutron accelerator for BNCT was developed at Budker Institute of Nuclear Physics, Novosibirsk. A neutron beam was obtained on this accelerator, which fully complies with the requirements of BNCT, as confirmed by studies on cell cultures and experiments with laboratory animals. The conducted experiments showed the relative safety of the method with the absence of negative effects on cell cultures and living organisms, and also confirmed the effectiveness of BNCT for malignant brain tumors.
Iodine neutron capture therapy
NASA Astrophysics Data System (ADS)
Ahmed, Kazi Fariduddin
A new technique, Iodine Neutron Capture Therapy (INCT) is proposed to treat hyperthyroidism in people. Present thyroid therapies, surgical removal and 131I treatment, result in hypothyroidism and, for 131I, involve protracted treatment times and excessive whole-body radiation doses. The new technique involves using a low energy neutron beam to convert a fraction of the natural iodine stored in the thyroid to radioactive 128I, which has a 24-minute half-life and decays by emitting 2.12-MeV beta particles. The beta particles are absorbed in and damage some thyroid tissue cells and consequently reduce the production and release of thyroid hormones to the blood stream. Treatment times and whole-body radiation doses are thus reduced substantially. This dissertation addresses the first of the several steps needed to obtain medical profession acceptance and regulatory approval to implement this therapy. As with other such programs, initial feasibility is established by performing experiments on suitable small mammals. Laboratory rats were used and their thyroids were exposed to the beta particles coming from small encapsulated amounts of 128I. Masses of 89.0 mg reagent-grade elemental iodine crystals have been activated in the ISU AGN-201 reactor to provide 0.033 mBq of 128I. This activity delivers 0.2 Gy to the thyroid gland of 300-g male rats having fresh thyroid tissue masses of ˜20 mg. Larger iodine masses are used to provide greater doses. The activated iodine is encapsulated to form a thin (0.16 cm 2/mg) patch that is then applied directly to the surgically exposed thyroid of an anesthetized rat. Direct neutron irradiation of a rat's thyroid was not possible due to its small size. Direct in-vivo exposure of the thyroid of the rat to the emitted radiation from 128I is allowed to continue for 2.5 hours (6 half-lives). Pre- and post-exposure blood samples are taken to quantify thyroid hormone levels. The serum T4 concentration is measured by radioimmunoassay at
Liu, Zheng; Li, Gang; Liu, Linmao
2014-04-01
This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values. Copyright © 2014 Elsevier Ltd. All rights reserved.
Optimizing Dense Plasma Focus Neutron Yields with Fast Gas Jets
NASA Astrophysics Data System (ADS)
McMahon, Matthew; Kueny, Christopher; Stein, Elizabeth; Link, Anthony; Schmidt, Andrea
2016-10-01
We report a study using the particle-in-cell code LSP to perform fully kinetic simulations modeling dense plasma focus (DPF) devices with high density gas jets on axis. The high density jet models fast gas puffs which allow for more mass on axis while maintaining the optimal pressure for the DPF. As the density of the jet compared to the background fill increases we find the neutron yield increases, as does the variability in the neutron yield. Introducing perturbations in the jet density allow for consistent seeding of the m =0 instability leading to more consistent ion acceleration and higher neutron yields with less variability. Jets with higher on axis density are found to have the greatest yield. The optimal jet configuration is explored. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Detecting fast and thermal neutrons with a boron loaded liquid scintillator, EJ-339A.
Pino, F; Stevanato, L; Cester, D; Nebbia, G; Sajo-Bohus, L; Viesti, G
2014-09-01
A commercial boron-loaded liquid scintillator EJ-339 A was studied, using a (252)Cf source with/without polyethylene moderator, to examine the possibility of discriminating slow-neutron induced events in (10)B from fast-neutron events, resulting from proton recoils, and gamma-ray events. Despite the strong light quenching associated with neutron induced events in (10)B, correct classification of these events is shown to be possible with the aid of digital signal processing. Copyright © 2014 Elsevier Ltd. All rights reserved.
Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator
NASA Astrophysics Data System (ADS)
Skalyga, V.; Izotov, I.; Golubev, S.; Razin, S.; Sidorov, A.; Maslennikova, A.; Volovecky, A.; Kalvas, T.; Koivisto, H.; Tarvainen, O.
2014-12-01
Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D-D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm2 is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·1010 cm-2/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.
NASA Astrophysics Data System (ADS)
Velikaya, V. V.; Musabaeva, L. I.; Lisin, V. A.; Startseva, Zh. A.
2016-08-01
The study included 135 breast cancer patients (70 patients with locally recurrent breast cancer and 65 patients with locally advanced breast cancer with unfavorable prognostic factors) who received the neutron therapy alone or in combination with the photon therapy. The neutron therapy was shown to be effective in multimodality treatment of patients with locally advanced and locally recurrent breast cancer. The 8-year survival rate in patients without repeated breast cancer recurrence was 87.6 ± 8.7% after the neutron and neutron-photon therapy and 54.3 ± 9.2% after the electron beam therapy.
Yang, Miyoung; Kim, Joong-Sun; Song, Myoung-Sub; Kim, Jong-Choon; Shin, Taekyun; Lee, Seung-Sook; Kim, Sung-Ho; Moon, Changjong
2010-06-01
Our study compared the effects of high linear energy transfer (LET) fast neutrons on the induction of apoptosis and reduction of neurogenesis in the hippocampus of adult ICR mice with those of low-LET (60)Co gamma-rays, to evaluate the relative biological effectiveness (RBE) of fast neutrons in the adult hippocampal dentate gyrus (DG). The mice were exposed to 35 MeV fast neutrons or (60)Co gamma-rays. We evaluated acutely the incidence of apoptosis and expression of Ki-67 (a protein marker for cell proliferation originally defined by the monoclonal antibody Kiel-67) and doublecortin (DCX: an immature progenitor neuron marker) in the hippocampus after a single whole-body irradiation. The number of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labelling (TUNEL)-positive apoptotic nuclei in the DG increased and both Ki-67- and DCX-positive cells declined in a dose-dependent pattern, with fast neutrons or gamma-rays. In the hippocampus, which showed an apoptosis frequency between 2 and 8 per DG, the RBE of fast neutrons was approximately 1.9. Additionally, the inhibitory effects of fast neutrons on the expression frequencies of Ki-67 (4-8) and DCX (8-32) were approximately 3.2 and 2.5 times, respectively, the effects of gamma-rays at the same dose. Increased apoptotic cell death and decreased neurogenesis in the hippocampal DG were seen in a dose-dependent pattern after exposure to fast neutrons and gamma-rays. In addition, the different rate of hippocampal neurogenesis between different radiation qualities may be an index of RBE.
Fast neutron measurement at Soudan Mine using a large liquid scintillation detector
NASA Astrophysics Data System (ADS)
Zhang, Chao; Mei, Dongming
2014-03-01
Characterizing neutron background is extremely important to the success of rare-event physics searching for neutrinoless double-beta decay and dark matter searches. Measuring the energy spectrum of fast neutrons for an underground laboratory is difficult and it requires intensive R&D for a given technology. EJ-301 liquid scintillator(known also as NE-213) is implemented as the target for a 12 liter neutron detector fabricated at the University of South Dakota. The light output response to atmospheric neutrons from a few MeV up to ~ 70 MeV has been calibrated for this detector. The detector has been taking data at Soudan Mine for over two years. We report the measured muon-induced neutrons in this paper. This work is supported in part by NSF PHY-0758120, PHYS-0919278, PHYS-0758120, PHYS-1242640, DOE grant DE-FG02-10ER46709, the Office of Research at the University of South Dakota and a 2010 research center support by the State of South Dakota.
Ionizing Energy Depositions After Fast Neutron Interactions in Silicon
Bergmann, Benedikt; Pospisil, Stanislav; Caicedo, Ivan; ...
2016-06-01
In our study we present the ionizing energy depositions in a 300 μm thick silicon layer after fast neutron impact. With the Time-of-Flight (ToF) technique, the ionizing energy deposition spectra of recoil silicons and secondary charged particles were assigned to (quasi-)monoenergetic neutron energies in the range from 180 keV to hundreds of MeV. We also show and interpret representative measured energy spectra. By separating the ionizing energy losses of the recoil silicon from energy depositions by products of nuclear reactions, the competition of ionizing (IEL) and non-ionizing energy losses (NIEL) of a recoil silicon within the silicon lattice was investigated.more » Furthermore, the data give supplementary information to the results of a previous measurement and are compared with different theoretical predictions.« less
Ionizing Energy Depositions After Fast Neutron Interactions in Silicon
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bergmann, Benedikt; Pospisil, Stanislav; Caicedo, Ivan
In our study we present the ionizing energy depositions in a 300 μm thick silicon layer after fast neutron impact. With the Time-of-Flight (ToF) technique, the ionizing energy deposition spectra of recoil silicons and secondary charged particles were assigned to (quasi-)monoenergetic neutron energies in the range from 180 keV to hundreds of MeV. We also show and interpret representative measured energy spectra. By separating the ionizing energy losses of the recoil silicon from energy depositions by products of nuclear reactions, the competition of ionizing (IEL) and non-ionizing energy losses (NIEL) of a recoil silicon within the silicon lattice was investigated.more » Furthermore, the data give supplementary information to the results of a previous measurement and are compared with different theoretical predictions.« less
Boron Neutron Capture Therapy - A Literature Review
Nedunchezhian, Kavitaa; Thiruppathy, Manigandan; Thirugnanamurthy, Sarumathi
2016-01-01
Boron Neutron Capture Therapy (BNCT) is a radiation science which is emerging as a hopeful tool in treating cancer, by selectively concentrating boron compounds in tumour cells and then subjecting the tumour cells to epithermal neutron beam radiation. BNCT bestows upon the nuclear reaction that occurs when Boron-10, a stable isotope, is irradiated with low-energy thermal neutrons to yield α particles (Helium-4) and recoiling lithium-7 nuclei. A large number of 10 Boron (10B) atoms have to be localized on or within neoplastic cells for BNCT to be effective, and an adequate number of thermal neutrons have to be absorbed by the 10B atoms to maintain a lethal 10B (n, α) lithium-7 reaction. The most exclusive property of BNCT is that it can deposit an immense dose gradient between the tumour cells and normal cells. BNCT integrates the fundamental focusing perception of chemotherapy and the gross anatomical localization proposition of traditional radiotherapy. PMID:28209015
Commissioning of intensity modulated neutron radiotherapy (IMNRT).
Burmeister, Jay; Spink, Robyn; Liang, Liang; Bossenberger, Todd; Halford, Robert; Brandon, John; Delauter, Jonathan; Snyder, Michael
2013-02-01
Intensity modulated neutron radiotherapy (IMNRT) has been developed using inhouse treatment planning and delivery systems at the Karmanos Cancer Center∕Wayne State University Fast Neutron Therapy facility. The process of commissioning IMNRT for clinical use is presented here. Results of commissioning tests are provided including validation measurements using representative patient plans as well as those from the TG-119 test suite. IMNRT plans were created using the Varian Eclipse optimization algorithm and an inhouse planning system for calculation of neutron dose distributions. Tissue equivalent ionization chambers and an ionization chamber array were used for point dose and planar dose distribution comparisons with calculated values. Validation plans were delivered to water and virtual water phantoms using TG-119 measurement points and evaluation techniques. Photon and neutron doses were evaluated both inside and outside the target volume for a typical IMNRT plan to determine effects of intensity modulation on the photon dose component. Monitor unit linearity and effects of beam current and gantry angle on output were investigated, and an independent validation of neutron dosimetry was obtained. While IMNRT plan quality is superior to conventional fast neutron therapy plans for clinical sites such as prostate and head and neck, it is inferior to photon IMRT for most TG-119 planning goals, particularly for complex cases. This results significantly from current limitations on the number of segments. Measured and calculated doses for 11 representative plans (six prostate∕five head and neck) agreed to within -0.8 ± 1.4% and 5.0 ± 6.0% within and outside the target, respectively. Nearly all (22∕24) ion chamber point measurements in the two phantom arrangements were within the respective confidence intervals for the quantity [(measured-planned)∕prescription dose] derived in TG-119. Mean differences for all measurements were 0.5% (max = 7.0%) and 1.4% (max = 4
Measurement of neutron dose equivalent outside and inside of the treatment vault of GRID therapy.
Wang, Xudong; Charlton, Michael A; Esquivel, Carlos; Eng, Tony Y; Li, Ying; Papanikolaou, Nikos
2013-09-01
To evaluate the neutron and photon dose equivalent rates at the treatment vault entrance (Hn,D and HG), and to study the secondary radiation to the patient in GRID therapy. The radiation activation on the grid was studied. A Varian Clinac 23EX accelerator was working at 18 MV mode with a grid manufactured by .decimal, Inc. The Hn,D and HG were measured using an Andersson-Braun neutron REM meter, and a Geiger Müller counter. The radiation activation on the grid was measured after the irradiation with an ion chamber γ-ray survey meter. The secondary radiation dose equivalent to patient was evaluated by etched track detectors and OSL detectors on a RANDO(®) phantom. Within the measurement uncertainty, there is no significant difference between the Hn,D and HG with and without a grid. However, the neutron dose equivalent to the patient with the grid is, on average, 35.3% lower than that without the grid when using the same field size and the same amount of monitor unit. The photon dose equivalent to the patient with the grid is, on average, 44.9% lower. The measured average half-life of the radiation activation in the grid is 12.0 (± 0.9) min. The activation can be categorized into a fast decay component and a slow decay component with half-lives of 3.4 (± 1.6) min and 15.3 (± 4.0) min, respectively. There was no detectable radioactive contamination found on the surface of the grid through a wipe test. This work indicates that there is no significant change of the Hn,D and HG in GRID therapy, compared with a conventional external beam therapy. However, the neutron and scattered photon dose equivalent to the patient decrease dramatically with the grid and can be clinical irrelevant. Meanwhile, the users of a grid should be aware of the possible high dose to the radiation worker from the radiation activation on the surface of the grid. A delay in handling the grid after the beam delivery is suggested.
Soodak, H.; Wigner, E.P.
1961-07-25
A reactor comprising fissionable material in concentration sufficiently high so that the average neutron enengy within the reactor is at least 25,000 ev is described. A natural uranium blanket surrounds the reactor, and a moderating reflector surrounds the blanket. The blanket is thick enough to substantially eliminate flow of neutrons from the reflector.
NASA Astrophysics Data System (ADS)
Israelashvili, I.; Coimbra, A. E. C.; Vartsky, D.; Arazi, L.; Shchemelinin, S.; Caspi, E. N.; Breskin, A.
2017-09-01
Gamma-ray and fast-neutron imaging was performed with a novel liquid xenon (LXe) scintillation detector read out by a Gaseous Photomultiplier (GPM). The 100 mm diameter detector prototype comprised a capillary-filled LXe converter/scintillator, coupled to a triple-THGEM imaging-GPM, with its first electrode coated by a CsI UV-photocathode, operated in Ne/5%CH4 at cryogenic temperatures. Radiation localization in 2D was derived from scintillation-induced photoelectron avalanches, measured on the GPM's segmented anode. The localization properties of 60Co gamma-rays and a mixed fast-neutron/gamma-ray field from an AmBe neutron source were derived from irradiation of a Pb edge absorber. Spatial resolutions of 12± 2 mm and 10± 2 mm (FWHM) were reached with 60Co and AmBe sources, respectively. The experimental results are in good agreement with GEANT4 simulations. The calculated ultimate expected resolutions for our application-relevant 4.4 and 15.1 MeV gamma-rays and 1-15 MeV neutrons are 2-4 mm and ~ 2 mm (FWHM), respectively. These results indicate the potential applicability of the new detector concept to Fast-Neutron Resonance Radiography (FNRR) and Dual-Discrete-Energy Gamma Radiography (DDEGR) of large objects.
Monte Carlo simulation of secondary neutron dose for scanning proton therapy using FLUKA
Lee, Chaeyeong; Lee, Sangmin; Lee, Seung-Jae; Song, Hankyeol; Kim, Dae-Hyun; Cho, Sungkoo; Jo, Kwanghyun; Han, Youngyih; Chung, Yong Hyun
2017-01-01
Proton therapy is a rapidly progressing field for cancer treatment. Globally, many proton therapy facilities are being commissioned or under construction. Secondary neutrons are an important issue during the commissioning process of a proton therapy facility. The purpose of this study is to model and validate scanning nozzles of proton therapy at Samsung Medical Center (SMC) by Monte Carlo simulation for beam commissioning. After the commissioning, a secondary neutron ambient dose from proton scanning nozzle (Gantry 1) was simulated and measured. This simulation was performed to evaluate beam properties such as percent depth dose curve, Bragg peak, and distal fall-off, so that they could be verified with measured data. Using the validated beam nozzle, the secondary neutron ambient dose was simulated and then compared with the measured ambient dose from Gantry 1. We calculated secondary neutron dose at several different points. We demonstrated the validity modeling a proton scanning nozzle system to evaluate various parameters using FLUKA. The measured secondary neutron ambient dose showed a similar tendency with the simulation result. This work will increase the knowledge necessary for the development of radiation safety technology in medical particle accelerators. PMID:29045491
Waker, A J; Maughan, R L
1986-11-01
For fast neutron therapy and radiobiology beams, knowledge of the primary neutron spectrum is the most fundamental requirement for the definition of radiation quality. However, microdosimetric measurements in the form of single-event spectra not only complement the primary neutron spectrum as a statement of radiation quality but also provide a sensitive method of detecting changes in the radiation field in situations where it is no longer possible to have precise knowledge of the primary neutron spectrum, for example after collimator changes and in positions where the radiation field consists of a large scattered component. For the various collimator arrangements employed at the Gray Laboratory facility small perturbations of the radiation field are observed which can be related to a softening of the primary neutron spectrum with increasing field size of the collimator. Gamma fraction determinations are in very good agreement with measurements employing the dual chamber technique and also show small changes with collimator field size giving rise to gamma components ranging from 0.09 to 0.12, the higher values being measured for the larger field sizes. Quality changes represented by the shape of the measured event-size spectra and the derived microdosimetric parameters were greatest for off axis and phantom measurements. With increasing depth in water, yD was found to decrease from 47.3 keV micron-1 at 5 cm to 35.6 keV micron-1 at 15 cm depth, and the gamma fraction was found to increase from 0.23 to 0.40. Although there is no generally accepted and agreed method of relating microdosimetric information to biological effectiveness, the dual radiation theory in its original form (Kellerer and Rossi 1972) has been shown to be a very useful model for the assessment of the biological effectiveness of fast neutrons (Kellerer et al 1976). The microdosimetric parameter which is used in the dual radiation model is the dose mean specific energy corrected for saturation zeta
MEASUREMENT OF SECONDARY NEUTRONS GENERATED DURING PROTON THERAPY.
Vykydal, Z; Andrlík, M; Bártová, H; Králík, M; Šolc, J; Vondráček, V
2016-12-01
Measurements described in this article were carried out with the aim of evaluating risks of the patient exposure to secondary neutrons during treatment at the Proton Therapy Centre Prague. The neutron spectral fluence was measured by means of the extended Bonner sphere spectrometer (EBS). The article presents secondary neutron spectral fluences obtained by the EBS with passive thermoluminescent detectors, i.e. pairs of 6 LiF and 7 LiF chips. Measurements were performed in two positions: the first one behind the Nylon 6 phantom, and the second one close to the range shifter to evaluate their contribution to the generation of neutrons. Both the Nylon 6 phantom and the range shifter were irradiated with a pencil beam of protons 4 mm in diameter and the energy of 200 MeV. The results are supplemented with the values of effective dose derived from neutron spectral fluences. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
NASA Astrophysics Data System (ADS)
Qi, L.; Wilson, J. N.; Lebois, M.; Al-Adili, A.; Chatillon, A.; Choudhury, D.; Gatera, A.; Georgiev, G.; Göök, A.; Laurent, B.; Maj, A.; Matea, I.; Oberstedt, A.; Oberstedt, S.; Rose, S. J.; Schmitt, C.; Wasilewska, B.; Zeiser, F.
2018-03-01
Prompt fission gamma-ray spectra (PFGS) have been measured for the 239Pu(n,f) reaction using fast neutrons at Ēn=1.81 MeV produced by the LICORNE directional neutron source. The setup makes use of LaBr3 scintillation detectors and PARIS phoswich detectors to measure the emitted prompt fission gamma rays (PFG). The mean multiplicity, average total energy release per fission and average energy of photons are extracted from the unfolded PFGS. These new measurements provide complementary information to other recent work on thermal neutron induced fission of 239Pu and spontaneous fission of 252Cf.
Determination of the fast-neutron-induced fission cross-section of 242Pu at nELBE
NASA Astrophysics Data System (ADS)
Kögler, Toni; Beyer, Roland; Junghans, Arnd R.; Schwengner, Ronald; Wagner, Andreas
2018-03-01
The fast-neutron-induced fission cross section of 242Pu was determined in the energy range of 0.5 MeV to 10MeV at the neutron time-of-flight facility nELBE. Using a parallel-plate fission ionization chamber this quantity was measured relative to 235U(n,f). The number of target nuclei was thereby calculated by means of measuring the spontaneous fission rate of 242Pu. An MCNP 6 neutron transport simulation was used to correct the relative cross section for neutron scattering. The determined results are in good agreement with current experimental and evaluated data sets.
Khattab, K; Sulieman, I
2009-04-01
The MCNP-4C code, based on the probabilistic approach, was used to model the 3D configuration of the core of the Syrian miniature neutron source reactor (MNSR). The continuous energy neutron cross sections from the ENDF/B-VI library were used to calculate the thermal and fast neutron fluxes in the inner and outer irradiation sites of MNSR. The thermal fluxes in the MNSR inner irradiation sites were also measured experimentally by the multiple foil activation method ((197)Au (n, gamma) (198)Au and (59)Co (n, gamma) (60)Co). The foils were irradiated simultaneously in each of the five MNSR inner irradiation sites to measure the thermal neutron flux and the epithermal index in each site. The calculated and measured results agree well.
Ishikawa, M; Ono, K; Sakurai, Y; Unesaki, H; Uritani, A; Bengua, G; Kobayashi, T; Tanaka, K; Kosako, T
2004-11-01
A new thermal neutron monitor for boron neutron capture therapy was developed in this study. We called this monitor equipped boron-loaded plastic scintillator that uses optical fiber for signal transmission as an [scintillator with optical fiber] SOF detector. A water phantom experiment was performed to verify how the SOF detector compared with conventional method of measuring thermal neutron fluence. Measurements with a single SOF detector yielded indistinguishable signals for thermal neutrons and gamma rays. To account for the gamma ray contribution in the signal recorded by the SOF detector, a paired SOF detector system was employed. This was composed of an SOF detector with boron-loaded scintillator and an SOF detector with a boron-free scintillator. The difference between the recorded counts of these paired SOF detectors was used as the measure of the gamma ray contribution in the measured neutron fluence. The paired SOF detectors were ascertained to be effective in measuring thermal neutron flux in the range above 10(6)(n/cm(2)/s). Clinical trials using paired SOF to measure thermal neutron flux during therapy confirmed that paired SOF detectors were effective as a real-time thermal neutron flux monitor.
NASA Astrophysics Data System (ADS)
Bromberger, B.; Bar, D.; Brandis, M.; Dangendorf, V.; Goldberg, M. B.; Kaufmann, F.; Mor, I.; Nolte, R.; Schmiedel, M.; Tittelmeier, K.; Vartsky, D.; Wershofen, H.
2012-03-01
An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. The induced activity was determined by analyzing the gamma spectra. Based on the calculated radioactive inventory in the container, the dose levels due to the induced gamma radiation were calculated at several distances from the container and in relevant time windows after the irradiation, in order to evaluate the radiation exposure of the cargo handling staff, air crew and passengers during flight. The possibility of remanent long-lived radioactive inventory after cargo is delivered to the client is also of concern and was evaluated.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chen, Y; Lin, Y; Medical Physics Research Center, Institute for Radiological Research, Chang Gung University / Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
Purpose: Secondary fast neutrons and gamma rays are mainly produced due to the interaction of the primary proton beam with the beam delivery nozzle. These secondary radiation dose to patients and radiation workers are unwanted. The purpose of this study is to estimate the neutron and gamma dose equivalent out of the treatment volume during the wobbling proton therapy system. Methods: Two types of thermoluminescent (TL) dosimeters, TLD-600 ({sup 6}LiF: Mg, Ti) and TLD-700 ({sup 7}LiF: Mg, Ti) were used in this study. They were calibrated in the standard neutron and gamma sources at National Standards Laboratory. Annealing procedure ismore » 400°C for 1 hour, 100°C for 2 hours and spontaneously cooling down to the room temperature in a programmable oven. Two-peak method (a kind of glow curve analysis technique) was used to evaluate the TL response corresponding to the neutron and gamma dose. The TLD pairs were placed outside the treatment field at the neutron-gamma mixed field with 190-MeV proton beam produced by the wobbling system through the polyethylene plate phantom. The results of TLD measurement were compared to the Monte Carlo simulation. Results: The initial experiment results of calculated dose equivalents are 0.63, 0.38, 0.21 and 0.13 mSv per Gy outside the field at the distance of 50, 100, 150 and 200 cm. Conclusion: The TLD-600 and TLD-700 pairs are convenient to estimate neutron and gamma dosimetry during proton therapy. However, an accurate and suitable glow curve analysis technique is necessary. During the wobbling system proton therapy, our results showed that the neutron and gamma doses outside the treatment field are noticeable. This study was supported by the grants from the Chang Gung Memorial Hospital (CMRPD1C0682)« less
Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors
NASA Astrophysics Data System (ADS)
Verma, V.; Barbot, L.; Filliatre, P.; Hellesen, C.; Jammes, C.; Svärd, S. Jacobsson
2017-07-01
Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment.
NASA Astrophysics Data System (ADS)
Khorshidi, A.; Ghafoori-Fard, H.; Sadeghi, M.
2014-05-01
Low-energy protons from the cyclotron in the range of 15-30 MeV and low current have been simulated on beryllium (Be) target with a lead moderator around the target. This research was accomplished to design an epithermal neutron beam for Boron Neutron Capture Therapy (BNCT) using the moderated neutron on the average produced from 9Be target via (p, xn) reaction in Adiabatic Resonance Crossing (ARC) concept. Generation of neutron to proton ratio, energy distribution, flux and dose components in head phantom have been simulated by MCNP5 code. The reflector and collimator were designed in prevention and collimation of derivation neutrons from proton bombarding. The scalp-skull-brain phantom consisting of bone and brain equivalent material has been simulated in order to evaluate the dosimetric effect on the brain. Results of this analysis demonstrated while the proton energy decreased, the dose factor altered according to filters thickness. The maximum epithermal flux revealed using fluental, Fe and bismuth (Bi) filters with thicknesses of 9.4, 3 and 2 cm, respectively and also the epithermal to thermal neutron flux ratio was 103.85. The potential of the ARC method to replace or complement the current reactor-based supply sources of BNCT purposes.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hentschel, R; Mukherjee, B
2014-06-01
Purpose: In proton therapy, it could be desirable to measure out-of-field fast neutron doses at critical locations near and outside the patient body. Methods: The working principle of a novel clinical neutron dose monitor is verified by MCNPX simulation. The device is based on a small PE moderator of just 5.5cm side length for easy handling covered with a thermal neutron suppression layer. In the simulation, a polystyrene phantom is bombarded with a standard proton beam. The secondary thermal neutron flux produced inside the moderator by the impinging fast neutrons from the treatment volume is estimated by pairs of α-Al2O3:Cmore » (TLD500) chips which are evaluated offline after the treatment either by TL or OSL methods. The first chip is wrapped with 0.5mm natural Gadolinium foil converting the thermal neutrons to gammas via (n,γ) reaction. The second chip is wrapped with a dummy material. The chip centers have a distance of 2cm from each other. Results: The simulation shows that the difference of gamma doses in the TLD500 chips is correlated to the mean fast neutron dose delivered to the moderator material. Different outer shielding materials have been studied. 0.5mm Cadmium shielding is preferred for cost reasons and convenience. Replacement of PE moderator material by other materials like lead or iron at any place is unfavorable. The spatial orientation of the moderator cube is uncritical. Using variance reduction techniques like splitting/Russian roulette, the TLD500 gamma dose simulation give positive differences up to distances of 0.5m from the treatment volume. Conclusion: Applicability and basic layout of a novel clinical neutron dose monitor are demonstrated. The monitor measures PE neutron doses at locations outside the patient body up to distances of 0.5m from the treatment volume. Tissue neutron doses may be calculated using neutron kerma factors.« less
Phenotypic and genomic analysis of a fast neutron mutant population resource in soybean
USDA-ARS?s Scientific Manuscript database
Mutagenized populations have become indispensable resources for introducing variation and studying gene function in plant genomics research. We utilized fast neutron radiation to induce deletion mutations in the soybean genome and phenotypically screened the resulting population. We exposed approxim...
Gravitational Waves from Rotating Neutron Stars and Evaluation of fast Chirp Transform Techniques
NASA Technical Reports Server (NTRS)
Strohmayer, Tod E.; White, Nicholas E. (Technical Monitor)
2000-01-01
X-ray observations suggest that neutron stars in low mass X-ray binaries (LMXB) are rotating with frequencies from 300 - 600 Hz. These spin rates are significantly less than the break-up rates for essentially all realistic neutron star equations of state, suggesting that some process may limit the spin frequencies of accreting neutron stars to this range. If the accretion induced spin up torque is in equilibrium with gravitational radiation losses, these objects could be interesting sources of gravitational waves. I present a brief summary of current measurements of neutron star spins in LMXBs based on the observations of high-Q oscillations during thermonuclear bursts (so called 'burst oscillations'). Further measurements of neutron star spins will be important in exploring the gravitational radiation hypothesis in more detail. To this end I also present a study of fast chirp transform (FCT) techniques as described by Jenet and Prince in the context of searching for the chirping signals observed during X-ray bursts.
Applications of a Fast Neutron Detector System to Verification of Special Nuclear Materials
NASA Astrophysics Data System (ADS)
Mayo, Douglas R.; Byrd, Roger C.; Ensslin, Norbert; Krick, Merlyn S.; Mercer, David J.; Miller, Michael C.; Prettyman, Thomas H.; Russo, Phyllis A.
1998-04-01
An array of boron-loaded plastic optically coupled to bismuth germanate scintillators has been developed to detect neutrons for measurement of special nuclear materials. The phoswiched detection system has the advantage of a high neutron detection efficiency and short die-away time. This is achieved by mixing the moderator (plastic) and the detector (^10B) at the molecular level. Simulations indicate that the neutron capture probabilities equal or exceed those of the current thermal neutron multiplicity techniques which have the moderator (polyethylene) and detectors (^3He gas proportional tubes) macroscopically separate. Experiments have been performed to characterize the response of these detectors and validate computer simulations. The fast neutron detection system may be applied to the quantitative assay of plutonium in high (α,n) backgrounds, with emphasis on safeguards and enviromental scenarios. Additional applications of the insturment, in a non-quantative mode, has been tested for possible verification activities involving dismantlement of nuclear weapons. A description of the detector system, simulations and preliminary data will be presented.
Khorshidi, Abdollah
2017-01-01
The reactor has increased its area of application into medicine especially boron neutron capture therapy (BNCT); however, accelerator-driven neutron sources can be used for therapy purposes. The present study aimed to discuss an alternative method in BNCT functions by a small cyclotron with low current protons based on Karaj cyclotron in Iran. An epithermal neutron spectrum generator was simulated with 30 MeV proton energy for BNCT purposes. A low current of 300 μA of the proton beam in spallation target concept via 9Be target was accomplished to model neutron spectrum using 208Pb moderator around the target. The graphite reflector and dual layer collimator were planned to prevent and collimate the neutrons produced from proton interactions. Neutron yield per proton, energy distribution, flux, and dose components in the simulated head phantom were estimated by MCNPX code. The neutron beam quality was investigated by diverse filters thicknesses. The maximum epithermal flux transpired using Fluental, Fe, Li, and Bi filters with thicknesses of 7.4, 3, 0.5, and 4 cm, respectively; as well as the epithermal to thermal neutron flux ratio was 161. Results demonstrated that the induced neutrons from a low energy and low current proton may be effective in tumor therapy using 208Pb moderator with average lethargy and also graphite reflector with low absorption cross section to keep the generated neutrons. Combination of spallation-based BNCT and proton therapy can be especially effective, if a high beam intensity cyclotron becomes available.
Dommert, M; Reginatto, M; Zboril, M; Fiedler, F; Helmbrecht, S; Enghardt, W; Lutz, B
2017-11-28
Bonner sphere measurements are typically analyzed using unfolding codes. It is well known that it is difficult to get reliable estimates of uncertainties for standard unfolding procedures. An alternative approach is to analyze the data using Bayesian parameter estimation. This method provides reliable estimates of the uncertainties of neutron spectra leading to rigorous estimates of uncertainties of the dose. We extend previous Bayesian approaches and apply the method to stray neutrons in proton therapy environments by introducing a new parameterized model which describes the main features of the expected neutron spectra. The parameterization is based on information that is available from measurements and detailed Monte Carlo simulations. The validity of this approach has been validated with results of an experiment using Bonner spheres carried out at the experimental hall of the OncoRay proton therapy facility in Dresden. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Analysis of Neutron Production in Passively Scattered Ion-Beam Therapy.
Heo, Seunguk; Yoo, Seunghoon; Song, Yongkeun; Kim, Eunho; Shin, Jaeik; Han, Soorim; Jung, Wongyun; Nam, Sanghee; Lee, Rena; Lee, Kitae; Cho, Sungho
2017-07-01
A new treatment facility for heavy ion therapy since 2010 was constructed. In the broad beam, a range shifter, ridge filter and multi leaf collimator (MLC) for the generation of the spread-out Bragg peak is used. In this case, secondary neutrons produced by the interactions of the ion field with beam-modifying devices (e.g. double-scattering system, beam shaping collimators and range compensators) are very important for patient safety. Therefore, these components must be carefully examined in the context of secondary neutron yield and associated secondary cancer risk. In this article, Monte Carlo simulation has been carried out with the FLUktuierende KAskade particle transport code, the fluence and distribution of neutron generation and the neutron dose equivalent from the broad beam components are compared using carbon and proton beams. As a result, it is confirmed that the yield of neutron production using a carbon beam from all components of the broad beam was higher than using a proton beam. The ambient dose by neutrons per heavy ion and proton ion from the MLC surface was 0.12-0.18 and 0.0067-0.0087 pSv, respectively, which shows that heavy ions generate more neutrons than protons. However, ambient dose per treatment 2 Gy, which means physical dose during treatment by ion beam, is higher than carbon beam because proton therapy needs more beam flux to make 2-Gy prescription dose. Therefore, the neutron production from the MLC, which is closed to the patient, is a very important parameter for patient safety. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Neutrons in active proton therapy: Parameterization of dose and dose equivalent.
Schneider, Uwe; Hälg, Roger A; Lomax, Tony
2017-06-01
One of the essential elements of an epidemiological study to decide if proton therapy may be associated with increased or decreased subsequent malignancies compared to photon therapy is an ability to estimate all doses to non-target tissues, including neutron dose. This work therefore aims to predict for patients using proton pencil beam scanning the spatially localized neutron doses and dose equivalents. The proton pencil beam of Gantry 1 at the Paul Scherrer Institute (PSI) was Monte Carlo simulated using GEANT. Based on the simulated neutron dose and neutron spectra an analytical mechanistic dose model was developed. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed model in order to calculate the neutron component of the delivered dose distribution for each treated patient. The neutron dose was estimated for two patient example cases. The analytical neutron dose model represents the three-dimensional Monte Carlo simulated dose distribution up to 85cm from the proton pencil beam with a satisfying precision. The root mean square error between Monte Carlo simulation and model is largest for 138MeV protons and is 19% and 20% for dose and dose equivalent, respectively. The model was successfully integrated into the PSI treatment planning system. In average the neutron dose is increased by 10% or 65% when using 160MeV or 177MeV instead of 138MeV. For the neutron dose equivalent the increase is 8% and 57%. The presented neutron dose calculations allow for estimates of dose that can be used in subsequent epidemiological studies or, should the need arise, to estimate the neutron dose at any point where a subsequent secondary tumour may occur. It was found that the neutron dose to the patient is heavily increased with proton energy. Copyright © 2016. Published by Elsevier GmbH.
Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling
Bloom, Everett E.; Stiegler, James O.; Rowcliffe, Arthur F.; Leitnaker, James M.
1977-03-08
The present invention is based on the discovery that radiation-induced voids which occur during fast neutron irradiation can be controlled by small but effective additions of titanium and silicon. The void-suppressing effect of these metals in combination is demonstrated and particularly apparent in austenitic stainless steels.
Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling
Bloom, Everett E.; Stiegler, James O.; Rowcliffe, Arthur F.; Leitnaker, James M.
1979-01-01
The present invention is based on the discovery that radiation-induced voids which occur during fast neutron irradiation can be controlled by small but effective additions of titanium and silicon. The void-suppressing effect of these metals in combination is demonstrated and particularly apparent in austenitic stainless steels.
A long-lived tritiated titanium target for fast neutron production
NASA Astrophysics Data System (ADS)
Hughey, B. J.
1995-03-01
Diagnostic techniques using neutron beams have a broad spectrum of applications in advanced manufacturing, explosives and contraband detection, medicine, and industry. The most suitable nuclear reaction for producing large fluxes of fast neutrons at low bombarding energy is the H(d,n)-3 He-4, i.e. d-T, reaction. The lifetime of currently used d-T neutron generators is limited by the gradual evolution of tritium gas from the target during bombardment. This paper is a report of work in progress to develop a method for inhibiting the replacement of tritium with beam deuterons and thus preventing the evolution of tritium gas leading to reduced neutron yield. It is anticipated that tritiated target lifetime can be increased by at least an order of magnitude by using a range-thin tritiated titanium target mounted on a substrate with a high hydrogen diffusivity, such as niobium. Lifetime can be further enhanced by increasing the deuteron beam bombarding energy from the typical value of 200 keV to 600 keV. The results of experiments demonstrating the effect of hydrogen diffusion coefficient on concentration of implanted beam deuterons in candidate substrate materials (Cu, Pd, and Nb) are presented, and issues relevant to the fabrication of a tritiated titanium target on a niobium substrate are discussed.
Designing of the 14 MeV neutron moderator for BNCT
NASA Astrophysics Data System (ADS)
Cheng, Dao-Wen; Lu, Jing-Bin; Yang, Dong; Liu, Yu-Min; Wang, Hui-Dong; Ma, Ke-Yan
2012-09-01
In boron neutron capture therapy (BNCT), the ratio of the fast neutron flux to the neutron flux in the tumor (RFNT) must be less than 3%. If a D-T neutron generator is used in BNCT, the 14 MeV neutron moderator must be optimized to reduce the RFNT. Based on the neutron moderation theory and the simulation results, tungsten, lead and diamond were used to moderate the 14 MeV neutrons. Satisfying RFNT of less than 3%, the maximum neutron flux in the tumor was achieved with a three-layer moderator comprised of a 3 cm thick tungsten layer, a 14 cm thick lead layer and a 21 cm thick diamond layer.
Hsieh, Mindy; Liu, Yingzi; Mostafaei, Farshad; Poulson, Jean M; Nie, Linda H
2017-02-01
Boron neutron capture therapy (BNCT) is a binary treatment modality that uses high LET particles to achieve tumor cell killing. Deuterium-deuterium (DD) compact neutron generators have advantages over nuclear reactors and large accelerators as the BNCT neutron source, such as their compact size, low cost, and relatively easy installation. The purpose of this study is to design a beam shaping assembly (BSA) for a DD neutron generator and assess the potential of a DD-based BNCT system using Monte Carlo (MC) simulations. The MC model consisted of a head phantom, a DD neutron source, and a BSA. The head phantom had tally cylinders along the centerline for computing neutron and photon fluences and calculating the dose as a function of depth. The head phantom was placed at 4 cm from the BSA. The neutron source was modeled to resemble the source of our current DD neutron generator. A BSA was designed to moderate and shape the 2.45-MeV DD neutrons to the epithermal (0.5 eV to 10 keV) range. The BSA had multiple components, including moderator, reflector, collimator, and filter. Various materials and configurations were tested for each component. Each BSA layout was assessed in terms of the in-air and in-phantom parameters. The maximum brain dose was limited to 12.5 Gray-Equivalent (Gy-Eq) and the skin dose to 18 Gy-Eq. The optimized BSA configuration included 30 cm of lead for reflector, 45 cm of LiF, and 10 cm of MgF 2 for moderator, 10 cm of lead for collimator, and 0.1 mm of cadmium for thermal neutron filter. Epithermal flux at the beam aperture was 1.0 × 10 5 n epi /cm 2 -s; thermal-to-epithermal neutron ratio was 0.05; fast neutron dose per epithermal was 5.5 × 10 -13 Gy-cm 2 /φ epi , and photon dose per epithermal was 2.4 × 10 -13 Gy-cm 2 /φ epi . The AD, AR, and the advantage depth dose rate were 12.1 cm, 3.7, and 3.2 × 10 -3 cGy-Eq/min, respectively. The maximum skin dose was 0.56 Gy-Eq. The DD neutron yield that is needed to
Optimizing Dense Plasma Focus Neutron Yields With Fast Gas Jets
NASA Astrophysics Data System (ADS)
McMahon, Matthew; Stein, Elizabeth; Higginson, Drew; Kueny, Christopher; Link, Anthony; Schmidt, Andrea
2017-10-01
We report a study using the particle-in-cell code LSP to perform fully kinetic simulations modeling dense plasma focus (DPF) devices with high density gas jets on axis. The high-density jets are modeled in the large-eddy Navier-Stokes code CharlesX, which is suitable for modeling both sub-sonic and supersonic gas flow. The gas pattern, which is essentially static on z-pinch time scales, is imported from CharlesX to LSP for neutron yield predictions. Fast gas puffs allow for more mass on axis while maintaining the optimal pressure for the DPF. As the density of a subsonic jet increases relative to the background fill, we find the neutron yield increases, as does the variability in the neutron yield. Introducing perturbations in the jet density via super-sonic flow (also known as Mach diamonds) allow for consistent seeding of the m =0 instability leading to more consistent ion acceleration and higher neutron yields with less variability. Jets with higher on axis density are found to have the greatest yield. The optimal jet configuration and the necessary jet conditions for increasing neutron yield and reducing yield variability are explored. Simulations of realistic jet profiles are performed and compared to the ideal scenario. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (15-ERD-034) at LLNL.
Fast ion beta limit measurements by collimated neutron detection in MST plasmas
NASA Astrophysics Data System (ADS)
Capecchi, William; Anderson, Jay; Bonofiglo, Phillip; Kim, Jungha; Sears, Stephanie
2015-11-01
Fast ion orbits in the reversed field pinch (RFP) are well ordered and classically confined despite magnetic field stochasticity generated by multiple tearing modes. Classical TRANSP modeling of a 1MW tangentially injected hydrogen neutral beam in MST deuterium plasmas predicts a core-localized fast ion density that can be up to 25% of the electron density and a fast ion beta of many times the local thermal beta. However, neutral particle analysis of an NBI-driven mode (presumably driven by a fast ion pressure gradient) shows mode-induced transport of core-localized fast ions and a saturated fast ion density. The TRANSP modeling is presumed valid until the onset of the beam-driven mode and gives an initial estimate of the volume-averaged fast ion beta of 1-2% (local core value up to 10%). A collimated neutron detector for fusion product profile measurements will be used to determine the spatial distribution of fast ions, allowing for a first measurement of the critical fast-ion pressure gradient required for mode destabilization. Testing/calibration data and initial fast-ion profiles will be presented. Characterization of both the local and global fast ion beta will be done for deuterium beam injection into deuterium plasmas for comparison to TRANSP predictions. Work supported by US DOE.
