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Sample records for 660 mev protons

  1. Research program for the 660 MeV proton accelerator driven MOX-plutonium subcritical assembly

    NASA Astrophysics Data System (ADS)

    Barashenkov, V. S.; Buttsev, V. S.; Buttseva, G. L.; Dudarev, S. Ju.; Polanski, A.; Puzynin, I. V.; Sissakian, A. N.

    2000-07-01

    This paper presents the research program of the Experimental Accelerator Driven System (ADS), which employs a subcritical assembly and a 660 MeV proton accelerator operating in the Laboratory of Nuclear Problems at the Joint Institute for Nuclear Research in Dubna. Mixed-oxide (MOX) fuel (25% PuO2+75% UO2) designed for the BN-600 reactor use will be adopted for the core of the assembly. The present conceptual design of the experimental subcritical assembly is based on a core nominal unit capacity of 15 kW (thermal). This corresponds to the multiplication coefficient keff=0.945, energetic gain G=30, and accelerator beam power of 0.5 kW.

  2. Proton-Proton Scattering at 105 Mev and 75 Mev

    DOE R&D Accomplishments Database

    Birge, R. W.; Kruse, U. E.; Ramsey, N. F.

    1951-01-31

    The scattering of protons by protons provides an important method for studying the nature of nuclear forces. Recent proton-proton scattering experiments at energies as high as thirty Mev{sup 1} have failed to show any appreciable contribution to the cross section from higher angular momentum states, but it is necessary to bring in tensor forces to explain the magnitude of the observed cross section.

  3. Accelerator driven system based on plutonium subcritical reactor and 660 MeV phasotron

    SciTech Connect

    Arkhipov, V. A.; Barashenkov, V. S.; Buttsev, V. S.; Chultem, D.; Furman, V. I.; Maltsev, A. A.; Onischenko, L. M.; Pogodajev, G. N.; Popov, Yu. P.; Puzynin, I. V.; Sissakian, A. N.; Dudarev, S. Yu.; Gudowski, W.; Janczyszyn, J.; Polanski, A.; Taczanowski, S.

    1999-11-16

    The proposal presents a PLUTONIUM BASED ENERGY AMPLIFIER TESTING CONCEPT which employs a plutonium subcritical assembly and a 660 MeV proton accelerator, operating in the the JINR (Dubna, Russia). To make the present conceptual design of the Plutonium Energy Amplifier we have chosen a nominal unit capacity of 20 kW (thermal). This corresponds to the multiplication coefficient keff between 0.94 and 0.95 and the energetic gain about 20.

  4. Accelerator Driven System Based on Plutonium Subcritical Reactor and 660 MeV Phasotron

    SciTech Connect

    Arkhipov, V.A.; Barashenkov, V.S.; Buttsev, V.S.; Chultem, D.; Dudarev, S.Yu.; Furman, V.I.; Gudowski, W.; Janczyszyn, J.; Maltsev, A.A.; Onischenko, L.M.; Pogodajev, G.N.; Polanski, A.; Popov, Yu.P.; Puzynin, I.V.; Sissakian, A.N.; Taczanowski, S.

    1999-12-31

    The proposal presents a PLUTONIUM BASED ENERGY AMPLIFIER TESTING CONCEPT which employs a plutonium subcritical assembly and a 660 MeV proton accelerator. operating in the JINR (Dubna, Russia). To make the present conceptual design of the Plutonium Energy Amplifier we have chosen a nominal unit capacity of 20 kW (thermal). This corresponds to a multiplication coefficient, keff, between 0.94 and 0.95 and an energy gain about 20.

  5. Shielding measurements for 230-Mev protons

    SciTech Connect

    Siebers, J.V.; DeLuca, P.M. Jr.; Pearson, D.W. . Dept. of Medical Physics); Coutrakon, G. . Medical Center)

    1993-09-01

    Energetic neutrons, produced as protons interact with matter, dominate the radiation shielding environment for proton accelerators. Because of the scarcity of data describing the shielding required to protect personnel from these neutrons, absorbed dose and dose-equivalent values are measured as a function of depth in a thick concrete shield at neutron emission angles of 0, 22, 45, and 90 deg for 230-MeV protons incident upon stopping-length aluminum, iron, and lead targets. Neutron attenuation lengths vary sharply with angle but are independent of the target material. Comparing results with prior shielding calculations, the High-Energy Transport Code overestimates neutron production and attenuation lengths in the forward direction. Analytical methods compare favorably in the forward direction but overestimate the production and attenuation lengths at large angles. The results presented are useful for determining the shielding requirements for proton radiotherapy facilities and as a benchmark for future calculations.