Methods for absorbing neutrons
Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID
2012-07-24
A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.
GPU-based prompt gamma ray imaging from boron neutron capture therapy.
Yoon, Do-Kun; Jung, Joo-Young; Jo Hong, Key; Sil Lee, Keum; Suk Suh, Tae
2015-01-01
The purpose of this research is to perform the fast reconstruction of a prompt gamma ray image using a graphics processing unit (GPU) computation from boron neutron capture therapy (BNCT) simulations. To evaluate the accuracy of the reconstructed image, a phantom including four boron uptake regions (BURs) was used in the simulation. After the Monte Carlo simulation of the BNCT, the modified ordered subset expectation maximization reconstruction algorithm using the GPU computation was used to reconstruct the images with fewer projections. The computation times for image reconstruction were compared between the GPU and the central processing unit (CPU). Also, the accuracy of the reconstructed image was evaluated by a receiver operating characteristic (ROC) curve analysis. The image reconstruction time using the GPU was 196 times faster than the conventional reconstruction time using the CPU. For the four BURs, the area under curve values from the ROC curve were 0.6726 (A-region), 0.6890 (B-region), 0.7384 (C-region), and 0.8009 (D-region). The tomographic image using the prompt gamma ray event from the BNCT simulation was acquired using the GPU computation in order to perform a fast reconstruction during treatment. The authors verified the feasibility of the prompt gamma ray image reconstruction using the GPU computation for BNCT simulations.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Krieger, John N.; Krall, John M.; Laramore, George E.
1987-01-01
Between June, 1977 and April, 1983 the Radiation Therapy Oncology Group (RTOG) sponsored a Phase III study comparing fast neutron radiotherapy as part of a mixed beam (neutron/photon) regimen with conventional photon (x-ray) radiotherapy for patients with locally advanced (stages C and o1 ) adenocarcinoma of the prostate. A total of 91 analyzable patients were entered into the study with -the two treatment groups being balanced in regard to all major prognostic variables. The current analysis is for a median follow-up of 6.7 years (range 3.4-9.0). Actuarial curves are presented for local/regional control, overall survival and "determinantal" survival. The resultsmore » are statistically significant in favor of the mixed beam group for all of the above parameters. At 5 years the local control rate is 81% on the mixed beam arm compared to 60% on the photon arm. Histologic evidence of residual prostatic carcinoma was documented in six patients with no clinical evidence of disease on both treatment arms. The actuarial overall survival rate at S years is 70% on the mixed beam compared to 56% on the photon arm. The determinantal survival at 5 years was 82%. on the mixed beam arm compared to 61% on the photon arm. The type of therapy appeared to be the most important predictor of both local tumor control and patient survival in a step-wise Cox analysis. There was no difference in the treatment related morbidity for the two patient groups. Mixed beam therapy may be superior to standard photon radiotherapy for treatment of locally advanced prostate cancer.« less
Phenotypic and genomic analyses of a fast neutron mutant population resource in soybean
USDA-ARS?s Scientific Manuscript database
Mutagenized populations have become indispensable resources for introducing variation and studying gene function in plant genomics research. In this study, fast neutron (FN) radiation was used to induce deletion mutations in the soybean (Glycine max (L.) Merrill) genome. Approximately 120,000 soybea...
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chandrashekhar, MVS
The objective is to develop and implement a superior low-cost, large area (potentially >32in), easily deployable, close proximity, harsh environment innovative neutron sensor needed for next generation fuel cycle monitoring. We will exploit recent breakthroughs at the PI’s lab on the electrochemistry of epitaxial graphene (EG) formed on commercial SiC wafers, a transformative nanomaterial system with superior radiation detection and durability properties to develop a new paradigm in detection for fast neutrons, a by-product of fission reactors. There are currently few effective detection/monitoring schemes, especially solid-state ones at present. This is essential for monitoring and control of future fuel cyclesmore » to make them more efficient and reliable. By exploiting these novel materials, as well as innovative hybrid SiC/EG/Cladding device architectures conceived by the team, will develop low-cost, high performance solutions to fast-neutron detection. Finally, we will also explore 3-terminal device implementations for neutron detectors with built-in electronic gain to further shrink these devices and improve their sensitivity.« less
Boron containing compounds and their preparation and use in neutron capture therapy
Gabel, D.
1992-09-01
The present invention pertains to boron containing thiouracil derivatives, their method of preparations, and their use in the therapy of malignant melanoma using boron neutron capture therapy. No Drawings
Boron neutron capture therapy of malignant brain tumors at the Brookhaven Medical Research Reactor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Joel, D.D.; Coderre, J.A.; Chanana, A.D.
1996-12-31
Boron neutron capture therapy (BNCT) is a bimodal form of radiation therapy for cancer. The first component of this treatment is the preferential localization of the stable isotope {sup 10}B in tumor cells by targeting with boronated compounds. The tumor and surrounding tissue is then irradiated with a neutron beam resulting in thermal neutron/{sup 10}B reactions ({sup 10}B(n,{alpha}){sup 7}Li) resulting in the production of localized high LET radiation from alpha and {sup 7}Li particles. These products of the neutron capture reaction are very damaging to cells, but of short range so that the majority of the ionizing energy released ismore » microscopically confined to the vicinity of the boron-containing compound. In principal it should be possible with BNCT to selectively destroy small nests or even single cancer cells located within normal tissue. It follows that the major improvements in this form of radiation therapy are going to come largely from the development of boron compounds with greater tumor selectivity, although there will certainly be advances made in neutron beam quality as well as the possible development of alternative sources of neutron beams, particularly accelerator-based epithermal neutron beams.« less
Cellular uptake and in vitro antitumor efficacy of composite liposomes for neutron capture therapy.
Peters, Tanja; Grunewald, Catrin; Blaickner, Matthias; Ziegner, Markus; Schütz, Christian; Iffland, Dorothee; Hampel, Gabriele; Nawroth, Thomas; Langguth, Peter
2015-02-22
Neutron capture therapy for glioblastoma has focused mainly on the use of (10)B as neutron capture isotope. However, (157)Gd offers several advantages over boron, such as higher cross section for thermal neutrons and the possibility to perform magnetic resonance imaging during neutron irradiation, thereby combining therapy and diagnostics. We have developed different liposomal formulations of gadolinium-DTPA (Magnevist®) for application in neutron capture therapy of glioblastoma. The formulations were characterized physicochemically and tested in vitro in a glioma cell model for their effectiveness. Liposomes entrapping gadolinium-DTPA as neutron capture agent were manufactured via lipid/film-extrusion method and characterized with regard to size, entrapment efficiency and in vitro release. For neutron irradiation, F98 and LN229 glioma cells were incubated with the newly developed liposomes and subsequently irradiated at the thermal column of the TRIGA reactor in Mainz. The dose rate derived from neutron irradiation with (157)Gd as neutron capturing agent was calculated via Monte Carlo simulations and set in relation to the respective cell survival. The liposomal Gd-DTPA reduced cell survival of F98 and LN229 cells significantly. Differences in liposomal composition of the formulations led to distinctly different outcome in cell survival. The amount of cellular Gd was not at all times proportional to cell survival, indicating that intracellular deposition of formulated Gd has a major influence on cell survival. The majority of the dose contribution arises from photon cross irradiation compared to a very small Gd-related dose. Liposomal gadolinium formulations represent a promising approach for neutron capture therapy of glioblastoma cells. The liposome composition determines the uptake and the survival of cells following radiation, presumably due to different uptake pathways of liposomes and intracellular deposition of gadolinium-DTPA. Due to the small range of
Pozzi, E; Nigg, D W; Miller, M; Thorp, S I; Heber, E M; Zarza, L; Estryk, G; Monti Hughes, A; Molinari, A J; Garabalino, M; Itoiz, M E; Aromando, R F; Quintana, J; Trivillin, V A; Schwint, A E
2009-07-01
The National Atomic Energy Commission of Argentina (CNEA) constructed a novel thermal neutron source for use in boron neutron capture therapy (BNCT) applications at the RA-3 research reactor facility located in Buenos Aires. The aim of the present study was to perform a dosimetric characterization of the facility and undertake radiobiological studies of BNCT in an experimental model of oral cancer in the hamster cheek pouch. The free-field thermal flux was 7.1 x 10(9) n cm(-2)s(-1) and the fast neutron flux was 2.5 x 10(6) n cm(-2)s(-1), indicating a very well-thermalized neutron field with negligible fast neutron dose. For radiobiological studies it was necessary to shield the body of the hamster from the neutron flux while exposing the everted cheek pouch bearing the tumors. To that end we developed a lithium (enriched to 95% in (6)Li) carbonate enclosure. Groups of tumor-bearing hamsters were submitted to BPA-BNCT, GB-10-BNCT, (GB-10+BPA)-BNCT or beam only treatments. Normal (non-cancerized) hamsters were treated similarly to evaluate normal tissue radiotoxicity. The total physical dose delivered to tumor with the BNCT treatments ranged from 6 to 8.5 Gy. Tumor control at 30 days ranged from 73% to 85%, with no normal tissue radiotoxicity. Significant but reversible mucositis in precancerous tissue surrounding tumors was associated to BPA-BNCT. The therapeutic success of different BNCT protocols in treating experimental oral cancer at this novel facility was unequivocally demonstrated.
Generation of peanut mutants by fast neutron irradiation combined with in vitro culture
Wang, Jing-Shan; Sui, Jiong-Ming; Xie, Yong-Dun; Guo, Hui-Jun; Qiao, Li-Xian; Zhao, Li-Lan; Yu, Shan-Lin; Liu, Lu-Xiang
2015-01-01
Induced mutations have played an important role in the development of new plant varieties. In this study, we investigated the effects of fast neutron irradiation on somatic embryogenesis combined with plant regeneration in embryonic leaflet culture to develop new peanut (Arachis hypogaea L.) germplasm for breeding. The dry seeds of the elite cultivar Luhua 11 were irradiated with fast neutrons at dosages of 9.7, 14.0 and 18.0 Gy. The embryonic leaflets were separated and incubated in a medium with 10.0-mg/l 2,4-D to induce somatic embryogenesis. Next, they were incubated in a medium with 4.0-mg/l BAP for plant regeneration. As the irradiation dosage increased, the frequency of both somatic embryo formation and plantlet regeneration decreased. The regenerated plantlets were grafted onto rootstocks and were transplanted into the field. Later, the mature seeds of the regenerated plants were harvested. The M2 generation plants from most of the regenerated cultivars exhibited variations and segregation in vigor, plant height, branch and pod number, pod size, and pod shape. To determine whether the phenotypes were associated with genomic modification, we compared the DNA polymorphisms between the wild-type plants and 19 M3-generation individuals from different regenerated plants. We used 20 pairs of simple sequence repeat (SSR) primers and detected polymorphisms between most of the mutants and the wild-type plants (Luhua 11). Our results indicate that using a combination of fast neutron irradiation and tissue culture is an effective approach for creating new peanut germplasm. PMID:25653418
Lee, Pei-Yi; Liu, Yuan-Hao; Jiang, Shiang-Huei
2014-06-01
High energy proton beam (>8MeV) is favorable for producing neutrons with high yield. However, the produced neutrons are of high energies. These high energy neutrons can cause severe fast neutron contamination and degrade the BNCT treatment quality if they are not appropriately moderated. Hence, this study aims to briefly discuss the issue, from the viewpoint of fast neutron contamination control, whether high energy proton beam is ideal for AB-BNCT or not. In this study, D2O, PbF4, CaF2, and Fluental(™) were used standalone as moderator materials to slow down 1-, 6-, and 10-MeV parallelly incident neutrons. From the calculated results, we concluded that neutrons produced by high energy proton beam could not be easily moderated by a single moderator to an acceptable contamination level and still with reasonable epithermal neutron beam intensity. Hence, much more complicated and sophisticated designs of beam shaping assembly have to be developed when using high energy proton beams. Copyright © 2014 Elsevier Ltd. All rights reserved.
Coupled neutronics and thermal-hydraulics numerical simulations of a Molten Fast Salt Reactor (MFSR)
NASA Astrophysics Data System (ADS)
Laureau, A.; Rubiolo, P. R.; Heuer, D.; Merle-Lucotte, E.; Brovchenko, M.
2014-06-01
Coupled neutronics and thermalhydraulic numerical analyses of a molten salt fast reactor are presented. These preliminary numerical simulations are carried-out using the Monte Carlo code MCNP and the Computation Fluid Dynamic code OpenFOAM. The main objectives of this analysis performed at steady-reactor conditions are to confirm the acceptability of the current neutronic and thermalhydraulic designs of the reactor, to study the effects of the reactor operating conditions on some of the key MSFR design parameters such as the temperature peaking factor. The effects of the precursor's motion on the reactor safety parameters such as the effective fraction of delayed neutrons have been evaluated.
Fast response neutron emission monitor for fusion reactor using stilbene scintillator and Flash-ADC.
Itoga, T; Ishikawa, M; Baba, M; Okuji, T; Oishi, T; Nakhostin, M; Nishitani, T
2007-01-01
The stilbene neutron detector which has been used for neutron emission profile monitoring in JT-60U has been improved, to respond to the requirement to observe the high-frequency phenomena in megahertz region such as toroidicity-induced Alfvén Eigen mode in burning plasma as well as the spatial profile and the energy spectrum. This high-frequency phenomenon is of great interest and one of the key issues in plasma physics in recent years. To achieve a fast response in the stilbene detector, a Flash-ADC is applied and the wave form of the anode signal stored directly, and neutron/gamma discrimination was carried out via software with a new scheme for data acquisition mode to extend the count rate limit to MHz region from 1.3 x 10(5) neutron/s in the past, and confirmed the adequacy of the method.
A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment.
Holley, A T; Broussard, L J; Davis, J L; Hickerson, K; Ito, T M; Liu, C-Y; Lyles, J T M; Makela, M; Mammei, R R; Mendenhall, M P; Morris, C L; Mortensen, R; Pattie, R W; Rios, R; Saunders, A; Young, A R
2012-07-01
The UCNA collaboration is making a precision measurement of the β asymmetry (A) in free neutron decay using polarized ultracold neutrons (UCN). A critical component of this experiment is an adiabatic fast passage neutron spin flipper capable of efficient operation in ambient magnetic fields on the order of 1 T. The requirement that it operate in a high field necessitated the construction of a free neutron spin flipper based, for the first time, on a birdcage resonator. The design, construction, and initial testing of this spin flipper prior to its use in the first measurement of A with UCN during the 2007 run cycle of the Los Alamos Neutron Science Center's 800 MeV proton accelerator is detailed. These studies determined the flipping efficiency of the device, averaged over the UCN spectrum present at the location of the spin flipper, to be ̅ε=0.9985(4).
Boron Neutron Capture Therapy in the Treatment of Recurrent Laryngeal Cancer.
Haapaniemi, Aaro; Kankaanranta, Leena; Saat, Riste; Koivunoro, Hanna; Saarilahti, Kauko; Mäkitie, Antti; Atula, Timo; Joensuu, Heikki
2016-05-01
To investigate the safety and efficacy of boron neutron capture therapy (BNCT) as a larynx-preserving treatment option for patients with recurrent laryngeal cancer. Six patients with locally recurrent squamous cell laryngeal carcinoma and 3 patients with persistent laryngeal cancer after prior treatment were treated with BNCT at the FiR1 facility (Espoo, Finland) in 2006 to 2012. The patients had received prior radiation therapy with or without concomitant chemotherapy to a cumulative median dose of 66 Gy. The median tumor diameter was 2.9 cm (range, 1.4-10.9 cm) before BNCT. Boron neutron capture therapy was offered on a compassionate basis to patients who either refused laryngectomy (n=7) or had an inoperable tumor (n=2). Boronophenylalanine-fructose (400 mg/kg) was used as the boron carrier and was infused over 2 hours intravenously before neutron irradiation. Six patients received BNCT once and 3 twice. The estimated average gross tumor volume dose ranged from 22 to 38 Gy (W) (mean; 29 Gy [W]). Six of the 8 evaluable patients responded to BNCT; 2 achieved complete and 4 partial response. One patient died early and was not evaluable for response. Most common side effects were stomatitis, fatigue, and oral pain. No life-threatening or grade 4 toxicity was observed. The median time to progression within the target volume was 6.6 months, and the median overall survival time 13.3 months after BNCT. One patient with complete response is alive and disease-free with a functioning larynx 60 months after BNCT. Boron neutron capture therapy given after prior external beam radiation therapy is well tolerated. Most patients responded to BNCT, but long-term survival with larynx preservation was infrequent owing to cancer progression. Selected patients with recurrent laryngeal cancer may benefit from BNCT. Copyright © 2016 Elsevier Inc. All rights reserved.
Feeding of Rh and Ag isomers in fast-neutron-induced reactions
Fotiades, Nikolaos; Devlin, Matthew James; Nelson, Ronald Owen; ...
2016-10-17
In (n,n') reactions on stable Ir and Au isotopes in the mass A=190 region, the experimentally established feeding of the isomers relative to the feeding of the corresponding ground states increases with increasing neutron energy, up to the neutron energy where the (n,2n) reaction channel opens up, and then decreases. In order to check for similar behavior in the mass A=100 region, the feeding of isomers and ground states in fast-neutron-induced reactions on stable isotopes in this mass region was studied. This is of especial interest for Rh which can be used as a radiochemical detector. Here, excited states weremore » studied using the (n,n'γ), (n,2nγ), and (n,3nγ) reactions on 103Rh and 109Ag. A germanium detector array for γ-ray detection and the broad-spectrum pulsed neutron source of the Los Alamos Neutron Science Center's Weapons Neutron Research facility were used for the measurement. The energy of the incident neutrons was determined using the time-of-flight technique. Absolute partial γ-ray cross sections were measured for 57 transitions feeding isomers and ground states in 101,102,103Rh and 107,108,109Ag. The feeding of the isomers was found to be very similar in the corresponding reaction channels and it is compared to the feeding determined for the ground states. In conclusion, the opening of reaction channels at higher neutron energies removes angular momentum from the residual nucleus and reduces the population of the higher-spin isomers relative to the feeding of the lower-spin ground states. Similar behavior was observed in the mass A=190 region in the feeding of higher-spin isomers, but the reverse behavior was observed in 176Lu with a lower-spin isomer and a higher-spin ground state.« less
Feeding of Rh and Ag isomers in fast-neutron-induced reactions
NASA Astrophysics Data System (ADS)
Fotiades, N.; Devlin, M.; Nelson, R. O.; Kawano, T.; Carroll, J. J.
2016-10-01
Background: In (n ,n' ) reactions on stable Ir and Au isotopes in the mass A =190 region, the experimentally established feeding of the isomers relative to the feeding of the corresponding ground states increases with increasing neutron energy, up to the neutron energy where the (n ,2 n ) reaction channel opens up, and then decreases. Purpose: In order to check for similar behavior in the mass A =100 region, the feeding of isomers and ground states in fast-neutron-induced reactions on stable isotopes in this mass region was studied. This is of especial interest for Rh which can be used as a radiochemical detector. Methods: Excited states were studied using the (n ,n'γ ), (n ,2 n γ ), and (n ,3 n γ ) reactions on 103Rh and 109Ag. A germanium detector array for γ -ray detection and the broad-spectrum pulsed neutron source of the Los Alamos Neutron Science Center's Weapons Neutron Research facility were used for the measurement. The energy of the incident neutrons was determined using the time-of-flight technique. Results: Absolute partial γ -ray cross sections were measured for 57 transitions feeding isomers and ground states in 101,102,103Rh and 107,108,109Ag. The feeding of the isomers was found to be very similar in the corresponding reaction channels and it is compared to the feeding determined for the ground states. Conclusions: The opening of reaction channels at higher neutron energies removes angular momentum from the residual nucleus and reduces the population of the higher-spin isomers relative to the feeding of the lower-spin ground states. Similar behavior was observed in the mass A =190 region in the feeding of higher-spin isomers, but the reverse behavior was observed in 176Lu with a lower-spin isomer and a higher-spin ground state.
Feeding of Rh and Ag isomers in fast-neutron-induced reactions
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fotiades, Nikolaos; Devlin, Matthew James; Nelson, Ronald Owen
In (n,n') reactions on stable Ir and Au isotopes in the mass A=190 region, the experimentally established feeding of the isomers relative to the feeding of the corresponding ground states increases with increasing neutron energy, up to the neutron energy where the (n,2n) reaction channel opens up, and then decreases. In order to check for similar behavior in the mass A=100 region, the feeding of isomers and ground states in fast-neutron-induced reactions on stable isotopes in this mass region was studied. This is of especial interest for Rh which can be used as a radiochemical detector. Here, excited states weremore » studied using the (n,n'γ), (n,2nγ), and (n,3nγ) reactions on 103Rh and 109Ag. A germanium detector array for γ-ray detection and the broad-spectrum pulsed neutron source of the Los Alamos Neutron Science Center's Weapons Neutron Research facility were used for the measurement. The energy of the incident neutrons was determined using the time-of-flight technique. Absolute partial γ-ray cross sections were measured for 57 transitions feeding isomers and ground states in 101,102,103Rh and 107,108,109Ag. The feeding of the isomers was found to be very similar in the corresponding reaction channels and it is compared to the feeding determined for the ground states. In conclusion, the opening of reaction channels at higher neutron energies removes angular momentum from the residual nucleus and reduces the population of the higher-spin isomers relative to the feeding of the lower-spin ground states. Similar behavior was observed in the mass A=190 region in the feeding of higher-spin isomers, but the reverse behavior was observed in 176Lu with a lower-spin isomer and a higher-spin ground state.« less
Shimaoka, T; Kaneko, J H; Arikawa, Y; Isobe, M; Sato, Y; Tsubota, M; Nagai, T; Kojima, S; Abe, Y; Sakata, S; Fujioka, S; Nakai, M; Shiraga, H; Azechi, H; Chayahara, A; Umezawa, H; Shikata, S
2015-05-01
A neutron bang time and burn history monitor in inertial confinement fusion with fast ignition are necessary for plasma diagnostics. In the FIREX project, however, no detector attained those capabilities because high-intensity X-rays accompanied fast electrons used for plasma heating. To solve this problem, single-crystal CVD diamond was grown and fabricated into a radiation detector. The detector, which had excellent charge transportation property, was tested to obtain a response function for intense X-rays. The applicability for neutron bang time and burn history monitor was verified experimentally. Charge collection efficiency of 99.5% ± 0.8% and 97.1% ± 1.4% for holes and electrons were obtained using 5.486 MeV alpha particles. The drift velocity at electric field which saturates charge collection efficiency was 1.1 ± 0.4 × 10(7) cm/s and 1.0 ± 0.3 × 10(7) cm/s for holes and electrons. Fast response of several ns pulse width for intense X-ray was obtained at the GEKKO XII experiment, which is sufficiently fast for ToF measurements to obtain a neutron signal separately from X-rays. Based on these results, we confirmed that the single-crystal CVD diamond detector obtained neutron signal with good S/N under ion temperature 0.5-1 keV and neutron yield of more than 10(9) neutrons/shot.
NASA Astrophysics Data System (ADS)
Hälg, R. A.; Besserer, J.; Boschung, M.; Mayer, S.; Lomax, A. J.; Schneider, U.
2014-05-01
In radiation therapy, high energy photon and proton beams cause the production of secondary neutrons. This leads to an unwanted dose contribution, which can be considerable for tissues outside of the target volume regarding the long term health of cancer patients. Due to the high biological effectiveness of neutrons in regards to cancer induction, small neutron doses can be important. This study quantified the neutron doses for different radiation therapy modalities. Most of the reports in the literature used neutron dose measurements free in air or on the surface of phantoms to estimate the amount of neutron dose to the patient. In this study, dose measurements were performed in terms of neutron dose equivalent inside an anthropomorphic phantom. The neutron dose equivalent was determined using track etch detectors as a function of the distance to the isocenter, as well as for radiation sensitive organs. The dose distributions were compared with respect to treatment techniques (3D-conformal, volumetric modulated arc therapy and intensity-modulated radiation therapy for photons; spot scanning and passive scattering for protons), therapy machines (Varian, Elekta and Siemens linear accelerators) and radiation quality (photons and protons). The neutron dose equivalent varied between 0.002 and 3 mSv per treatment gray over all measurements. Only small differences were found when comparing treatment techniques, but substantial differences were observed between the linear accelerator models. The neutron dose equivalent for proton therapy was higher than for photons in general and in particular for double-scattered protons. The overall neutron dose equivalent measured in this study was an order of magnitude lower than the stray dose of a treatment using 6 MV photons, suggesting that the contribution of the secondary neutron dose equivalent to the integral dose of a radiotherapy patient is small.
Hälg, R A; Besserer, J; Boschung, M; Mayer, S; Lomax, A J; Schneider, U
2014-05-21
In radiation therapy, high energy photon and proton beams cause the production of secondary neutrons. This leads to an unwanted dose contribution, which can be considerable for tissues outside of the target volume regarding the long term health of cancer patients. Due to the high biological effectiveness of neutrons in regards to cancer induction, small neutron doses can be important. This study quantified the neutron doses for different radiation therapy modalities. Most of the reports in the literature used neutron dose measurements free in air or on the surface of phantoms to estimate the amount of neutron dose to the patient. In this study, dose measurements were performed in terms of neutron dose equivalent inside an anthropomorphic phantom. The neutron dose equivalent was determined using track etch detectors as a function of the distance to the isocenter, as well as for radiation sensitive organs. The dose distributions were compared with respect to treatment techniques (3D-conformal, volumetric modulated arc therapy and intensity-modulated radiation therapy for photons; spot scanning and passive scattering for protons), therapy machines (Varian, Elekta and Siemens linear accelerators) and radiation quality (photons and protons). The neutron dose equivalent varied between 0.002 and 3 mSv per treatment gray over all measurements. Only small differences were found when comparing treatment techniques, but substantial differences were observed between the linear accelerator models. The neutron dose equivalent for proton therapy was higher than for photons in general and in particular for double-scattered protons. The overall neutron dose equivalent measured in this study was an order of magnitude lower than the stray dose of a treatment using 6 MV photons, suggesting that the contribution of the secondary neutron dose equivalent to the integral dose of a radiotherapy patient is small.
A novel liquid-Xenon detector concept for combined fast-neutrons and gamma imaging and spectroscopy
NASA Astrophysics Data System (ADS)
Breskin, A.; Israelashvili, I.; Cortesi, M.; Arazi, L.; Shchemelinin, S.; Chechik, R.; Dangendorf, V.; Bromberger, B.; Vartsky, D.
2012-06-01
A new detector concept is presented for combined imaging and spectroscopy of fast-neutrons and gamma rays. It comprises a liquid-Xenon (LXe) converter and scintillator coupled to a UV-sensitive gaseous imaging photomultiplier (GPM). Radiation imaging is obtained by localization of the scintillation-light from LXe with the position-sensitive GPM. The latter comprises a cascade of Thick Gas Electron Multipliers (THGEM), where the first element is coated with a CsI UV-photocathode. We present the concept and provide first model-simulation results of the processes involved and the expected performances of a detector having a LXe-filled capillaries converter. The new detector concept has potential applications in combined fast-neutron and gamma-ray screening of hidden explosives and fissile materials with pulsed sources.
Sato, Eisuke; Zaboronok, Alexander; Yamamoto, Tetsuya; Nakai, Kei; Taskaev, Sergey; Volkova, Olga; Mechetina, Ludmila; Taranin, Alexander; Kanygin, Vladimir; Isobe, Tomonori; Mathis, Bryan J; Matsumura, Akira
2018-01-01
Abstract In the current article, we provide in vitro efficacy evaluation of a unique accelerator-based neutron source, constructed at the Budker Institute of Nuclear Physics (Novosibirsk, Russian Federation), for boron neutron capture therapy (BNCT), which is particularly effective in the case of invasive cancers. U251MG, CHO-K1 and V79 cells were incubated and irradiated in various concentrations of boric acid with epithermal neutrons for 2–3 h in a plexiglass phantom, using 2.0 MeV proton energy and 1.5–3.0 mA proton current, resulting in a neutron fluence of 2.16 × 1012 cm−2. The survival curves of cells loaded with boron were normalized to those irradiated without boron (to exclude the influence of the fast neutron and gamma dose components) and fit to the linear–quadratic (LQ) model. Colony formation assays showed the following cell survival rates (means ± SDs): CHO-K1: 0.348 ± 0.069 (10 ppm), 0.058 ± 0.017 (20 ppm), 0.018 ± 0.005 (40 ppm); V79: 0.476 ± 0.160 (10 ppm), 0.346 ± 0.053 (20 ppm), 0.078 ± 0.015 (40 ppm); and U251MG: 0.311 ± 0.061 (10 ppm), 0.131 ± 0.022 (20 ppm), 0.020 ± 0.010 (40 ppm). The difference between treated cells and controls was significant in all cases (P < 0.01) and confirmed that the neutron source and irradiation regimen were sufficient for control over cell colony formation. We believe our study will serve as a model for ongoing in vitro experiments on neutron capture therapy to advance in this area for further development of accelerator-based BNCT into the clinical phase. PMID:29281044
Bubble masks for time-encoded imaging of fast neutrons.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brubaker, Erik; Brennan, James S.; Marleau, Peter
2013-09-01
Time-encoded imaging is an approach to directional radiation detection that is being developed at SNL with a focus on fast neutron directional detection. In this technique, a time modulation of a detected neutron signal is inducedtypically, a moving mask that attenuates neutrons with a time structure that depends on the source position. An important challenge in time-encoded imaging is to develop high-resolution two-dimensional imaging capabilities; building a mechanically moving high-resolution mask presents challenges both theoretical and technical. We have investigated an alternative to mechanical masks that replaces the solid mask with a liquid such as mineral oil. Instead of fixedmore » blocks of solid material that move in pre-defined patterns, the oil is contained in tubing structures, and carefully introduced air gapsbubblespropagate through the tubing, generating moving patterns of oil mask elements and air apertures. Compared to current moving-mask techniques, the bubble mask is simple, since mechanical motion is replaced by gravity-driven bubble propagation; it is flexible, since arbitrary bubble patterns can be generated by a software-controlled valve actuator; and it is potentially high performance, since the tubing and bubble size can be tuned for high-resolution imaging requirements. We have built and tested various single-tube mask elements, and will present results on bubble introduction and propagation as a function of tubing size and cross-sectional shape; real-time bubble position tracking; neutron source imaging tests; and reconstruction techniques demonstrated on simple test data as well as a simulated full detector system.« less
Tanaka, Kenichi; Endo, Satoru; Hoshi, Masaharu
2010-01-01
The imaging plate (IP) technique is tried to be used as a handy method to measure the spatial neutron distribution via the (157)Gd(n,gamma)(158)Gd reaction for neutron capture therapy (NCT). For this purpose, IP is set in a water phantom and irradiated in a mixed field of neutrons and gamma-rays. The Hiroshima University Radiobiological Research Accelerator is utilized for this experiment. The neutrons are moderated with 20-cm-thick D(2)O to obtain suitable neutron field for NCT. The signal for IP doped with Gd as a neutron-response enhancer is subtracted with its contribution by gamma-rays, which was estimated using IP without Gd. The gamma-ray response of Gd-doped IP to non-Gd IP is set at 1.34, the value measured for (60)Co gamma-rays, in estimating the gamma-ray contribution to Gd-doped IP signal. Then measured distribution of the (157)Gd(n,gamma)(158)Gd reaction rate agrees within 10% with the calculated value based on the method that has already been validated for its reproducibility of Au activation. However, the evaluated distribution of the (157)Gd(n,gamma)(158)Gd reaction rate is so sensitive to gamma-ray energy, e.g. the discrepancy of the (157)Gd(n,gamma)(158)Gd reaction rate between measurement and calculation becomes 30% for the photon energy change from 33keV to 1.253MeV.
NASA Technical Reports Server (NTRS)
Livingston, R. A.; Schweitzer, J. S.; Parsons, Ann M.; Arens, Ellen E.
2010-01-01
The liquid hydrogen and oxygen cryogenic storage tanks at John F. Kennedy Space Center (KSC) use expanded perlite as thermal insulation. Th ere is evidence that some of the perlite has compacted over time, com promising the thermal performance and possibly also structural integr ity of the tanks. Therefore an Non-destructive Testing (NDT) method for measuring the perlite density or void fraction is urgently needed. Methods based on neutrons are good candidates because they can readil y penetrate through the 1.75 cm outer steel shell and through the ent ire 120 cm thickness of the perlite zone. Neutrons interact with the nuclei of materials to produce characteristic gamma rays which are the n detected. The gamma ray signal strength is proportional to the atom ic number density. Consequently, if the perlite is compacted then the count rates in the individual peaks in the gamma ray spectrum will i ncrease. Perlite is a feldspathic volcanic rock made up of the major elements Si, AI, Na, K and 0 along with some water. With commercially available portable neutron generators it is possible to produce simul taneously fluxes of neutrons in two energy ranges: fast (14 MeV) and thermal (25 meV). Fast neutrons produce gamma rays by inelastic scatt ering which is sensitive to Fe and O. Thermal neutrons produce gamma rays by radiative capture in prompt gamma neutron activation (PGNA) and this is sensitive to Si, AI, Na, Kand H. Thus the two energy ranges produce complementary information. The R&D program has three phases: numerical simulations of neutron and gamma ray transport with MCNP s oftware, evaluation of the system in the laboratory on test articles and finally mapping of the perlite density in the cryogenic tanks at KSC. The preliminary MCNP calculations have shown that the fast/therma l neutron NDT method is capable of distinguishing between expanded an d compacted perlite with excellent statistics.
Fast neutron response of 6Li-depleted CLYC detectors up to 20 MeV
NASA Astrophysics Data System (ADS)
D`Olympia, N.; Chowdhury, P.; Jackson, E. G.; Lister, C. J.
2014-11-01
The response of 6Li-depleted Cs2LiYCl6 (CLYC) to high-energy neutrons has been investigated using a pair of 1 in.×1 in. crystals. These are the first two detectors of their kind, which will comprise a 16-element array for studies in fast neutron spectroscopy. Their thermal neutron response has been compared with standard CLYC crystals with a 6Li enrichment of 95%, demonstrating excellent suppression of the overwhelming thermal neutron background. The response to mono-energetic neutrons over a range of 0.5 to 20 MeV was tested. From this, the response function, energy resolution, and pulse-shape discrimination up to 20 MeV were characterized. Detailed Monte Carlo investigations with MCNPX have been used to show that the dominant reaction mechanisms contributing to the observed response are 35Cl(n,p) and 35Cl(n,α). Preliminary investigations have also demonstrated the possibility for separating events from these two reactions.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ferone, Raffaello; Issa, Fatima; Ottaviani, Laurent
In the framework of the European I SMART project, we have designed and made new SiC-based nuclear radiation detectors able to operate in harsh environments and to detect both fast and thermal neutrons. In this paper, we report experimental results of fast neutron irradiation campaign at high temperature (106 deg. C) in quasi-realistic working conditions. Our device does not suffer from high temperature, and spectra do show strong stability, preserving features. These experiments, as well as others in progress, show the I SMART SiC-based device skills to operate in harsh environments, whereas other materials would strongly suffer from degradation. Workmore » is still demanded to test our device at higher temperatures and to enhance efficiency in order to make our device fully exploitable from an industrial point of view. (authors)« less
High Conduction Neutron Absorber to Simulate Fast Reactor Environment in an Existing Test Reactor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Guillen, Donna; Greenwood, Lawrence R.; Parry, James
2014-06-22
A need was determined for a thermal neutron absorbing material that could be cooled in a gas reactor environment without using large amounts of a coolant that would thermalize the neutron flux. A new neutron absorbing material was developed that provided high conduction so a small amount of water would be sufficient for cooling thereby thermalizing the flux as little as possible. An irradiation experiment was performed to assess the effects of radiation and the performance of a new neutron absorbing material. Neutron fluence monitors were placed inside specially fabricated holders within a set of drop-in capsules and irradiated formore » up to four cycles in the Advanced Test Reactor. Following irradiation, the neutron fluence monitor wires were analyzed by gamma and x-ray spectrometry to determine the activities of the activation products. The adjusted neutron fluences were calculated and grouped into three bins – thermal, epithermal and fast to evaluate the spectral shift created by the new material. Fluence monitors were evaluated after four different irradiation periods to evaluate the effects of burn-up in the absorbing material. Additionally, activities of the three highest activity isotopes present in the specimens are given.« less
NASA Astrophysics Data System (ADS)
You, Yan; Yoshida, Katsumi; Yano, Toyohiko
2018-05-01
Boron carbide (B4C) is a leading candidate neutron absorber material for sodium-cooled fast nuclear reactors owing to its excellent neutron-capture capability. The formation and migration energies of the neutron-irradiation-induced defects, including vacancies, neutron-capture reaction products, and knocked-out atoms were studied by density functional theory calculations. The vacancy-type defects tend to migrate to the C–B–C chains of B4C, which indicates that the icosahedral cage structures of B4C have strong resistance to neutron irradiation. We found that lithium and helium atoms had significantly lower migration barriers along the rhombohedral (111) plane of B4C than perpendicular to this plane. This implies that the helium and lithium interstitials tended to follow a two-dimensional diffusion regime in B4C at low temperatures which explains the formation of flat disk like helium bubbles experimentally observed in B4C pellets after neutron irradiation. The knocked-out atoms are considered to be annihilated by the recombination of the close pairs of self-interstitials and vacancies.
Geant4 beam model for boron neutron capture therapy: investigation of neutron dose components.
Moghaddasi, Leyla; Bezak, Eva
2018-03-01
Boron neutron capture therapy (BNCT) is a biochemically-targeted type of radiotherapy, selectively delivering localized dose to tumour cells diffused in normal tissue, while minimizing normal tissue toxicity. BNCT is based on thermal neutron capture by stable [Formula: see text]B nuclei resulting in emission of short-ranged alpha particles and recoil [Formula: see text]Li nuclei. The purpose of the current work was to develop and validate a Monte Carlo BNCT beam model and to investigate contribution of individual dose components resulting of neutron interactions. A neutron beam model was developed in Geant4 and validated against published data. The neutron beam spectrum, obtained from literature for a cyclotron-produced beam, was irradiated to a water phantom with boron concentrations of 100 μg/g. The calculated percentage depth dose curves (PDDs) in the phantom were compared with published data to validate the beam model in terms of total and boron depth dose deposition. Subsequently, two sensitivity studies were conducted to quantify the impact of: (1) neutron beam spectrum, and (2) various boron concentrations on the boron dose component. Good agreement was achieved between the calculated and measured neutron beam PDDs (within 1%). The resulting boron depth dose deposition was also in agreement with measured data. The sensitivity study of several boron concentrations showed that the calculated boron dose gradually converged beyond 100 μg/g boron concentration. This results suggest that 100μg/g tumour boron concentration may be optimal and above this value limited increase in boron dose is expected for a given neutron flux.
Note: Fast neutron efficiency in CR-39 nuclear track detectors
DOE Office of Scientific and Technical Information (OSTI.GOV)
Cavallaro, S.
2015-03-15
CR-39 samples are commonly employed for fast neutron detection in fusion reactors and in inertial confinement fusion experiments. The literature reported efficiencies are strongly depending on experimental conditions and, in some cases, highly dispersed. The present note analyses the dependence of efficiency as a function of various parameters and experimental conditions in both the radiator-assisted and the stand-alone CR-39 configurations. Comparisons of literature experimental data with Monte Carlo calculations and optimized efficiency values are shown and discussed.
Bavarnegin, Elham; Sadremomtaz, Alireza; Khalafi, Hossein; Kasesaz, Yaser
2016-01-01
Determination of in-phantom quality factors of Tehran research reactor (TRR) boron neutron capture therapy (BNCT) beam. The doses from thermal neutron reactions with 14N and 10B are calculated by kinetic energy released per unit mass approach, after measuring thermal neutron flux using neutron activation technique. Gamma dose is measured using TLD-700 dosimeter. Different dose components have been measured in a head phantom which has been designed and constructed for BNCT purpose in TRR. Different in-phantom beam quality factors have also been determined. This study demonstrates that the TRR BNCT beam line has potential for treatment of superficial tumors.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Shimaoka, T., E-mail: t.shimaoka@eng.hokudai.ac.jp; Kaneko, J. H.; Tsubota, M.
A neutron bang time and burn history monitor in inertial confinement fusion with fast ignition are necessary for plasma diagnostics. In the FIREX project, however, no detector attained those capabilities because high-intensity X-rays accompanied fast electrons used for plasma heating. To solve this problem, single-crystal CVD diamond was grown and fabricated into a radiation detector. The detector, which had excellent charge transportation property, was tested to obtain a response function for intense X-rays. The applicability for neutron bang time and burn history monitor was verified experimentally. Charge collection efficiency of 99.5% ± 0.8% and 97.1% ± 1.4% for holes andmore » electrons were obtained using 5.486 MeV alpha particles. The drift velocity at electric field which saturates charge collection efficiency was 1.1 ± 0.4 × 10{sup 7} cm/s and 1.0 ± 0.3 × 10{sup 7} cm/s for holes and electrons. Fast response of several ns pulse width for intense X-ray was obtained at the GEKKO XII experiment, which is sufficiently fast for ToF measurements to obtain a neutron signal separately from X-rays. Based on these results, we confirmed that the single-crystal CVD diamond detector obtained neutron signal with good S/N under ion temperature 0.5–1 keV and neutron yield of more than 10{sup 9} neutrons/shot.« less
NASA Astrophysics Data System (ADS)
Lin, Yung-Chieh; Lee, Chung-Chi; Chao, Tsi-Chian; Tsai, Hui-Yu
2017-11-01
Neutron production is a concern in proton therapy, particularly in scattering proton beam delivery systems. Despite this fact, little is known about the effects of secondary neutron exposure around wobbling scattered proton treatment nozzles. The objective of this study was to estimate the neutron dose level resulting from the use of a wobbling scattered proton treatment unit. We applied the Monte Carlo method for predict the ambient neutron dose equivalent, H*(10), per absorbed dose at the treatment isocenter, D, in the proton therapy center of Chang Gung Memorial Hospital, Linkou, Taiwan. For a 190-MeV proton beam, H* (10) / D values typically decreased with the distance from the isocenter, being 1.106 mSv/Gy at the isocenter versus 0.112 mSv/Gy at a distance of 150 cm from the isocenter. The H* (10) / D values generally decreased as the neutron receptors moved away from the isocenter, and increased when the angle from the initial beam axis increased. The ambient neutron dose equivalents were observed to be slightly lower in the direction of multileaf collimator movement. For radiation protection, the central axis of a proton-treated patient is suggested to be at the 0° angle of the beam. If the beam direction at the 90° angle is necessary, the patient axis is suggested to be along with the direction of MLC movement. Our study provides the neutron dose level and neutron energy fluence for the first wobbling proton system at the proton therapy center of Chang Gung Memorial Hospital.
GPU-based prompt gamma ray imaging from boron neutron capture therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yoon, Do-Kun; Jung, Joo-Young; Suk Suh, Tae, E-mail: suhsanta@catholic.ac.kr
Purpose: The purpose of this research is to perform the fast reconstruction of a prompt gamma ray image using a graphics processing unit (GPU) computation from boron neutron capture therapy (BNCT) simulations. Methods: To evaluate the accuracy of the reconstructed image, a phantom including four boron uptake regions (BURs) was used in the simulation. After the Monte Carlo simulation of the BNCT, the modified ordered subset expectation maximization reconstruction algorithm using the GPU computation was used to reconstruct the images with fewer projections. The computation times for image reconstruction were compared between the GPU and the central processing unit (CPU).more » Also, the accuracy of the reconstructed image was evaluated by a receiver operating characteristic (ROC) curve analysis. Results: The image reconstruction time using the GPU was 196 times faster than the conventional reconstruction time using the CPU. For the four BURs, the area under curve values from the ROC curve were 0.6726 (A-region), 0.6890 (B-region), 0.7384 (C-region), and 0.8009 (D-region). Conclusions: The tomographic image using the prompt gamma ray event from the BNCT simulation was acquired using the GPU computation in order to perform a fast reconstruction during treatment. The authors verified the feasibility of the prompt gamma ray image reconstruction using the GPU computation for BNCT simulations.« less
Matsumoto, Shinnosuke; Koba, Yusuke; Kohno, Ryosuke; Lee, Choonsik; Bolch, Wesley E; Kai, Michiaki
2016-04-01
Proton therapy has the physical advantage of a Bragg peak that can provide a better dose distribution than conventional x-ray therapy. However, radiation exposure of normal tissues cannot be ignored because it is likely to increase the risk of secondary cancer. Evaluating secondary neutrons generated by the interaction of the proton beam with the treatment beam-line structure is necessary; thus, performing the optimization of radiation protection in proton therapy is required. In this research, the organ dose and energy spectrum were calculated from secondary neutrons using Monte Carlo simulations. The Monte Carlo code known as the Particle and Heavy Ion Transport code System (PHITS) was used to simulate the transport proton and its interaction with the treatment beam-line structure that modeled the double scattering body of the treatment nozzle at the National Cancer Center Hospital East. The doses of the organs in a hybrid computational phantom simulating a 5-y-old boy were calculated. In general, secondary neutron doses were found to decrease with increasing distance to the treatment field. Secondary neutron energy spectra were characterized by incident neutrons with three energy peaks: 1×10, 1, and 100 MeV. A block collimator and a patient collimator contributed significantly to organ doses. In particular, the secondary neutrons from the patient collimator were 30 times higher than those from the first scatter. These results suggested that proactive protection will be required in the design of the treatment beam-line structures and that organ doses from secondary neutrons may be able to be reduced.
A Project of Boron Neutron Capture Therapy System based on a Proton Linac Neutron Source
NASA Astrophysics Data System (ADS)
Kiyanagi, Yoshikai; Asano, Kenji; Arakawa, Akihiro; Fukuchi, Shin; Hiraga, Fujio; Kimura, Kenju; Kobayashi, Hitoshi; Kubota, Michio; Kumada, Hiroaki; Matsumoto, Hiroshi; Matsumoto, Akira; Sakae, Takeji; Saitoh, Kimiaki; Shibata, Tokushi; Yoshioka, Masakazu
At present, the clinical trials of Boron Neutron Capture Therapy (BNCT) are being performed at research reactor facilities. However, an accelerator based BNCT has a merit that it can be built in a hospital. So, we just launched a development project for the BNCT based on an accelerator in order to establish and to spread the BNCT as an effective therapy in the near future. In the project, a compact proton linac installed in a hospital will be applied as a neutron source, and energy of the proton beam is planned to be less than about 10 MeV to reduce the radioactivity. The BNCT requires epithermal neutron beam with an intensity of around 1x109 (n/cm2/sec) to deliver the therapeutic dose to a deeper region in a body and to complete the irradiation within an hour. From this condition, the current of the proton beam required is estimated to be a few mA on average. Enormous heat deposition in the target is a big issue. We are aiming at total optimization of the accelerator based BNCT from the linac to the irradiation position. Here, the outline of the project is introduced and the moderator design is presented.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Benoit Forget; Mehdi Asgari; Rodolfo M. Ferrer
2007-11-01
As part of the GNEP program, it is envisioned to build a fast reactor for the transmutation of minor actinides. The spent nuclear fuel from the current fleet of light water reactors would be recycled, the current baseline is the UREX+1a process, and would act as a feed for the fast reactor. As the fuel is irradiated in a fast reactor a certain quantity of minor actinides would thus build up in the fuel stream creating possible concerns with the neutron emission of these minor actinides for fuel transportation, handling and fabrication. Past neutronic analyses had not tracked minor actinidesmore » above Cm-246 in the transmutation chain, because of the small influence on the overall reactor performance and cycle parameters. However, when trying to quantify the neutron emission from the recycled fuel with high minor actinide content, these higher isotopes play an essential role and should be included in the analysis. In this paper, the influence of tracking these minor actinides on the calculated neutron emission is presented. Also presented is the particular influence of choosing a different evaluated cross section data set to represent the minor actinides above Cm-246. The first representation uses the cross-sections provided by MC2-2 for all isotopes, while the second representation uses infinitely diluted ENDF/BVII.0 cross-sections for Cm-247 to Cf-252 and MC2-2 for all other isotopes.« less
NASA Astrophysics Data System (ADS)
Hwang, Dae Hee; Hong, Ser Gi; Kim, Jae Cheon; Kim, Gi Dong; Kim, Yong Kyun
2015-10-01
RAON is a Korean heavy-ion accelerator complex that is planned to be built by 2021. Deuterons (53 MeV) and protons (88 MeV) accelerated by using a low-energy driver linac (SCL1) are delivered to the neutron production target in the Neutron Science Facility (NSF) to produce high-energy neutrons in the interval from 1 to 88 MeV with high fluxes of the order of 1012 n/cm2-sec. The repetition rate of the neutron beam ranges from 1 kHz to 1 MHz, and the maximum beam current is ~12 μA at 1 MHz. The beam width is 1 ~ 2 ns. The high-energy and high-rate fast neutrons are used to estimate accurate neutron-induced cross sections for various nuclides at the NSF. A MICROMEGAS (MICRO Mesh Gaseous Structure), which is a gaseous detector initially developed for tracking in high-rate, high-energy physics experiments, is tentatively being considered as a neutron beam monitor. It can be used to measure both the energy distribution and the flux of the neutron beam. In this study, a MICROMEGAS detector for installation at the NSF was designed and investigated. 6Li, 10B, 235U and 238U targets are being considered as neutron/charged particle converters. For the low-energy region, 6Li(n,α)t and 10B(n,α)7Li are used in the energy range from thermal to 1 MeV. 235U(n,f) and 238U(n,f) reactions are used for high-energy region up to 90 MeV. All calculations are performed by using the GEANT4 toolkit.
Boron Neutron Capture Therapy in the Treatment of Recurrent Laryngeal Cancer
DOE Office of Scientific and Technical Information (OSTI.GOV)
Haapaniemi, Aaro, E-mail: aaro.haapaniemi@hus.fi; Kankaanranta, Leena; Saat, Riste
2016-05-01
Purpose: To investigate the safety and efficacy of boron neutron capture therapy (BNCT) as a larynx-preserving treatment option for patients with recurrent laryngeal cancer. Methods and Materials: Six patients with locally recurrent squamous cell laryngeal carcinoma and 3 patients with persistent laryngeal cancer after prior treatment were treated with BNCT at the FiR1 facility (Espoo, Finland) in 2006 to 2012. The patients had received prior radiation therapy with or without concomitant chemotherapy to a cumulative median dose of 66 Gy. The median tumor diameter was 2.9 cm (range, 1.4-10.9 cm) before BNCT. Boron neutron capture therapy was offered on a compassionate basis to patientsmore » who either refused laryngectomy (n=7) or had an inoperable tumor (n=2). Boronophenylalanine-fructose (400 mg/kg) was used as the boron carrier and was infused over 2 hours intravenously before neutron irradiation. Results: Six patients received BNCT once and 3 twice. The estimated average gross tumor volume dose ranged from 22 to 38 Gy (W) (mean; 29 Gy [W]). Six of the 8 evaluable patients responded to BNCT; 2 achieved complete and 4 partial response. One patient died early and was not evaluable for response. Most common side effects were stomatitis, fatigue, and oral pain. No life-threatening or grade 4 toxicity was observed. The median time to progression within the target volume was 6.6 months, and the median overall survival time 13.3 months after BNCT. One patient with complete response is alive and disease-free with a functioning larynx 60 months after BNCT. Conclusions: Boron neutron capture therapy given after prior external beam radiation therapy is well tolerated. Most patients responded to BNCT, but long-term survival with larynx preservation was infrequent owing to cancer progression. Selected patients with recurrent laryngeal cancer may benefit from BNCT.« less
Brown, Nicholas R.; Powers, Jeffrey J.; Feng, B.; ...
2015-05-21
This paper presents analyses of possible reactor representations of a nuclear fuel cycle with continuous recycling of thorium and produced uranium (mostly U-233) with thorium-only feed. The analysis was performed in the context of a U.S. Department of Energy effort to develop a compendium of informative nuclear fuel cycle performance data. The objective of this paper is to determine whether intermediate spectrum systems, having a majority of fission events occurring with incident neutron energies between 1 eV and 10 5 eV, perform as well as fast spectrum systems in this fuel cycle. The intermediate spectrum options analyzed include tight latticemore » heavy or light water-cooled reactors, continuously refueled molten salt reactors, and a sodium-cooled reactor with hydride fuel. All options were modeled in reactor physics codes to calculate their lattice physics, spectrum characteristics, and fuel compositions over time. Based on these results, detailed metrics were calculated to compare the fuel cycle performance. These metrics include waste management and resource utilization, and are binned to accommodate uncertainties. The performance of the intermediate systems for this selfsustaining thorium fuel cycle was similar to a representative fast spectrum system. However, the number of fission neutrons emitted per neutron absorbed limits performance in intermediate spectrum systems.« less
Boron Neutron Capture Therapy for Malignant Brain Tumors
MIYATAKE, Shin-Ichi; KAWABATA, Shinji; HIRAMATSU, Ryo; KUROIWA, Toshihiko; SUZUKI, Minoru; KONDO, Natsuko; ONO, Koji
2016-01-01
Boron neutron capture therapy (BNCT) is a biochemically targeted radiotherapy based on the nuclear capture and fission reactions that occur when non-radioactive boron-10, which is a constituent of natural elemental boron, is irradiated with low energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei. Therefore, BNCT enables the application of a high dose of particle radiation selectively to tumor cells in which boron-10 compound has been accumulated. We applied BNCT using nuclear reactors for 167 cases of malignant brain tumors, including recurrent malignant gliomas, newly diagnosed malignant gliomas, and recurrent high-grade meningiomas from January 2002 to May 2014. Here, we review the principle and history of BNCT. In addition, we introduce fluoride-18-labeled boronophenylalanine positron emission tomography and the clinical results of BNCT for the above-mentioned malignant brain tumors. Finally, we discuss the recent development of accelerators producing epithermal neutron beams. This development could provide an alternative to the current use of specially modified nuclear reactors as a neutron source, and could allow BNCT to be performed in a hospital setting. PMID:27250576
Boron Neutron Capture Therapy for Malignant Brain Tumors.
Miyatake, Shin-Ichi; Kawabata, Shinji; Hiramatsu, Ryo; Kuroiwa, Toshihiko; Suzuki, Minoru; Kondo, Natsuko; Ono, Koji
2016-07-15
Boron neutron capture therapy (BNCT) is a biochemically targeted radiotherapy based on the nuclear capture and fission reactions that occur when non-radioactive boron-10, which is a constituent of natural elemental boron, is irradiated with low energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei. Therefore, BNCT enables the application of a high dose of particle radiation selectively to tumor cells in which boron-10 compound has been accumulated. We applied BNCT using nuclear reactors for 167 cases of malignant brain tumors, including recurrent malignant gliomas, newly diagnosed malignant gliomas, and recurrent high-grade meningiomas from January 2002 to May 2014. Here, we review the principle and history of BNCT. In addition, we introduce fluoride-18-labeled boronophenylalanine positron emission tomography and the clinical results of BNCT for the above-mentioned malignant brain tumors. Finally, we discuss the recent development of accelerators producing epithermal neutron beams. This development could provide an alternative to the current use of specially modified nuclear reactors as a neutron source, and could allow BNCT to be performed in a hospital setting.
DOT National Transportation Integrated Search
1978-02-01
We investigated the relative biological effectiveness (RBE) of fast neutrons compared with X-rays in impeding development of immunity to an infective agent, the intestinal cestode Hymenolepis nana. Mice were irradiated with neutrons or X-rays and 2 d...
21 CFR 892.5300 - Medical neutron radiation therapy system.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Medical neutron radiation therapy system. 892.5300 Section 892.5300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment support, treatment planning computer programs...
21 CFR 892.5300 - Medical neutron radiation therapy system.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical neutron radiation therapy system. 892.5300 Section 892.5300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment support, treatment planning computer programs...
21 CFR 892.5300 - Medical neutron radiation therapy system.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Medical neutron radiation therapy system. 892.5300 Section 892.5300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment support, treatment planning computer programs...
21 CFR 892.5300 - Medical neutron radiation therapy system.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Medical neutron radiation therapy system. 892.5300 Section 892.5300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment support, treatment planning computer programs...
21 CFR 892.5300 - Medical neutron radiation therapy system.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Medical neutron radiation therapy system. 892.5300 Section 892.5300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment support, treatment planning computer programs...
Maughan, Richard L; Yudelev, Mark; Aref, Amr; Chuba, Paul J; Forman, Jeffrey; Blosser, Emanuel J; Horste, Timothy
2002-04-01
The d(48.5) + Be neutron beam from the Harper Hospital superconducting cyclotron is collimated using a unique multirod collimator (MRC). A computer controlled multileaf collimator (MLC) is being designed to improve efficiency and allow for the future development of intensity modulated radiation therapy with neutrons. For the current study the use of focused or unfocused collimator leaves has been studied. Since the engineering effort associated with the leaf design and materials choice impacts significantly on cost, it was desirable to determine the clinical impact of using unfocused leaves in the MLC design. The MRC is a useful tool for studying the effects of using focused versus unfocused beams on beam penumbra. The effects of the penumbra for the different leaf designs on tumor and normal tissue DVHs in two selected sites (prostate and head and neck) was investigated. The increase in the penumbra resulting from using unfocused beams was small (approximately 1.5 mm for a 5 x 5 cm2 field and approximately 7.6 mm for a 25 x 25 cm2 field at 10 cm depth) compared to the contribution of phantom scatter to the penumbra width (5.4 and 20 mm for the small and large fields at 10 cm depth, respectively). Comparison of DVHs for tumor and critical normal tissue in a prostate and head and neck case showed that the dosimetric disadvantages of using an unfocused rather than focused beam were minimal and only significant at shallow depths. For the rare cases, where optimum penumbra conditions are required, a MLC incorporating tapered leaves and, thus, providing focused collimation in one plane is necessary.
Dose Calibration of the ISS-RAD Fast Neutron Detector
NASA Technical Reports Server (NTRS)
Zeitlin, C.
2015-01-01
The ISS-RAD instrument has been fabricated by Southwest Research Institute and delivered to NASA for flight to the ISS in late 2015 or early 2016. ISS-RAD is essentially two instruments that share a common interface to ISS. The two instruments are the Charged Particle Detector (CPD), which is very similar to the MSL-RAD detector on Mars, and the Fast Neutron Detector (FND), which is a boron-loaded plastic scintillator with readout optimized for the 0.5 to 10 MeV energy range. As the FND is completely new, it has been necessary to develop methodology to allow it to be used to measure the neutron dose and dose equivalent. This talk will focus on the methods developed and their implementation using calibration data obtained in quasi-monoenergetic (QMN) neutron fields at the PTB facility in Braunschweig, Germany. The QMN data allow us to determine an approximate response function, from which we estimate dose and dose equivalent contributions per detected neutron as a function of the pulse height. We refer to these as the "pSv per count" curves for dose equivalent and the "pGy per count" curves for dose. The FND is required to provide a dose equivalent measurement with an accuracy of ?10% of the known value in a calibrated AmBe field. Four variants of the analysis method were developed, corresponding to two different approximations of the pSv per count curve, and two different implementations, one for real-time analysis onboard ISS and one for ground analysis. We will show that the preferred method, when applied in either real-time or ground analysis, yields good accuracy for the AmBe field. We find that the real-time algorithm is more susceptible to chance-coincidence background than is the algorithm used in ground analysis, so that the best estimates will come from the latter.
Accelerator-based epithermal neutron sources for boron neutron capture therapy of brain tumors.
Blue, Thomas E; Yanch, Jacquelyn C
2003-01-01
This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines in high-energy physics facilities are not considered. An ABNS for BNCT is composed of: (1) the accelerator hardware for producing a high current charged particle beam, (2) an appropriate neutron-producing target and target heat removal system (HRS), and (3) a moderator/reflector assembly to render the flux energy spectrum of neutrons produced in the target suitable for patient irradiation. As a consequence of the efforts of researchers throughout the world, progress has been made on the design, manufacture, and testing of these three major components. Although an ABNS facility has not yet been built that has optimally assembled these three components, the feasibility of clinically useful ABNSs has been clearly established. Both electrostatic and radio frequency linear accelerators of reasonable cost (approximately 1.5 M dollars) appear to be capable of producing charged particle beams, with combinations of accelerated particle energy (a few MeV) and beam currents (approximately 10 mA) that are suitable for a hospital-based ABNS for BNCT. The specific accelerator performance requirements depend upon the charged particle reaction by which neutrons are produced in the target and the clinical requirements for neutron field quality and intensity. The accelerator performance requirements are more demanding for beryllium than for lithium as a target. However, beryllium targets are more easily cooled. The accelerator performance requirements are also more demanding for greater neutron field quality and intensity. Target HRSs that are based on submerged-jet impingement and
Physics of epi-thermal boron neutron capture therapy (epi-thermal BNCT).
Seki, Ryoichi; Wakisaka, Yushi; Morimoto, Nami; Takashina, Masaaki; Koizumi, Masahiko; Toki, Hiroshi; Fukuda, Mitsuhiro
2017-12-01
The physics of epi-thermal neutrons in the human body is discussed in the effort to clarify the nature of the unique radiologic properties of boron neutron capture therapy (BNCT). This discussion leads to the computational method of Monte Carlo simulation in BNCT. The method is discussed through two examples based on model phantoms. The physics is kept at an introductory level in the discussion in this tutorial review.
NEUTRONIC REACTOR DESIGN TO REDUCE NEUTRON LOSS
Mills, F.T.
1961-05-01
A nuclear reactor construction is described in which an unmoderated layer of the fissionable material is inserted between the moderated portion of the reactor core and the core container steel wall which is surrounded by successive layers of pure fertile material and fertile material having moderator. The unmoderated layer of the fissionable material will insure that a greater portion of fast neutrons will pass through the steel wall than would thermal neutrons. As the steel has a smaller capture cross-section for the fast neutrons, then greater numbers of the neutrons will pass into the blanket thereby increasing the over-all efficiency of the reactor.
Neutronic Reactor Design to Reduce Neutron Loss
Miles, F. T.
1961-05-01
A nuclear reactor construction is described in which an unmoderated layer of the fissionable material is inserted between the moderated portion of the reactor core and the core container steel wall. The wall is surrounded by successive layers of pure fertile material and moderator containing fertile material. The unmoderated layer of the fissionable material will insure that a greater portion of fast neutrons will pass through the steel wall than would thermal neutrons. Since the steel has a smaller capture cross section for the fast neutrons, greater nunnbers of neutrons will pass into the blanket, thereby increasing the over-all efficiency of the reactor. (AEC)
el-Akkad, S; Schultz, H P; Ahmad, K; Clubb, B; McArthur, P; Dobson, H; DeVol, E
1992-01-01
The King Faisal Specialist Hospital and Research Centre is the only center in the Middle East that incorporates a neutron therapy facility. The neutron beam is produced by a cyclotron, which produces a beam by either a (d(15)+Be) or (p(26)+Be) reaction. The beam from the proton reaction is selected for therapy because of its superior physical characteristics. These were verified by an intercomparison conducted by the European Organization for Research on Treatment of Cancer (EORTC) Heavy Particle Therapy Group. Full beam data are presented. The first study in the neutron therapy Program is on the treatment of squamous cancers of the head and neck. This consists of two parts. Part I is a dose searching phase and Part II is a comparison of our current photon treatment versus neutrons using the neutron dose selected by Part I of the study. Results of the dose searching phase (Part I) are presented.
Characterisation of an accelerator-based neutron source for BNCT versus beam energy
NASA Astrophysics Data System (ADS)
Agosteo, S.; Curzio, G.; d'Errico, F.; Nath, R.; Tinti, R.
2002-01-01
Neutron capture in 10B produces energetic alpha particles that have a high linear energy transfer in tissue. This results in higher cell killing and a higher relative biological effectiveness compared to photons. Using suitably designed boron compounds which preferentially localize in cancerous cells instead of healthy tissues, boron neutron capture therapy (BNCT) has the potential of providing a higher tumor cure rate within minimal toxicity to normal tissues. This clinical approach requires a thermal neutron source, generally a nuclear reactor, with a fluence rate sufficient to deliver tumorcidal doses within a reasonable treatment time (minutes). Thermal neutrons do not penetrate deeply in tissue, therefore BNCT is limited to lesions which are either superficial or otherwise accessible. In this work, we investigate the feasibility of an accelerator-based thermal neutron source for the BNCT of skin melanomas. The source was designed via MCNP Monte Carlo simulations of the thermalization of a fast neutron beam, generated by 7 MeV deuterons impinging on a thick target of beryllium. The neutron field was characterized at several deuteron energies (3.0-6.5 MeV) in an experimental structure installed at the Van De Graaff accelerator of the Laboratori Nazionali di Legnaro, in Italy. Thermal and epithermal neutron fluences were measured with activation techniques and fast neutron spectra were determined with superheated drop detectors (SDD). These neutron spectrometry and dosimetry studies indicated that the fast neutron dose is unacceptably high in the current design. Modifications to the current design to overcome this problem are presented.
Fast Neutron Spectrum Potassium Worth for Space Power Reactor Design Validation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bess, John D.; Marshall, Margaret A.; Briggs, J. Blair
2015-03-01
A variety of critical experiments were constructed of enriched uranium metal (oralloy ) during the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. The purposes of these experiments included the evaluation of storage, casting, and handling limits for the Y-12 Plant and providing data for verification of calculation methods and cross-sections for nuclear criticality safety applications. These included solid cylinders of various diameters, annuli of various inner and outer diameters, two and three interacting cylinders of various diameters, and graphite and polyethylene reflected cylinders and annuli. Ofmore » the hundreds of delayed critical experiments, one was performed that consisted of uranium metal annuli surrounding a potassium-filled, stainless steel can. The outer diameter of the annuli was approximately 13 inches (33.02 cm) with an inner diameter of 7 inches (17.78 cm). The diameter of the stainless steel can was 7 inches (17.78 cm). The critical height of the configurations was approximately 5.6 inches (14.224 cm). The uranium annulus consisted of multiple stacked rings, each with radial thicknesses of 1 inch (2.54 cm) and varying heights. A companion measurement was performed using empty stainless steel cans; the primary purpose of these experiments was to test the fast neutron cross sections of potassium as it was a candidate for coolant in some early space power reactor designs.The experimental measurements were performed on July 11, 1963, by J. T. Mihalczo and M. S. Wyatt (Ref. 1) with additional information in its corresponding logbook. Unreflected and unmoderated experiments with the same set of highly enriched uranium metal parts were performed at the Oak Ridge Critical Experiments Facility in the 1960s and are evaluated in the International Handbook for Evaluated Criticality Safety Benchmark Experiments (ICSBEP Handbook) with the identifier HEU MET FAST 051. Thin
NASA Astrophysics Data System (ADS)
Yamamoto, T.; Matsumura, A.; Yamamoto, K.; Kumada, H.; Shibata, Y.; Nose, T.
2002-07-01
The aim of this study was to determine the in-phantom thermal neutron distribution derived from neutron beams for intraoperative boron neutron capture therapy (IOBNCT). Gold activation wires arranged in a cylindrical water phantom with (void-in-phantom) or without (standard phantom) a cylinder styrene form placed inside were irradiated by using the epithermal beam (ENB) and the mixed thermal-epithermal beam (TNB-1) at the Japan Research Reactor No 4. With ENB, we observed a flattened distribution of thermal neutron flux and a significantly enhanced thermal flux delivery at a depth compared with the results of using TNB-1. The thermal neutron distribution derived from both the ENB and TNB-1 was significantly improved in the void-in-phantom, and a double high dose area was formed lateral to the void. The flattened distribution in the circumference of the void was observed with the combination of ENB and the void-in-phantom. The measurement data suggest that the ENB may provide a clinical advantage in the form of an enhanced and flattened dose delivery to the marginal tissue of a post-operative cavity in which a residual and/or microscopically infiltrating tumour often occurs. The combination of the epithermal neutron beam and IOBNCT will improve the clinical results of BNCT for brain tumours.
The γ-ray angular distribution in fast neutron inelastic scattering from iron
NASA Astrophysics Data System (ADS)
Beyer, Roland; Dietz, Mirco; Bemmerer, Daniel; Junghans, Arnd R.; Kögler, Toni; Massarczyk, Ralph; Müller, Stefan; Schmidt, Konrad; Schwengner, Ronald; Szücs, Tamás; Takács, Marcell P.; Wagner, Andreas
2018-04-01
The angular distribution of γ-rays emitted after inelastic scattering of fast neutrons from iron was determined at the n ELBE neutron time-of-flight facility. An iron sample of natural isotopic composition was irradiated by a continuous photo-neutron spectrum in the energy range from about 0.1 up to 10 MeV. The de-excitation γ-rays of the four lowest excited states of 56Fe and the first excited state of 54Fe were detected using a setup of five high-purity germanium (HPGe) detectors and five LaBr3 scintillation detectors positioned around the sample at 30°, 55°, 90°, 125° and 150° with respect to the incoming neutron beam. The resulting angular distributions were fitted by Legendre polynomials up to 4th order and the angular distribution coefficients a2 and a4 were extracted. The angular distribution coefficients of three transitions in 56Fe are reported here for the first time. The results are applied to a previous measurement of the inelastic scattering cross section determined using a single HPGe detector positioned at 125°. Using the updated γ-ray angular distribution, the previous cross section results are in good agreement with reference data.
A 13C(d,n)-based epithermal neutron source for Boron Neutron Capture Therapy.
Capoulat, M E; Kreiner, A J
2017-01-01
Boron Neutron Capture Therapy (BNCT) requires neutron sources suitable for in-hospital siting. Low-energy particle accelerators working in conjunction with a neutron producing reaction are the most appropriate choice for this purpose. One of the possible nuclear reactions is 13 C(d,n) 14 N. The aim of this work is to evaluate the therapeutic capabilities of the neutron beam produced by this reaction, through a 30mA beam of deuterons of 1.45MeV. A Beam Shaping Assembly design was computationally optimized. Depth dose profiles in a Snyder head phantom were simulated with the MCNP code for a number of BSA configurations. In order to optimize the treatment capabilities, the BSA configuration was determined as the one that allows maximizing both the tumor dose and the penetration depth while keeping doses to healthy tissues under the tolerance limits. Significant doses to tumor tissues were achieved up to ∼6cm in depth. Peak doses up to 57Gy-Eq can be delivered in a fractionated scheme of 2 irradiations of approximately 1h each. In a single 1h irradiation, lower but still acceptable doses to tumor are also feasible. Treatment capabilities obtained here are comparable to those achieved with other accelerator-based neutron sources, making of the 13 C(d,n) 14 N reaction a realistic option for producing therapeutic neutron beams through a low-energy particle accelerator. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
Fast neutron induced structural rearrangements at a soybean NAP1 locus result in gnarled trichomes
USDA-ARS?s Scientific Manuscript database
A soybean (Glycine max (L.) Merr.) gnarled trichome mutant, exhibiting stunted trichomes compared to wild-type, was identified in a fast neutron mutant population. Genetic mapping using whole genome sequence-based bulked segregant analysis identified a 26.6 megabase interval on chromosome 20 that ...
NASA Astrophysics Data System (ADS)
Hosseini, Seyed Abolfazl; Afrakoti, Iman Esmaili Paeen
2017-04-01
Accurate unfolding of the energy spectrum of a neutron source gives important information about unknown neutron sources. The obtained information is useful in many areas like nuclear safeguards, nuclear nonproliferation, and homeland security. In the present study, the energy spectrum of a poly-energetic fast neutron source is reconstructed using the developed computational codes based on the Group Method of Data Handling (GMDH) and Decision Tree (DT) algorithms. The neutron pulse height distribution (neutron response function) in the considered NE-213 liquid organic scintillator has been simulated using the developed MCNPX-ESUT computational code (MCNPX-Energy engineering of Sharif University of Technology). The developed computational codes based on the GMDH and DT algorithms use some data for training, testing and validation steps. In order to prepare the required data, 4000 randomly generated energy spectra distributed over 52 bins are used. The randomly generated energy spectra and the simulated neutron pulse height distributions by MCNPX-ESUT for each energy spectrum are used as the output and input data. Since there is no need to solve the inverse problem with an ill-conditioned response matrix, the unfolded energy spectrum has the highest accuracy. The 241Am-9Be and 252Cf neutron sources are used in the validation step of the calculation. The unfolded energy spectra for the used fast neutron sources have an excellent agreement with the reference ones. Also, the accuracy of the unfolded energy spectra obtained using the GMDH is slightly better than those obtained from the DT. The results obtained in the present study have good accuracy in comparison with the previously published paper based on the logsig and tansig transfer functions.
Final Stage in the Design of a Boron Neutron Capture Therapy facility at CEADEN, Cuba
DOE Office of Scientific and Technical Information (OSTI.GOV)
Cabal, F. Padilla; Martin, G.
A neutron beam simulation study is carried out to determine the most suitable neutron energy for treatment of shallow and deep-seated brain tumors in the context of Boron Neutron Capture Therapy (BNCT). Two figures-of-merit, the therapeutic gain and the neutron fluence are utilized as beam assessment parameters. An irradiation cavity is used instead of a parallel beam port for the therapy. Calculations are performed using the MCNP5 code. After the optimization of our beam-shaper a study of the dose distribution in the head, neck, tyroids, lungs and upper and middle spine had been made. The therapeutic gain is increased whilemore » the current required for one hour treatment is decreased in comparison with the trading prototypes of NG used for BNCT.« less
Binns, P J; Riley, K J; Harling, O K; Kiger, W S; Munck af Rosenschöld, P M; Giusti, V; Capala, J; Sköld, K; Auterinen, I; Serén, T; Kotiluoto, P; Uusi-Simola, J; Marek, M; Viererbl, L; Spurny, F
2005-12-01
An international collaboration was organized to undertake a dosimetry exchange to enable the future combination of clinical data from different centers conducting neutron capture therapy trials. As a first step (Part I) the dosimetry group from the Americas, represented by MIT, visited the clinical centers at Studsvik (Sweden), VTT Espoo (Finland), and the Nuclear Research Institute (NRI) at Rez (Czech Republic). A combined VTT/NRI group reciprocated with a visit to MIT. Each participant performed a series of dosimetry measurements under equivalent irradiation conditions using methods appropriate to their clinical protocols. This entailed in-air measurements and dose versus depth measurements in a large water phantom. Thermal neutron flux as well as fast neutron and photon absorbed dose rates were measured. Satisfactory agreement in determining absorbed dose within the experimental uncertainties was obtained between the different groups although the measurement uncertainties are large, ranging between 3% and 30% depending upon the dose component and the depth of measurement. To improve the precision in the specification of absorbed dose amongst the participants, the individually measured dose components were normalized to the results from a single method. Assuming a boron concentration of 15 microg g(-1) that is typical of concentrations realized clinically with the boron delivery compound boronophenylalanine-fructose, systematic discrepancies in the specification of the total biologically weighted dose of up to 10% were apparent between the different groups. The results from these measurements will be used in future to normalize treatment plan calculations between the different clinical dosimetry protocols as Part II of this study.
[Possibilities of boron neutron capture therapy in the treatment of malignant brain tumors].
Kanygin, V V; Kichigin, A I; Gubanova, N V; Taskaev, S Yu
2015-01-01
Boron neutron capture therapy (BNCT) that is of the highest attractiveness due to its selective action directly on malignant tumor cells is a promising approach to treating cancers. Clinical interest in BNCT focuses in neuro-oncology on therapy for gliomas, glioblastoma in particular, and BNCT may be used in brain metastatic involvement. This needs an epithermal neutron source that complies with the requirements for BNCT, as well as a 10B-containing agent that will selectively accumulate in tumor tissue. The introduction of BNCT into clinical practice to treat patients with glial tumors will be able to enhance therapeutic efficiency.
Fast neutron radiation induced Glu-B1 deficient lines of an elite bread wheat variety
USDA-ARS?s Scientific Manuscript database
Five isogenic wheat lines deficient in high-molecular weight subunit (HMW-GS) proteins encoded by the B-genome were identified from a fast-neutron radiation-mutagenized population of Summit, an elite variety of bread wheat (Triticum aestivum L.). The mutant lines differ from the wild-type progenit...
Dewi, Novriana; Mi, Peng; Yanagie, Hironobu; Sakurai, Yuriko; Morishita, Yasuyuki; Yanagawa, Masashi; Nakagawa, Takayuki; Shinohara, Atsuko; Matsukawa, Takehisa; Yokoyama, Kazuhito; Cabral, Horacio; Suzuki, Minoru; Sakurai, Yoshinori; Tanaka, Hiroki; Ono, Koji; Nishiyama, Nobuhiro; Kataoka, Kazunori; Takahashi, Hiroyuki
2016-04-01
A more immediate impact for therapeutic approaches of current clinical research efforts is of major interest, which might be obtained by developing a noninvasive radiation dose-escalation strategy, and neutron capture therapy represents one such novel approach. Furthermore, some recent researches on neutron capture therapy have focused on using gadolinium as an alternative or complementary for currently used boron, taking into account several advantages that gadolinium offers. Therefore, in this study, we carried out feasibility evaluation for both single and multiple injections of gadolinium-based MRI contrast agent incorporated in calcium phosphate nanoparticles as neutron capture therapy agent. In vivo evaluation was performed on colon carcinoma Col-26 tumor-bearing mice irradiated at nuclear reactor facility of Kyoto University Research Reactor Institute with average neutron fluence of 1.8 × 10(12) n/cm(2). Antitumor effectivity was evaluated based on tumor growth suppression assessed until 27 days after neutron irradiation, followed by histopathological analysis on tumor slice. The experimental results showed that the tumor growth of irradiated mice injected beforehand with Gd-DTPA-incorporating calcium phosphate-based nanoparticles was suppressed up to four times higher compared to the non-treated group, supported by the results of histopathological analysis. The results of antitumor effectivity observed on tumor-bearing mice after neutron irradiation indicated possible effectivity of gadolinium-based neutron capture therapy treatment.
Robertson, deceased, J. Craig; Rowland, Mark S.
1989-03-21
A pulsed neutron detector and system for detecting low intensity fast neutron pulses has a body of beryllium adjacent a body of hydrogenous material the latter of which acts as a beta particle detector, scintillator, and moderator. The fast neutrons (defined as having En>1.5 MeV) react in the beryllium and the hydrogenous material to produce larger numbers of slow neutrons than would be generated in the beryllium itself and which in the beryllium generate hellium-6 which decays and yields beta particles. The beta particles reach the hydrogenous material which scintillates to yield light of intensity related to the number of fast neutrons. A photomultiplier adjacent the hydrogenous material (scintillator) senses the light emission from the scintillator. Utilization means, such as a summing device, sums the pulses from the photo-multiplier for monitoring or other purposes.
Changes in prescribed doses for the Seattle neutron therapy system
NASA Astrophysics Data System (ADS)
Popescu, A.
2008-06-01
From the beginning of the neutron therapy program at the University of Washington Medical Center, the neutron dose distribution in tissue has been calculated using an in-house treatment planning system called PRISM. In order to increase the accuracy of the absorbed dose calculations, two main improvements were made to the PRISM treatment planning system: (a) the algorithm was changed by the addition of an analytical expression of the central axis wedge factor dependence with field size and depth developed at UWMC. Older versions of the treatment-planning algorithm used a constant central axis wedge factor; (b) a complete newly commissioned set of measured data was introduced in the latest version of PRISM. The new version of the PRISM algorithm allowed for the use of the wedge profiles measured at different depths instead of one wedge profile measured at one depth. The comparison of the absorbed dose calculations using the old and the improved algorithm showed discrepancies mainly due to the missing central axis wedge factor dependence with field size and depth and due to the absence of the wedge profiles at depths different from 10 cm. This study concludes that the previously reported prescribed doses for neutron therapy should be changed.
Performance Study of an aSi Flat Panel Detector for Fast Neutron Imaging of Nuclear Waste
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schumann, M.; Mauerhofer, E.; Engels, R.
Radioactive waste must be characterized to check its conformance for intermediate storage and final disposal according to national regulations. For the determination of radio-toxic and chemo-toxic contents of radioactive waste packages non-destructive analytical techniques are preferentially used. Fast neutron imaging is a promising technique to assay large and dense items providing, in complementarity to photon imaging, additional information on the presence of structures in radioactive waste packages. Therefore the feasibility of a compact Neutron Imaging System for Radioactive waste Analysis (NISRA) using 14 MeV neutrons is studied in a cooperation framework of Forschungszentrum Juelich GmbH, RWTH Aachen University and Siemensmore » AG. However due to the low neutron emission of neutron generators in comparison to research reactors the challenging task resides in the development of an imaging detector with a high efficiency, a low sensitivity to gamma radiation and a resolution sufficient for the purpose. The setup is composed of a commercial D-T neutron generator (Genie16GT, Sodern) with a surrounding shielding made of polyethylene, which acts as a collimator and an amorphous silicon flat panel detector (aSi, 40 x 40 cm{sup 2}, XRD-1642, Perkin Elmer). Neutron detection is achieved using a general propose plastic scintillator (EJ-260, Eljen Technology) linked to the detector. The thermal noise of the photodiodes is reduced by employing an entrance window made of aluminium. Optimal gain and integration time for data acquisition are set by measuring the response of the detector to the radiation of a 500 MBq {sup 241}Am-source. Detector performance was studied by recording neutron radiography images of materials with various, but well known, chemical compositions, densities and dimensions (Al, C, Fe, Pb, W, concrete, polyethylene, 5 x 8 x 10 cm{sup 3}). To simulate gamma-ray emitting waste radiographs in presence of a gamma-ray sources ({sup 60}Co, {sup 137}Cs
Measured thermal and fast neutron fluence rates for ATF-1 holders during ATR cycle 160A
DOE Office of Scientific and Technical Information (OSTI.GOV)
Walker, B. J.; Miller, D. T.
This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 160A which were measured by the Radiation Measurements Laboratory (RML).
A new Recoil Proton Telescope for energy and fluence measurement of fast neutron fields
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lebreton, Lena; Bachaalany, Mario; Husson, Daniel
The spectrometer ATHENA (Accurate Telescope for High Energy Neutron metrology Applications), is being developed at the IRSN / LMDN (Institut de Radioprotection et de Surete nucleaire / Laboratoire de Metrologie et de dosimetrie des neutrons) and aims at characterizing energy and fluence of fast neutron fields. The detector is a Recoil Proton Telescope and measures neutron fields in the range of 5 to 20 MeV. This telescope is intended to become a primary standard for both energy and fluence measurements. The neutron detection is achieved by a polyethylene radiator for n-p conversion, three 50{sub m} thick silicon sensors that usemore » CMOS technology for the proton tracking and a 3 mm thick silicon diode to measure the residual proton energy. This first prototype used CMOS sensors called MIMOSTAR, initially developed for heavy ion physics. The use of CMOS sensors and silicon diode increases the intrinsic efficiency of the detector by a factor of ten compared with conventional designs. The first prototype has already been done and was a successful study giving the results it offered in terms of energy and fluence measurements. For mono energetic beams going from 5 to 19 MeV, the telescope offered an energy resolution between 5 and 11% and fluence difference going from 5 to 7% compared to other home standards. A second and final prototype of the detector is being designed. It will hold upgraded CMOS sensors called FastPixN. These CMOS sensors are supposed to run 400 times faster than the older version and therefore give the telescope the ability to support neutron flux in the order of 107 to 108cm{sup 2}:s{sup 1}. The first prototypes results showed that a 50 m pixel size is enough for a precise scattering angle reconstruction. Simulations using MCNPX and GEANT4 are already in place for further improvements. A DeltaE diode will replace the third CMOS sensor and will be installed right before the silicon diode for a better recoil proton selection. The final
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hep, J.; Konecna, A.; Krysl, V.
2011-07-01
This paper describes the application of effective source in forward calculations and the adjoint method to the solution of fast neutron fluence and activation detector activities in the reactor pressure vessel (RPV) and RPV cavity of a VVER-440 reactor. Its objective is the demonstration of both methods on a practical task. The effective source method applies the Boltzmann transport operator to time integrated source data in order to obtain neutron fluence and detector activities. By weighting the source data by time dependent decay of the detector activity, the result of the calculation is the detector activity. Alternatively, if the weightingmore » is uniform with respect to time, the result is the fluence. The approach works because of the inherent linearity of radiation transport in non-multiplying time-invariant media. Integrated in this way, the source data are referred to as the effective source. The effective source in the forward calculations method thereby enables the analyst to replace numerous intensive transport calculations with a single transport calculation in which the time dependence and magnitude of the source are correctly represented. In this work, the effective source method has been expanded slightly in the following way: neutron source data were performed with few group method calculation using the active core calculation code MOBY-DICK. The follow-up neutron transport calculation was performed using the neutron transport code TORT to perform multigroup calculations. For comparison, an alternative method of calculation has been used based upon adjoint functions of the Boltzmann transport equation. Calculation of the three-dimensional (3-D) adjoint function for each required computational outcome has been obtained using the deterministic code TORT and the cross section library BGL440. Adjoint functions appropriate to the required fast neutron flux density and neutron reaction rates have been calculated for several significant points within
Deagostino, Annamaria; Protti, Nicoletta; Alberti, Diego; Boggio, Paolo; Bortolussi, Silva; Altieri, Saverio; Crich, Simonetta Geninatti
2016-05-01
Gadolinium neutron capture therapy (Gd-NCT) is currently under development as an alternative approach for cancer therapy. All of the clinical experience to date with NCT is done with (10)B, known as boron neutron capture therapy (BNCT), a binary treatment combining neutron irradiation with the delivery of boron-containing compounds to tumors. Currently, the use of Gd for NCT has been getting more attention because of its highest neutron cross-section. Although Gd-NCT was first proposed many years ago, its development has suffered due to lack of appropriate tumor-selective Gd agents. This review aims to highlight the recent advances for the design, synthesis and biological testing of new Gd- and B-Gd-containing compounds with the task of finding the best systems able to improve the NCT clinical outcome.
[Effect of fasting-dietary therapy in patients with arterial hypertension and obesity].
Murav'ev, S A; Okonechnikova, N S; Dmitrieva, O A; Makarova, G A
2010-01-01
35 patients with arterial hypertension and obesity against the background of fasting-diet therapy and after 1 and 6 months after treatment conducted daily monitoring of blood pressure, microalbuminuria and glomerular filtration rate, the study of color and contrast sensitivity of retinal eyes. Fasting-diet therapy within 11 days results in reliable reduced daily average AD and stabilization of load pressure indicators; reduction originally pathological microalbuminurii at 18%, increase in the number of patients with normal speed glomerular filtering 48%; improving of eyes function, these changes are saved within 1-6 months after treatment without the using of antihypertensive therapy.
Hiramatsu, Ryo; Kawabata, Shinji; Tanaka, Hiroki; Sakurai, Yoshinori; Suzuki, Minoru; Ono, Koji; Miyatake, Shin-ichi; Kuroiwa, Toshihiko; Hao, Erhong; Vicente, M Graça H
2015-03-01
Carboranyl-containing chlorins have emerged as promising dual sensitizers for use in both photodynamic therapy (PDT) and boron neutron capture therapy (BNCT), by virtue of their known tumor affinity, low cytotoxicity in dark conditions, and their strong absorptions in the red region of the optical spectrum. Tetrakis(p-carboranylthio-tetrafluorophenyl)chlorin (TPFC) is a new synthetic carboranyl-containing chlorin of high boron content (24% by weight). To evaluate TPFC's applicability as sensitizer for both PDT and BNCT, we performed an in vitro and in vivo study using F98 rat glioma cells and F98 rat glioma-bearing brain tumor models. For the in vivo BNCT study, we used boronophenylalanine (BPA), which is currently used in clinical BNCT studies, via intravenous administration (i.v.) and/or used TPFC via convection-enhanced delivery (CED), a method for local drug infusion directly into the brain. In the in vitro PDT study, the cell surviving fraction following laser irradiation (9 J/cm(2) ) was 0.035 whereas in the in vitro BNCT study, the cell surviving fraction following neutron irradiation (thermal neutron = 1.73 × 10(12) n/cm(2) ) was 0.04. In the in vivo BNCT study, the median survival time following concomitant administration of BPA (i.v.) and TPFC (CED) was 42 days (95% confidence interval; 37-43 days). © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.
HIRAMATSU, RYO; KAWABATA, SHINJI; TANAKA, HIROKI; SAKURAI, YOSHINORI; SUZUKI, MINORU; ONO, KOJI; MIYATAKE, SHIN-ICHI; KUROIWA, TOSHIHIKO; HAO, ERHONG; VICENTE, M. GRAÇA H.
2015-01-01
Carboranyl-containing chlorins have emerged as promising dual sensitizers for use in both photodynamic therapy (PDT) and boron neutron capture therapy (BNCT), by virtue of their known tumor affinity, low cytotoxicity in dark conditions, and their strong absorptions in the red region of the optical spectrum. Tetrakis(p-carboranylthio-tetrafluorophenyl)chlorin (TPFC) is a new synthetic carboranyl-containing chlorin of high boron content (24% by weight). To evaluate TPFC’s applicability as sensitizer for both PDT and BNCT, we performed an in vitro and in vivo study using F98 rat glioma cells and F98 rat glioma-bearing brain tumor models. For the in vivo BNCT study, we used boronophenylalanine (BPA), which is currently used in clinical BNCT studies, via intravenous administration (i.v.) and/or used TPFC via convection-enhanced delivery (CED), a method for local drug infusion directly into the brain. In the in vitro PDT study, the cell surviving fraction following laser irradiation (9 J/cm2) was 0.035 whereas in the in vitro BNCT study, the cell surviving fraction following neutron irradiation (thermal neutron = 1.73 × 1012 n/cm2) was 0.04. In the in vivo BNCT study, the median survival time following concomitant administration of BPA (i.v.) and TPFC (CED) was 42 days (95% confidence interval; 37–43 days). PMID:25546823
NASA Astrophysics Data System (ADS)
Kelley, Ryan P.
With an increasing quantity of spent nuclear fuel being stored at power plants across the United States, the demand exists for a new method of cask monitoring. Certifying these casks for transportation and long-term storage is a unique dilemma: their sealed nature lends added security, but at the cost of requiring non-invasive measurement techniques to verify their contents. This research will design and develop a new method of passively scanning spent fuel casks using 4He scintillation detectors to make this process more accurate. 4He detectors are a relatively new technological development whose full capabilities have not yet been exploited. These detectors take advantage of the high 4He cross section for elastic scattering at fast neutron energies, particularly the resonance around 1 MeV. If one of these elastic scattering interactions occurs within the detector, the 4He nucleus takes energy from the incident neutron, then de-excites by scintillation. Photomultiplier Tubes (PMTs) at either end of the detector tube convert this emitted light into an electrical signal. The goal of this research is to use the neutron spectroscopy features of 4He scintillation detectors to maintain accountability of spent fuel in storage. This project will support spent fuel safeguards and the detection of fissile material, in order to minimize the risk of nuclear proliferation and terrorism.
Jung, Joo-Young; Yoon, Do-Kun; Barraclough, Brendan; Lee, Heui Chang; Suh, Tae Suk; Lu, Bo
2017-06-13
The aim of this study is to compare between proton boron fusion therapy (PBFT) and boron neutron capture therapy (BNCT) and to analyze dose escalation using a Monte Carlo simulation. We simulated a proton beam passing through the water with a boron uptake region (BUR) in MCNPX. To estimate the interaction between neutrons/protons and borons by the alpha particle, the simulation yielded with a variation of the center of the BUR location and proton energies. The variation and influence about the alpha particle were observed from the percent depth dose (PDD) and cross-plane dose profile of both the neutron and proton beams. The peak value of the maximum dose level when the boron particle was accurately labeled at the region was 192.4% among the energies. In all, we confirmed that prompt gamma rays of 478 keV and 719 keV were generated by the nuclear reactions in PBFT and BNCT, respectively. We validated the dramatic effectiveness of the alpha particle, especially in PBFT. The utility of PBFT was verified using the simulation and it has a potential for application in radiotherapy.
Barraclough, Brendan; Lee, Heui Chang; Suh, Tae Suk; Lu, Bo
2017-01-01
The aim of this study is to compare between proton boron fusion therapy (PBFT) and boron neutron capture therapy (BNCT) and to analyze dose escalation using a Monte Carlo simulation. We simulated a proton beam passing through the water with a boron uptake region (BUR) in MCNPX. To estimate the interaction between neutrons/protons and borons by the alpha particle, the simulation yielded with a variation of the center of the BUR location and proton energies. The variation and influence about the alpha particle were observed from the percent depth dose (PDD) and cross-plane dose profile of both the neutron and proton beams. The peak value of the maximum dose level when the boron particle was accurately labeled at the region was 192.4% among the energies. In all, we confirmed that prompt gamma rays of 478 keV and 719 keV were generated by the nuclear reactions in PBFT and BNCT, respectively. We validated the dramatic effectiveness of the alpha particle, especially in PBFT. The utility of PBFT was verified using the simulation and it has a potential for application in radiotherapy. PMID:28427153
Spectral unfolding of fast neutron energy distributions
NASA Astrophysics Data System (ADS)
Mosby, Michelle; Jackman, Kevin; Engle, Jonathan
2015-10-01
The characterization of the energy distribution of a neutron flux is difficult in experiments with constrained geometry where techniques such as time of flight cannot be used to resolve the distribution. The measurement of neutron fluxes in reactors, which often present similar challenges, has been accomplished using radioactivation foils as an indirect probe. Spectral unfolding codes use statistical methods to adjust MCNP predictions of neutron energy distributions using quantified radioactive residuals produced in these foils. We have applied a modification of this established neutron flux characterization technique to experimentally characterize the neutron flux in the critical assemblies at the Nevada National Security Site (NNSS) and the spallation neutron flux at the Isotope Production Facility (IPF) at Los Alamos National Laboratory (LANL). Results of the unfolding procedure are presented and compared with a priori MCNP predictions, and the implications for measurements using the neutron fluxes at these facilities are discussed.
Elastic neutron scattering studies at 96 MeV for transmutation.
Osterlund, M; Blomgren, J; Hayashi, M; Mermod, P; Nilsson, L; Pomp, S; Ohrn, A; Prokofiev, A V; Tippawan, U
2007-01-01
Elastic neutron scattering from (12)C, (14)N, (16)O, (28)Si, (40)Ca, (56)Fe, (89)Y and (208)Pb has been studied at 96 MeV in the10-70 degrees interval, using the SCANDAL (SCAttered Nucleon Detection AssembLy) facility. The results for (12)C and (208)Pb have recently been published, while the data on the other nuclei are under analysis. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. A novel method for normalisation of the absolute scale of the cross section has been used. The estimated normalisation uncertainty, 3%, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. Elastic neutron scattering is of utmost importance for a vast number of applications. Besides its fundamental importance as a laboratory for tests of isospin dependence in the nucleon-nucleon, and nucleon-nucleus, interaction, knowledge of the optical potentials derived from elastic scattering come into play in virtually every application where a detailed understanding of nuclear processes is important. Applications for these measurements are dose effects due to fast neutrons, including fast neutron therapy, as well as nuclear waste incineration and single event upsets in electronics. The results at light nuclei of medical relevance ((12)C, (14)N and (16)O) are presented separately. In the present contribution, results on the heavier nuclei are presented, among which several are of relevance to shielding of fast neutrons.
High intensity, pulsed thermal neutron source
Carpenter, J.M.
1973-12-11
This invention relates to a high intensity, pulsed thermal neutron source comprising a neutron-producing source which emits pulses of fast neutrons, a moderator block adjacent to the last neutron source, a reflector block which encases the fast neutron source and the moderator block and has a thermal neutron exit port extending therethrough from the moderator block, and a neutron energy- dependent decoupling reflector liner covering the interior surfaces of the thermal neutron exit port and surrounding all surfaces of the moderator block except the surface viewed by the thermal neutron exit port. (Official Gazette)
Wade, E.J.
1958-09-16
This patent relates to a reflector means for a neutronic reactor. A reflector comprised of a plurality of vertically movable beryllium control members is provided surrounding the sides of the reactor core. An absorber of fast neutrons comprised of natural uramum surrounds the reflector. An absorber of slow neutrons surrounds the absorber of fast neutrons and is formed of a plurality of beryllium blocks having natural uranium members distributcd therethrough. in addition, a movable body is positioned directly below the core and is comprised of a beryllium reflector and an absorbing member attached to the botiom thereof, the absorbing member containing a substance selected from the goup consisting of natural urantum and Th/sup 232/.
Dosimetry in Thermal Neutron Irradiation Facility at BMRR
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hu, J. P.; Holden, N. E.; Reciniello, R. N.
Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; includingmore » (1) in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2) out of core moderator remodeling, done by replacing thicker D 2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3) beam shutter upgrade to reduce strayed neutrons and gamma dose, (4) beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5) beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates) to reduce prompt gamma and fast neutron doses, (6) sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7) holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4 - 7
Dosimetry in Thermal Neutron Irradiation Facility at BMRR
NASA Astrophysics Data System (ADS)
Hu, J.-P.; Holden, N. E.; Reciniello, R. N.
2016-02-01
Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1) in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2) out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3) beam shutter upgrade to reduce strayed neutrons and gamma dose, (4) beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5) beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates) to reduce prompt gamma and fast neutron doses, (6) sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7) holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4-7% lower than
NASA Astrophysics Data System (ADS)
Gradoboev, A. V.; Orlova, K. N.; Simonova, A. V.
2018-05-01
The paper presents the research results of watt and volt characteristics of LEDs based upon AlGaInP heterostructures with multiple quantum wells in the active region. The research is completed for LEDs (emission wavelengths 624 nm and 590 nm) under irradiation by fast neutron and gamma-quanta in passive powering mode. Watt-voltage characteristics in the average and high electron injection areas are described as a power function of the operating voltage. It has been revealed that the LEDs transition from average electron injection area to high electron injection area occurs by overcoming the transition area. It disappears as it get closer to the limit result of the irradiation LEDs that is low electron injection mode in the entire supply voltage range. It has been established that the gamma radiation facilitates initial defects restructuring only 42% compared to 100% when irradiation is performed by fast neutrons. Ratio between measured on the boundary between low and average electron injection areas current value and the contribution magnitude of the first stage LEDs emissive power reducing is established. It is allows to predict LEDs resistance to irradiation by fast neutrons and gamma rays.
Cyclotron Provides Neutron Therapy for Cancer Patients
1978-01-21
A cancer patient undergoes treatment in the Neutron Therapy Treatment Facility, or Cylotron, at the National Aeronautics and Space Administration (NASA) Lewis Research Center. After World War II Lewis researchers became interested in nuclear energy for propulsion. The focused their efforts on thermodynamics and strength of materials after radiation. In 1950 an 80-person Nuclear Reactor Division was created, and a cyclotron was built behind the Materials and Structures Laboratory. An in-house nuclear school was established to train these researchers in their new field. NASA cancelled its entire nuclear program in January 1973, just as the cyclotron was about to resume operations after a major upgrade. In 1975 the Cleveland Clinic Foundation partnered with NASA Lewis to use the cyclotron for a new type of radiation treatment for cancer patients. The cyclotron split beryllium atoms which caused neutrons to be released. The neutrons were streamed directly at the patient’s tumor. The facility had a dual-beam system that could target the tumor both vertically and horizontally. Over the course of five years, the cyclotron was used to treat 1200 patients. It was found to be particularly effective on salivary gland, prostrate, and other tumors. It was not as successful with tumors of the central nervous system. The program was terminated in 1980 as the Clinic began concentrating on non-radiation treatments.
Tandem-ESQ for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kreiner, A. J.; Escuela de Ciencia y Tecnologia, Universidad de Gral San Martin; CONICET,
2007-02-12
A folded tandem, with 1.25 MV terminal voltage, combined with an ElectroStatic Quadrupole (ESQ) chain is being proposed as a machine for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT). The machine is shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the on the 7Li(p,n)7Be reaction, to perform BNCT treatment for deep seated tumors in less than an hour.
Capoulat, M E; Minsky, D M; Kreiner, A J
2014-03-01
The 9Be(d,n)10B reaction was studied as an epithermal neutron source for brain tumor treatment through Boron Neutron Capture Therapy (BNCT). In BNCT, neutrons are classified according to their energies as thermal (<0.5 eV), epithermal (from 0.5 eV to 10 keV) or fast (>10 keV). For deep-seated tumors epithermal neutrons are needed. Since a fraction of the neutrons produced by this reaction are quite fast (up to 5-6 MeV, even for low-bombarding energies), an efficient beam shaping design is required. This task was carried out (1) by selecting the combinations of bombarding energy and target thickness that minimize the highest-energy neutron production; and (2) by the appropriate choice of the Beam Shaping Assembly (BSA) geometry, for each of the combinations found in (1). The BSA geometry was determined as the configuration that maximized the dose deliverable to the tumor in a 1 h treatment, within the constraints imposed by the healthy tissue dose adopted tolerance. Doses were calculated through the MCNP code. The highest dose deliverable to the tumor was found for an 8 μm target and a deuteron beam of 1.45 MeV. Tumor weighted doses ≥40 Gy can be delivered up to about 5 cm in depth, with a maximum value of 51 Gy at a depth of about 2 cm. This dose performance can be improved by relaxing the treatment time constraint and splitting the treatment into two 1-h sessions. These good treatment capabilities strengthen the prospects for a potential use of this reaction in BNCT. Copyright © 2013 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Livingston, R. A.; Schweitzer, J. S.; Parsons, A. M.; Arens, E. E.
2014-02-01
The liquid hydrogen and oxygen cryogenic storage tanks at John F. Kennedy Space Center (KSC) use expanded perlite as thermal insulation. Some of the perlite may have compacted over time, compromising the thermal performance and also the structural integrity of the tanks. Neutrons can readily penetrate through the 1.75 cm outer steel shell and through the entire 120 cm thick perlite zone. Neutrons interactions with materials produce characteristic gamma rays which are then detected. In compacted perlite the count rates in the individual peaks in the gamma ray spectrum will increase. Portable neutron generators can produce neutron simultaneous fluxes in two energy ranges: fast (14 MeV) and thermal (25 meV). Fast neutrons produce gamma rays by inelastic scattering which is sensitive to Si, Al, Fe and O. Thermal neutrons produce gamma rays by radiative capture in prompt gamma neutron activation (PGNA), which is sensitive to Si, Al, Na, K and H among others. The results of computer simulations using the software MCNP and measurements on a test article suggest that the most promising approach would be to operate the system in time-of-flight mode by pulsing the neutron generator and observing the subsequent die away curve in the PGNA signal.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Livingston, R. A.; Schweitzer, J. S.; Parsons, A. M.
2014-02-18
The liquid hydrogen and oxygen cryogenic storage tanks at John F. Kennedy Space Center (KSC) use expanded perlite as thermal insulation. Some of the perlite may have compacted over time, compromising the thermal performance and also the structural integrity of the tanks. Neutrons can readily penetrate through the 1.75 cm outer steel shell and through the entire 120 cm thick perlite zone. Neutrons interactions with materials produce characteristic gamma rays which are then detected. In compacted perlite the count rates in the individual peaks in the gamma ray spectrum will increase. Portable neutron generators can produce neutron simultaneous fluxes inmore » two energy ranges: fast (14 MeV) and thermal (25 meV). Fast neutrons produce gamma rays by inelastic scattering which is sensitive to Si, Al, Fe and O. Thermal neutrons produce gamma rays by radiative capture in prompt gamma neutron activation (PGNA), which is sensitive to Si, Al, Na, K and H among others. The results of computer simulations using the software MCNP and measurements on a test article suggest that the most promising approach would be to operate the system in time-of-flight mode by pulsing the neutron generator and observing the subsequent die away curve in the PGNA signal.« less
Wang, Xin; Poenisch, Falk; Sahoo, Narayan; Zhu, Ronald X; Lii, MingFwu; Gillin, Michael T; Li, Jing; Grosshans, David
2016-09-08
This is a real case study to minimize the neutron dose equivalent (H) to a fetus using spot scanning proton beams with favorable beam energies and angles. Minimum neutron dose exposure to the fetus was achieved with iterative planning under the guidance of neutron H measurement. Two highly conformal treatment plans, each with three spot scanning beams, were planned to treat a 25-year-old pregnant female with aggressive recurrent chordoma of the base of skull who elected not to proceed with termination. Each plan was scheduled for delivery every other day for robust target coverage. Neutron H to the fetus was measured using a REM500 neutron survey meter placed at the fetus position of a patient simulating phantom. 4.1 and 44.1 μSv/fraction were measured for the two initial plans. A vertex beam with higher energy and the fetal position closer to its central axis was the cause for the plan that produced an order higher neutron H. Replacing the vertex beam with a lateral beam reduced neutron H to be comparable with the other plan. For a prescription of 70 Gy in 35 fractions, the total neutron H to the fetus was estimated to be 0.35 mSv based on final measurement in single fraction. In comparison, the passive scattering proton plan and photon plan had an estimation of 26 and 70 mSv, respectively, for this case. While radiation therapy in pregnant patients should be avoided if at all possible, our work demonstrated spot scanning beam limited the total neutron H to the fetus an order lower than the suggested 5 mSv regulation threshold. It is far superior than passive scattering beam and careful beam selection with lower energy and keeping fetus further away from beam axis are essential in minimizing the fetus neutron exposure. © 2016 The Authors.
Iyengar, Anagha; Beach, Matthew; Newby, Robert J.; ...
2015-11-12
Neutron background measurements using a mobile trailer-based system were conducted in Knoxville, Tennessee. The 0.5 m 2 system consisting of 8 EJ-301 liquid scintillation detectors was used to collect neutron background measurements in order to better understand the systematic background variations that depend solely on the street-level measurement position in a local, downtown area. Data was collected along 5 different streets in the downtown Knoxville area, and the measurements were found to be repeatable. Using 10-min measurements, fractional uncertainty in each measured data point was <2%. Compared with fast neutron background count rates measured away from downtown Knoxville, a reductionmore » in background count rates ranging from 10-50% was observed in the downtown area, sometimes varying substantially over distances of tens of meters. These reductions are attributed to the shielding of adjacent buildings, quantified in part here by the metric angle-of-open-sky. The adjacent buildings may serve to shield cosmic ray neutron flux.« less
NASA Astrophysics Data System (ADS)
Iyengar, A.; Beach, M.; Newby, R. J.; Fabris, L.; Heilbronn, L. H.; Hayward, J. P.
2015-02-01
Neutron background measurements using a mobile trailer-based system were conducted in Knoxville, Tennessee, USA. The 0.5 m2 system, consisting of eight EJ-301 liquid scintillation detectors, was used to collect neutron background measurements in order to better understand the systematic variations in background that depend solely on the street-level measurement position in a downtown area. Data was collected along 5 different streets, and the measurements were found to be repeatable. Using 10-min measurements, the fractional uncertainty in each measured data point was <2%. Compared with fast neutron background count rates measured away from downtown Knoxville, a reduction in background count rates ranging from 10% to 50% was observed in the downtown area, sometimes varying substantially over distances of tens of meters. These reductions are attributed to the net shielding of the cosmic ray neutron flux by adjacent buildings. For reference, the building structure as observed at street level is quantified in part here by a measured angle-of-open-sky metric.
Boron neutron capture therapy for recurrent high-grade meningiomas.
Kawabata, Shinji; Hiramatsu, Ryo; Kuroiwa, Toshihiko; Ono, Koji; Miyatake, Shin-Ichi
2013-10-01
Similar to glioblastomas, high-grade meningiomas are difficult pathologies to control. In this study, the authors used boron neutron capture therapy (BNCT), a tumor-selective intensive particle radiation modality, to treat high-grade meningioma. From June 2005 to September 2011, BNCT was applied 28 times in 20 cases of recurrent high-grade meningioma. All patients had previously undergone intensive treatments such as repetitive surgeries and multiple sessions of radiation therapy. Fluorine-18-labeled boronophenylalanine ((18)F-BPA) PET was performed before BNCT in 19 of the 20 cases; BPA is itself a therapeutic compound. Compound uptake, tumor shrinkage, long-term control rate including survival time, and failure pattern of the treated patients were all evaluated. Eighteen of 19 cases studied using (18)F-BPA PET showed good BPA uptake, with ratios of tumor to normal brain greater than 2.7. These ratios indicated the likely effects of BNCT prior to neutron irradiation. The original tumor sizes were between 4.3 cm(3) and 109 cm(3). A mean tumor volume reduction of 64.5% was obtained after BNCT within just 2 months. The median follow-up duration was 13 months. Six patients are still alive; at present, the median survival times after BNCT and diagnosis are 14.1 months (95% CI 8.6-40.4 months) and 45.7 months (95% CI 32.4-70.7 months), respectively. Clinical symptoms before BNCT, such as hemiparesis and facial pain, were improved after BNCT in symptomatic cases. Systemic metastasis, intracranial distant recurrence outside the radiation field, CSF dissemination, and local tumor progression were observed in 6, 7, 3, and 3 cases, respectively, during the clinical course. Apparent pseudoprogression was observed in at least 3 cases. Symptomatic radiation injuries occurred in 6 cases, and were controllable in all but 1 case. Boron neutron capture therapy may be especially effective in cases of high-grade meningioma.
Gabel, D.
1991-06-04
The present invention pertains to boron containing thiouracil derivatives, their method of preparations, and their use in the therapy of malignant melanoma using boron neutron capture therapy. No Drawings
Plastic fiber scintillator response to fast neutrons
NASA Astrophysics Data System (ADS)
Danly, C. R.; Sjue, S.; Wilde, C. H.; Merrill, F. E.; Haight, R. C.
2014-11-01
The Neutron Imaging System at NIF uses an array of plastic scintillator fibers in conjunction with a time-gated imaging system to form an image of the neutron emission from the imploded capsule. By gating on neutrons that have scattered from the 14.1 MeV DT energy to lower energy ranges, an image of the dense, cold fuel around the hotspot is also obtained. An unmoderated spallation neutron beamline at the Weapons Neutron Research facility at Los Alamos was used in conjunction with a time-gated imaging system to measure the yield of a scintillating fiber array over several energy bands ranging from 1 to 15 MeV. The results and comparison to simulation are presented.
Plastic fiber scintillator response to fast neutrons.
Danly, C R; Sjue, S; Wilde, C H; Merrill, F E; Haight, R C
2014-11-01
The Neutron Imaging System at NIF uses an array of plastic scintillator fibers in conjunction with a time-gated imaging system to form an image of the neutron emission from the imploded capsule. By gating on neutrons that have scattered from the 14.1 MeV DT energy to lower energy ranges, an image of the dense, cold fuel around the hotspot is also obtained. An unmoderated spallation neutron beamline at the Weapons Neutron Research facility at Los Alamos was used in conjunction with a time-gated imaging system to measure the yield of a scintillating fiber array over several energy bands ranging from 1 to 15 MeV. The results and comparison to simulation are presented.
On the studies of thermodynamics properties of fast neutron irradiated (LixK1-x)2SO4 crystals
NASA Astrophysics Data System (ADS)
El-Khatib, A. M.; Kassem, M. E.; Gomaa, N. G.; Mahmoud, S. A.
The effect of fast neutron irradiation on the thermodynamic properties of (LixK1-x)2SO4, (x = 0.1, 0.2,˙˙˙˙˙˙˙˙0.5) has been studied. The measurements were carried out in the vicinity of phase transition. The study reveals that as the lithium content decreases the first high temperature phase Tc = 705 K disappears, while the second one is shifted to lower temperature. It is observed also that the specific heat, Cp, decreases sharply with neutron integrated fluence φ and increases once more. Both entropy and enthalpy changes increase with the increase of neutron integrated fluence.
An Assessment of the Potential Use of BNNTs for Boron Neutron Capture Therapy.
Ferreira, Tiago H; Miranda, Marcelo C; Rocha, Zildete; Leal, Alexandre S; Gomes, Dawidson A; Sousa, Edesia M B
2017-04-12
Currently, nanostructured compounds have been standing out for their optical, mechanical, and chemical features and for the possibilities of manipulation and regulation of complex biological processes. One of these compounds is boron nitride nanotubes (BNNTs), which are a nanostructured material analog to carbon nanotubes, but formed of nitrogen and boron atoms. BNNTs present high thermal stability along with high chemical inertia. Among biological applications, its biocompatibility, cellular uptake, and functionalization potential can be highlighted, in addition to its eased utilization due to its nanometric size and tumor cell internalization. When it comes to new forms of therapy, we can draw attention to boron neutron capture therapy (BNCT), an experimental radiotherapy characterized by a boron-10 isotope carrier inside the target and a thermal neutron beam focused on it. The activation of the boron-10 atom by a neutron generates a lithium atom, a gamma ray, and an alpha particle, which can be used to destroy tumor tissues. The aim of this work was to use BNNTs as a boron-10 carrier for BNCT and to demonstrate its potential. The nanomaterial was characterized through XRD, FTIR, and SEM. The WST-8 assay was performed to confirm the cell viability of BNNTs. The cells treated with BNNTs were irradiated with the neutron beam of a Triga reactor, and the apoptosis caused by the activation of the BNNTs was measured with a calcein AM/propidium iodide test. The results demonstrate that this nanomaterial is a promising candidate for cancer therapy through BNCT.
NEUTRON MEASURING METHOD AND APPARATUS
Seaborg, G.T.; Friedlander, G.; Gofman, J.W.
1958-07-29
A fast neutron fission detecting apparatus is described consisting of a source of fast neutrons, an ion chamber containing air, two electrodes within the ion chamber in confronting spaced relationship, a high voltage potential placed across the electrodes, a shield placed about the source, and a suitable pulse annplifier and recording system in the electrode circuit to record the impulse due to fissions in a sannple material. The sample material is coated onto the active surface of the disc electrode and shielding means of a material having high neutron capture capabilities for thermal neutrons are provided in the vicinity of the electrodes and about the ion chamber so as to absorb slow neutrons of thermal energy to effectively prevent their diffusing back to the sample and causing an error in the measurement of fast neutron fissions.
Study on High Speed Lithium Jet For Neutron Source of Boron Neutron Capture Therapy (BNCT)
NASA Astrophysics Data System (ADS)
Takahashi, Minoru; Kobayashi, Tooru; Zhang, Mingguang; Mák, Michael; Štefanica, Jirí; Dostál, Václav; Zhao, Wei
The feasibility study of a liquid lithium type proton beam target was performed for the neutron source of the boron neutron capture therapy (BNCT). As the candidates of the liquid lithium target, a thin sheet jet and a thin film flow on a concave wall were chosen, and a lithium flow experiment was conducted to investigate the hydrodynamic stability of the targets. The surfaces of the jets and film flows with a thickness of 0.5 mm and a width of 50 mm were observed by means of photography. It has been found that a stable sheet jet and a stable film flow on a concave wall can be formed up to certain velocities by using a straight nozzle and a curved nozzle with the concave wall, respectively.
Zandi, Nadia; Afarideh, Hossein; Aboudzadeh, Mohammad Reza; Rajabifar, Saeed
2018-02-01
The aim of this work is to increase the magnitude of the fast neutron flux inside the flux trap where radionuclides are produced. For this purpose, three new designs of the flux trap are proposed and the obtained fast and thermal neutron fluxes compared with each other. The first and second proposed designs were a sealed cube contained air and D 2 O, respectively. The results of calculated production yield all indicated the superiority of the latter by a factor of 55% in comparison to the first proposed design. The third proposed design was based on changing the surrounding of the sealed cube by locating two fuel plates near that. In this case, the production yield increased up to 70%. Copyright © 2017. Published by Elsevier Ltd.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Abedin, Ahmad Firdaus Zainal, E-mail: firdaus087@gmail.com; Ibrahim, Noorddin; Zabidi, Noriza Ahmad
2015-04-29
Neutron radiation is able to determine the signature of land mine detection based on backscattering energy spectrum of landmine. In this study, the Monte Carlo simulation of backscattered fast neutrons was performed on four basic elements of land mine; hydrogen, nitrogen, oxygen and carbon. The moderation of fast neutrons to thermal neutrons and their resonances cross-section between 0.01 eV until 14 MeV were analysed. The neutrons energies were divided into 29 groups and ten million neutrons particles histories were used. The geometries consist of four main components: neutrons source, detectors, landmine and soil. The neutrons source was placed at the originmore » coordinate and shielded with carbon and polyethylene. Americium/Beryllium neutron source was placed inside lead casing of 1 cm thick and 2.5 cm height. Polyethylene was used to absorb and disperse radiation and was placed outside the lead shield of width 10 cm and height 7 cm. Two detectors were placed between source with distance of 8 cm and radius of 1.9 cm. Detectors of Helium-3 was used for neutron detection as it has high absorption cross section for thermal neutrons. For the anomaly, the physical is in cylinder form with radius of 10 cm and 8.9 cm height. The anomaly is buried 5 cm deep in the bed soil measured 80 cm radius and 53.5 cm height. The results show that the energy spectrum for the four basic elements of landmine with specific pattern which can be used as indication for the presence of landmines.« less
Neutron medical treatment of tumours — a survey of facilities
NASA Astrophysics Data System (ADS)
Wagner, F. M.; Loeper-Kabasakal, B.; Breitkreutz, H.
2012-03-01
Neutron therapy has two branches: Fast Neutron Therapy (FNT) and Boron Neutron Capture Therapy (BNCT). The mean neutron energies used for FNT range from 2 MeV to 25 MeV whereas the maximum energy for BNCT is about 10 keV. Neutron generators for FNT have been cyclotrons, accelerators and reactors, whereas BNCT is so far bound to reactors. Both therapies use the effects of high-LET radiation (secondary recoil protons and alpha particles, respectively) and can attack otherwise radioresistant tumours, however, with the hazard of adverse effects for irradiated healthy tissue. FNT has been administered to about 30,000 patients world-wide. From formerly 40 facilities, only eight are operational or stand-by today. The reasons for this development have been, on the one hand, related to technical and economical conditions; on the other hand, strong side effects and insufficient proof of clinical results in the early years as well as increasing competition with new clinical methods have reduced patient numbers. In fact, strict observations of indications, appropriate therapy-planning including low-LET radiation, and consequent treatment of side effects have lead to remarkable results in the meantime. BNCT initially was developed for the treatment of extremely aggressive forms of brain tumour, taking advantage of the action of the blood-brain-barrier which allows for a boronated compound to be selectively enriched in tumour cells. Meanwhile, also malignant melanoma (MM) and Head-and-Neck (H&T) tumours are treated because of their relative radioresistance. At present, epithermal beams with sufficient flux are available only at two facilities. Existing research reactors were indispensable in the development of BNCT, but are to be replaced by hospital-based epithermal neutron sources. Clinical results indicate significantly increased survival times, but the number of patients ever treated is still below 1,000. 3D-dose calculation systems have been developed at several facilities
Proceedings of the first international symposium on neutron capture therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fairchild, R.G.; Brownell, G.L.
This meeting was arranged jointly by MIT and BNL in order to illuminate progress in the synthesis and targeting of boron compounds and to evaluate and document progress in radiobiological and dosimetric aspects of neutron capture therapy. It is hoped that this meeting will facilitate transfer of information between groups working in these fields, and encourage synergistic collaboration.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Takeda, T.; Shimazu, Y.; Hibi, K.
2012-07-01
Under the R and D project to improve the modeling accuracy for the design of fast breeder reactors the authors are developing a neutronics calculation method for designing a large commercial type sodium- cooled fast reactor. The calculation method is established by taking into account the special features of the reactor such as the use of annular fuel pellet, inner duct tube in large fuel assemblies, large core. The Verification and Validation, and Uncertainty Qualification (V and V and UQ) of the calculation method is being performed by using measured data from the prototype FBR Monju. The results of thismore » project will be used in the design and analysis of the commercial type demonstration FBR, known as the Japanese Sodium fast Reactor (JSFR). (authors)« less
Adams, Robert; Zboray, Robert; Cortesi, Marco; Prasser, Horst-Michael
2014-04-01
A conceptual design optimization of a fast neutron tomography system was performed. The system is based on a compact deuterium-deuterium fast neutron generator and an arc-shaped array of individual neutron detectors. The array functions as a position sensitive one-dimensional detector allowing tomographic reconstruction of a two-dimensional cross section of an object up to 10 cm across. Each individual detector is to be optically isolated and consists of a plastic scintillator and a Silicon Photomultiplier for measuring light produced by recoil protons. A deterministic geometry-based model and a series of Monte Carlo simulations were used to optimize the design geometry parameters affecting the reconstructed image resolution. From this, it is expected that with an array of 100 detectors a reconstructed image resolution of ~1.5mm can be obtained. Other simulations were performed in order to optimize the scintillator depth (length along the neutron path) such that the best ratio of direct to scattered neutron counts is achieved. This resulted in a depth of 6-8 cm and an expected detection efficiency of 33-37%. Based on current operational capabilities of a prototype neutron generator being developed at the Paul Scherrer Institute, planned implementation of this detector array design should allow reconstructed tomograms to be obtained with exposure times on the order of a few hours. Copyright © 2014 Elsevier Ltd. All rights reserved.
Subthreshold neutron interrogator for detection of radioactive materials
Evans, Michael L.; Menlove, Howard O.; Baker, Michael P.
1980-01-01
A device for detecting fissionable material such as uranium in low concentrations by interrogating with photoneutrons at energy levels below 500 keV, and typically about 26 keV. Induced fast neutrons having energies above 500 keV by the interrogated fissionable material are detected by a liquid scintillator or recoil proportional counter which is sensitive to the induced fast neutrons. Since the induced fast neutrons are proportional to the concentration of fissionable material, detection of induced fast neutrons indicate concentration of the fissionable material.
Feasibility of fast neutron analysis for the detection of explosives buried in soil
NASA Astrophysics Data System (ADS)
Faust, A. A.; McFee, J. E.; Bowman, C. L.; Mosquera, C.; Andrews, H. R.; Kovaltchouk, V. D.; Ing, H.
2011-12-01
A commercialized thermal neutron analysis (TNA) sensor has been developed to confirm the presence of buried bulk explosives as part of a multi-sensor anti-tank landmine detection system. Continuing improvements to the TNA system have included the use of an electronic pulsed neutron generator that offers the possibility of applying fast neutron analysis (FNA) methods to improve the system's detection capability. This paper describes an investigation into the use of FNA as a complementary component in such a TNA system. The results of a modeling study using simple geometries and a full model of the TNA sensor head are presented, as well as preliminary results from an experimental associated particle imaging (API) system that supports the modeling study results. The investigation has concluded that the pulsed beam FNA approach would not improve the detection performance of a TNA system for landmine or buried IED detection in a confirmation role, and could not be made into a practical stand-alone detection system for buried anti-tank landmines. Detection of buried landmines and IEDs by FNA remains a possibility, however, through the use of the API technique.
NASA Astrophysics Data System (ADS)
Krasikov, E.; Nikolaenko, V.
2017-01-01
Fast neutron intensity influence on reactor materials radiation damage is a critically important question in the problem of the correct use of the accelerated irradiation tests data for substantiation of the materials workability in real irradiation conditions that is low neutron intensity. Investigations of the fast neutron intensity (flux) influence on radiation damage and experimental data scattering reveal the existence of non-monotonous sections in kinetics of the reactor pressure vessels (RPV) steel damage. Discovery of the oscillations as indicator of the self-organization processes presence give reasons for new ways searching on reactor pressure vessel (RPV) steel radiation stability increasing and attempt of the self-restoring metal elaboration. Revealing of the wavelike process in the form of non monotonous parts of the kinetics of radiation embrittlement testifies that periodic transformation of the structure take place. This fact actualizes the problem of more precise definition of the RPV materials radiation embrittlement mechanisms and gives reasons for search of the ways to manage the radiation stability (nanostructuring and so on to stimulate the radiation defects annihilation), development of the means for creating of more stableness self recovering smart materials.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Akishev, Yu. S., E-mail: akishev@triniti.ru; Karal’nik, V. B.; Petryakov, A. V.
2017-02-15
The ultrahigh charging of dust particles in a plasma under exposure to an electron beam with an energy up to 25 keV and the formation of a flux of fast ions coming from the plasma and accelerating in the strong field of negatively charged particles are considered. Particles containing tritium or deuterium atoms are considered as targets. The calculated rates of thermonuclear fusion reactions in strongly charged particles under exposure to accelerated plasma ions are presented. The neutron generation rate in reactions with accelerated deuterium and tritium ions has been calculated for these targets. The neutron yield has been calculatedmore » when varying the plasma-forming gas pressure, the plasma density, the target diameter, and the beam electron current density. Deuterium and tritium-containing particles are shown to be the most promising plasmaforming gas–target material pair for the creation of a compact gas-discharge neutron source based on the ultrahigh charging of dust particles by beam electrons with an energy up to 25 keV.« less
MAGIC polymer gel for dosimetric verification in boron neutron capture therapy
Heikkinen, Sami; Kotiluoto, Petri; Serén, Tom; Seppälä, Tiina; Auterinen, Iiro; Savolainen, Sauli
2007-01-01
Radiation‐sensitive polymer gels are among the most promising three‐dimensional dose verification tools developed to date. We tested the normoxic polymer gel dosimeter known by the acronym MAGIC (methacrylic and ascorbic acid in gelatin initiated by copper) to evaluate its use in boron neutron capture therapy (BNCT) dosimetry. We irradiated a large cylindrical gel phantom (diameter: 10 cm; length: 20 cm) in the epithermal neutron beam of the Finnish BNCT facility at the FiR 1 nuclear reactor. Neutron irradiation was simulated with a Monte Carlo radiation transport code MCNP. To compare dose–response, gel samples from the same production batch were also irradiated with 6 MV photons from a medical linear accelerator. Irradiated gel phantoms then underwent magnetic resonance imaging to determine their R2 relaxation rate maps. The measured and normalized dose distribution in the epithermal neutron beam was compared with the dose distribution calculated by computer simulation. The results support the feasibility of using MAGIC gel in BNCT dosimetry. PACS numbers: 87.53.Qc, 87.53.Wz, 87.66.Ff PMID:17592463
Treatment Planning for Accelerator-Based Boron Neutron Capture Therapy
NASA Astrophysics Data System (ADS)
Herrera, María S.; González, Sara J.; Minsky, Daniel M.; Kreiner, Andrés J.
2010-08-01
Glioblastoma multiforme and metastatic melanoma are frequent brain tumors in adults and presently still incurable diseases. Boron Neutron Capture Therapy (BNCT) is a promising alternative for this kind of pathologies. Accelerators have been proposed for BNCT as a way to circumvent the problem of siting reactors in hospitals and for their relative simplicity and lower cost among other advantages. Considerable effort is going into the development of accelerator-based BNCT neutron sources in Argentina. Epithermal neutron beams will be produced through appropriate proton-induced nuclear reactions and optimized beam shaping assemblies. Using these sources, computational dose distributions were evaluated in a real patient with diagnosed glioblastoma treated with BNCT. The simulated irradiation was delivered in order to optimize dose to the tumors within the normal tissue constraints. Using Monte Carlo radiation transport calculations, dose distributions were generated for brain, skin and tumor. Also, the dosimetry was studied by computing cumulative dose-volume histograms for volumes of interest. The results suggest acceptable skin average dose and a significant dose delivered to tumor with low average whole brain dose for irradiation times less than 60 minutes, indicating a good performance of an accelerator-based BNCT treatment.
Treatment Planning for Accelerator-Based Boron Neutron Capture Therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Herrera, Maria S.; Gonzalez, Sara J.; Minsky, Daniel M.
2010-08-04
Glioblastoma multiforme and metastatic melanoma are frequent brain tumors in adults and presently still incurable diseases. Boron Neutron Capture Therapy (BNCT) is a promising alternative for this kind of pathologies. Accelerators have been proposed for BNCT as a way to circumvent the problem of siting reactors in hospitals and for their relative simplicity and lower cost among other advantages. Considerable effort is going into the development of accelerator-based BNCT neutron sources in Argentina. Epithermal neutron beams will be produced through appropriate proton-induced nuclear reactions and optimized beam shaping assemblies. Using these sources, computational dose distributions were evaluated in a realmore » patient with diagnosed glioblastoma treated with BNCT. The simulated irradiation was delivered in order to optimize dose to the tumors within the normal tissue constraints. Using Monte Carlo radiation transport calculations, dose distributions were generated for brain, skin and tumor. Also, the dosimetry was studied by computing cumulative dose-volume histograms for volumes of interest. The results suggest acceptable skin average dose and a significant dose delivered to tumor with low average whole brain dose for irradiation times less than 60 minutes, indicating a good performance of an accelerator-based BNCT treatment.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Johnson, James T.; Thompson, Scott J.; Watson, Scott M.
We present a multi-channel, fast neutron/gamma ray detector array system that utilizes ZnS(Ag) scintillator detectors. The system employs field programmable gate arrays (FPGAs) to do real-time all digital neutron/gamma ray discrimination with pulse height and time histograms to allow count rates in excess of 1,000,000 pulses per second per channel. The system detector number is scalable in blocks of 16 channels.
Measured thermal and fast neutron fluence rates for ATF-1 holders during ATR cycle 158B/159A
DOE Office of Scientific and Technical Information (OSTI.GOV)
Smith, Larry Don; Miller, David Torbet; Walker, Billy Justin
2016-11-01
This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 158B/159A which were measured by the Radiation Measurements Laboratory (RML).
NASA Astrophysics Data System (ADS)
Koseoglou, P.; Vagena, E.; Stoulos, S.; Manolopoulou, M.
2016-09-01
Neutron spectrum of the sub-critical nuclear assembly-reactor of Aristotle University of Thessaloniki was measured at three radial distances from the reactor core. The neutron activation technique was applied irradiating 15 thick foils - disc of various elements at each position. The data of 38 (n, γ), (n, p) and (n, α) reactions were analyzed for specific activity determination. Discs instead of foils were used due to the relevant low neutron flux, so the gamma self-absorption as well as the neutron self-shielding factors has been calculated using GEANT simulations in order to determine the activity induced. The specific activities calculated for all isotopes studied were the input to the SANDII code, which was built specifically for the neutron spectrum de-convolution when the neutron activation technique is used. For the optimization of the results a technique was applied in order to minimize the influence of the initial-"guessed" spectrum shape SANDII uses. The neutron spectrum estimated presents a peak in the regions of (i) thermal neutrons ranged between 0.001 and 1 eV peaking at neutron energy ∼0.1 eV and (ii) fast neutrons ranged between 0.1 and 20 MeV peaking at neutron energy ∼1.2 MeV. The reduction of thermal neutrons is higher than the fast one as the distance from the reactor core increases since thermal neutrons capture by natural U-fuel has higher cross section than the fast neutrons.
Prolonged fasting with fluid therapy is related to poorer outcomes in medical patients.
Kyriakos, Georgios; Calleja-Fernández, Alicia; Ávila-Turcios, Dalia; Cano-Rodríguez, Isidoro; Ballesteros Pomar, María D; Vidal-Casariego, Alfonso
2013-01-01
An inadequate fluid therapy can worsen the outcomes of surgical patients, but there are no data in medical patients. The aim of this study was to determine the adequacy of fluid therapy in hospitalised patients of medical wards, and its influence on outcomes. Cross-sectional study including nil-per-os patients admitted in medical wards of the Complejo Asistencial Universitario de León. The administered fluid therapy was compared with the standardised requirements. Nutritional status was evaluated with Subjective Global Assessment. Fasting was considered inappropriate if it lasted > 7 days in well-nourished, and >5 days in malnourished patients if nutritional support had not been provided. Fluid therapy lasted 4 (IQR = 2) days, and fasting was inadequately maintained in 27% of patients. Fluid requirements were correctly fulfilled, but patients received an excess of sodium (+58.4%) and chloride (+62.2%), and potassium administration was insufficient (-35.1%). Glucose supply was 68.8 (29.2) g/d, and 99% received < 130 g/d. Patients with an inadequate duration of fasting had a longer hospital stay after adjusting for sex, age, nutritional status, infused volume, electrolytes, glucose and diseases. Only malnutrition predicted mortality during hospitalisation (OR 10.5; 95%CI 1.3 to 83.2), when multivariate analysis was performed. Fasting medical patients receive an inadequate supply of glucose and electrolytes. Prolonged fluid therapy and malnutrition may worsen the outcomes of these patients, independently of other conditions like age or diseases. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.
Neutron track length estimator for GATE Monte Carlo dose calculation in radiotherapy.
Elazhar, H; Deschler, T; Létang, J M; Nourreddine, A; Arbor, N
2018-06-20
The out-of-field dose in radiation therapy is a growing concern in regards to the late side-effects and secondary cancer induction. In high-energy x-ray therapy, the secondary neutrons generated through photonuclear reactions in the accelerator are part of this secondary dose. The neutron dose is currently not estimated by the treatment planning system while it appears to be preponderant for distances greater than 50 cm from the isocenter. Monte Carlo simulation has become the gold standard for accurately calculating the neutron dose under specific treatment conditions but the method is also known for having a slow statistical convergence, which makes it difficult to be used on a clinical basis. The neutron track length estimator, a neutron variance reduction technique inspired by the track length estimator method has thus been developped for the first time in the Monte Carlo code GATE to allow a fast computation of the neutron dose in radiotherapy. The details of its implementation, as well as the comparison of its performances against the analog MC method, are presented here. A gain of time from 15 to 400 can be obtained by our method, with a mean difference in the dose calculation of about 1% in comparison with the analog MC method.
High-Energy Neutrons from the Moon
NASA Astrophysics Data System (ADS)
Maurice, S.; Feldman, W. C.; Lawrence, D. J.; Elphic, R. E.; Gasnault, O.; dUston, C.; Lucey, P. G.
1999-01-01
Galactic cosmic rays that impact the lunar soil produce neutrons with energies from fractions of eV's to about 100 MeV. The high-energy band from 0.6 to 8.0 MeV is referred as the "fast neutron" band, which is measured by Lunar Prospector (LP) Gamma Ray Spectrometer. Fast neutrons play an important role in neutron spectroscopy that may be summarized as follows: Fast neutrons define the total neutron input to the moderating process toward low-energy populations, so that epithermal and thermal neutron leakage currents must be normalized to the leakage of fast neutrons; they allow the determination of the burial depth of H, a measure necessary to understand characteristics of water deposits; they provide information on the surface content in heavy elements, such as Ti and Fe; and they provide a direct insight into the evaporation process. As discussed hereafter, fast neutrons may yield information on other oxides, such as Si02. missing data. Mare have numerous features, that are resolved in fast neutrons. For instance, the region extending northwest of Aristarchus (23.7 deg N, 47.4 W) is clearly separated from Montes Harbinger (27.0N, 41.0W) by a high-emission channel, and Mare Vaporum (13.3 N, 3.6 E) is separated from Sinus Aestuun (10.9N, 8.8W) by a low-emission area. We present a new technique to extract information on soil composition from the fast-neutron measurements. The analysis is applied to the central mare region. There are two steps for the development of the technique. 1. For the first step, which has been fully completed, we assume that variations of fast-neutron counting rates are due solely to TiO. and FeO. Upon this assumption, we correlate Clementine Spectral Reflectance Fe and Ti oxide maps with fast measurements. Above 16.5% of FeO, effects of Ti02 variations show in LP data. Below 6.5% of FeO, Fe cannot be discriminated; this is the region of most highland terrains. Under assumption of only two oxides to modulate the signal, we show that fast
Howell, Rebecca M; Burgett, E A
2014-09-01
Secondary neutrons are an unavoidable consequence of proton therapy. While the neutron dose is low compared to the primary proton dose, its presence and contribution to the patient dose is nonetheless important. The most detailed information on neutrons includes an evaluation of the neutron spectrum. However, the vast majority of the literature that has reported secondary neutron spectra in proton therapy is based on computational methods rather than measurements. This is largely due to the inherent limitations in the majority of neutron detectors, which are either not suitable for spectral measurements or have limited response at energies greater than 20 MeV. Therefore, the primary objective of the present study was to measure a secondary neutron spectrum from a proton therapy beam using a spectrometer that is sensitive to neutron energies over the entire neutron energy spectrum. The authors measured the secondary neutron spectrum from a 250-MeV passively scattered proton beam in air at a distance of 100 cm laterally from isocenter using an extended-range Bonner sphere (ERBS) measurement system. Ambient dose equivalent H*(10) was calculated using measured fluence and fluence-to-ambient dose equivalent conversion coefficients. The neutron fluence spectrum had a high-energy direct neutron peak, an evaporation peak, a thermal peak, and an intermediate energy continuum between the thermal and evaporation peaks. The H*(10) was dominated by the neutrons in the evaporation peak because of both their high abundance and the large quality conversion coefficients in that energy interval. The H*(10) 100 cm laterally from isocenter was 1.6 mSv per proton Gy (to isocenter). Approximately 35% of the dose equivalent was from neutrons with energies ≥20 MeV. The authors measured a neutron spectrum for external neutrons generated by a 250-MeV proton beam using an ERBS measurement system that was sensitive to neutrons over the entire energy range being measured, i.e., thermal to
Howell, Rebecca M.; Burgett, E. A.
2014-01-01
Purpose: Secondary neutrons are an unavoidable consequence of proton therapy. While the neutron dose is low compared to the primary proton dose, its presence and contribution to the patient dose is nonetheless important. The most detailed information on neutrons includes an evaluation of the neutron spectrum. However, the vast majority of the literature that has reported secondary neutron spectra in proton therapy is based on computational methods rather than measurements. This is largely due to the inherent limitations in the majority of neutron detectors, which are either not suitable for spectral measurements or have limited response at energies greater than 20 MeV. Therefore, the primary objective of the present study was to measure a secondary neutron spectrum from a proton therapy beam using a spectrometer that is sensitive to neutron energies over the entire neutron energy spectrum. Methods: The authors measured the secondary neutron spectrum from a 250-MeV passively scattered proton beam in air at a distance of 100 cm laterally from isocenter using an extended-range Bonner sphere (ERBS) measurement system. Ambient dose equivalent H*(10) was calculated using measured fluence and fluence-to-ambient dose equivalent conversion coefficients. Results: The neutron fluence spectrum had a high-energy direct neutron peak, an evaporation peak, a thermal peak, and an intermediate energy continuum between the thermal and evaporation peaks. The H*(10) was dominated by the neutrons in the evaporation peak because of both their high abundance and the large quality conversion coefficients in that energy interval. The H*(10) 100 cm laterally from isocenter was 1.6 mSv per proton Gy (to isocenter). Approximately 35% of the dose equivalent was from neutrons with energies ≥20 MeV. Conclusions: The authors measured a neutron spectrum for external neutrons generated by a 250-MeV proton beam using an ERBS measurement system that was sensitive to neutrons over the entire
TU-FG-BRB-07: GPU-Based Prompt Gamma Ray Imaging From Boron Neutron Capture Therapy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kim, S; Suh, T; Yoon, D
Purpose: The purpose of this research is to perform the fast reconstruction of a prompt gamma ray image using a graphics processing unit (GPU) computation from boron neutron capture therapy (BNCT) simulations. Methods: To evaluate the accuracy of the reconstructed image, a phantom including four boron uptake regions (BURs) was used in the simulation. After the Monte Carlo simulation of the BNCT, the modified ordered subset expectation maximization reconstruction algorithm using the GPU computation was used to reconstruct the images with fewer projections. The computation times for image reconstruction were compared between the GPU and the central processing unit (CPU).more » Also, the accuracy of the reconstructed image was evaluated by a receiver operating characteristic (ROC) curve analysis. Results: The image reconstruction time using the GPU was 196 times faster than the conventional reconstruction time using the CPU. For the four BURs, the area under curve values from the ROC curve were 0.6726 (A-region), 0.6890 (B-region), 0.7384 (C-region), and 0.8009 (D-region). Conclusion: The tomographic image using the prompt gamma ray event from the BNCT simulation was acquired using the GPU computation in order to perform a fast reconstruction during treatment. The authors verified the feasibility of the prompt gamma ray reconstruction using the GPU computation for BNCT simulations.« less
Thekkedath, Siji Cyriac; Raman, R Ganapathi; Musthafa, M M; Bakshi, A K; Pal, Rupali; Dawn, Sandipan; Kummali, Abdul Haneefa; Huilgol, Nagraj G; Selvam, T Palani; Datta, D
2016-01-01
The photo-neutron dose equivalents of 15 MV Elekta precise accelerators were measured for different depths in phantom, for various field sizes, at different distances from the isocenter in the patient plane and for various wedged fields. Fast and thermal neutrons are measured using passive detectors such as Columbia Resin-39 and pair of thermoluminescent dosimetry (TLD) 600 and TLD 700 detector from Elekta medical linear accelerator. It is found that fast photo-neutron dose rate decreases as the depth increases, with a maximum of 0.57 ± 0.08 mSv/Gy photon dose at surface and minimum of 0.09 ± 0.02 mSv/Gy photon dose at 15 cm depth of water equivalent phantom with 10 cm backscatter. Photo neutrons decreases from 1.28 ± 0.03 mSv/Gy to 0.063 ± 0.032 when measured at isocenter and at 100 cm far from the field edge along the longitudinal direction in the patient plane. Fast and thermal neutron doses increases from 0.65 ± 0.05 mSv/Gy to 1.08 ± 0.07 mSv/Gy as the field size increases; from 5 cm × 5 cm to 30 cm × 30 cm for fast neutrons. With increase in wedge field angle from 0° to 60°, it is observed that the fast neutron dose increases from 0.42 ± 0.03 mSv/Gy to 0.95 ± 0.05 mSv/Gy.s Measurements indicate the photo-neutrons at few field sizes are slightly higher than the International Electrotechnical Commission standard specifications. Photo-neutrons from Omni wedged fields are studied in details. These studies of the photo-neutron energy response will enlighten the neutron dose to radiation therapy patients and are expected to further improve radiation protection guidelines.
On the possible use of the MASURCA reactor as a flexible, high-intensity, fast neutron beam facility
NASA Astrophysics Data System (ADS)
Dioni, Luca; Jacqmin, Robert; Sumini, Marco; Stout, Brian
2017-09-01
In recent work [1, 2], we have shown that the MASURCA research reactor could be used to deliver a fairly-intense continuous fast neutron beam to an experimental room located next to the reactor core. As a consequence of the MASURCA favorable characteristics and diverse material inventories, the neutron beam intensity and spectrum can be further tailored to meet the users' needs, which could be of interest for several applications. Monte Carlo simulations have been performed to characterize in detail the extracted neutron (and photon) beam entering the experimental room. These numerical simulations were done for two different bare cores: A uranium metallic core (˜30% 235U enriched) and a plutonium oxide core (˜25% Pu fraction, ˜78% 239Pu). The results show that the distinctive resonance energy structures of the two core leakage spectra are preserved at the channel exit. As the experimental room is large enough to house a dedicated set of neutron spectrometry instruments, we have investigated several candidate neutron spectrum measurement techniques, which could be implemented to guarantee well-defined, repeatable beam conditions to users. Our investigation also includes considerations regarding the gamma rays in the beams.
Prototype Stilbene Neutron Collar
DOE Office of Scientific and Technical Information (OSTI.GOV)
Prasad, M. K.; Shumaker, D.; Snyderman, N.
2016-10-26
A neutron collar using stilbene organic scintillator cells for fast neutron counting is described for the assay of fresh low enriched uranium (LEU) fuel assemblies. The prototype stilbene collar has a form factor similar to standard He-3 based collars and uses an AmLi interrogation neutron source. This report describes the simulation of list mode neutron correlation data on various fuel assemblies including some with neutron absorbers (burnable Gd poisons). Calibration curves (doubles vs 235U linear mass density) are presented for both thermal and fast (with Cd lining) modes of operation. It is shown that the stilbene collar meets or exceedsmore » the current capabilities of He-3 based neutron collars. A self-consistent assay methodology, uniquely suited to the stilbene collar, using triples is described which complements traditional assay based on doubles calibration curves.« less
Characteristics of a heavy water photoneutron source in boron neutron capture therapy
NASA Astrophysics Data System (ADS)
Danial, Salehi; Dariush, Sardari; M. Salehi, Jozani
2013-07-01
Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors. Photons with energies greater than 8-10 MeV potentially generate neutrons through photonuclear interactions in the accelerator's treatment head, patient's body, and treatment room ambient. Electrons impinging on a heavy target generate a cascade shower of bremsstrahlung photons, the energy spectrum of which shows an end point equal to the electron beam energy. By varying the target thickness, an optimum thickness exists for which, at the given electron energy, maximum photon flux is achievable. If a source of high-energy photons i.e. bremsstrahlung, is conveniently directed to a suitable D2O target, a novel approach for production of an acceptable flux of filterable photoneturons for boron neutron capture therapy (BNCT) application is possible. This study consists of two parts. 1. Comparison and assessment of deuterium photonuclear cross section data. 2. Evaluation of the heavy water photonuclear source.
Neutron capture therapy with deep tissue penetration using capillary neutron focusing
Peurrung, Anthony J.
1997-01-01
An improved method for delivering thermal neutrons to a subsurface cancer or tumor which has been first doped with a dopant having a high cross section for neutron capture. The improvement is the use of a guide tube in cooperation with a capillary neutron focusing apparatus, or neutron focusing lens, for directing neutrons to the tumor, and thereby avoiding damage to surrounding tissue.
Thermal neutron filter design for the neutron radiography facility at the LVR-15 reactor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Soltes, Jaroslav; Faculty of Nuclear Sciences and Physical Engineering, CTU in Prague,; Viererbl, Ladislav
2015-07-01
In 2011 a decision was made to build a neutron radiography facility at one of the unused horizontal channels of the LVR-15 research reactor in Rez, Czech Republic. One of the key conditions for operating an effective radiography facility is the delivery of a high intensity, homogeneous and collimated thermal neutron beam at the sample location. Additionally the intensity of fast neutrons has to be kept as low as possible as the fast neutrons may damage the detectors used for neutron imaging. As the spectrum in the empty horizontal channel roughly copies the spectrum in the reactor core, which hasmore » a high ratio of fast neutrons, neutron filter components have to be installed inside the channel in order to achieve desired beam parameters. As the channel design does not allow the instalment of complex filters and collimators, an optimal solution represent neutron filters made of large single-crystal ingots of proper material composition. Single-crystal silicon was chosen as a favorable filter material for its wide availability in sufficient dimensions. Besides its ability to reasonably lower the ratio of fast neutrons while still keeping high intensities of thermal neutrons, due to its large dimensions, it suits as a shielding against gamma radiation from the reactor core. For designing the necessary filter dimensions the Monte-Carlo MCNP transport code was used. As the code does not provide neutron cross-section libraries for thermal neutron transport through single-crystalline silicon, these had to be created by approximating the theory of thermal neutron scattering and modifying the original cross-section data which are provided with the code. Carrying out a series of calculations the filter thickness of 1 m proved good for gaining a beam with desired parameters and a low gamma background. After mounting the filter inside the channel several measurements of the neutron field were realized at the beam exit. The results have justified the expected calculated
NASA Astrophysics Data System (ADS)
Huang, Chen-Hsi; Gilbert, Mark R.; Marian, Jaime
2018-02-01
Simulations of neutron damage under fusion energy conditions must capture the effects of transmutation, both in terms of accurate chemical inventory buildup as well as the physics of the interactions between transmutation elements and irradiation defect clusters. In this work, we integrate neutronics, primary damage calculations, molecular dynamics results, Re transmutation calculations, and stochastic cluster dynamics simulations to study neutron damage in single-crystal tungsten to mimic divertor materials. To gauge the accuracy and validity of the simulations, we first study the material response under experimental conditions at the JOYO fast reactor in Japan and the High Flux Isotope Reactor at Oak Ridge National Laboratory, for which measurements of cluster densities and hardening levels up to 2 dpa exist. We then provide calculations under expected DEMO fusion conditions. Several key mechanisms involving Re atoms and defect clusters are found to govern the accumulation of irradiation damage in each case. We use established correlations to translate damage accumulation into hardening increases and compare our results to the experimental measurements. We find hardening increases in excess of 5000 MPa in all cases, which casts doubts about the integrity of W-based materials under long-term fusion exposure.
NASA Astrophysics Data System (ADS)
Hara, K. Y.; Harada, H.; Toh, Y.; Hori, J.
2013-09-01
A gated photomultiplier tube (PMT) assembled with an LaBr3(Ce) detector was applied toward the prompt γ{hbox-}ray measurement of fast neutron capture reactions. Time-of-flight measurements of the neutron capture reactions of Cl and Al were performed using the 46-MeV electron linear accelerator at the Kyoto University Research Reactor Institute (KURRI) as a pulsed neutron source. The photomultiplier gating technique effectively suppressed the saturation of the PMT output and extended the energy region of the TOF measurement.
A Time of Flight Fast Neutron Imaging System Design Study
NASA Astrophysics Data System (ADS)
Canion, Bonnie; Glenn, Andrew; Sheets, Steven; Wurtz, Ron; Nakae, Les; Hausladen, Paul; McConchie, Seth; Blackston, Matthew; Fabris, Lorenzo; Newby, Jason
2017-09-01
LLNL and ORNL are designing an active/passive fast neutron imaging system that is flexible to non-ideal detector positioning. It is often not possible to move an inspection object in fieldable imager applications such as safeguards, arms control treaty verification, and emergency response. Particularly, we are interested in scenarios which inspectors do not have access to all sides of an inspection object, due to interfering objects or walls. This paper will present the results of a simulation-based design parameter study, that will determine the optimum system design parameters for a fieldable system to perform time-of-flight based imaging analysis. The imaging analysis is based on the use of an associated particle imaging deuterium-tritium (API DT) neutron generator to get the time-of-flight of radiation induced within an inspection object. This design study will investigate the optimum design parameters for such a system (e.g. detector size, ideal placement, etc.), as well as the upper and lower feasible design parameters that the system can expect to provide results within a reasonable amount of time (e.g. minimum/maximum detector efficiency, detector standoff, etc.). Ideally the final prototype from this project will be capable of using full-access techniques, such as transmission imaging, when the measurement circumstances allow, but with the additional capability of producing results at reduced accessibility.
Neutron capture therapy with deep tissue penetration using capillary neutron focusing
Peurrung, A.J.
1997-08-19
An improved method is disclosed for delivering thermal neutrons to a subsurface cancer or tumor which has been first doped with a dopant having a high cross section for neutron capture. The improvement is the use of a guide tube in cooperation with a capillary neutron focusing apparatus, or neutron focusing lens, for directing neutrons to the tumor, and thereby avoiding damage to surrounding tissue. 1 fig.
Absorption and photoluminescence study of Al 2O 3 single crystal irradiated with fast neutrons
NASA Astrophysics Data System (ADS)
Izerrouken, M.; Benyahia, T.
2010-10-01
Colour centers formation in Al 2O 3 by reactor neutrons were investigated by optical measurements (absorption and photoluminescence). The irradiation's were performed at 40 °C, up to fast neutron ( E n > 1.2 MeV) fluence of 1.4 × 10 18 n cm -2. After irradiation the coloration of the sample increases with the neutron fluence and absorption band at about 203, 255, 300, 357 and 450 nm appear in the UV-visible spectrum. The evolution of each absorption bands as a function of fluence and annealing temperature is presented and discussed. The results indicate that at higher fluence and above 350 °C the F + center starts to aggregate to F center clusters (F 2, F 2+ and F22+). These aggregates disappear completely above 650 °C whereas the F and F + centers persist even after annealing at 900 °C. It is clear also from the results that the absorption band at 300 nm is due to the contribution of both F 2 center and interstitial Ali+ ions.
Monte Carlo calculations of lung dose in ORNL phantom for boron neutron capture therapy.
Krstic, D; Markovic, V M; Jovanovic, Z; Milenkovic, B; Nikezic, D; Atanackovic, J
2014-10-01
Monte Carlo simulations were performed to evaluate dose for possible treatment of cancers by boron neutron capture therapy (BNCT). The computational model of male Oak Ridge National Laboratory (ORNL) phantom was used to simulate tumours in the lung. Calculations have been performed by means of the MCNP5/X code. In this simulation, two opposite neutron beams were considered, in order to obtain uniform neutron flux distribution inside the lung. The obtained results indicate that the lung cancer could be treated by BNCT under the assumptions of calculations. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hsieh, M; Liu, Y; Nie, L
2015-06-15
Purpose: To investigate the feasibility of a deuterium-deuterium (DD) neutron generator for application in boron neutron capture therapy (BNCT) of brain cancer Methods: MCNP simulations were performed using a head phantom and a monoenergetic neutron source, which resembles the point source in a DD generator that emits 2.45-MeV neutrons. Source energies ranging from 5eV to 2.45MeV were simulated to determine the optimal treatment energy. The phantom consisted of soft tissue, brain tissue, skull, skin layer, and a brain tumor of 5 cm in diameter. Tumor depth was varied from 5–10 cm. Boron-10 concentrations of 10 ppm, 15 ppm, and 30more » ppm were used in the soft/brain tissues, skin, and tumor, respectively. The neutron flux required to deliver 60 Gy to the tumor as well as the normal tissue doses were determined. Results: Beam energies between 5eV and 10keV obtained doses with the highest dose ratios (3.3–25.9) between the tumor and the brain at various depths. The dose ratio with 2.45-MeV neutrons ranged from 0.8–6.6. To achieve the desired tumor dose in 40 minutes, the required neutron flux for a DD generator was between 8.8E10 and 5.2E11 n/s and the resulting brain dose was between 2.3 and 18 Gy, depending on the tumor depth. The skin and soft tissue doses were within acceptable tolerances. The boron-neutron interaction accounted for 54–58% of the total dose. Conclusion: This study shows that the DD neutron generator can be a feasible neutron source for BNCT. The required neutron flux for treatment is achievable with the current DD neutron technology. With a well-designed beam shaping assembly and treatment geometry, the neutron flux can be further improved and a 60-Gy prescription can be accurately delivered to the target while maintaining tolerable normal tissue doses. Further experimental studies will be developed and conducted to validate the simulation results.« less
Wangerin, K; Culbertson, C N; Jevremovic, T
2005-08-01
The goal of this study was to evaluate the COG Monte Carlo radiation transport code, developed and tested by Lawrence Livermore National Laboratory, for gadolinium neutron capture therapy (GdNCT) related modeling. The validity of COG NCT model has been established for this model, and here the calculation was extended to analyze the effect of various gadolinium concentrations on dose distribution and cell-kill effect of the GdNCT modality and to determine the optimum therapeutic conditions for treating brain cancers. The computational results were compared with the widely used MCNP code. The differences between the COG and MCNP predictions were generally small and suggest that the COG code can be applied to similar research problems in NCT. Results for this study also showed that a concentration of 100 ppm gadolinium in the tumor was most beneficial when using an epithermal neutron beam.
NASA Technical Reports Server (NTRS)
Korff, S. A.; Mendell, R. B.; Merker, M.; Light, E. S.; Verschell, H. J.; Sandie, W. S.
1979-01-01
Contributions to fast neutron measurements in the atmosphere are outlined. The results of a calculation to determine the production, distribution and final disappearance of atmospheric neutrons over the entire spectrum are presented. An attempt is made to answer questions that relate to processes such as neutron escape from the atmosphere and C-14 production. In addition, since variations of secondary neutrons can be related to variations in the primary radiation, comment on the modulation of both radiation components is made.
Performance study of the neutron-TPC
NASA Astrophysics Data System (ADS)
Huang, Meng; Li, Yulan; Niu, Libo; Deng, Zhi; Cheng, Xiaolei; He, Li; Zhang, Hongyan; Fu, Jianqiang; Yan, Yangyang; Cai, Yiming; Li, Yuanjing
2017-02-01
Fast neutron spectrometers will play an important role in the future of the nuclear industry and nuclear physics experiments, in tasks such as fast neutron reactor monitoring, thermo-nuclear fusion plasma diagnostics, nuclear reaction cross-section measurement, and special nuclear material detection. Recently, a new fast neutron spectrometer based on a GEM (Gas Electron Multiplier amplification)-TPC (Time Projection Chamber), named the neutron-TPC, has been under development at Tsinghua University. It is designed to have a high energy resolution, high detection efficiency, easy access to the medium material, an outstanding n/γ suppression ratio, and a wide range of applications. This paper presents the design, test, and experimental study of the neutron-TPC. Based on the experimental results, the energy resolution (FWHM) of the neutron-TPC can reach 15.7%, 10.3% and 7.0% with detection efficiency higher than 10-5 for 1.2 MeV, 1.81 MeV and 2.5 MeV neutrons respectively. Supported by National Natural Science Foundation of China (11275109)
NASA Astrophysics Data System (ADS)
Mor, Ilan; Vartsky, David; Dangendorf, Volker; Tittelmeier, Kai.; Weierganz, Mathias; Goldberg, Mark Benjamin; Bar, Doron; Brandis, Michal
2018-06-01
We describe an analysis procedure for automatic unambiguous detection of fast-neutron-induced recoil proton tracks in a micro-capillary array filled with organic liquid scintillator. The detector is viewed by an intensified CCD camera. This imaging neutron detector possesses the capability to perform high position-resolution (few tens of μm), energy-dispersive transmission-imaging using ns-pulsed beams. However, when operated with CW or DC beams, it also features medium-quality spectroscopic capabilities for incident neutrons in the energy range 2-20 MeV. In addition to the recoil proton events which display a continuous extended track structure, the raw images exhibit complex ion-tracks from nuclear interactions of fast-neutrons in the scintillator, capillaries quartz-matrix and CCD. Moreover, as expected, one also observes a multitude of isolated scintillation spots of varying intensity (henceforth denoted "blobs") that originate from several different sources, such as: fragmented proton tracks, gamma-rays, heavy-ion reactions as well as events and noise that occur in the image-intensifier and CCD. In order to identify the continuous-track recoil proton events and distinguish them from all these background events, a rapid, computerized and automatic track-recognition-procedure was developed. Based on an appropriately weighted analysis of track parameters such as: length, width, area and overall light intensity, the method is capable of distinguishing a single continuous-track recoil proton from typically surrounding several thousands of background events that are found in each CCD frame.
Measurements of fast neutrons by bubble detectors
DOE Office of Scientific and Technical Information (OSTI.GOV)
Castillo, F.; Martinez, H.; Leal, B.
2013-07-03
Neutron bubble detectors have been studied using Am-Be and D-D neuron sources, which give limited energy information. The Bubble Detector Spectrometer (BDS) have six different energy thresholds ranging from 10 KeV to 10 Mev. The number of bubbles obtained in each measurement is related to the dose (standardized response R) equivalent neutrons through sensitivity (b / {mu}Sv) and also with the neutron flux (neutrons per unit area) through a relationship that provided by the manufacturer. Bubble detectors were used with six different answers (0.11 b/ {mu}Sv, 0093 b/{mu}Sv, 0.14 b/{mu}Sv, 0.17 b/{mu}Sv, 0051 b/{mu}Sv). To test the response of themore » detectors (BDS) radiate a set of six of them with different energy threshold, with a source of Am-Be, placing them at a distance of one meter from it for a few minutes. Also, exposed to dense plasma focus Fuego Nuevo II (FN-II FPD) of ICN-UNAM, apparatus which produces fusion plasma, generating neutrons by nuclear reactions of neutrons whose energy emitting is 2.45 MeV. In this case the detectors were placed at a distance of 50 cm from the pinch at 90 Degree-Sign this was done for a certain number of shots. In both cases, the standard response is reported (Dose in {mu}Sv) for each of the six detectors representing an energy range, this response is given by the expression R{sub i}= B{sub i} / S{sub i} where B{sub i} is the number of bubbles formed in each and the detector sensitivity (S{sub i}) is given for each detector in (b / {mu}Sv). Also, reported for both cases, the detected neutron flux (n cm{sup -2}), by a given ratio and the response involves both standardized R, as the average cross section sigma. The results obtained have been compared with the spectrum of Am-Be source. From these measurements it can be concluded that with a combination of bubble detectors, with different responses is possible to measure the equivalent dose in a range of 10 to 100 {mu}Sv fields mixed neutron and gamma, and pulsed generated
DOE Office of Scientific and Technical Information (OSTI.GOV)
Andersson, P., E-mail: peter.andersson@physics.uu.se; Andersson-Sunden, E.; Sjöstrand, H.
2014-08-01
In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantagemore » of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm{sup −1}, solid POM attenuation coefficient. The accuracy and precision is high enough to provide a
Andersson, P; Andersson-Sunden, E; Sjöstrand, H; Jacobsson-Svärd, S
2014-08-01
In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm(-1), solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful
NASA Technical Reports Server (NTRS)
1979-01-01
The patient shown is undergoing cancer radiation treatment in a hospital-like atmosphere but he is not in a hospital. The treatment room is at NASA's Lewis Research Center, Cleveland, Ohio. It is a converted portion of the Center's cyclotron facility, originally designed for radiation studies related to nuclear propulsion for aircraft and spacecraft. Under an agreement between the Center and the Cleveland Clinic Foundation, the 50 million volt cyclotron is now being used to evaluate the effectiveness of "fast neutron" therapy in the treatment of cancerous tumors.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Smirenkin, G.M.
1959-12-01
The method of threshold indicators was used for determining the magnitude of dT/sub ef//dE/sub n/. The fission neutrons were produced by fast and slow neutron bombardment. tron bombardment was accomplished in a paraffin block. Hollow metallic U/sup 235/ (90% enriched) and Pu/sup 239/ specimens with 50 mm outside diameters and 10 mm thick contained the threshold activator Ag/sup 107/(n,2n)Ag/sup 106m/. Measurements were made of the neutron flux above the threshold (9.5 Mev) of the Ag/sup 107/(n,2n)Ag/sup 106m/ reaction and the number of fission in the sphere (N/sub gamma /). The final data showed that for U/sup 235/ dT/sub ef//dE/sub n/more » = 0.008 plus or minus 0.004 and for Pu/sup 239/ dT/ sub ef/ /dE/sub n/ = tron fission distributions explain part of the error of the measurement. (R.V.J.)« less
Design of thermal neutron beam based on an electron linear accelerator for BNCT.
Zolfaghari, Mona; Sedaghatizadeh, Mahmood
2016-12-01
An electron linear accelerator (Linac) can be used for boron neutron capture therapy (BNCT) by producing thermal neutron flux. In this study, we used a Varian 2300 C/D Linac and MCNPX.2.6.0 code to simulate an electron-photoneutron source for use in BNCT. In order to decelerate the produced fast neutrons from the photoneutron source, which optimize the thermal neutron flux, a beam-shaping assembly (BSA) was simulated. After simulations, a thermal neutron flux with sharp peak at the beam exit was obtained in the order of 3.09×10 8 n/cm 2 s and 6.19×10 8 n/cm 2 s for uranium and enriched uranium (10%) as electron-photoneutron sources respectively. Also, in-phantom dose analysis indicates that the simulated thermal neutron beam can be used for treatment of shallow skin melanoma in time of about 85.4 and 43.6min for uranium and enriched uranium (10%) respectively. Copyright © 2016. Published by Elsevier Ltd.
Oncogenic transformation in C3H10T1/2 cells by low-energy neutrons.
Miller, R C; Marino, S A; Napoli, J; Shah, H; Hall, E J; Geard, C R; Brenner, D J
2000-03-01
Occupational exposure to neutrons typically includes significant doses of low-energy neutrons, with energies below 100 keV. In addition, the normal-tissue dose from boron neutron capture therapy will largely be from low-energy neutrons. Microdosimetric theory predicts decreasing biological effectiveness for neutrons with energies below about 350 keV compared with that for higher-energy neutrons; based on such considerations, and limited biological data, the current radiation weighting factor (quality factor) for neutrons with energies from 10 keV to 100 keV is less than that for higher-energy neutrons. By contrast, some reports have suggested that the biological effectiveness of low-energy neutrons is similar to that of fast neutrons. The purpose of the current work is to assess the relative biological effectiveness of low-energy neutrons for an endpoint of relevance to carcinogenesis: in vitro oncogenic transformation. Oncogenic transformation induction frequencies were determined for C3H10T1/2 cells exposed to two low-energy neutron beams, respectively, with dose-averaged energies of 40 and 70 keV, and the results were compared with those for higher-energy neutrons and X-rays. These results for oncogenic transformation provide evidence for a significant decrease in biological effectiveness for 40 keV neutrons compared with 350 keV neutrons. The 70 keV neutrons were intermediate in effectiveness between the 70 and 350 keV beams. A decrease in biological effectiveness for low-energy neutrons is in agreement with most (but not all) earlier biological studies, as well as microdosimetric considerations. The results for oncogenic transformation were consistent with the currently recommended decreased values for low-energy neutron radiation weighting factors compared with fast neutrons.
Fasting therapy for treating and preventing disease - current state of evidence.
Michalsen, Andreas; Li, Chenying
2013-01-01
Periods of deliberate fasting with restriction of solid food intake are practiced worldwide, mostly based on traditional, cultural or religious reasons. There is large empirical and observational evidence that medically supervised modified fasting (fasting cure, 200-500 kcal nutritional intake per day) with periods of 7-21 days is efficacious in the treatment of rheumatic diseases, chronic pain syndromes, hypertension, and metabolic syndrome. The beneficial effects of fasting followed by vegetarian diet in rheumatoid arthritis are confirmed by randomized controlled trials. Further beneficial effects of fasting are supported by observational data and abundant evidence from experimental research which found caloric restriction and intermittent fasting being associated with deceleration or prevention of most chronic degenerative and chronic inflammatory diseases. Intermittent fasting may also be useful as an accompanying treatment during chemotherapy of cancer. A further beneficial effect of fasting relates to improvements in sustainable lifestyle modification and adoption of a healthy diet, possibly mediated by fasting-induced mood enhancement. Various identified mechanisms of fasting point to its potential health-promoting effects, e.g., fasting-induced neuroendocrine activation and hormetic stress response, increased production of neurotrophic factors, reduced mitochondrial oxidative stress, general decrease of signals associated with aging, and promotion of autophagy. Fasting therapy might contribute to the prevention and treatment of chronic diseases and should be further evaluated in controlled clinical trials and observational studies. © 2014 S. Karger GmbH, Freiburg.
NASA Astrophysics Data System (ADS)
Sabo-Napadensky, I.; Weiss-Babai, R.; Gayer, A.; Vartsky, D.; Bar, D.; Mor, I.; Chacham-Zada, R.; Cohen, M.; Tamim, N.
2012-06-01
One of the main problems in neutron imaging is the scattered radiation that accompanies the direct neutrons that reach the imaging detectors and affect the image quality. We have developed a dedicated collimator for 14.2 MeV fast neutrons. The collimator optimizes the amount of scattered radiation to primary neutrons that arrive at the imaging plane. We have used different materials within the collimator in order to lower the scattered radiation that arrives at the scanned object. The image quality and the signal to noise ratios that are measured show that a mixture of BORAX (Na2B4O7ṡ10H2O) and water in the experimental beam collimator give the best results. We have used GEANT4 to simulate the collimator performance, the simulations predict the optimized material looking on the ratios of the scattered to primary neutrons that contribute in the detector. We present our experimental setup, report the results of the experimental and related simulation studies with neutrons beam generated by a 14.2 MeV D-T neutron generator.
CONTROL SYSTEM FOR NEUTRONIC REACTORS
Crever, F.E.
1962-05-01
BS>A slow-acting shim rod for control of major variations in reactor neutron flux and a fast-acting control rod to correct minor flux variations are employed to provide a sensitive, accurate control system. The fast-acting rod is responsive to an error signal which is produced by changes in the neutron flux from a predetermined optimum level. When the fast rod is thus actuated in a given direction, means is provided to actuate the slow-moving rod in that direction to return the fast rod to a position near the midpoint of its control range. (AEC)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Geng, C; Nanjing University of Aeronautics and Astronautics, Nanjing; Schuemann, J
Purpose: To determine the neutron contamination from the aperture in pencil beam scanning during proton therapy. Methods: A Monte Carlo based proton therapy research platform TOPAS and the UF-series hybrid pediatric phantoms were used to perform this study. First, pencil beam scanning (PBS) treatment pediatric plans with average spot size of 10 mm at iso-center were created and optimized for three patients with and without apertures. Then, the plans were imported into TOPAS. A scripting method was developed to automatically replace the patient CT with a whole body phantom positioned according to the original plan iso-center. The neutron dose equivalentmore » was calculated using organ specific quality factors for two phantoms resembling a 4- and 14-years old patient. Results: The neutron dose equivalent generated by the apertures in PBS is 4–10% of the total neutron dose equivalent for organs near the target, while roughly 40% for organs far from the target. Compared to the neutron dose equivalent caused by PBS without aperture, the results show that the neutron dose equivalent with aperture is reduced in the organs near the target, and moderately increased for those organs located further from the target. This is due to the reduction of the proton dose around the edge of the CTV, which causes fewer neutrons generated in the patient. Conclusion: Clinically, for pediatric patients, one might consider adding an aperture to get a more conformal treatment plan if the spot size is too large. This work shows the somewhat surprising fact that adding an aperture for beam scanning for facilities with large spot sizes reduces instead of increases a potential neutron background in regions near target. Changran Geng is supported by the Chinese Scholarship Council (CSC) and the National Natural Science Foundation of China (Grant No. 11475087)« less
A neutron camera system for MAST.
Cecconello, M; Turnyanskiy, M; Conroy, S; Ericsson, G; Ronchi, E; Sangaroon, S; Akers, R; Fitzgerald, I; Cullen, A; Weiszflog, M
2010-10-01
A prototype neutron camera has been developed and installed at MAST as part of a feasibility study for a multichord neutron camera system with the aim to measure the spatial and time resolved 2.45 MeV neutron emissivity profile. Liquid scintillators coupled to a fast digitizer are used for neutron/gamma ray digital pulse shape discrimination. The preliminary results obtained clearly show the capability of this diagnostic to measure neutron emissivity profiles with sufficient time resolution to study the effect of fast ion loss and redistribution due to magnetohydrodynamic activity. A minimum time resolution of 2 ms has been achieved with a modest 1.5 MW of neutral beam injection heating with a measured neutron count rate of a few 100 kHz.
Adherence to Anti Retroviral Therapy (ART) During Muslim Ramadan Fasting
Habib, A. G.; Shepherd, J. C.; Eng, M. K. L.; Babashani, M.; Jumare, J.; Yakubu, U.; Gebi, U. I.; Saad, M.; Ibrahim, H.; Blattner, W. A.
2010-01-01
Annual fasting during the month of Ramadan is observed in Muslim countries, some of which have widespread HIV infection. We studied treatment adherence and customary practices among 142 fasting `FT' and 101 non-fasting `NFT' patients on anti-retroviral therapy (ART) in Nigeria. Adherence on ART among FT and NFT patients was similar during Ramadan, 96% and 98%, and ever since commencement of ART, 80% and 88%, respectively. FT patients altered their typical daily behaviors by advancing morning and delaying evening doses thereby prolonging dosing intervals, eating heavier meals pre-dawn and on breakfast at sunset (78%), and changing or reducing their sleeping and waking times (40%). This preliminary study suggests that adherence and drug taking frequency appear uncompromised in FT HIV infected patients on ARVs. PMID:18521736
Yanagië, H.; Tomita, T.; Kobayashi, H.; Fujii, Y.; Takahashi, T.; Hasumi, K.; Nariuchi, H.; Sekiguchi, M.
1991-01-01
An immunoliposome containing a 10B-compound has been examined as a selective drug delivery system in boron neutron-capture therapy. Liposomes, conjugated with monoclonal antibodies specific for carcinoembryonic antigen (CEA) were shown to bind selectively to cells bearing CEA on their surface. The immunoliposomes attached to tumour cells suppressed growth in vitro upon thermal neutron irradiation and suppression was dependent upon the concentration of the 10B-compound in the liposomes and on the density of antibody conjugated to the liposomes. The results suggest that immunoliposomes containing the 10B-compound could act as a selective and efficient carrier of 10B atoms to target tumour cells in boron neutron-capture therapy. Images Figure 1 PMID:2021537
Boron neutron capture therapy for malignant melanoma: first clinical case report in China
Yong, Zhong; Song, Zewen; Zhou, Yongmao; Liu, Tong; Zhang, Zizhu; Zhao, Yanzhong; Chen, Yang; Jin, Congjun; Chen, Xiang; Lu, Jianyun; Han, Rui; Li, Pengzhou; Sun, Xulong; Wang, Guohui; Shi, Guangqing; Zhu, Shaihong
2016-01-01
A phase I/II clinical trial for treating malignant melanoma by boron neutron capture therapy (BNCT) was designed to evaluate whether the world’s first in-hospital neutron irradiator (IHNI) was qualified for BNCT. In this clinical trial planning to enroll 30 patients, the first case was treated on August 19, 2014. We present the protocol of this clinical trial, the treating procedure, and the clinical outcome of this first case. Only grade 2 acute radiation injury was observed during the first four weeks after BNCT and the injury healed after treatment. No late radiation injury was found during the 24-month follow-up. Based on positron emission tomography-computed tomography (PET/CT) scan, pathological analysis and gross examination, the patient showed a complete response to BNCT, indicating that BNCT is a potent therapy against malignant melanoma and IHNI has the potential to enable the delivery of BNCT in hospitals. PMID:28174492
NASA Astrophysics Data System (ADS)
Jančář, A.; Kopecký, Z.; Dressler, J.; Veškrna, M.; Matěj, Z.; Granja, C.; Solar, M.
2015-11-01
Recently invented plastic scintillator EJ-299-33 enables pulse-shape discrimination (PSD) and thus measurement of neutron and photon spectra in mixed fields. In this work we compare the PSD properties of EJ-299-33 plastic and the well-known NE-213 liquid scintillator in monoenergetic neutron fields generated by the Van de Graaff accelerator using the 3H(d, n)4He reaction. Pulses from the scintillators are processed by a newly developed digital measuring system employing the fast digitizer card. This card contains two AD converters connected to the measuring computer via 10 Gbps optical ethernet. The converters operate with a resolution of 12 bits and have two differential inputs with a sampling frequency 1 GHz. The resulting digital channels with different gains are merged into one composite channel with a higher digital resolution in a wide dynamic range of energies. Neutron signals are fully discriminated from gamma signals. Results are presented.
Estimates for Pu-239 loadings in burial ground culverts based on fast/slow neutron measurements
DOE Office of Scientific and Technical Information (OSTI.GOV)
Winn, W.G.; Hochel, R.C.; Hofstetter, K.J.
1989-08-15
This report provides guideline estimates for Pu-239 mass loadings in selected burial ground culverts. The relatively high recorded Pu-239 contents of these culverts have been appraised as suspect relative to criticality concerns, because they were assayed only with the solid waste monitor (SWM) per gamma-ray counting. After 1985, subsequent waste was also assayed with the neutron coincidence counter (NCC), and a comparison of the assay methods showed that the NCC generally yielded higher assays than the SWM. These higher NCC readings signaled a need to conduct non-destructive/non-intrusive nuclear interrogations of these culverts, and a technical team conducted scoping measurements tomore » illustrate potential assay methods based on neutron and/or gamma counting. A fast/slow neutron method has been developed to estimate the Pu-239 in the culverts. In addition, loading records include the SWM assays of all Pu-239 cuts of some of the culvert drums and these data are useful in estimating the corresponding NCC drum assays from NCC vs SWM data. Together, these methods yield predictions based on direct measurements and statistical inference.« less
NASA Technical Reports Server (NTRS)
Livingston, R. A.; Schweitzer, J. S.; Parsons, A. M.; Arens, E. E.
2010-01-01
MCNP simulations have been run to evaluate the feasibility of using a combination of fast and thermal neutrons as a nondestructive method to measure of the compaction of the perlite insulation in the liquid hydrogen and oxygen cryogenic storage tanks at John F. Kennedy Space Center (KSC). Perlite is a feldspathic volcanic rock made up of the major elements Si, AI, Na, K and 0 along with some water. When heated it expands from four to twenty times its original volume which makes it very useful for thermal insulation. The cryogenic tanks at Kennedy Space Center are spherical with outer diameters of 69-70 feet and lined with a layer of expanded perlite with thicknesses on the order of 120 cm. There is evidence that some of the perlite has compacted over time since the tanks were built 1965, affecting the thermal properties and possibly also the structural integrity of the tanks. With commercially available portable neutron generators it is possible to produce simultaneously fluxes of neutrons in two energy ranges: fast (14 Me V) and thermal (25 me V). The two energy ranges produce complementary information. Fast neutrons produce gamma rays by inelastic scattering, which is sensitive to Fe and O. Thermal neutrons produce gamma rays by prompt gamma neutron activation (PGNA) and this is sensitive to Si, Al, Na, K and H. The compaction of the perlite can be measured by the change in gamma ray signal strength which is proportional to the atomic number densities of the constituent elements. The MCNP simulations were made to determine the magnitude of this change. The tank wall was approximated by a I-dimensional slab geometry with an 11/16" outer carbon steel wall, an inner stainless wall and 120 cm thick perlite zone. Runs were made for cases with expanded perlite, compacted perlite or with various void fractions. Runs were also made to simulate the effect of adding a moderator. Tallies were made for decay-time analysis from t=0 to 10 ms; total detected gamma
Hashimoto, Y; Hiraga, F; Kiyanagi, Y
2015-12-01
We evaluated the accelerator beam power and the neutron-induced radioactivity of (9)Be(p, n) boron neutron capture therapy (BNCT) neutron sources having a MgF2, CaF2, or AlF3 moderator and driven by protons with energy from 8 MeV to 30 MeV. The optimal moderator materials were found to be MgF2 for proton energies less than 10 MeV because of lower required accelerator beam power and CaF2 for higher proton energies because of lower photon dose rate at the treatment position after neutron irradiation. Copyright © 2015 Elsevier Ltd. All rights reserved.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zheng Yuanshui; Liu Yaxi; Zeidan, Omar
Purpose: Neutron exposure is of concern in proton therapy, and varies with beam delivery technique, nozzle design, and treatment conditions. Uniform scanning is an emerging treatment technique in proton therapy, but neutron exposure for this technique has not been fully studied. The purpose of this study is to investigate the neutron dose equivalent per therapeutic dose, H/D, under various treatment conditions for uniform scanning beams employed at our proton therapy center. Methods: Using a wide energy neutron dose equivalent detector (SWENDI-II, ThermoScientific, MA), the authors measured H/D at 50 cm lateral to the isocenter as a function of proton range,more » modulation width, beam scanning area, collimated field size, and snout position. They also studied the influence of other factors on neutron dose equivalent, such as aperture material, the presence of a compensator, and measurement locations. They measured H/D for various treatment sites using patient-specific treatment parameters. Finally, they compared H/D values for various beam delivery techniques at various facilities under similar conditions. Results: H/D increased rapidly with proton range and modulation width, varying from about 0.2 mSv/Gy for a 5 cm range and 2 cm modulation width beam to 2.7 mSv/Gy for a 30 cm range and 30 cm modulation width beam when 18 Multiplication-Sign 18 cm{sup 2} uniform scanning beams were used. H/D increased linearly with the beam scanning area, and decreased slowly with aperture size and snout retraction. The presence of a compensator reduced the H/D slightly compared with that without a compensator present. Aperture material and compensator material also have an influence on neutron dose equivalent, but the influence is relatively small. H/D varied from about 0.5 mSv/Gy for a brain tumor treatment to about 3.5 mSv/Gy for a pelvic case. Conclusions: This study presents H/D as a function of various treatment parameters for uniform scanning proton beams. For similar
Neutron Exposures in Human Cells: Bystander Effect and Relative Biological Effectiveness
Seth, Isheeta; Schwartz, Jeffrey L.; Stewart, Robert D.; Emery, Robert; Joiner, Michael C.; Tucker, James D.
2014-01-01
Bystander effects have been observed repeatedly in mammalian cells following photon and alpha particle irradiation. However, few studies have been performed to investigate bystander effects arising from neutron irradiation. Here we asked whether neutrons also induce a bystander effect in two normal human lymphoblastoid cell lines. These cells were exposed to fast neutrons produced by targeting a near-monoenergetic 50.5 MeV proton beam at a Be target (17 MeV average neutron energy), and irradiated-cell conditioned media (ICCM) was transferred to unirradiated cells. The cytokinesis-block micronucleus assay was used to quantify genetic damage in radiation-naïve cells exposed to ICCM from cultures that received 0 (control), 0.5, 1, 1.5, 2, 3 or 4 Gy neutrons. Cells grown in ICCM from irradiated cells showed no significant increase in the frequencies of micronuclei or nucleoplasmic bridges compared to cells grown in ICCM from sham irradiated cells for either cell line. However, the neutron beam has a photon dose-contamination of 5%, which may modulate a neutron-induced bystander effect. To determine whether these low doses of contaminating photons can induce a bystander effect, cells were irradiated with cobalt-60 at doses equivalent to the percent contamination for each neutron dose. No significant increase in the frequencies of micronuclei or bridges was observed at these doses of photons for either cell line when cultured in ICCM. As expected, high doses of photons induced a clear bystander effect in both cell lines for micronuclei and bridges (p<0.0001). These data indicate that neutrons do not induce a bystander effect in these cells. Finally, neutrons had a relative biological effectiveness of 2.0±0.13 for micronuclei and 5.8±2.9 for bridges compared to cobalt-60. These results may be relevant to radiation therapy with fast neutrons and for regulatory agencies setting standards for neutron radiation protection and safety. PMID:24896095
Neutron exposures in human cells: bystander effect and relative biological effectiveness.
Seth, Isheeta; Schwartz, Jeffrey L; Stewart, Robert D; Emery, Robert; Joiner, Michael C; Tucker, James D
2014-01-01
Bystander effects have been observed repeatedly in mammalian cells following photon and alpha particle irradiation. However, few studies have been performed to investigate bystander effects arising from neutron irradiation. Here we asked whether neutrons also induce a bystander effect in two normal human lymphoblastoid cell lines. These cells were exposed to fast neutrons produced by targeting a near-monoenergetic 50.5 MeV proton beam at a Be target (17 MeV average neutron energy), and irradiated-cell conditioned media (ICCM) was transferred to unirradiated cells. The cytokinesis-block micronucleus assay was used to quantify genetic damage in radiation-naïve cells exposed to ICCM from cultures that received 0 (control), 0.5, 1, 1.5, 2, 3 or 4 Gy neutrons. Cells grown in ICCM from irradiated cells showed no significant increase in the frequencies of micronuclei or nucleoplasmic bridges compared to cells grown in ICCM from sham irradiated cells for either cell line. However, the neutron beam has a photon dose-contamination of 5%, which may modulate a neutron-induced bystander effect. To determine whether these low doses of contaminating photons can induce a bystander effect, cells were irradiated with cobalt-60 at doses equivalent to the percent contamination for each neutron dose. No significant increase in the frequencies of micronuclei or bridges was observed at these doses of photons for either cell line when cultured in ICCM. As expected, high doses of photons induced a clear bystander effect in both cell lines for micronuclei and bridges (p<0.0001). These data indicate that neutrons do not induce a bystander effect in these cells. Finally, neutrons had a relative biological effectiveness of 2.0 ± 0.13 for micronuclei and 5.8 ± 2.9 for bridges compared to cobalt-60. These results may be relevant to radiation therapy with fast neutrons and for regulatory agencies setting standards for neutron radiation protection and safety.
Fast-neutron/gamma-ray radiography scanner for the detection of contraband in air cargo containers
NASA Astrophysics Data System (ADS)
Eberhardt, J.; Liu, Y.; Rainey, S.; Roach, G.; Sowerby, B.; Stevens, R.; Tickner, J.
2006-05-01
There is a worldwide need for efficient inspection of cargo containers at airports, seaports and road border crossings. The main objectives are the detection of contraband such as illicit drugs, explosives and weapons. Due to the large volume of cargo passing through Australia's airports every day, it is critical that any scanning system should be capable of working on unpacked or consolidated cargo, taking at most 1-2 minutes per container. CSIRO has developed a fast-neutron/gamma-ray radiography (FNGR) method for the rapid screening of air freight. By combining radiographs obtained using 14 MeV neutrons and 60Co gamma-rays, high resolution images showing both density and material composition are obtained. A near full-scale prototype scanner has been successfully tested in the laboratory. With the support of the Australian Customs Service, a full-scale scanner has recently been installed and commissioned at Brisbane International Airport.
NASA Astrophysics Data System (ADS)
Klir, D.; Shishlov, A. V.; Kokshenev, V. A.; Kubes, P.; Labetsky, A. Yu; Rezac, K.; Cherdizov, R. K.; Cikhardt, J.; Cikhardtova, B.; Dudkin, G. N.; Fursov, F. I.; Garapatsky, A. A.; Kovalchuk, B. M.; Kravarik, J.; Kurmaev, N. E.; Orcikova, H.; Padalko, V. N.; Ratakhin, N. A.; Sila, O.; Turek, K.; Varlachev, V. A.
2015-04-01
Z-pinch experiments with deuterium gas puffs have been carried out on the GIT-12 generator at 3 MA currents. Recently, a novel configuration of a deuterium gas-puff z-pinch was used to accelerate deuterons and to generate fast neutrons. In order to form a homogeneous, uniformly conducting layer at a large initial radius, an inner deuterium gas puff was surrounded by an outer hollow cylindrical plasma shell. The plasma shell consisting of hydrogen and carbon ions was formed at the diameter of 350 mm by 48 plasma guns. A linear mass of the plasma shell was about 5 µg cm-1 whereas a total linear mass of deuterium gas in single or double shell gas puffs was about 100 µg cm-1. The implosion lasted 700 ns and seemed to be stable up to a 5 mm radius. During stagnation, m = 0 instabilities became more pronounced. When a disruption of necks occurred, the plasma impedance reached 0.4 Ω and high energy (>2 MeV) bremsstrahlung radiation together with high energy deuterons were produced. Maximum neutron energies of 33 MeV were observed by axial time-of-flight detectors. The observed neutron spectra could be explained by a suprathermal distribution of deuterons with a high energy tail f≤ft({{E}\\text{d}}\\right)\\propto E\\text{d}-(1.8+/- 0.2) . Neutron yields reached 3.6 × 1012 at a 2.7 MA current. A high neutron production efficiency of 6 × 107 neutrons per one joule of plasma energy resulted from the generation of high energy deuterons and from their magnetization inside plasmas.
Mascarenhas, Nicholas; Marleau, Peter; Brennan, James S.; Krenz, Kevin D.
2010-06-22
An instrument that will directly image the fast fission neutrons from a special nuclear material source has been described. This instrument can improve the signal to background compared to non imaging neutron detection techniques by a factor given by ratio of the angular resolution window to 4.pi.. In addition to being a neutron imager, this instrument will also be an excellent neutron spectrometer, and will be able to differentiate between different types of neutron sources (e.g. fission, alpha-n, cosmic ray, and D-D or D-T fusion). Moreover, the instrument is able to pinpoint the source location.
NASA Astrophysics Data System (ADS)
Régis, J.-M.; Jolie, J.; Saed-Samii, N.; Warr, N.; Pfeiffer, M.; Blanc, A.; Jentschel, M.; Köster, U.; Mutti, P.; Soldner, T.; Simpson, G. S.; Drouet, F.; Vancraeyenest, A.; de France, G.; Clément, E.; Stezowski, O.; Ur, C. A.; Urban, W.; Regan, P. H.; Podolyák, Zs.; Larijani, C.; Townsley, C.; Carroll, R.; Wilson, E.; Fraile, L. M.; Mach, H.; Paziy, V.; Olaizola, B.; Vedia, V.; Bruce, A. M.; Roberts, O. J.; Smith, J. F.; Scheck, M.; Kröll, T.; Hartig, A.-L.; Ignatov, A.; Ilieva, S.; Lalkovski, S.; Korten, W.; Mǎrginean, N.; Otsuka, T.; Shimizu, N.; Togashi, T.; Tsunoda, Y.
2017-05-01
Lifetimes of low-lying yrast states in neutron-rich 94,96,98Sr have been measured by Germanium-gated γ -γ fast timing with LaBr 3 (Ce ) detectors using the EXILL&FATIMA spectrometer at the Institut Laue-Langevin. Sr fission products were generated using cold-neutron-induced fission of 235U and stopped almost instantaneously within the thick target. The experimental B (E 2 ) values are compared with results of Monte Carlo shell-model calculations made without truncation on the occupation numbers of the orbits spanned by eight proton and eight neutron orbits and show good agreement. Similarly to the Zr isotopes, the abrupt shape transition in the Sr isotopes near neutron number N =60 is identified as being caused by many-proton excitations to its g9 /2 orbit.
Zeeneldin, Ahmed Abdelmabood; Gaber, Ayman Abdelsamee; Taha, Fatma Mohamed
2012-09-01
To estimate the effect of fasting during Ramadan (the ninth lunar month) on adherence to oral hormonal therapies (OHT) among breast cancer (BC) patients. During Ramadan 2010, 139 BC patients were interviewed at the Egyptian National Cancer Institute. They were asked about fasting as well as intake of OHT in Ramadan and in the preceding month. The median age was 50years and most patients were postmenopausal with good performance status and non-metastatic disease. The median number of fasting days was 18% and 93% of patients were fasting 80% or more of Ramadan. Tamoxifen and aromatase inhibitors were used in 64% and 36%, respectively. Adherence to OHT during Ramadan and its preceding month were 94.2% and 95.7%, respectively (p=0.77). In univariate analysis, non-adherence prior to Ramadan and shorter duration of OHT were predictors of non-adherence during Ramadan (P<0.001, 0.003, respectively). Fasting, age, performance status, presence of metastases and type of hormonal therapy were not good predictors of adherence. While most of patients receiving OHT for BC are fasting during Ramadan, this does not negatively impact compliance with treatment. Copyright © 2012. Published by Elsevier B.V.
NASA Astrophysics Data System (ADS)
Mayer, Michael; Nattress, Jason; Barhoumi Meddeb, Amira; Foster, Albert; Trivelpiece, Cory; Rose, Paul; Erickson, Anna; Ounaies, Zoubeida; Jovanovic, Igor
2015-10-01
Detection of shielded special nuclear material is crucial to countering nuclear terrorism and proliferation, but its detection is challenging. By observing the emission of delayed neutrons, which is a unique signature of nuclear fission, the presence of nuclear material can be inferred. We report on the observation of delayed neutrons from natural uranium by using monoenergetic photons and neutrons to induce fission. An interrogating beam of 4.4 MeV and 15.1 MeV gamma-rays and neutrons was produced using the 11B(d,n-γ)12C reaction and used to probe different targets. Neutron detectors with complementary Cherenkov detectors then discriminate material undergoing fission. A Li-doped glass-polymer composite neutron detector was used, which displays excellent n/ γ discrimination even at low energies, to observe delayed neutrons from uranium fission. Delayed neutrons have relatively low energies (~0.5 MeV) compared to prompt neutrons, which makes them difficult to detect using recoil-based detectors. Neutrons were counted and timed after the beam was turned off to observe the characteristic decaying time profile of delayed neutrons. The expected decay of neutron emission rate is in agreement with the common parametrization into six delayed neutron groups.
Evolution of thermo-physical properties and annealing of fast neutron irradiated boron carbide
NASA Astrophysics Data System (ADS)
Gosset, Dominique; Kryger, Bernard; Bonal, Jean-Pierre; Verdeau, Caroline; Froment, Karine
2018-03-01
Boron carbide is widely used as a neutron absorber in most nuclear reactors, in particular in fast neutron ones. The irradiation leads to a large helium production (up to 1022/cm3) together with a strong decrease of the thermal conductivity. In this paper, we have performed thermal diffusivity measurements and X-ray diffraction analyses on boron carbide samples coming from control rods of the French Phenix LMFBR reactor. The burnups range from 1021 to 8.1021/cm3. We first confirm the strong decrease of the thermal conductivity at the low burnup, together with high microstructural modifications: swelling, large micro-strains, high defects density, and disordered-like material conductivity. We observe the microstructural parameters are highly anisotropic, with high micro-strains and flattened coherent diffracting domains along the (00l) direction of the hexagonal structure. Performing heat treatments up to high temperature (2200 °C) allows us to observe the material thermal conductivity and microstructure restoration. It then appears the thermal conductivity healing is correlated to the micro-strain relaxation. We then assume the defects responsible for most of the damage are the helium bubbles and the associated stress fields.
A remotely triggered fast neutron detection instrument based on a plastic organic scintillator
NASA Astrophysics Data System (ADS)
Jones, A. R.; Aspinall, M. D.; Joyce, M. J.
2018-02-01
A detector system for the characterization of radiation fields of both fast neutrons and γ rays is described comprising of a gated photomultiplier tube (PMT), an EJ299-33 solid organic scintillator detector, and an external trigger circuit. The objective of this development was to conceive a means by which the PMT in such a system can be actuated remotely during the high-intensity bursts of pulsed γ-ray contamination that can arise during active interrogation procedures. The system is used to detect neutrons and γ rays using established pulse-shape discrimination (PSD) techniques. The gating circuit enables the PMT to be switched off remotely. This is compatible with use during intense radiation transients to avoid saturation and the disruption of the operation of the PMT during the burst. Data are presented in the form of pulse-height spectra and PSD scatter plots for the system triggered with a strobed light source. These confirm that the gain of the system and the throughput for both triggered and un-triggered scenarios are as expected, given the duty cycle of the stimulating radiation. This demonstrates that the triggering function does not perturb the system response of the detector.
A remotely triggered fast neutron detection instrument based on a plastic organic scintillator.
Jones, A R; Aspinall, M D; Joyce, M J
2018-02-01
A detector system for the characterization of radiation fields of both fast neutrons and γ rays is described comprising of a gated photomultiplier tube (PMT), an EJ299-33 solid organic scintillator detector, and an external trigger circuit. The objective of this development was to conceive a means by which the PMT in such a system can be actuated remotely during the high-intensity bursts of pulsed γ-ray contamination that can arise during active interrogation procedures. The system is used to detect neutrons and γ rays using established pulse-shape discrimination (PSD) techniques. The gating circuit enables the PMT to be switched off remotely. This is compatible with use during intense radiation transients to avoid saturation and the disruption of the operation of the PMT during the burst. Data are presented in the form of pulse-height spectra and PSD scatter plots for the system triggered with a strobed light source. These confirm that the gain of the system and the throughput for both triggered and un-triggered scenarios are as expected, given the duty cycle of the stimulating radiation. This demonstrates that the triggering function does not perturb the system response of the detector.
Designing a new type of neutron detector for neutron and gamma-ray discrimination via GEANT4.
Shan, Qing; Chu, Shengnan; Ling, Yongsheng; Cai, Pingkun; Jia, Wenbao
2016-04-01
Design of a new type of neutron detector, consisting of a fast neutron converter, plastic scintillator, and Cherenkov detector, to discriminate 14-MeV fast neutrons and gamma rays in a pulsed n-γ mixed field and monitor their neutron fluxes is reported in this study. Both neutrons and gamma rays can produce fluorescence in the scintillator when they are incident on the detector. However, only the secondary charged particles of the gamma rays can produce Cherenkov light in the Cherenkov detector. The neutron and gamma-ray fluxes can be calculated by measuring the fluorescence and Cherenkov light. The GEANT4 Monte Carlo simulation toolkit is used to simulate the whole process occurring in the detector, whose optimum parameters are known. Analysis of the simulation results leads to a calculation method of neutron flux. This method is verified by calculating the neutron fluxes using pulsed n-γ mixed fields with different n/γ ratios, and the results show that the relative errors of all calculations are <5%. Copyright © 2016 Elsevier Ltd. All rights reserved.
Moslehi, A; Raisali, G; Lamehi, M
2017-04-15
To find appropriate substitutions for the expensive plastics of A-150 and rexolite used in the construction of thick gas electron multiplier (THGEM)-based tissue-equivalent proportional counters, in the present work, the responses of a THGEM-based microdosimetric detector made of A-150 and rexolite and three others composed of plexiglas (PMMA), polyethylene and polystyrene plastics as the wall materials have been compared. Lineal energy distribution, frequency-averaged lineal energy, dose-averaged lineal energy, mean quality factor and dose-equivalent for 0.1, 1 and 10 MeV neutrons and also for 241Am-Be neutrons are calculated using Geant4 simulation toolkit. Frequency-averaged lineal energy, dose-averaged lineal energy, mean quality factor and dose-equivalent values for all plastics are found similar. In addition, the response of an indigenously constructed microdosemeter with PMMA walls is also measured for 241Am-Be neutrons. The experimental results are in good agreement with the simulation predictions. Conclusively, it was found that the three considered plastics can be used as good candidates instead of A-150 and rexolite plastics in fast neutron microdosimetry. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Proton recoil scintillator neutron rem meter
Olsher, Richard H.; Seagraves, David T.
2003-01-01
A neutron rem meter utilizing proton recoil and thermal neutron scintillators to provide neutron detection and dose measurement. In using both fast scintillators and a thermal neutron scintillator the meter provides a wide range of sensitivity, uniform directional response, and uniform dose response. The scintillators output light to a photomultiplier tube that produces an electrical signal to an external neutron counter.
NASA Astrophysics Data System (ADS)
Gräfe, James L.
2017-09-01
Proton therapy is an alternative external beam cancer treatment modality to the conventional linear accelerator-based X-ray radiotherapy. An inherent by-product of proton-nuclear interactions is the production of secondary neutrons. These neutrons have long been thought of as a secondary contaminant, nuisance, and source of secondary cancer risk. In this paper, a method is proposed to use these neutrons to identify and localize the presence of the tumor through neutron capture reactions with the gadolinium-based MRI contrast agent. This could provide better confidence in tumor targeting by acting as an additional quality assurance tool of tumor position during treatment. This effectively results in a neutron induced nuclear medicine scan. Gadolinium (Gd), is an ideal candidate for this novel nuclear contrast imaging procedure due to its unique nuclear properties and its widespread use as a contrast agent in MRI. Gd has one of the largest thermal neutron capture cross sections of all the stable nuclides, and the gadolinium-based contrast agents localize in leaky tissues and tumors. Initial characteristics of this novel concept were explored using the Monte Carlo code MCNP6. The number of neutron capture reactions per Gy of proton dose was found to be approximately 50,000 neutron captures/Gy, for a 8 cm3 tumor containing 300 ppm Gd at 8 cm depth with a simple simulation designed to represent the active delivery method. Using the passive method it is estimated that this number can be up to an order of magnitude higher. The thermal neutron distribution was found to not be localized within the spread out Bragg peak (SOBP) for this geometrical configuration and therefore would not allow for the identification of a geometric miss of the tumor by the proton SOBP. However, this potential method combined with nuclear medicine imaging and fused with online CBCT and prior MRI or CT imaging could help to identify tumor position during treatment. More computational and
NASA Astrophysics Data System (ADS)
Lerche, R. A.; Cable, M. D.; Phillion, D. W.
1990-09-01
We are developing a streak camera based instrument to diagnose the fusion reaction rate (burn history) within laser-driven ICF targets filled with D-T fuel. Recently, we attempted measurements using the 16.7 MeV gamma ray emitted in the T(d,gamma)He(5) fusion reaction. Pb glass which has a large cross section for pair production acts as a gamma-ray-to-light converter. Gamma rays interact within the glass to form electron-positron pairs that produce large amounts (1000 photons/gamma ray) of prompt (less than 10 ps) Cerenkov light as they slow down. In our experimental instrument, an f/10 Cassegrain telescope optically couples light produced within the converter to a streak camera having 20-ps resolution. Experiments using high-yield (10(exp 13) D-T neutrons), direct-drive targets at Nova produced good signals with widths of 200 ps. Time-of-flight measurements show the signals to be induced by neutrons rather than gamma rays. The Pb glass appears to act as a fast neutron-to-light converter. We continue to study the interactions process and the possibility of using the 16.7 MeV gamma rays for burn time measurements.
Grusell, E; Condé, H; Larsson, B; Rönnqvist, T; Sornsuntisook, O; Crawford, J; Reist, H; Dahl, B; Sjöstrand, N G; Russel, G
1990-01-01
Spallation is induced in a heavy material by 72-MeV protons. The resulting neutrons can be characterized by an evaporation spectrum with a peak energy of less than 2 MeV. The neutrons are moderated in two steps: first in iron and then in carbon. Results from neutron fluence measurements in a perspex phantom placed close to the moderator are presented. Monte Carlo calculations of neutron fluence in a water phantom are also presented under some chosen configurations of spallation source and moderator. The calculations and measurements are in good agreement and show that, for proton currents of less than 0.5 mA, useful thermal-neutron fluences are attainable in the depth of the brain. However, the dose contribution from the unavoidable gamma background component has not been included in the present investigation.
Achilli, Cesare; Grandi, Stefania; Ciana, Annarita; Guidetti, Gianni F; Malara, Alessandro; Abbonante, Vittorio; Cansolino, Laura; Tomasi, Corrado; Balduini, Alessandra; Fagnoni, Maurizio; Merli, Daniele; Mustarelli, Piercarlo; Canobbio, Ilaria; Balduini, Cesare; Minetti, Giampaolo
2014-04-01
Boron neutron capture therapy (BNCT) is a radiotherapy treatment based on the accumulation in the tumor of a (10)B-containing drug and subsequent irradiation with low energy neutrons, which bring about the decay of (10)B to (7)Li and an α particle, causing the death of the neoplastic cell. The effectiveness of BNCT is limited by the low delivery and accumulation of the used boron-containing compounds. Here we report the development and the characterization of BPO4 nanoparticles (NPs) as a novel possible alternative drug for BNCT. An extensive analysis of BPO4 NP biocompatibility was performed using both mature blood cells (erythrocytes, neutrophils and platelets) and a model of hematopoietic progenitor cells. A time- and concentration-dependent cytotoxicity study was performed on neoplastic coloncarcinoma and osteosarcoma cell lines. BPO4 functionalization with folic acid, introduced to improve the uptake by tumor cells, appeared to effectively limit the unwanted effects of NPs on the analyzed blood components. Boron neutron capture therapy (BNCT) is a radiotherapy treatment modality based on the accumulation of a (10)B-containing drug and subsequent irradiation with low energy neutrons, inducing the decay of (10)B to (7)Li and an α particle, causing neoplastic cell death. This team of authors reports on a folic acid functionalized BPO4 nanoparticle with improved characteristics compared with conventional BNCT approaches, as demonstrated in tumor cell lines, and hopefully to be followed by translational human studies. © 2014.
Accidental neutron dosimetry with human hair
NASA Astrophysics Data System (ADS)
Ekendahl, Daniela; Bečková, Věra; Zdychová, Vlasta; Bulánek, Boris; Prouza, Zdeněk; Štefánik, Milan
2014-11-01
Human hair contains sulfur, which can be activated by fast neutrons. The 32S(n,p)32P reaction with a threshold of 2.5 MeV was used for fast neutron dose estimation. It is a very important parameter for individual dose reconstruction with regards to the heterogeneity of the neutron transfer to the human body. Samples of human hair were irradiated in a radial channel of a training reactor VR-1. 32P activity in hair was measured both, directly by means of a proportional counter, and as ash dispersed in a liquid scintillator. Based on neutron spectrum estimation, a relationship between the neutron dose and induced activity was derived. The experiment verified the practical feasibility of this dosimetry method in cases of criticality accidents or malevolent acts with nuclear materials.
Fast internal dynamics in alcohol dehydrogenase
DOE Office of Scientific and Technical Information (OSTI.GOV)
Monkenbusch, M.; Stadler, A., E-mail: a.stadler@fz-juelich.de; Biehl, R.
2015-08-21
Large-scale domain motions in alcohol dehydrogenase (ADH) have been observed previously by neutron spin-echo spectroscopy (NSE). We have extended the investigation on the dynamics of ADH in solution by using high-resolution neutron time-of-flight (TOF) and neutron backscattering (BS) spectroscopy in the incoherent scattering range. The observed hydrogen dynamics were interpreted in terms of three mobility classes, which allowed a simultaneous description of the measured TOF and BS spectra. In addition to the slow global protein diffusion and domain motions observed by NSE, a fast internal process could be identified. Around one third of the protons in ADH participate in themore » fast localized diffusive motion. The diffusion coefficient of the fast internal motions is around two third of the value of the surrounding D{sub 2}O solvent. It is tempting to associate the fast internal process with solvent exposed amino acid residues with dangling side chains.« less
Measuring neutron spectra in radiotherapy using the nested neutron spectrometer.
Maglieri, Robert; Licea, Angel; Evans, Michael; Seuntjens, Jan; Kildea, John
2015-11-01
Out-of-field neutron doses resulting from photonuclear interactions in the head of a linear accelerator pose an iatrogenic risk to patients and an occupational risk to personnel during radiotherapy. To quantify neutron production, in-room measurements have traditionally been carried out using Bonner sphere systems (BSS) with activation foils and TLDs. In this work, a recently developed active detector, the nested neutron spectrometer (NNS), was tested in radiotherapy bunkers. The NNS is designed for easy handling and is more practical than the traditional BSS. Operated in current-mode, the problem of pulse pileup due to high dose-rates is overcome by measuring current, similar to an ionization chamber. In a bunker housing a Varian Clinac 21EX, the performance of the NNS was evaluated in terms of reproducibility, linearity, and dose-rate effects. Using a custom maximum-likelihood expectation-maximization algorithm, measured neutron spectra at various locations inside the bunker were then compared to Monte Carlo simulations of an identical setup. In terms of dose, neutron ambient dose equivalents were calculated from the measured spectra and compared to bubble detector neutron dose equivalent measurements. The NNS-measured spectra for neutrons at various locations in a treatment room were found to be consistent with expectations for both relative shape and absolute magnitude. Neutron fluence-rate decreased with distance from the source and the shape of the spectrum changed from a dominant fast neutron peak near the Linac head to a dominant thermal neutron peak in the moderating conditions of the maze. Monte Carlo data and NNS-measured spectra agreed within 30% at all locations except in the maze where the deviation was a maximum of 40%. Neutron ambient dose equivalents calculated from the authors' measured spectra were consistent (one standard deviation) with bubble detector measurements in the treatment room. The NNS may be used to reliably measure the neutron
NASA Astrophysics Data System (ADS)
Traini, G.; Battistoni, G.; Giacometti, V.; Gioscio, E.; Marafini, M.; Mirabelli, R.; Pinci, D.; Sarti, A.; Sciubba, A.; Patera, V.
2018-04-01
The risk of developing a second malignant cancer as a late time consequence of undergoing a treatment, is one of the main concerns in particle therapy (PT). Since neutrons can release a significant dose far away from the tumour region, a precise characterisation of their production point, kinetic energy and abundance is eagerly needed. The treatment planning system (TPS) software that predicts the normal tissue toxicity in the target region and the risk of late complications in the whole body is currently based on the poorly known production cross-sections and will greatly benefit from improved precision double differential measurements. The MONDO (MOnitor for Neutron Dose in hadrOntherapy) project aims to build an ultrafast neutron tracker that could be used to characterise the production of secondary neutrons with energies in the 20–400 MeV range. The neutron tracking will proceed via the detection of recoil protons produced in two consecutive (n, p) elastic scattering interactions. The MONDO detector consists of a 10 × 10 × 20 cm3 matrix of thin scintillating fibres, arranged in orthogonally oriented layers. A compact read-out sensor with single photon detection capabilities employing the CMOS SPAD technology has been developed in collaboration with Fondazione Bruno Kessler (FBK). The detector will be completed by the end of 2018. A 4 × 4 × 4.8 cm3 prototype has been built using 250 μ m thick scintillating fibres of squared section and was tested using a proton beam and minimum ionising particles. In this contribution we present the experimental results related to the prototype test performed with a proton beam at the Proton Therapy Centre of the Trento Hospital (PTC) in May 2017. The results are compared with the results of a Monte Carlo simulation performed with the FLUKA software.
NASA Astrophysics Data System (ADS)
Osuský, F.; Bahdanovich, R.; Farkas, G.; Haščík, J.; Tikhomirov, G. V.
2017-01-01
The paper is focused on development of the coupled neutronics-thermal hydraulics model for the Gas-cooled Fast Reactor. It is necessary to carefully investigate coupled calculations of new concepts to avoid recriticality scenarios, as it is not possible to ensure sub-critical state for a fast reactor core under core disruptive accident conditions. Above mentioned calculations are also very suitable for development of new passive or inherent safety systems that can mitigate the occurrence of the recriticality scenarios. In the paper, the most promising fuel material compositions together with a geometry model are described for the Gas-cooled fast reactor. Seven fuel pin and fuel assembly geometry is proposed as a test case for coupled calculation with three different enrichments of fissile material in the form of Pu-UC. The reflective boundary condition is used in radial directions of the test case and vacuum boundary condition is used in axial directions. During these condition, the nuclear system is in super-critical state and to achieve a stable state (which is numerical representation of operational conditions) it is necessary to decrease the reactivity of the system. The iteration scheme is proposed, where SCALE code system is used for collapsing of a macroscopic cross-section into few group representation as input for coupled code NESTLE.
NASA Astrophysics Data System (ADS)
Andersson, P.; Valldor-Blücher, J.; Andersson Sundén, E.; Sjöstrand, H.; Jacobsson-Svärd, S.
2014-08-01
The FANTOM system is a tabletop sized fast-neutron radiography and tomography system newly developed at the Applied Nuclear Physics Division of Uppsala University. The main purpose of the system is to provide time-averaged steam-and-water distribution measurement capability inside the metallic structures of two-phase test loops for light water reactor thermal-hydraulic studies using a portable fusion neutron generator. The FANTOM system provides a set of 1D neutron transmission data, which may be inserted into tomographic reconstruction algorithms to achieve a 2D mapping of the steam-and-water distribution. In this paper, the selected design of FANTOM is described and motivated. The detector concept is based on plastic scintillator elements, separated for spatial resolution. Analysis of pulse heights on an event-to-event basis is used for energy discrimination. Although the concept allows for close stacking of a large number of detector elements, this demonstrator is equipped with only three elements in the detector and one additional element for monitoring the yield from the neutron generator. The first measured projections on test objects of known configurations are presented. These were collected using a Sodern Genie 16 neutron generator with an isotropic yield of about 1E8 neutrons per second, and allowed for characterization of the instrument's capabilities. At an energy threshold of 10 MeV, the detector offered a count rate of about 500 cps per detector element. The performance in terms of spatial resolution was validated by fitting a Gaussian Line Spread Function to the experimental data, a procedure that revealed a spatial unsharpness in good agreement with the predicted FWHM of 0.5 mm.
NASA Astrophysics Data System (ADS)
Bortolussi, S.; Protti, N.; Ferrari, M.; Postuma, I.; Fatemi, S.; Prata, M.; Ballarini, F.; Carante, M. P.; Farias, R.; González, S. J.; Marrale, M.; Gallo, S.; Bartolotta, A.; Iacoviello, G.; Nigg, D.; Altieri, S.
2018-01-01
University of Pavia is equipped with a TRIGA Mark II research nuclear reactor, operating at a maximum steady state power of 250 kW. It has been used for many years to support Boron Neutron Capture Therapy (BNCT) research. An irradiation facility was constructed inside the thermal column of the reactor to produce a sufficient thermal neutron flux with low epithermal and fast neutron components, and low gamma dose. In this irradiation position, the liver of two patients affected by hepatic metastases from colon carcinoma were irradiated after borated drug administration. The facility is currently used for cell cultures and small animal irradiation. Measurements campaigns have been carried out, aimed at characterizing the neutron spectrum and the gamma dose component. The neutron spectrum has been measured by means of multifoil neutron activation spectrometry and a least squares unfolding algorithm; gamma dose was measured using alanine dosimeters. Results show that in a reference position the thermal neutron flux is (1.20 ± 0.03) ×1010 cm-2 s-1 when the reactor is working at the maximum power of 250 kW, with the epithermal and fast components, respectively, 2 and 3 orders of magnitude lower than the thermal component. The ratio of the gamma dose with respect to the thermal neutron fluence is 1.2 ×10-13 Gy/(n/cm2).
Active detection of shielded SNM with 60-keV neutrons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hagmann, C; Dietrich, D; Hall, J
2008-07-08
Fissile materials, e.g. {sup 235}U and {sup 239}Pu, can be detected non-invasively by active neutron interrogation. A unique characteristic of fissile material exposed to neutrons is the prompt emission of high-energy (fast) fission neutrons. One promising mode of operation subjects the object to a beam of medium-energy (epithermal) neutrons, generated by a proton beam impinging on a Li target. The emergence of fast secondary neutrons then clearly indicates the presence of fissile material. Our interrogation system comprises a low-dose 60-keV neutron generator (5 x 10{sup 6}/s), and a 1 m{sup 2} array of scintillators for fast neutron detection. Preliminary experimentalmore » results demonstrate the detectability of small quantities (370 g) of HEU shielded by steel (200 g/cm{sup 2}) or plywood (30 g/cm{sup 2}), with a typical measurement time of 1 min.« less
Boron analysis for neutron capture therapy using particle-induced gamma-ray emission.
Nakai, Kei; Yamamoto, Yohei; Okamoto, Emiko; Yamamoto, Tetsuya; Yoshida, Fumiyo; Matsumura, Akira; Yamada, Naoto; Kitamura, Akane; Koka, Masashi; Satoh, Takahiro
2015-12-01
The neutron source of BNCT is currently changing from reactor to accelerator, but peripheral facilities such as a dose-planning system and blood boron analysis have still not been established. To evaluate the potential application of particle-induced gamma-ray emission (PIGE) for boron measurement in clinical boron neutron capture therapy, boronophenylalanine dissolved within a cell culture medium was measured using PIGE. PIGE detected 18 μgB/mL f-BPA in the culture medium, and all measurements of any given sample were taken within 20 min. Two hours of f-BPA exposure was required to create a boron distribution image. However, even though boron remained in the cells, the boron on the cell membrane could not be distinguished from the boron in the cytoplasm. Copyright © 2015 Elsevier Ltd. All rights reserved.
Neutron Collar Evolution and Fresh PWR Assembly Measurements with a New Fast Neutron Passive Collar
DOE Office of Scientific and Technical Information (OSTI.GOV)
Menlove, Howard Olsen; Geist, William H.; Root, Margaret A.
The passive neutron collar approach removes the effect of poison rods when using a 1mm Gd liner. This project sets out to solve the following challenges: BWR fuel assemblies have less mass and less neutron multiplication than PWR; and effective removal of cosmic ray spallation neutron bursts needed via QC tests.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hannan, M.A.; Gibson, D.P.
1985-10-01
The sensitizing effects of caffeine were studied in baby hamster kidney (BHK-21) cells and human lymphocytes following irradiation with gamma rays and fast neutrons. Caffeine sensitization occurred only when log-phase BHK cells and mitogen-stimulated lymphocytes were exposed to the two radiations. Noncycling (confluent) cells of BHK resulted in a shouldered survival curve following gamma irradiation while a biphasic curve was obtained with the log-phase cells. Survival in the case of lymphocytes was estimated by measurement of (TH)thymidine uptake. The relative biological effectiveness (RBE) of fast neutrons was found to be greater at survival levels corresponding to the resistant portions ofmore » the survival curves (shoulder or resistant tail). In both cell types, no reduction in RBE was observed when caffeine was present, because caffeine affected both gamma and neutron survival by the same proportion.« less
Test of Fibre Bragg Gratings samples under High Fast Neutrons Fluence
NASA Astrophysics Data System (ADS)
Cheymol, G.; Remy, L.; Gusarov, A.; Kinet, D.; Mégret, P.; Laffont, G.; Blanchet, T.; Morana, A.; Marin, E.; Girard, S.
2018-01-01
Optical fibre sensors (OFS) are worthy of interest for measurements in nuclear reactor thanks to their unique features, particularly compact size and remote multi-point sensing for some of them. But besides non negligible constraints associated with the high temperature environment of the experiments of interest, it is well known that the performances of OFS can be severely affected by high level of radiations. The Radiation Induced Attenuation (RIA) in the fibre is probably most known effect, which can be to some extent circumvented by using rad hard fibres to limit the dynamic loss. However, when the fast neutron fluence reaches 1018 to 1019 n/cm2, the density and index variations associated to structural changes may deteriorate drastically the performances of OFS even if they are based on rad hard fibres, by causing direct errors in the measurements of temperature and/or strain changes. The aim of the present study is to access the effect of nuclear radiations on the Fabry Perot (FP) and of Fibre Bragg Grating (FBG) sensors through the comparison of measurements made on these OFS - or part of them - before and after irradiation [1]. In the context of development of OFS for high irradiation environment and especially for Material Testing Reactors (MTRs), Sake 2 experiment consists in an irradiation campaign at high level of gamma and neutron fluxes conducted on samples of fibre optics - bare or functionalised with FBG. The irradiation was performed at two levels of fast neutron fluence: 1 and 3.1019 n/cm2 (E>1MeV), at 250°± 25°C, in the SCK•CEN BR2 reactor (Mol Belgium). An irradiation capsule was designed to allow irradiation at the specified temperature without active control. The neutron fluence was measured with activation dosimeters and the results were compared with MCPN computations. Investigation of bare samples gives information on the density changes, while for the FBGs both density and refractive index perturbation are involved. Some results for
Fast Neutron Tomography of Low-Z Object in High-Z Material Shielding
NASA Astrophysics Data System (ADS)
Babai, Ruth Weiss; Sabo-Napadensky, Iris; Bar, Doron; Mor, Ilan; Tamim, Noam; Dangendorf, Volker; Tittelmeier, Kai; Bromberger, Benjamin; Weierganz, Mathias
The technique and first results of Fast Neutron Tomography (FNCT) experiments are presented which are performed at the accelerator facility of PTB, Germany. A high-intensity neutron beam of broad spectral distribution with an average energy of 5.5 MeV, was produced by 11.5 MeV deuterons impinging upon a thick beryllium target. The capability of FNCT for high contrast imaging of low-Z materials embedded in thick high-Z shielding materials is demonstrated, which is superior to more conventional high-energy X-ray imaging techniques. For demonstrating the method special test objects were prepared: One consisted of an assembled polyethylene cylinder with holes of various diameters and directions drilled in its surface and inner parts. The plastic phantom was inserted into lead cylinders of different thicknesses. The detector system consisted of a plastic scintillator along with a dedicated optics, image-intensifier and a CCD camera. Two scintillator screens were compared: a bulk plastic scintillator screen and a fibres optical scintillator screen. The tomographic scans were taken in two geometrical configurations: cone beam and semi-fan beam configuration. The image quality favours the semi-fan beam configuration which on the other hand is more time consuming The obtained tomographic images and a comparison of the imaging quality between the different experimental conditions will be presented.
DNA damage induced by boron neutron capture therapy is partially repaired by DNA ligase IV.
Kondo, Natsuko; Sakurai, Yoshinori; Hirota, Yuki; Tanaka, Hiroki; Watanabe, Tsubasa; Nakagawa, Yosuke; Narabayashi, Masaru; Kinashi, Yuko; Miyatake, Shin-ichi; Hasegawa, Masatoshi; Suzuki, Minoru; Masunaga, Shin-ichiro; Ohnishi, Takeo; Ono, Koji
2016-03-01
Boron neutron capture therapy (BNCT) is a particle radiation therapy that involves the use of a thermal or epithermal neutron beam in combination with a boron ((10)B)-containing compound that specifically accumulates in tumor. (10)B captures neutrons and the resultant fission reaction produces an alpha ((4)He) particle and a recoiled lithium nucleus ((7)Li). These particles have the characteristics of high linear energy transfer (LET) radiation and therefore have marked biological effects. High-LET radiation is a potent inducer of DNA damage, specifically of DNA double-strand breaks (DSBs). The aim of the present study was to clarify the role of DNA ligase IV, a key player in the non-homologous end-joining repair pathway, in the repair of BNCT-induced DSBs. We analyzed the cellular sensitivity of the mouse embryonic fibroblast cell lines Lig4-/- p53-/- and Lig4+/+ p53-/- to irradiation using a thermal neutron beam in the presence or absence of (10)B-para-boronophenylalanine (BPA). The Lig4-/- p53-/- cell line had a higher sensitivity than the Lig4+/+ p53-/-cell line to irradiation with the beam alone or the beam in combination with BPA. In BNCT (with BPA), both cell lines exhibited a reduction of the 50 % survival dose (D 50) by a factor of 1.4 compared with gamma-ray and neutron mixed beam (without BPA). Although it was found that (10)B uptake was higher in the Lig4+/+ p53-/- than in the Lig4-/- p53-/- cell line, the latter showed higher sensitivity than the former, even when compared at an equivalent (10)B concentration. These results indicate that BNCT-induced DNA damage is partially repaired using DNA ligase IV.
NASA Astrophysics Data System (ADS)
Sakurai, Yoshinori; Tanaka, Hiroki; Takata, Takushi; Fujimoto, Nozomi; Suzuki, Minoru; Masunaga, Shinichiro; Kinashi, Yuko; Kondo, Natsuko; Narabayashi, Masaru; Nakagawa, Yosuke; Watanabe, Tsubasa; Ono, Koji; Maruhashi, Akira
2015-07-01
At the Kyoto University Research Reactor Institute (KURRI), a clinical study of boron neutron capture therapy (BNCT) using a neutron irradiation facility installed at the research nuclear reactor has been regularly performed since February 1990. As of November 2014, 510 clinical irradiations were carried out using the reactor-based system. The world's first accelerator-based neutron irradiation system for BNCT clinical irradiation was completed at this institute in early 2009, and the clinical trial using this system was started in 2012. A shift of BCNT from special particle therapy to a general one is now in progress. To promote and support this shift, improvements to the irradiation system, as well as its preparation, and improvements in the physical engineering and the medical physics processes, such as dosimetry systems and quality assurance programs, must be considered. The recent advances in BNCT at KURRI are reported here with a focus on physical engineering and medical physics topics.
Neutron fluences and energy spectra in the Cosmos-2044 biosatellite orbit
NASA Technical Reports Server (NTRS)
Dudkin, V. E.; Akopova, A. B.; Melkumyan, L. V.; Benton, E. V.; Frank, A. L.
1992-01-01
Joint Soviet-American measurements of the neutron component of space radiation (SR) were carried out during the flight of the Soviet biosatellite Cosmos-2044. Neutron flux densities and differential energy spectra were measured inside and on the external surface of the spacecraft. Three energy intervals were employed: thermal (En < or = 0.2 eV), resonance (0.2 eV < En < 1.0 MeV) and fast (En > or = 1.0 MeV) neutrons. The first two groups were measured with U.S. 6LiF detectors, while fast neutrons were recorded both by U.S. fission foils and Soviet nuclear emulsions. Estimations were made of the contributions to absorbed and equivalent doses from each neutron energy interval and a correlation was presented between fast neutron fluxes, measured outside the satellite, and the phase of solar activity (SA). Average dose equivalent rates of 0.018 and 0.14 mrem d-1 were measured for thermal and resonance neutrons, respectively, outside the spacecraft. The corresponding values for fast neutrons were 3.3 (U.S.) and 1.8 (U.S.S.R.) mrem d-1. Inside the spacecraft, a value of 3.5 mrem d-1 was found.
NASA Astrophysics Data System (ADS)
Korenev, Sergey; Sikolenko, Vadim
2004-09-01
The advantage of neutron-scattering studies as compared to the standard X-ray technique is the high penetration of neutrons that allow us to study volume effects. The high resolution of instrumentation on the basis neutron scattering allows measurement of the parameters of lattice structure with high precision. We suggest the use of neutron scattering from pulsed neutron sources for analysis of materials irradiated with pulsed high current electron and ion beams. The results of preliminary tests using this method for Ni foils that have been studied by neutron diffraction at the IBR-2 (Pulsed Fast Reactor at Joint Institute for Nuclear Research) are presented.
Multipurpose neutron generators based on the radio frequency quadrupole linear accelerator
NASA Astrophysics Data System (ADS)
Hamm, Robert W.
2000-12-01
Neutron generators based on the Radio Frequency Quadrupole accelerator are now used for a variety of applications. These compact linear accelerators can produce from 108 to more than 1013 neutrons/second using either proton or deuteron beams to bombard beryllium targets. They exhibit long lifetimes at full output, as there is little target or beam degradation. Since they do not use radioactive materials, licensing requirements are less stringent than for isotopic sources or tritium sealed tube generators. The light weight and compact size of these robust systems make them transportable. The low divergence output beam from the RFQ also allows use of a remote target, which can reduce the seize of the shielding and moderator. The RFQ linac can be designed with a wide range of output beam energy and used with other targets such as lithium and deuterium to produce a neutron spectrum tailored to a specific application. These pulsed systems are well-suited for applications requiring a high peak neutron flux, including activation analysis of very short-lived reaction products. They can replace conventional sources in non-destructive testing applications such as thermal or fast neutron radiography, and can also be used for cancer therapy.
Fast neutron-gamma discrimination on neutron emission profile measurement on JT-60U.
Ishii, K; Shinohara, K; Ishikawa, M; Baba, M; Isobe, M; Okamoto, A; Kitajima, S; Sasao, M
2010-10-01
A digital signal processing (DSP) system is applied to stilbene scintillation detectors of the multichannel neutron emission profile monitor in JT-60U. Automatic analysis of the neutron-γ pulse shape discrimination is a key issue to diminish the processing time in the DSP system, and it has been applied using the two-dimensional (2D) map. Linear discriminant function is used to determine the dividing line between neutron events and γ-ray events on a 2D map. In order to verify the validity of the dividing line determination, the pulse shape discrimination quality is evaluated. As a result, the γ-ray contamination in most of the beam heating phase was negligible compared with the statistical error with 10 ms time resolution.
Observation of Neutron Skyshine from an Accelerator Based Neutron Source
NASA Astrophysics Data System (ADS)
Franklyn, C. B.
2011-12-01
A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >1011 nṡs-1. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.
Observation of Neutron Skyshine from an Accelerator Based Neutron Source
DOE Office of Scientific and Technical Information (OSTI.GOV)
Franklyn, C. B.
2011-12-13
A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It ismore » further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Stash, A. I., E-mail: astas@yandex.ru; Ivanov, S. A.; Stefanovich, S. Yu.
Neutron irradiation is a unique tool for forming new structural states of ferroelectrics, which cannot be obtained by conventional methods. The inf luence of the irradiation by two doses of fast neutrons (F = 1 × 10{sup 17} and 3 × 10{sup 17} cm{sup –2}) on the structure and properties of KNbO{sub 3} single crystals has been considered for the first time. The developed method for taking into account the experimental correction to the diffuse scattering has been used to analyze the structural changes occurring in KNbO{sub 3} samples at T = 295 K and their correlations with the behaviormore » of dielectric and nonlinear optical characteristics. The irradiation to the aforementioned doses retains the KNbO{sub 3} polar structure, shifting Т{sub Ð}¡ to lower temperatures and significantly affecting only the thermal parameters and microstructure of single crystals. Neutron irradiation with small atomic displacements provides a structure similar to the high-temperature modification of an unirradiated KNbO{sub 3} crystal.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zasneda, Sabriani; Widita, Rena
2010-06-22
Boron Neutron Capture Therapy (BNCT) is a cancer therapy by utilizing thermal neutron to produce alpha particles and lithium nuclei. The superiority of BNCT is that the radiation effects could be limited only for the tumor cells. BNCT radiation dose depends on the distribution of boron in the tumor. Absorbed dose to the cells from the reaction 10B (n, {alpha}) 7Li was calculated near interface medium containing boron and boron-free region. The method considers the contribution of the alpha particle and recoiled lithium particle to the absorbed dose and the variation of Linear Energy Transfer (LET) charged particles energy. Geometricalmore » factor data of boron distribution for the spherical surface is used to calculate the energy absorbed in the tumor cells, brain and scalp for case Glioblastoma Multiforme. The result shows that the optimal dose in tumor is obtained for boron concentrations of 22.1 mg {sup 10}B/g blood.« less
NASA Astrophysics Data System (ADS)
Singh, Vishwanath P.; Badiger, N. M.; El-Khayatt, A. M.
2014-06-01
We have computed γ-ray exposure buildup factors (EBF) of some building materials; glass, marble, flyash, cement, limestone, brick, plaster of paris (POP) and gypsum for energy 0.015-15 MeV up to 40 mfp (mfp, mean free path) penetration depth. Also, the macroscopic effective removal cross-sections (ΣR) for fast neutron were calculated. We discussed the dependency of EBF values on photon energy, penetration depth and chemical elements. The half-value layer and kinetic energy per unit mass relative to air of building materials were calculated for assessment of shielding effectiveness. Shielding thicknesses for glass, marble, flyash, cement, limestone and gypsum plaster (or Plaster of Paris, POP) were found comparable with ordinary concrete. Among the studied materials limestone and POP showed superior shielding properties for γ-ray and neutron, respectively. Radiation safety inside houses, schools and primary health centers for sheltering and annual dose can be assessed by the determination of shielding parameters of common building materials.
Kawasaki, Riku; Sasaki, Yoshihiro; Akiyoshi, Kazunari
2017-01-29
Boron neutron capture therapy, based on the release of thermal neutron irradiation from boron, is a targeted radiation therapy for cancer. Targeted and sufficient accumulation of boron in tumor cells to achieve cytotoxic efficacy and reduce off-target effects remains a challenge. Carborane has been investigated for use as a delivery agent in boron neutron capture therapy because of its high boron content and chemical stability; however, it is cytotoxic, making safe delivery difficult. The aim of this study was to investigate the potential of carborane-bearing pullulan nanogels to safely and effectively deliver boron to tumor cells in vitro and in vivo and, consequently, assess their potential as a boron neutron capture therapeutic. Murine fibrosarcoma cells (CMS5a) were used for in vitro investigations of nanogel cytotoxicity, cell uptake. A mouse fibrosarcoma xenograft model was used to investigate the bio-distribution of nanogels after intravenous administration. The nanogels produced no apparent cytotoxicity and underwent cell uptake in CMS5a cells after a 24 h incubation at up to 2000 μg/mL and 400 μg/mL, respectively. The internalized nanogels were localized around the nuclear membrane. The nanogels were administered intravenously to mice bearing fibrosarcoma xenografts. Nanogel tumor localization likely occurred through the enhanced permeation and retention effect. The nanogels successfully reduced the cytotoxicity of carborane, were internalized into tumor cells, acted as a dual-delivery therapeutic and accumulated in tumors in vivo. Consequently, they demonstrate significant potential as a boron neutron capture therapeutic. Copyright © 2016 Elsevier Inc. All rights reserved.
Belfield, Eric J.; Gan, Xiangchao; Mithani, Aziz; Brown, Carly; Jiang, Caifu; Franklin, Keara; Alvey, Elizabeth; Wibowo, Anjar; Jung, Marko; Bailey, Kit; Kalwani, Sharan; Ragoussis, Jiannis; Mott, Richard; Harberd, Nicholas P.
2012-01-01
Ionizing radiation has long been known to induce heritable mutagenic change in DNA sequence. However, the genome-wide effect of radiation is not well understood. Here we report the molecular properties and frequency of mutations in phenotypically selected mutant lines isolated following exposure of the genetic model flowering plant Arabidopsis thaliana to fast neutrons (FNs). Previous studies suggested that FNs predominantly induce deletions longer than a kilobase in A. thaliana. However, we found a higher frequency of single base substitution than deletion mutations. While the overall frequency and molecular spectrum of fast-neutron (FN)–induced single base substitutions differed substantially from those of “background” mutations arising spontaneously in laboratory-grown plants, G:C>A:T transitions were favored in both. We found that FN-induced G:C>A:T transitions were concentrated at pyrimidine dinucleotide sites, suggesting that FNs promote the formation of mutational covalent linkages between adjacent pyrimidine residues. In addition, we found that FNs induced more single base than large deletions, and that these single base deletions were possibly caused by replication slippage. Our observations provide an initial picture of the genome-wide molecular profile of mutations induced in A. thaliana by FN irradiation and are particularly informative of the nature and extent of genome-wide mutation in lines selected on the basis of mutant phenotypes from FN-mutagenized A. thaliana populations. PMID:22499668
SERA -- An advanced treatment planning system for neutron therapy and BNCT
DOE Office of Scientific and Technical Information (OSTI.GOV)
Nigg, D.W.; Wemple, C.A.; Wessol, D.E.
1999-09-01
Detailed treatment planning calculations on a patient-specific basis are required for boron neutron capture therapy (BNCT). Two integrated treatment planning systems developed specifically for BNCT have been in clinical use in the United States over the past few years. The MacNCTPLAN BNCT treatment planning system is used in the clinical BNCT trials that are underway at the Massachusetts Institute of Technology. A second system, BNCT{_}rtpe (BNCT radiation therapy planning environment), developed independently by the Idaho national Engineering and Environmental Laboratory (INEEL) in collaboration with Montana State University (MSU), is used for treatment planning in the current series of BNCT clinicalmore » trials for glioblastoma at Brookhaven National Laboratory (BNL). This latter system is also licensed for use at several other BNCT research facilities worldwide. Although the currently available BNCT planning systems have served their purpose well, they suffer from somewhat long computation times (2 to 3 CPU-hours or more per field) relative to standard photon therapy planning software. This is largely due to the need for explicit three-dimensional solutions to the relevant transport equations. The simplifying approximations that work well for photon transport computations are not generally applicable to neutron transport computations. Greater computational speeds for BNCT treatment planning must therefore generally be achieved through the application of improved numerical techniques rather than by simplification of the governing equations. Recent efforts at INEEL and MSU have been directed toward this goal. This has resulted in a new paradigm for this type of calculation and the subsequent creation of the new simulation environment for radiotherapy applications (SERA) treatment planning system for BNCT. SERA is currently in initial clinical testing in connection with the trials at BNL, and it is expected to replace the present BNCT{_}rtpe system upon general
NASA Astrophysics Data System (ADS)
Sunaryo, Geni R.; Katsumura, Yosuke; Ishigure, Kenkichi
1995-05-01
The G-values of water decomposition products under the irradiations with γ-rays and fast neutrons up to 250°C have been determined in previous studies. In order to clarify the characteristics of the determined G-values, computer simulations under the simplified conditions in nuclear reactors have been carried out. The recent G-values for γ-radiolysis reported by Elliot, Chenier and Quellete [(1990) Can. J. Chem.68, 712; (1993) J. Chem. Soc. Faraday Trans.89, 1193], Kent and Sims [(1992) Water Chemistry of Nuclear Reactor Systems 6, p. 153. BNES, London], and Sunaryo, Katsumura, Shirai, Hiroishi and Ishigure [(1994) Radiat. Phys. Chem.44, 273] and Sunaryo, Katsumura, Hiroishi and Ishigure [(1995) Radiat. Phys. Chem.45, 131] are almost equivalent from the point of simulations. On the contrary, G-values for fast neutron radiolysis give a significant influence to the result, which arises from the higher molecular yields and smaller radical yields of water decomposition in fast neutron radiolysis, and it has been revealed that the dose evaluation in the reactor is inevitably important. In addition, it was pointed out by the simulations that reverse reactions for H 2+ .OH→ .H+H 2O and e aq-+H +→ .H, be neglected at room temperature, become important at higher temperatures.
A collimated neutron detector for RFP plasmas in MST
DOE Office of Scientific and Technical Information (OSTI.GOV)
Capecchi, W. J., E-mail: capecchi@wisc.edu; Anderson, J. K.; Bonofiglo, P. J.
The neutron emissivity profile in the Madison Symmetric Torus is being reconstructed through the use of a collimated neutron detector. A scintillator-photomultiplier tube (PMT) system is employed to detect the fusion neutrons with the plasma viewing volume defined by a 55 cm deep, 5 cm diameter aperture. Effective detection of neutrons from the viewing volume is achieved through neutron moderation using 1300 lbs of high density polyethylene shielding, which modeling predicts attenuates the penetrating flux by a factor of 10{sup 4} or more. A broad spectrum of gamma radiation is also present due to the unconfined fusion proton bombardment ofmore » the thick aluminum vacuum vessel. A 15 cm cylindrical liquid scintillator of 3.8 cm diameter is used to further increase directional sensitivity. A fast (5 ns rise time) preamplifier and digitization at 500 MHz prevent pulse pile-up even at high count rates (∼10{sup 4}/s). The entire neutron camera system is situated on an adjustable inclining base which provides the differing plasma viewing volumes necessary for reconstruction of the neutron emissivity profile. This profile, directly related to the fast-ion population, allows for an investigation of the critical fast-ion pressure gradient required to destabilize a neutral beam driven Alfvénic mode which has been shown to transport fast ions.« less
Fast neutron-gamma discrimination on neutron emission profile measurement on JT-60U
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ishii, K.; Okamoto, A.; Kitajima, S.
2010-10-15
A digital signal processing (DSP) system is applied to stilbene scintillation detectors of the multichannel neutron emission profile monitor in JT-60U. Automatic analysis of the neutron-{gamma} pulse shape discrimination is a key issue to diminish the processing time in the DSP system, and it has been applied using the two-dimensional (2D) map. Linear discriminant function is used to determine the dividing line between neutron events and {gamma}-ray events on a 2D map. In order to verify the validity of the dividing line determination, the pulse shape discrimination quality is evaluated. As a result, the {gamma}-ray contamination in most of themore » beam heating phase was negligible compared with the statistical error with 10 ms time resolution.« less
NASA Astrophysics Data System (ADS)
Guan, X.; Murata, I.; Wang, T.
2017-09-01
The performance of an epithermal neutron flux monitor developed for boron neutron capture therapy (BNCT) is verified by Monte Carlo simulations using accelerator-based neutron sources (ABNSs). The results indicate that the developed epithermal neutron flux monitor works well and it can be efficiently used in practical applications to measure the epithermal neutron fluxes of ABNSs in a high accuracy.
Neutron assay in mixed radiation fields with a 6Li-loaded plastic scintillator
NASA Astrophysics Data System (ADS)
Balmer, M. J. I.; Gamage, K. A. A.; Taylor, G. C.
2015-08-01
A novel technique for assay of thermal and fast neutrons in a 6Li-loaded plastic scintillator is presented. Existing capture-gated thermal neutron detection techniques were evaluated with the 6Li-loaded plastic scintillator studied in this work. Using simulations and experimental work, shortcomings in its performance were highlighted. As a result, it was proposed that by separating the combined fast and thermal neutron events from gamma events, using established pulse shape discrimination techniques, the thermal neutron events could then be assayed. Experiments were conducted at the National Physical Laboratory, Teddington, performing neutron assays with seven different neutron fields using the proposed technique. For each field, thermal and fast neutron content was estimated and were shown to corroborate with the seven synthesised fields.
Time-resolved neutron imaging at ANTARES cold neutron beamline
NASA Astrophysics Data System (ADS)
Tremsin, A. S.; Dangendorf, V.; Tittelmeier, K.; Schillinger, B.; Schulz, M.; Lerche, M.; Feller, W. B.
2015-07-01
In non-destructive evaluation with X-rays light elements embedded in dense, heavy (or high-Z) matrices show little contrast and their structural details can hardly be revealed. Neutron radiography, on the other hand, provides a solution for those cases, in particular for hydrogenous materials, owing to the large neutron scattering cross section of hydrogen and uncorrelated dependency of neutron cross section on the atomic number. The majority of neutron imaging experiments at the present time is conducted with static objects mainly due to the limited flux intensity of neutron beamline facilities and sometimes due to the limitations of the detectors. However, some applications require the studies of dynamic phenomena and can now be conducted at several high intensity beamlines such as the recently rebuilt ANTARES beam line at the FRM-II reactor. In this paper we demonstrate the capabilities of time resolved imaging for repetitive processes, where different phases of the process can be imaged simultaneously and integrated over multiple cycles. A fast MCP/Timepix neutron counting detector was used to image the water distribution within a model steam engine operating at 10 Hz frequency. Within <10 minutes integration the amount of water was measured as a function of cycle time with a sub-mm spatial resolution, thereby demonstrating the capabilities of time-resolved neutron radiography for the future applications. The neutron spectrum of the ANTARES beamline as well as transmission spectra of a Fe sample were also measured with the Time Of Flight (TOF) technique in combination with a high resolution beam chopper. The energy resolution of our setup was found to be ~ 0.8% at 5 meV and ~ 1.7% at 25 meV. The background level (most likely gammas and epithermal/fast neutrons) of the ANTARES beamline was also measured in our experiments and found to be on the scale of 3% when no filters are installed in the beam. Online supplementary data available from stacks.iop.org/jinst/10
Neutron Imaging at LANSCE—From Cold to Ultrafast
Nelson, Ronald Owen; Vogel, Sven C.; Hunter, James F.; ...
2018-02-23
In recent years, neutron radiography and tomography have been applied at different beam lines at Los Alamos Neutron Science Center (LANSCE), covering a very wide neutron energy range. The field of energy-resolved neutron imaging with epi-thermal neutrons, utilizing neutron absorption resonances for contrast as well as quantitative density measurements, was pioneered at the Target 1 (Lujan center), Flight Path 5 beam line and continues to be refined. Applications include: imaging of metallic and ceramic nuclear fuels, fission gas measurements, tomography of fossils and studies of dopants in scintillators. The technique provides the ability to characterize materials opaque to thermal neutronsmore » and to utilize neutron resonance analysis codes to quantify isotopes to within 0.1 atom %. The latter also allows measuring fuel enrichment levels or the pressure of fission gas remotely. More recently, the cold neutron spectrum at the ASTERIX beam line, also located at Target 1, was used to demonstrate phase contrast imaging with pulsed neutrons. This extends the capabilities for imaging of thin and transparent materials at LANSCE. In contrast, high-energy neutron imaging at LANSCE, using unmoderated fast spallation neutrons from Target 4 [Weapons Neutron Research (WNR) facility] has been developed for applications in imaging of dense, thick objects. Using fast (ns), time-of-flight imaging, enables testing and developing imaging at specific, selected MeV neutron energies. The 4FP-60R beam line has been reconfigured with increased shielding and new, larger collimation dedicated to fast neutron imaging. The exploration of ways in which pulsed neutron beams and the time-of-flight method can provide additional benefits is continuing. We will describe the facilities and instruments, present application examples and recent results of all these efforts at LANSCE.« less
Neutron Imaging at LANSCE—From Cold to Ultrafast
DOE Office of Scientific and Technical Information (OSTI.GOV)
Nelson, Ronald Owen; Vogel, Sven C.; Hunter, James F.
In recent years, neutron radiography and tomography have been applied at different beam lines at Los Alamos Neutron Science Center (LANSCE), covering a very wide neutron energy range. The field of energy-resolved neutron imaging with epi-thermal neutrons, utilizing neutron absorption resonances for contrast as well as quantitative density measurements, was pioneered at the Target 1 (Lujan center), Flight Path 5 beam line and continues to be refined. Applications include: imaging of metallic and ceramic nuclear fuels, fission gas measurements, tomography of fossils and studies of dopants in scintillators. The technique provides the ability to characterize materials opaque to thermal neutronsmore » and to utilize neutron resonance analysis codes to quantify isotopes to within 0.1 atom %. The latter also allows measuring fuel enrichment levels or the pressure of fission gas remotely. More recently, the cold neutron spectrum at the ASTERIX beam line, also located at Target 1, was used to demonstrate phase contrast imaging with pulsed neutrons. This extends the capabilities for imaging of thin and transparent materials at LANSCE. In contrast, high-energy neutron imaging at LANSCE, using unmoderated fast spallation neutrons from Target 4 [Weapons Neutron Research (WNR) facility] has been developed for applications in imaging of dense, thick objects. Using fast (ns), time-of-flight imaging, enables testing and developing imaging at specific, selected MeV neutron energies. The 4FP-60R beam line has been reconfigured with increased shielding and new, larger collimation dedicated to fast neutron imaging. The exploration of ways in which pulsed neutron beams and the time-of-flight method can provide additional benefits is continuing. We will describe the facilities and instruments, present application examples and recent results of all these efforts at LANSCE.« less
Melville, G; Melville, P
2013-02-01
Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. We are investigating the reduction of radium by transmutation by bombarding Ra-226 with high-energy neutrons from a neutron source to produce Ra-225 and hence Ac-225, which can be used as a generator to produce Bi-213 for use in 'Targeted Alpha Therapy' for cancer. This paper examines the possibility of producing Ac-225 by neutron capture using a theoretical model in which neutron energy is convoluted with the corresponding neutron cross sections of Ra-226. The total integrated yield can then be obtained. This study shows that an intense beam of high-energy neutrons could initiate neutron capture on Ra-226 to produce Ra-225 and hence practical amounts of Ac-225 and a useful reduction of Ra-226. Copyright © 2012 Elsevier Ltd. All rights reserved.
Liu, H B; Brugger, R M; Rorer, D C; Tichler, P R; Hu, J P
1994-10-01
Beams of epithermal neutrons are being used in the development of boron neutron capture therapy for cancer. This report describes a design study in which 235U fission plates and moderators are used to produce an epithermal neutron beam with higher intensity and better quality than the beam currently in use at the Brookhaven Medical Research Reactor (BMRR). Monte Carlo calculations are used to predict the neutron and gamma fluxes and absorbed doses produced by the proposed design. Neutron flux measurements at the present epithermal treatment facility (ETF) were made to verify and compare with the computed results where feasible. The calculations indicate that an epithermal neutron beam produced by a fission-plate converter could have an epithermal neutron intensity of 1.2 x 10(10) n/cm2.s and a fast neutron dose per epithermal neutron of 2.8 x 10(-11) cGy.cm2/nepi plus being forward directed. This beam would be built into the beam shutter of the ETF at the BMRR. The feasibility of remodeling the facility is discussed.
Sun, Ting; Zhang, Zizhu; Li, Bin; Chen, Guilin; Xie, Xueshun; Wei, Yongxin; Wu, Jie; Zhou, Youxin; Du, Ziwei
2013-08-06
Glioma stem cells in the quiescent state are resistant to clinical radiation therapy. An almost inevitable glioma recurrence is due to the persistence of these cells. The high linear energy transfer associated with boron neutron capture therapy (BNCT) could kill quiescent and proliferative cells. The present study aimed to evaluate the effects of BNCT on glioma stem/progenitor cells in vitro. The damage induced by BNCT was assessed using cell cycle progression, apoptotic cell ratio and apoptosis-associated proteins expression. The surviving fraction and cell viability of glioma stem/progenitor cells were decreased compared with differentiated glioma cells using the same boronophenylalanine pretreatment and the same dose of neutron flux. BNCT induced cell cycle arrest in the G2/M phase and cell apoptosis via the mitochondrial pathway, with changes in the expression of associated proteins. Glioma stem/progenitor cells, which are resistant to current clinical radiotherapy, could be effectively killed by BNCT in vitro via cell cycle arrest and apoptosis using a prolonged neutron irradiation, although radiosensitivity of glioma stem/progenitor cells was decreased compared with differentiated glioma cells when using the same dose of thermal neutron exposure and boronophenylalanine pretreatment. Thus, BNCT could offer an appreciable therapeutic advantage to prevent tumor recurrence, and may become a promising treatment in recurrent glioma.
NASA Astrophysics Data System (ADS)
Andreani, C.; Senesi, R.; Paccagnella, A.; Bagatin, M.; Gerardin, S.; Cazzaniga, C.; Frost, C. D.; Picozza, P.; Gorini, G.; Mancini, R.; Sarno, M.
2018-02-01
This paper presents a neutron accelerated study of soft errors in advanced electronic devices used in space missions, i.e. Flash memories performed at the ChipIr and VESUVIO beam lines at the ISIS spallation neutron source. The two neutron beam lines are set up to mimic the space environment spectra and allow neutron irradiation tests on Flash memories in the neutron energy range above 10 MeV and up to 800 MeV. The ISIS neutron energy spectrum is similar to the one occurring in the atmospheric as well as in space and planetary environments, with intensity enhancements varying in the range 108- 10 9 and 106- 10 7 respectively. Such conditions are suitable for the characterization of the atmospheric, space and planetary neutron radiation environments, and are directly applicable for accelerated tests of electronic components as demonstrated here in benchmark measurements performed on flash memories.
Neutron activation analysis system
Taylor, M.C.; Rhodes, J.R.
1973-12-25
A neutron activation analysis system for monitoring a generally fluid media, such as slurries, solutions, and fluidized powders, including two separate conduit loops for circulating fluid samples within the range of radiation sources and detectors is described. Associated with the first loop is a neutron source that emits s high flux of slow and thermal neutrons. The second loop employs a fast neutron source, the flux from which is substantially free of thermal neutrons. Adjacent to both loops are gamma counters for spectrographic determination of the fluid constituents. Other gsmma sources and detectors are arranged across a portion of each loop for deterMining the fluid density. (Official Gazette)
NASA Astrophysics Data System (ADS)
Zacharatou Jarlskog, Christina; Lee, Choonik; Bolch, Wesley E.; Xu, X. George; Paganetti, Harald
2008-02-01
Proton beams used for radiotherapy will produce neutrons when interacting with matter. The purpose of this study was to quantify the equivalent dose to tissue due to secondary neutrons in pediatric and adult patients treated by proton therapy for brain lesions. Assessment of the equivalent dose to organs away from the target requires whole-body geometrical information. Furthermore, because the patient geometry depends on age at exposure, age-dependent representations are also needed. We implemented age-dependent phantoms into our proton Monte Carlo dose calculation environment. We considered eight typical radiation fields, two of which had been previously used to treat pediatric patients. The other six fields were additionally considered to allow a systematic study of equivalent doses as a function of field parameters. For all phantoms and all fields, we simulated organ-specific equivalent neutron doses and analyzed for each organ (1) the equivalent dose due to neutrons as a function of distance to the target; (2) the equivalent dose due to neutrons as a function of patient age; (3) the equivalent dose due to neutrons as a function of field parameters; and (4) the ratio of contributions to secondary dose from the treatment head versus the contribution from the patient's body tissues. This work reports organ-specific equivalent neutron doses for up to 48 organs in a patient. We demonstrate quantitatively how organ equivalent doses for adult and pediatric patients vary as a function of patient's age, organ and field parameters. Neutron doses increase with increasing range and modulation width but decrease with field size (as defined by the aperture). We analyzed the ratio of neutron dose contributions from the patient and from the treatment head, and found that neutron-equivalent doses fall off rapidly as a function of distance from the target, in agreement with experimental data. It appears that for the fields used in this study, the neutron dose lateral to the
Exploring Boron Neutron Capture Therapy for non-small cell lung cancer.
Farías, Rubén O; Bortolussi, Silva; Menéndez, Pablo R; González, Sara J
2014-12-01
Boron Neutron Capture Therapy (BNCT) is a radiotherapy that combines biological targeting and high LET radiation. It consists in the enrichment of tumour with (10)B and in the successive irradiation of the target with low energy neutrons producing charged particles that mainly cause non-repairable damages to the cells. The feasibility to treat Non Small Cells Lung Cancer (NSCLC) with BNCT was explored. This paper proposes a new approach to determine treatment plans, introducing the possibility to choose the irradiation start and duration to maximize the tumour dose. A Tumour Control Probability (TCP) suited for lung BNCT as well as other high dose radiotherapy schemes was also introduced. Treatment plans were evaluated in localized and disseminated lung tumours. Semi-ideal and real energy spectra beams were employed to assess the best energy range and the performance of non-tailored neutron sources for lung tumour treatments. The optimal neutron energy is within [500 eV-3 keV], lower than the 10 keV suggested for the treatment of deep-seated tumours in the brain. TCPs higher than 0.6 and up to 0.95 are obtained for all cases. Conclusions drawn from [Suzuki et al., Int Canc Conf J 1 (4) (2012) 235-238] supporting the feasibility of BNCT for shallow lung tumours are confirmed, however discussions favouring the treatment of deeper lesions and disseminated disease are also opened. Since BNCT gives the possibility to deliver a safe and potentially effective treatment for NSCLC, it can be considered a suitable alternative for patients with few or no treatment options. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
COUPLED FAST-THERMAL POWER BREEDER REACTOR
Avery, R.
1961-07-18
A nuclear reactor having a region operating predominantly on fast neutrons and another region operating predominantly on slow neutrons is described. The fast region is a plutonium core and the slow region is a natural uranium blanket around the core. Both of these regions are free of moderator. A moderating reflector surrounds the uranium blanket. The moderating material and thickness of the reflector are selected so that fissions in the uranium blanket make a substantial contribution to the reactivity of the reactor.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Maekawa, Fujio; Meigo, Shin-ichiro; Kasugai, Yoshimi
2005-05-15
A neutronic benchmark experiment on a simulated spallation neutron target assembly was conducted by using the Alternating Gradient Synchrotron at Brookhaven National Laboratory and was analyzed to investigate the prediction capability of Monte Carlo simulation codes used in neutronic designs of spallation neutron sources. The target assembly consisting of a mercury target, a light water moderator, and a lead reflector was bombarded by 1.94-, 12-, and 24-GeV protons, and the fast neutron flux distributions around the target and the spectra of thermal neutrons leaking from the moderator were measured in the experiment. In this study, the Monte Carlo particle transportmore » simulation codes NMTC/JAM, MCNPX, and MCNP-4A with associated cross-section data in JENDL and LA-150 were verified based on benchmark analysis of the experiment. As a result, all the calculations predicted the measured quantities adequately; calculated integral fluxes of fast and thermal neutrons agreed approximately within {+-}40% with the experiments although the overall energy range encompassed more than 12 orders of magnitude. Accordingly, it was concluded that these simulation codes and cross-section data were adequate for neutronics designs of spallation neutron sources.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kawasaki, Riku; JST-ERATO, Japan Science and Technology Agency; Sasaki, Yoshihiro
Boron neutron capture therapy, based on the release of thermal neutron irradiation from boron, is a targeted radiation therapy for cancer. Targeted and sufficient accumulation of boron in tumor cells to achieve cytotoxic efficacy and reduce off-target effects remains a challenge. Carborane has been investigated for use as a delivery agent in boron neutron capture therapy because of its high boron content and chemical stability; however, it is cytotoxic, making safe delivery difficult. The aim of this study was to investigate the potential of carborane-bearing pullulan nanogels to safely and effectively deliver boron to tumor cells in vitro and in vivo and,more » consequently, assess their potential as a boron neutron capture therapeutic. Murine fibrosarcoma cells (CMS5a) were used for in vitro investigations of nanogel cytotoxicity, cell uptake. A mouse fibrosarcoma xenograft model was used to investigate the bio-distribution of nanogels after intravenous administration. The nanogels produced no apparent cytotoxicity and underwent cell uptake in CMS5a cells after a 24 h incubation at up to 2000 μg/mL and 400 μg/mL, respectively. The internalized nanogels were localized around the nuclear membrane. The nanogels were administered intravenously to mice bearing fibrosarcoma xenografts. Nanogel tumor localization likely occurred through the enhanced permeation and retention effect. The nanogels successfully reduced the cytotoxicity of carborane, were internalized into tumor cells, acted as a dual-delivery therapeutic and accumulated in tumors in vivo. Consequently, they demonstrate significant potential as a boron neutron capture therapeutic. - Highlights: • A carborane-bearing pullulan nanogel is developed as a boron delivery agent. • The nanogels are cell-friendly and show effective cell uptake for drug delivery. • The nanogels show passive tumor targeting by enhanced permeation and retention.« less
NAKAMURA, Satoshi; IMAMICHI, Shoji; MASUMOTO, Kazuyoshi; ITO, Masashi; WAKITA, Akihisa; OKAMOTO, Hiroyuki; NISHIOKA, Shie; IIJIMA, Kotaro; KOBAYASHI, Kazuma; ABE, Yoshihisa; IGAKI, Hiroshi; KURITA, Kazuyoshi; NISHIO, Teiji; MASUTANI, Mitsuko; ITAMI, Jun
2017-01-01
This study aimed to evaluate the residual radioactivity in mice induced by neutron irradiation with an accelerator-based boron neutron capture therapy (BNCT) system using a solid Li target. The radionuclides and their activities were evaluated using a high-purity germanium (HP-Ge) detector. The saturated radioactivity of the irradiated mouse was estimated to assess the radiation protection needs for using the accelerator-based BNCT system. 24Na, 38Cl, 80mBr, 82Br, 56Mn, and 42K were identified, and their saturated radioactivities were (1.4 ± 0.1) × 102, (2.2 ± 0.1) × 101, (3.4 ± 0.4) × 102, 2.8 ± 0.1, 8.0 ± 0.1, and (3.8 ± 0.1) × 101 Bq/g/mA, respectively. The 24Na activation rate at a given neutron fluence was found to be consistent with the value reported from nuclear-reactor-based BNCT experiments. The induced activity of each nuclide can be estimated by entering the saturated activity of each nuclide, sample mass, irradiation time, and proton current into the derived activation equation in our accelerator-based BNCT system. PMID:29225308
Nakamura, Satoshi; Imamichi, Shoji; Masumoto, Kazuyoshi; Ito, Masashi; Wakita, Akihisa; Okamoto, Hiroyuki; Nishioka, Shie; Iijima, Kotaro; Kobayashi, Kazuma; Abe, Yoshihisa; Igaki, Hiroshi; Kurita, Kazuyoshi; Nishio, Teiji; Masutani, Mitsuko; Itami, Jun
2017-01-01
This study aimed to evaluate the residual radioactivity in mice induced by neutron irradiation with an accelerator-based boron neutron capture therapy (BNCT) system using a solid Li target. The radionuclides and their activities were evaluated using a high-purity germanium (HP-Ge) detector. The saturated radioactivity of the irradiated mouse was estimated to assess the radiation protection needs for using the accelerator-based BNCT system. 24 Na, 38 Cl, 80m Br, 82 Br, 56 Mn, and 42 K were identified, and their saturated radioactivities were (1.4 ± 0.1) × 10 2 , (2.2 ± 0.1) × 10 1 , (3.4 ± 0.4) × 10 2 , 2.8 ± 0.1, 8.0 ± 0.1, and (3.8 ± 0.1) × 10 1 Bq/g/mA, respectively. The 24 Na activation rate at a given neutron fluence was found to be consistent with the value reported from nuclear-reactor-based BNCT experiments. The induced activity of each nuclide can be estimated by entering the saturated activity of each nuclide, sample mass, irradiation time, and proton current into the derived activation equation in our accelerator-based BNCT system.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Mossman, K.L.; Chencharick, J.D.; Scheer, A.C.
1979-04-01
Changes in gustatory function were measured in 51 patients with various forms of cancer who received radiation to the head and neck region. Forty patients (group I) were treated with conventional photon radiation (e.g. 66 Gy/7 weeks), and 11 patients (group II) were treated with cyclotron produced fast neutrons (e.g. 22 Gy/7 weeks). Taste acuity was measured for four taste qualities (salt, sweet, sour, and bitter) by a forced choice-three stimulus drop technique which measured detection and recognition thresholds and by a forced scaling technique which measured taste intensity responsiveness. Subjective complaints of anorexia, dysgeusia, taste loss, and xerostomia weremore » also recorded. Patients were studied before, during and up to two months after therapy. Prior to therapy, detection and recognition thresholds, intensity responsiveness, and the frequency of subjective complaints in patients from groups I and II were statistically equivalent. During and up to 2 months after therapy, taste impairment and frequency of subjective complaints increased significantly in neutron and photon treated patients, but were statistically equivalent. Results of this study indicate that gustatory tissue response as measured by taste detection and recognition and intensity responsiveness, and the frequency of subjective complaints related to taste are statistically equivalent in patients before, during, or up 2 months after they were given either neutron or photon radiation for tumors of the head and neck.« less
Hardening neutron spectrum for advanced actinide transmutation experiments in the ATR.
Chang, G S; Ambrosek, R G
2005-01-01
The most effective method for transmuting long-lived isotopes contained in spent nuclear fuel into shorter-lived fission products is in a fast neutron spectrum reactor. In the absence of a fast test reactor in the United States, initial irradiation testing of candidate fuels can be performed in a thermal test reactor that has been modified to produce a test region with a hardened neutron spectrum. Such a test facility, with a spectrum similar but somewhat softer than that of the liquid-metal fast breeder reactor (LMFBR), has been constructed in the INEEL's Advanced Test Reactor (ATR). The radial fission power distribution of the actinide fuel pin, which is an important parameter in fission gas release modelling, needs to be accurately predicted and the hardened neutron spectrum in the ATR and the LMFBR fast neutron spectrum is compared. The comparison analyses in this study are performed using MCWO, a well-developed tool that couples the Monte Carlo transport code MCNP with the isotope depletion and build-up code ORIGEN-2. MCWO analysis yields time-dependent and neutron-spectrum-dependent minor actinide and Pu concentrations and detailed radial fission power profile calculations for a typical fast reactor (LMFBR) neutron spectrum and the hardened neutron spectrum test region in the ATR. The MCWO-calculated results indicate that the cadmium basket used in the advanced fuel test assembly in the ATR can effectively depress the linear heat generation rate in the experimental fuels and harden the neutron spectrum in the test region.
Neutron collimator design of neutron radiography based on the BNCT facility
NASA Astrophysics Data System (ADS)
Yang, Xiao-Peng; Yu, Bo-Xiang; Li, Yi-Guo; Peng, Dan; Lu, Jin; Zhang, Gao-Long; Zhao, Hang; Zhang, Ai-Wu; Li, Chun-Yang; Liu, Wan-Jin; Hu, Tao; Lü, Jun-Guang
2014-02-01
For the research of CCD neutron radiography, a neutron collimator was designed based on the exit of thermal neutron of the Boron Neutron Capture Therapy (BNCT) reactor. Based on the Geant4 simulations, the preliminary choice of the size of the collimator was determined. The materials were selected according to the literature data. Then, a collimator was constructed and tested on site. The results of experiment and simulation show that the thermal neutron flux at the end of the neutron collimator is greater than 1.0×106 n/cm2/s, the maximum collimation ratio (L/D) is 58, the Cd-ratio(Mn) is 160 and the diameter of collimator end is 10 cm. This neutron collimator is considered to be applicable for neutron radiography.
NASA Astrophysics Data System (ADS)
Terranova, Nicholas; Serot, Olivier; Archier, Pascal; De Saint Jean, Cyrille; Sumini, Marco
2017-09-01
Fission product yields (FY) are fundamental nuclear data for several applications, including decay heat, shielding, dosimetry, burn-up calculations. To be safe and sustainable, modern and future nuclear systems require accurate knowledge on reactor parameters, with reduced margins of uncertainty. Present nuclear data libraries for FY do not provide consistent and complete uncertainty information which are limited, in many cases, to only variances. In the present work we propose a methodology to evaluate covariance matrices for thermal and fast neutron induced fission yields. The semi-empirical models adopted to evaluate the JEFF-3.1.1 FY library have been used in the Generalized Least Square Method available in CONRAD (COde for Nuclear Reaction Analysis and Data assimilation) to generate covariance matrices for several fissioning systems such as the thermal fission of U235, Pu239 and Pu241 and the fast fission of U238, Pu239 and Pu240. The impact of such covariances on nuclear applications has been estimated using deterministic and Monte Carlo uncertainty propagation techniques. We studied the effects on decay heat and reactivity loss uncertainty estimation for simplified test case geometries, such as PWR and SFR pin-cells. The impact on existing nuclear reactors, such as the Jules Horowitz Reactor under construction at CEA-Cadarache, has also been considered.
Michiue, Hiroyuki; Sakurai, Yoshinori; Kondo, Natsuko; Kitamatsu, Mizuki; Bin, Feng; Nakajima, Kiichiro; Hirota, Yuki; Kawabata, Shinji; Nishiki, Tei-ichi; Ohmori, Iori; Tomizawa, Kazuhito; Miyatake, Shin-ichi; Ono, Koji; Matsui, Hideki
2014-03-01
New anti-cancer therapy with boron neutron capture therapy (BNCT) is based on the nuclear reaction of boron-10 with neutron irradiation. The median survival of BNCT patients with glioblastoma was almost twice as long as those receiving standard therapy in a Japanese BNCT clinical trial. In this clinical trial, two boron compounds, BPA (boronophenylalanine) and BSH (sodium borocaptate), were used for BNCT. BPA is taken up into cells through amino acid transporters that are expressed highly in almost all malignant cells, but BSH cannot pass through the cell membrane and remains outside the cell. We simulated the energy transfer against the nucleus at different locations of boron from outside the cell to the nuclear region with neutron irradiation and concluded that there was a marked difference between inside and outside the cell in boron localization. To overcome this disadvantage of BSH in BNCT, we used a cell-penetrating peptide system for transduction of BSH. CPP (cell-membrane penetrating peptide) is very common peptide domains that transduce many physiologically active substances into cells in vitro and in vivo. BSH-fused CPPs can penetrate the cell membrane and localize inside a cell. To increase the boron ratio in one BSH-peptide molecule, 8BSH fused to 11R with a dendritic lysine structure was synthesized and administrated to malignant glioma cells and a brain tumor mouse model. 8BSH-11R localized at the cell nucleus and showed a very high boron value in ICP results. With neutron irradiation, the 8BSH-11R administrated group showed a significant cancer killing effect compared to the 100 times higher concentration of BSH-administrated group. We concluded that BSH-fused CPPs were one of the most improved and potential boron compounds in the next-stage BNCT trial and 8BSH-11R may be applied in the clinical setting. Copyright © 2013 Elsevier Ltd. All rights reserved.
Neutron influences and energy spectra in the Cosmos-2044 biosatellite orbit
NASA Technical Reports Server (NTRS)
Dudkin, V. E.; Potapov, Yu. V.; Akopova, A. B.; Melkumyan, L. V.; Rshtuni, Sh. B.; Benton, E, V.; Frank, A. L.
1995-01-01
Joint Soviet-American measurements of the neutron component of space radiation (SR) were carried out during the flight of the Soviet biosatellite Cosmos-2044. Neutron flux densities and differential energy spectra were measured inside and on the external surface of the spacecraft. Three energy intervals were employed: thermal (E(sub n) less than or equal to 0.2 eV), resonance (0.2 eV less than E(sub n) less than 1.0 MeV) and fast (E(sub n) greater than or equal to 1.0 MeV) neutrons. The first two groups were measured with U.S. (6)LiF detectors, while fast neutrons were recorded both by U.S. fission foils and Soviet nuclear emulsions. Estimations were made of the contributions to absorbed and equivalent doses from each neutron energy interval and a correlation was presented between fast neutron fluxes, measured outside the satellite, and the phase of solar activity (SA). Average dose equivalent rates of 0.018 and 0.14 mrem d(exp -1) were measured for thermal and resonance neutrons, respectively, outside the spacecraft. The corresponding values for fast neutrons were 3.3 (U.S.) and 1.8 (U.S.S.R.) mrem d(exp -1). Inside the spacecraft, a value of 3.5 mrem d(exp -1) was found.
Optimization of Boron Neutron Capture Therapy for the Treatment of Undifferentiated Thyroid Cancer
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dagrosa, Maria Alejandra; Thomasz, Lisa M.Sc.; Longhino, Juan
Purpose: To analyze the possible increase in efficacy of boron neutron capture therapy (BNCT) for undifferentiated thyroid carcinoma (UTC) by using p-boronophenylalanine (BPA) plus 2,4-bis ({alpha},{beta}-dihydroxyethyl)-deutero-porphyrin IX (BOPP) and BPA plus nicotinamide (NA) as a radiosensitizer of the BNCT reaction. Methods and Materials: Nude mice were transplanted with a human UTC cell line (ARO), and after 15 days they were treated as follows: (1) control, (2) NCT (neutrons alone), (3) NCT plus NA (100 mg/kg body weight [bw]/day for 3 days), (4) BPA (350 mg/kg bw) + neutrons, (5) BPA + NA + neutrons, and (6) BPA + BOPP (60more » mg/kg bw) + neutrons. The flux of the mixed (thermal + epithermal) neutron beam was 2.8 x 10{sup 8} n/cm{sup 2}/sec for 83.4 min. Results: Neutrons alone or with NA caused some tumor growth delay, whereas in the BPA, BPA + NA, and BPA + BOPP groups a 100% halt of tumor growth was observed in all mice at 26 days after irradiation. When the initial tumor volume was 50 mm{sup 3} or less, complete remission was found with BPA + NA (2 of 2 mice), BPA (1 of 4), and BPA + BOPP (7 of 7). After 90 days of complete regression, recurrence of the tumor was observed in BPA + NA (2 of 2) and BPA + BOPP (1 of 7). The determination of apoptosis in tumor samples by measurements of caspase-3 activity showed an increase in the BNCT (BPA + NA) group at 24 h (p < 0.05 vs. controls) and after the first week after irradiation in the three BNCT groups. Terminal transferase dUTP nick end labeling analysis confirmed these results. Conclusions: Although NA combined with BPA showed an increase of apoptosis at early times, only the group irradiated after the combined administration of BPA and BOPP showed a significantly improved therapeutic response.« less
NASA Astrophysics Data System (ADS)
Kasatov, D. A.; Kolesnikov, J. A.; Koshkarev, A. M.; Kuznetsov, A. S.; Makarov, A. N.; Sokolova, E. O.; Sorokin, I. N.; Sycheva, T. V.; Taskaev, S. Yu.; Shchudlo, I. M.
2016-12-01
An epithermal neutron source that is based on a vacuum insulation tandem accelerator (VITA) and lithium target was created in the Budker Institute of Nuclear Physics for the development of boron neutron capture therapy (BNCT). A stationary proton beam with 2 MeV energy and 1.6 mA current has been obtained. To carry out BNCT, it is necessary to increase the beam parameters up to 2.3 MeV and 3 mA. Ways to increase the parameters of the proton beam have been proposed and discussed in this paper. The results of the experiments are presented.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kankaanranta, Leena; Seppaelae, Tiina; Koivunoro, Hanna
Purpose: To investigate the safety of boronophenylalanine-mediated boron neutron capture therapy (BNCT) in the treatment of malignant gliomas that progress after surgery and conventional external beam radiation therapy. Methods and Materials: Adult patients who had histologically confirmed malignant glioma that had progressed after surgery and external beam radiotherapy were eligible for this Phase I study, provided that >6 months had elapsed from the last date of radiation therapy. The first 10 patients received a fixed dose, 290 mg/kg, of L-boronophenylalanine-fructose (L-BPA-F) as a 2-hour infusion before neutron irradiation, and the remaining patients were treated with escalating doses of L-BPA-F, eithermore » 350 mg/kg, 400 mg/kg, or 450 mg/kg, using 3 patients on each dose level. Adverse effects were assessed using National Cancer Institute Common Toxicity Criteria version 2.0. Results: Twenty-two patients entered the study. Twenty subjects had glioblastoma, and 2 patients had anaplastic astrocytoma, and the median cumulative dose of prior external beam radiotherapy was 59.4 Gy. The maximally tolerated L-BPA-F dose was reached at the 450 mg/kg level, where 4 of 6 patients treated had a grade 3 adverse event. Patients who were given >290 mg/kg of L-BPA-F received a higher estimated average planning target volume dose than those who received 290 mg/kg (median, 36 vs. 31 Gy [W, i.e., a weighted dose]; p = 0.018). The median survival time following BNCT was 7 months. Conclusions: BNCT administered with an L-BPA-F dose of up to 400 mg/kg as a 2-hour infusion is feasible in the treatment of malignant gliomas that recur after conventional radiation therapy.« less
NEUTRON CAPTURE THERAPY OF A CEREBELLAR HEMANGIOSARCOMA AFTER SURGICAL AND RADIATION TREATMENT
DOE Office of Scientific and Technical Information (OSTI.GOV)
Farr, L.E.; Yamamoto, L.Y.
1961-10-01
A patient with a hioghly maliognant vascular sarcoma of the cerebellum was treated hv neutron capture therapy. Almost complete elimination of the neoplasm was attained. Other than the skin, normal tissues about and within the neoplastioc mass did not appear to be adversely affected. An unusual and unexpected bulbar conjunctivitis was observed as a complication. The degree of control attained by this experimental procedure was more positive than that previously attained by surgery or conventional x-ray therapy. This is the first attempt to control an intracranial tumor other than glioblastoma multiforme by this procedure. The patient is noteworthy for themore » extreme retention of carbon dioxiode, 60 milli-equivalents per liter in the blood, apparently resulting from functional disturbances of the respiratory center. (auth)« less
Differential neutron energy spectra measured on spacecraft low Earth orbit
NASA Technical Reports Server (NTRS)
Benton, E. V.; Frank, A. L.; Dudkin, E. V.; Potapov, Yu. V.; Akopova, A. B.; Melkumyan, L. V.
1995-01-01
Two methods for measuring neutrons in the range from thermal energies to dozens of MeV were used. In the first method, alpha-particles emitted from the (sup 6) Li(n.x)T reaction are detected with the help of plastic nuclear track detectors, yielding results on thermal and resonance neutrons. Also, fission foils are used to detect fast neutrons. In the second method, fast neutrons are recorded by nuclear photographic emulsions (NPE). The results of measurements on board various satellites are presented. The neutron flux density does not appear to correlate clearly with orbital parameters. Up to 50% of neutrons are due to albedo neutrons from the atmosphere while the fluxes inside the satellites are 15-20% higher than those on the outside. Estimates show that the neutron contribution to the total equivalent radiation dose reaches 20-30%.
Optimization of the Army’s Fast Neutron Moderator for Radiography
2013-02-26
thermal neutron flux from a commercially available high-energy D-T neutron generator. This paper details the steps taken to increase exposure rates...experiment was to have increased thermal neutron flux rates and shorter exposure times than previously achieved. Additional technology developments...This reduced the thermalizing efficiency of the moderator at higher energies, resulted in a large loss of neutron flux at the image plane, and
2013-01-01
Background Glioma stem cells in the quiescent state are resistant to clinical radiation therapy. An almost inevitable glioma recurrence is due to the persistence of these cells. The high linear energy transfer associated with boron neutron capture therapy (BNCT) could kill quiescent and proliferative cells. Methods The present study aimed to evaluate the effects of BNCT on glioma stem/progenitor cells in vitro. The damage induced by BNCT was assessed using cell cycle progression, apoptotic cell ratio and apoptosis-associated proteins expression. Results The surviving fraction and cell viability of glioma stem/progenitor cells were decreased compared with differentiated glioma cells using the same boronophenylalanine pretreatment and the same dose of neutron flux. BNCT induced cell cycle arrest in the G2/M phase and cell apoptosis via the mitochondrial pathway, with changes in the expression of associated proteins. Conclusions Glioma stem/progenitor cells, which are resistant to current clinical radiotherapy, could be effectively killed by BNCT in vitro via cell cycle arrest and apoptosis using a prolonged neutron irradiation, although radiosensitivity of glioma stem/progenitor cells was decreased compared with differentiated glioma cells when using the same dose of thermal neutron exposure and boronophenylalanine pretreatment. Thus, BNCT could offer an appreciable therapeutic advantage to prevent tumor recurrence, and may become a promising treatment in recurrent glioma. PMID:23915425
Fast neutron production from lithium converters and laser driven protons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Storm, M.; Jiang, S.; Wertepny, D.
2013-05-15
Experiments to generate neutrons from the {sup 7}Li(p,n){sup 7}Be reaction with 60 J, 180 fs laser pulses have been performed at the Texas Petawatt Laser Facility at the University of Texas at Austin. The protons were accelerated from the rear surface of a thin target membrane using the target-normal-sheath-acceleration mechanism. The neutrons were generated in nuclear reactions caused by the subsequent proton bombardment of a pure lithium foil of natural isotopic abundance. The neutron energy ranged up to 2.9 MeV. The total yield was estimated to be 1.6 × 10{sup 7} neutrons per steradian. An extreme ultra-violet light camera, usedmore » to image the target rear surface, correlated variations in the proton yield and peak energy to target rear surface ablation. Calculations using the hydrodynamics code FLASH indicated that the ablation resulted from a laser pre-pulse of prolonged intensity. The ablation severely limited the proton acceleration and neutron yield.« less
The 14 MeV Neutron Irradiation Facility in MARIA Reactor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Prokopowicz, R.; Pytel, K.; Dorosz, M.
2015-07-01
The MARIA reactor with thermal neutron flux density up to 3x10{sup 14} cm{sup -2} s{sup -1} and a number of vertical channels is well suited to material testing by thermal neutron treatment. Beside of that some fast neutron irradiation facilities are operated in MARIA reactor as well. One of them is thermal to 14 MeV neutron converter launched in 2014. It is especially devoted to fusion devices material testing irradiation. The ITER and DEMO research thermonuclear facilities are to be run using the deuterium - tritium fusion reaction. Fast neutrons (of energy approximately 14 MeV) resulting from the reaction aremore » essential to carry away the released thermonuclear energy and to breed tritium. However, constructional materials of which thermonuclear reactors are to be built must be specially selected to survive intense fluxes of fast neutrons. Strong sources of 14 MeV neutrons are needed if research on resistance of candidate materials to such fluxes is to be carried out effectively. Nuclear reactor-based converter capable to convert thermal neutrons into 14 MeV fast neutrons may be used to that purpose. The converter based on two stage nuclear reaction on lithium-6 and deuterium compounds leading to 14 MeV neutron production. The reaction chain is begun by thermal neutron capture by lithium-6 nucleus resulted in triton release. The neutron and triton transport calculations have been therefore carried-out to estimate the thermal to 14 MeV neutron conversion efficiency and optimize converter construction. The usable irradiation space of ca. 60 cm{sup 3} has been obtained. The released energy have been calculated. Heat transport has been asses to ensure proper device cooling. A set of thermocouples has been installed in converter to monitor its temperature distribution on-line. Influence of converter on reactor operation has been studied. Safety analyses of steady states and transients have been done. Performed calculations and analyses allow designing the
A feasibility study of the Tehran research reactor as a neutron source for BNCT.
Kasesaz, Yaser; Khalafi, Hossein; Rahmani, Faezeh; Ezati, Arsalan; Keyvani, Mehdi; Hossnirokh, Ashkan; Shamami, Mehrdad Azizi; Monshizadeh, Mahdi
2014-08-01
Investigation on the use of the Tehran Research Reactor (TRR) as a neutron source for Boron Neutron Capture Therapy (BNCT) has been performed by calculating and measuring energy spectrum and the spatial distribution of neutrons in all external irradiation facilities, including six beam tubes, thermal column, and the medical room. Activation methods with multiple foils and a copper wire have been used for the mentioned measurements. The results show that (1) the small diameter and long length beam tubes cannot provide sufficient neutron flux for BNCT; (2) in order to use the medical room, the TRR core should be placed in the open pool position, in this situation the distance between the core and patient position is about 400 cm, so neutron flux cannot be sufficient for BNCT; and (3) the best facility which can be adapted for BNCT application is the thermal column, if all graphite blocks can be removed. The epithermal and fast neutron flux at the beginning of this empty column are 4.12×10(9) and 1.21×10(9) n/cm(2)/s, respectively, which can provide an appropriate neutron beam for BNCT by designing and constructing a proper Beam Shaping Assembly (BSA) structure. Copyright © 2014 Elsevier Ltd. All rights reserved.
RBE, reference RBE and clinical RBE: applications of these concepts in hadron therapy.
Wambersie, A
1999-06-01
Introduction of heavy particles (hadrons) into radiation therapy aims at improving the physical selectivity of the irradiation (e.g. proton beams), or the radiobiological differential effect (e.g. fast neutrons), or both (e.g. heavy-ion beams). Each of these new therapy modalities requires several types of information before prescribing safely the doses to patients, as well as for recording and reporting the treatments: (i) absorbed dose measured in a homogeneous phantom in reference conditions; (ii) dose distribution computed at the level of the target volume(s) and the normal tissues at risk; (iii) radiation quality from which a RBE evaluation could be predicted and (iv) RBE measured on biological systems or derived from clinical observation. In hadron therapy, the RBE of the different beams raises specific problems. For fast neutrons, the RBE varies within wide limits (about 2 to 5) depending on the neutron energy spectrum, dose, and biological system. For protons, the RBE values range between smaller limits (about 1.0 to 1.2). A clinical benefit can thus not be expected from RBE differences. However, the proton RBE problem cannot be ignored since dose differences of about 5% can be detected clinically in some cases. The situation is most complex with heavy ions since RBE variations are at least as large as for fast neutrons, as a function of particle type and energy, dose and biological system. In addition, RBE varies with depth. Radiation quality thus has to be taken into account when prescribing and reporting a treatment. This can be done in different ways: (a) description of the method of beam production; (b) computed LET spectra and/or measured microdosimetric spectra at the points clinically relevant; (c) RBE determination. The most relevant RBE data are those obtained for late tolerance of normal tissues at 2 Gy per fraction ("reference RBE"). The "clinical RBE" selected by the radiation oncologist when prescribing the treatment will be close to the
NASA Astrophysics Data System (ADS)
Burlon, Alejandro A.; Girola, Santiago; Valda, Alejandro A.; Minsky, Daniel M.; Kreiner, Andrés J.
2010-08-01
In the frame of the construction of a Tandem Electrostatic Quadrupole Accelerator facility devoted to the Accelerator-Based Boron Neutron Capture Therapy, a Beam Shaping Assembly has been characterized by means of Monte-Carlo simulations and measurements. The neutrons were generated via the 7Li(p, n)7Be reaction by irradiating a thick LiF target with a 2.3 MeV proton beam delivered by the TANDAR accelerator at CNEA. The emerging neutron flux was measured by means of activation foils while the beam quality and directionality was evaluated by means of Monte Carlo simulations. The parameters show compliance with those suggested by IAEA. Finally, an improvement adding a beam collimator has been evaluated.
Radial Flux Distribution of Low-Energy Neutrons.
ERIC Educational Resources Information Center
Higinbotham, J.
1979-01-01
Describes an experiment designed to illustrate the basic principle involved in the process of moderation of fast neutrons by water, and the monitoring of the low-energy neutron flux using indium as a probe. (GA)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Swift, Alicia L; Grogan, Brandon R; Mullens, James Allen
This work tests a systematic procedure for analyzing data acquired by the Nuclear Materials Identification System (NMIS) at Oak Ridge National Laboratory with fast-neutron imaging and high-purity germanium (HPGe) gamma spectrometry capabilities. NMIS has been under development by the US Department of Energy Office of Nuclear Verification since the mid-1990s, and prior to that by the National Nuclear Security Administration Y-12 National Security Complex, with NMIS having been used at Y-12 for template matching to confirm inventory and receipts. In this present work, a complete set of NMIS time coincidence, fast-neutron imaging, fission mapping, and HPGe gamma-ray spectrometry data wasmore » obtained from Monte Carlo simulations for a configuration of fissile and nonfissile materials. The data were then presented for analysis to someone who had no prior knowledge of the unknown object to accurately determine the description of the object by applying the previously-mentioned procedure to the simulated data. The best approximation indicated that the unknown object was composed of concentric cylinders: a void inside highly enriched uranium (HEU) (84.7 {+-} 1.9 wt % {sup 235}U), surrounded by depleted uranium, surrounded by polyethylene. The final estimation of the unknown object had the correct materials and geometry, with error in the radius estimates of material regions varying from 1.58% at best and 4.25% at worst; error in the height estimates varied from 2% to 12%. The error in the HEU enrichment estimate was 5.9 wt % (within 2.5{sigma} of the true value). The accuracies of the determinations could be adequate for arms control applications. Future work will apply this iterative reconstructive procedure to other unknown objects to further test and refine it.« less
NASA Astrophysics Data System (ADS)
Jebali, R.; Scherzinger, J.; Annand, J. R. M.; Chandra, R.; Davatz, G.; Fissum, K. G.; Friederich, H.; Gendotti, U.; Hall-Wilton, R.; Håkansson, E.; Kanaki, K.; Lundin, M.; Murer, D.; Nilsson, B.; Rosborg, A.; Svensson, H.
2015-09-01
A first comparison has been made between the pulse-shape discrimination characteristics of a novel 4He-based pressurized scintillation detector and a NE-213 liquid-scintillator reference detector using an Am/Be mixed-field neutron and gamma-ray source and a high-resolution scintillation-pulse digitizer. In particular, the capabilities of the two fast neutron detectors to discriminate between neutrons and gamma-rays were investigated. The NE-213 liquid-scintillator reference cell produced a wide range of scintillation-light yields in response to the gamma-ray field of the source. In stark contrast, due to the size and pressure of the 4He gas volume, the 4He-based detector registered a maximum scintillation-light yield of 750keVee to the same gamma-ray field. Pulse-shape discrimination for particles with scintillation-light yields of more than 750keVee was excellent in the case of the 4He-based detector. Above 750keVee its signal was unambiguously neutron, enabling particle identification based entirely upon the amount of scintillation light produced.
First neutron generation in the BINP accelerator based neutron source.
Bayanov, B; Burdakov, A; Chudaev, V; Ivanov, A; Konstantinov, S; Kuznetsov, A; Makarov, A; Malyshkin, G; Mekler, K; Sorokin, I; Sulyaev, Yu; Taskaev, S
2009-07-01
Pilot innovative facility for neutron capture therapy was built at Budker Institute of Nuclear Physics, Novosibirsk. This facility is based on a compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915 MeV protons bombarding a lithium target using (7)Li(p,n)(7)Be threshold reaction. The results of the first experiments on neutron generation are reported and discussed.
An Approach in Radiation Therapy Treatment Planning: A Fast, GPU-Based Monte Carlo Method.
Karbalaee, Mojtaba; Shahbazi-Gahrouei, Daryoush; Tavakoli, Mohammad B
2017-01-01
An accurate and fast radiation dose calculation is essential for successful radiation radiotherapy. The aim of this study was to implement a new graphic processing unit (GPU) based radiation therapy treatment planning for accurate and fast dose calculation in radiotherapy centers. A program was written for parallel running based on GPU. The code validation was performed by EGSnrc/DOSXYZnrc. Moreover, a semi-automatic, rotary, asymmetric phantom was designed and produced using a bone, the lung, and the soft tissue equivalent materials. All measurements were performed using a Mapcheck dosimeter. The accuracy of the code was validated using the experimental data, which was obtained from the anthropomorphic phantom as the gold standard. The findings showed that, compared with those of DOSXYZnrc in the virtual phantom and for most of the voxels (>95%), <3% dose-difference or 3 mm distance-to-agreement (DTA) was found. Moreover, considering the anthropomorphic phantom, compared to the Mapcheck dose measurements, <5% dose-difference or 5 mm DTA was observed. Fast calculation speed and high accuracy of GPU-based Monte Carlo method in dose calculation may be useful in routine radiation therapy centers as the core and main component of a treatment planning verification system.
NASA Astrophysics Data System (ADS)
Yeamans, C. B.; Gharibyan, N.
2016-11-01
At the National Ignition Facility, the diagnostic instrument manipulator-based neutron activation spectrometer is used as a diagnostic of implosion performance for inertial confinement fusion experiments. Additionally, it serves as a platform for independent neutronic experiments and may be connected to fast recording systems for neutron effect tests on active electronics. As an implosion diagnostic, the neutron activation spectrometers are used to quantify fluence of primary DT neutrons, downscattered neutrons, and neutrons above the primary DT neutron energy created by reactions of upscattered D and T in flight. At a primary neutron yield of 1015 and a downscattered fraction of neutrons in the 10-12 MeV energy range of 0.04, the downscattered neutron fraction can be measured to a relative uncertainty of 8%. Significant asymmetries in downscattered neutrons have been observed. Spectrometers have been designed and fielded to measure the tritium-tritium and deuterium-tritium neutron outputs simultaneously in experiments using DT/TT fusion ratio as a direct measure of mix of ablator into the gas.
Yeamans, C B; Gharibyan, N
2016-11-01
At the National Ignition Facility, the diagnostic instrument manipulator-based neutron activation spectrometer is used as a diagnostic of implosion performance for inertial confinement fusion experiments. Additionally, it serves as a platform for independent neutronic experiments and may be connected to fast recording systems for neutron effect tests on active electronics. As an implosion diagnostic, the neutron activation spectrometers are used to quantify fluence of primary DT neutrons, downscattered neutrons, and neutrons above the primary DT neutron energy created by reactions of upscattered D and T in flight. At a primary neutron yield of 10 15 and a downscattered fraction of neutrons in the 10-12 MeV energy range of 0.04, the downscattered neutron fraction can be measured to a relative uncertainty of 8%. Significant asymmetries in downscattered neutrons have been observed. Spectrometers have been designed and fielded to measure the tritium-tritium and deuterium-tritium neutron outputs simultaneously in experiments using DT/TT fusion ratio as a direct measure of mix of ablator into the gas.
Schneider, Christopher; Newhauser, Wayne; Farah, Jad
2015-05-18
Exposure to stray neutrons increases the risk of second cancer development after proton therapy. Previously reported analytical models of this exposure were difficult to configure and had not been investigated below 100 MeV proton energy. The purposes of this study were to test an analytical model of neutron equivalent dose per therapeutic absorbed dose at 75 MeV and to improve the model by reducing the number of configuration parameters and making it continuous in proton energy from 100 to 250 MeV. To develop the analytical model, we used previously published H/D values in water from Monte Carlo simulations of a general-purpose beamline for proton energies from 100 to 250 MeV. We also configured and tested the model on in-air neutron equivalent doses measured for a 75 MeV ocular beamline. Predicted H/D values from the analytical model and Monte Carlo agreed well from 100 to 250 MeV (10% average difference). Predicted H/D values from the analytical model also agreed well with measurements at 75 MeV (15% average difference). The results indicate that analytical models can give fast, reliable calculations of neutron exposure after proton therapy. This ability is absent in treatment planning systems but vital to second cancer risk estimation.
Solid polystyrene and deuterated polystyrene light output response to fast neutrons
NASA Astrophysics Data System (ADS)
Simpson, R.; Danly, C.; Glebov, V. Yu.; Hurlbut, C.; Merrill, F. E.; Volegov, P. L.; Wilde, C.
2016-04-01
The Neutron Imaging System has proven to be an important diagnostic in studying DT implosion characteristics at the National Ignition Facility. The current system depends on a polystyrene scintillating fiber array, which detects fusion neutrons born in the DT hotspot as well as neutrons that have scattered to lower energies in the surrounding cold fuel. Increasing neutron yields at NIF, as well as a desire to resolve three-dimensional information about the fuel assembly, have provided the impetus to build and install two additional next-generation neutron imaging systems. We are currently investigating a novel neutron imaging system that will utilize a deuterated polystyrene (CD) fiber array instead of standard hydrogen-based polystyrene (CH). Studies of deuterated xylene or deuterated benzene liquid scintillator show an improvement in imaging resolution by a factor of two [L. Disdier et al., Rev. Sci. Instrum. 75, 2134 (2004)], but also a reduction in light output [V. Bildstein et al., Nucl. Instrum. Methods Phys. Res., Sect. A 729, 188 (2013); M. I. Ojaruega, Ph.D. thesis, University of Michigan, 2009; M. T. Febbraro, Ph.D. thesis, University of Michigan, 2014] as compared to standard plastic. Tests of the relative light output of deuterated polystyrene and standard polystyrene were completed using 14 MeV fusion neutrons generated through implosions of deuterium-tritium filled capsules at the OMEGA laser facility. In addition, we collected data of the relative response of these two scintillators to a wide energy range of neutrons (1-800 MeV) at the Weapons Neutrons Research Facility. Results of these measurements are presented.
Solid polystyrene and deuterated polystyrene light output response to fast neutrons.
Simpson, R; Danly, C; Glebov, V Yu; Hurlbut, C; Merrill, F E; Volegov, P L; Wilde, C
2016-04-01
The Neutron Imaging System has proven to be an important diagnostic in studying DT implosion characteristics at the National Ignition Facility. The current system depends on a polystyrene scintillating fiber array, which detects fusion neutrons born in the DT hotspot as well as neutrons that have scattered to lower energies in the surrounding cold fuel. Increasing neutron yields at NIF, as well as a desire to resolve three-dimensional information about the fuel assembly, have provided the impetus to build and install two additional next-generation neutron imaging systems. We are currently investigating a novel neutron imaging system that will utilize a deuterated polystyrene (CD) fiber array instead of standard hydrogen-based polystyrene (CH). Studies of deuterated xylene or deuterated benzene liquid scintillator show an improvement in imaging resolution by a factor of two [L. Disdier et al., Rev. Sci. Instrum. 75, 2134 (2004)], but also a reduction in light output [V. Bildstein et al., Nucl. Instrum. Methods Phys. Res., Sect. A 729, 188 (2013); M. I. Ojaruega, Ph.D. thesis, University of Michigan, 2009; M. T. Febbraro, Ph.D. thesis, University of Michigan, 2014] as compared to standard plastic. Tests of the relative light output of deuterated polystyrene and standard polystyrene were completed using 14 MeV fusion neutrons generated through implosions of deuterium-tritium filled capsules at the OMEGA laser facility. In addition, we collected data of the relative response of these two scintillators to a wide energy range of neutrons (1-800 MeV) at the Weapons Neutrons Research Facility. Results of these measurements are presented.
Lin, Sy-Yu; Lin, Chen-Jou; Liao, Jiunn-Wang; Peir, Jinn-Jer; Chen, Wei-Lin; Chi, Chin-Wen; Lin, Yung-Chang; Liu, Yu-Ming; Chou, Fong-In
2013-11-01
Hepatocellular carcinoma (HCC) is a common malignant tumor with poor prognosis. Boron neutron capture therapy (BNCT) may provide an alternative therapy for HCC. This study investigated the therapeutic efficacy of boric acid (BA)-mediated BNCT for HCC in a rat model. The pharmacokinetic and biodistribution of BA in N1S1 tumor-bearing rats were analyzed. Rats were injected with 25 mg B/kg body weight via tail veins before neutron irradiation at the Tsing Hua Open-pool Reactor, and the efficacy of BNCT was evaluated from the tumor size, tumor blood flow, and biochemical analyses. HCC-bearing rats administered BNCT showed reductions in tumor size on ultrasound imaging, as well as an obvious reduction in the distribution of tumor blood flow. The lesion located in livers had disappeared on the 80th day after BNCT; a recovery of values to normal levels was also recorded. BA-mediated BNCT is a promising alternative for liver cancer therapy since the present study demonstrated the feasibility of curing a liver tumor and restoring liver function in rats. Efforts are underway to investigate the histopathological features and the detailed mechanisms of BA-mediated BNCT.
Demonstration of a Single-Crystal Reflector-Filter for Enhancing Slow Neutron Beams
Muhrer, Guenter; Schönfeldt, Troels; Iverson, Erik B.; ...
2016-06-14
The cold polycrystalline beryllium reflector-filter concept has been used to enhance the cold neutron emission of cryogenic hydrogen moderators, while suppressing the intermediate wavelength and fast neutron emission at the same time. While suppressing the fast neutron emission is often desired, the suppression of intermediate wavelength neutrons is often unwelcome. It has been hypothesized that replacing the polycrystalline reflector-filter concept with a single-crystal reflector-filter concept would overcome the suppression of intermediate wavelength neutrons and thereby extend the usability of the reflector-filter concept to shorter but still important wavelengths. In this paper we present the first experimental data on a single-crystalmore » reflector-filter and compare experimental results with hypothesized performance. We find that a single-crystal reflector-filter retains the long-wavelength benefit of the polycrystalline reflector-filter, without suffering the same loss of important intermediate wavelength neutrons. Ultimately, this finding extends the applicability of the reflector-filter concept to intermediate wavelengths, and furthermore indicates that the reflector-filter benefits arise from its interaction with fast (background) neutrons, not with intermediate wavelength neutrons of potential interest in many types of neutron scattering.« less
Low-power lead-cooled fast reactor loaded with MOX-fuel
NASA Astrophysics Data System (ADS)
Sitdikov, E. R.; Terekhova, A. M.
2017-01-01
Fast reactor for the purpose of implementation of research, education of undergraduate and doctoral students in handling innovative fast reactors and training specialists for atomic research centers and nuclear power plants (BRUTs) was considered. Hard neutron spectrum achieved in the fast reactor with compact core and lead coolant. Possibility of prompt neutron runaway of the reactor is excluded due to the low reactivity margin which is less than the effective fraction of delayed neutrons. The possibility of using MOX fuel in the BRUTs reactor was examined. The effect of Keff growth connected with replacement of natural lead coolant to 208Pb coolant was evaluated. The calculations and reactor core model were performed using the Serpent Monte Carlo code.
NASA Astrophysics Data System (ADS)
Richardson, Norman E., IV
Since the beginning of the nuclear age, there has been a strong demand for the development of efficient technologies for the detection of ionizing radiation. According to the United States' Department of Energy, the accurate assessment of fissile materials is essential in achieving the nonproliferation goals of enhancing safety and security of nuclear fuel cycle and nuclear energy facilities. Nuclear materials can be characterized by the measurement of prompt and delayed neutrons and gamma rays emitted in spontaneous or induced fission reactions and neutrons emitted in fission reactions are the distinctive signatures of nuclear materials. Today, the most widely used neutron detection technologies rely on thermal neutron capture reactions using a moderating material to cause the neutron to lose its energy prior to the detection event. This is necessary because as the fission event occurs, neutrons are emitted carrying high amounts of energy, typically on the order of mega electron volts (MeV). These energetic particles are classified as "fast" neutrons. For detecting the thermal neutrons, the Helium-3 (3He) gas-filled counters are arguably the most widely used technology of neutron detection. 3He counters have been the scientific standard for the nuclear engineering community for several decades, and have earned their place as a reliable technique for the detection of neutrons. However, 3He gas-filled counters have several disadvantages. First, gas-filled counters are not rigid and are sensitive to vibrations. Secondly, gas-filled counters are prone to the count rate limitations due to the physical processes of charge multiplication and transport in the gas medium in the electric field. Lastly, 3He gas-filled counters suffer from a supply shortage of the 3He isotope. As it is stated in [3], this shortage is created by the new demand for Helium-3 due to the deployment of neutron detectors at the borders after the 9/11 attack to help secure the nation against smuggled
Neutron Imaging Development at China Academy of Engineering Physics (CAEP)
NASA Astrophysics Data System (ADS)
Li, Hang; Wang, Sheng; Cao, Chao; Huo, Heyong; Tang, Bin
Based the China Mianyang Research Reactor (CMRR) and D-T accelerator neutron source, thermal neutron, cold neutron and fast neutron imaging facilities are all installed at China Academy of Engineering Physics (CAEP). Various samples have been imaged by different energy neutrons and shown the neutron imaging application in industry, aerospace and so on. The facilities parameters and recent neutron imaging development will be shown in this paper.
High yield neutron generators using the DD reaction
NASA Astrophysics Data System (ADS)
Vainionpaa, J. H.; Harris, J. L.; Piestrup, M. A.; Gary, C. K.; Williams, D. L.; Apodaca, M. D.; Cremer, J. T.; Ji, Qing; Ludewigt, B. A.; Jones, G.
2013-04-01
A product line of high yield neutron generators has been developed at Adelphi technology inc. The generators use the D-D fusion reaction and are driven by an ion beam supplied by a microwave ion source. Yields of up to 5 × 109 n/s have been achieved, which are comparable to those obtained using the more efficient D-T reaction. The microwave-driven plasma uses the electron cyclotron resonance (ECR) to produce a high plasma density for high current and high atomic ion species. These generators have an actively pumped vacuum system that allows operation at reduced pressure in the target chamber, increasing the overall system reliability. Since no radioactive tritium is used, the generators can be easily serviced, and components can be easily replaced, providing essentially an unlimited lifetime. Fast neutron source size can be adjusted by selecting the aperture and target geometries according to customer specifications. Pulsed and continuous operation has been demonstrated. Minimum pulse lengths of 50 μs have been achieved. Since the generators are easily serviceable, they offer a long lifetime neutron generator for laboratories and commercial systems requiring continuous operation. Several of the generators have been enclosed in radiation shielding/moderator structures designed for customer specifications. These generators have been proven to be useful for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA) and fast neutron radiography. Thus these generators make excellent fast, epithermal and thermal neutron sources for laboratories and industrial applications that require neutrons with safe operation, small footprint, low cost and small regulatory burden.
Neutron Resonance Radiography for Explosives Detection: Technical Challenges
DOE Office of Scientific and Technical Information (OSTI.GOV)
Raas, W L; Blackburn, B; Boyd, E
2005-11-09
Fast Neutron Resonance Radiography (NRR) has recently become a focus of investigation as a supplement to conventional x-ray systems as a non-invasive, non-destructive means of detecting explosive material concealed in checked luggage or cargo containers at airports. Using fast (1-6 MeV) neutrons produced by the D(d,n){sup 3}He reaction, NRR provides both an imaging capability and the ability to determine the chemical composition of materials in baggage or cargo. Elemental discrimination is achieved by exploiting the resonance features of the neutron cross-section for oxygen, nitrogen, carbon, and hydrogen. Simulations have shown the effectiveness of multiple-element NRR through Monte Carlo transport methods;more » this work is focused on the development of a prototype system that will incorporate an accelerator-based neutron source and a neutron detection and imaging system to demonstrate the realistic capabilities of NRR in distinguishing the elemental components of concealed objects. Preliminary experiments have exposed significant technical difficulties unapparent in simulations, including the presence of image contamination from gamma ray production, the detection of low-fluence fast neutrons in a gamma field, and the mechanical difficulties inherent in the use of thin foil windows for gas cell confinement. To mitigate these concerns, a new gas target has been developed to simultaneously reduce gamma ray production and increase structural integrity in high flux gas targets. Development of a neutron imaging system and neutron counting based on characteristic neutron pulse shapes have been investigated as a means of improving signal to noise ratios, reducing irradiation times, and increasing the accuracy of elemental determination.« less