  6. Parity Violation in Proton-Proton Scattering at 47 Mev.

    NASA Astrophysics Data System (ADS)

    Tanner, Danelle Mary

    A measurement of parity-violation in proton-proton scattering at 47 MeV has been completed by observing the longitudinal analyzing power. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). where (sigma)('+)((sigma)('-)) is the scattering cross section for positive (negative) helicity. Polarized protons from an atomic beam ion source were accelerated by the 224-cm Texas A&M University cyclotron to an energy of 50 MeV, producing a vertically polarized beam. A superconducting solenoid magnet precessed the beam polarization into the horizontal plane after which a 47.6(DEGREES) bending magnet precessed the polarization into the longtitudinal direction (p(,z) = 0.69 (+OR-) 0.02). RF transitions reversed the polarization direction every 21 msec. Protons scattered from the high pressure ((DBLTURN)37 atm), 42-cm long H(,2) gas target were detected by four plastic scintillators located in the target chamber. Photomultiplier tubes amplified the light from the scintillators, providing a signal proportional to the scattered beam intensity. A lock-in amplifier (LIA) synchronized to the spin-flip frequency compared the scattered intensity to the total beam intensity, measured with a Faraday cup. The output of the LIA was integrated for one second and then read by an ADC. Polarimeters were used to monitor both beam intensity and polarization profiles. A series of tests were performed to determine the role of spurious asymmetries due to changes in beam position and angle, and due to beam intensity modulations correlated with the spin reversal. The result after correction for beam intensity modulation was A(,z) = -(4.6 (+OR-) 2.6) x 10('-7). A more conservative result, taking into account all of the possible spurious asymmetries was A(,z) = -(4.6 (+OR-) 4.2) x 10('-7).

  7. A P + DEUTERON PROTON POLARIMETER AT 200 MEV.

    SciTech Connect

    HUANG,H.; ROSER,T.; ZELENSKI,A.; KURITA,K.; STEPHENSON,E.; TOOLE,R.

    2002-06-02

    There has been concern about the analyzing power of the p-Carbon polarimeter at the end of 200 MeV LINAC of BNL. A new polarimeter based on proton-deuteron scattering was installed and we have repeated the calibration of proton-Carbon scattering at 12 degrees and 200 MeV against proton-deuteron scattering. The result is consistent with the value of A=0.62 now used to measure the beam polarization at the end of the LINAC.

  8. Response of the Li-7-enriched Cs2LiYCl6:Ce (CLYC-7) scintillator to 6-60 MeV neutrons

    NASA Astrophysics Data System (ADS)

    Woolf, Richard S.; Hutcheson, Anthony L.; Phlips, Bernard F.; Wulf, Eric A.

    2015-12-01

    We discuss a test campaign designed to irradiate the 7Li-enriched Cs2LiYCl6:Ce3+ (CLYC-7) scintillator with 6-60 MeV neutrons using the cyclotron located at the Crocker Nuclear Laboratory in Davis, CA. CLYC-7 is a newly developed scintillator that exhibits the ability to make good γ-ray measurements and has the ability to detect and discriminate fast neutrons via pulse shape discrimination (PSD) while functioning as a spectrometer. This allows a single detector to make good measurement of both stimuli simultaneously. The response of this scintillation detector has been investigated below 20 MeV [1] but has yet to be explored for energies greater than 20 MeV. Understanding the spectral and pulse shape response across a broad energy range is important for any radiation detection instrumentation capable of detecting multiple species. At the highest energies sampled, the CLYC-7 PSD demonstrated not only the standard electron/proton separation expected in a mixed γ/n field but the ability to discriminate locally produced deuterons, tritons and α particles. We show the results from the four different neutron beam energies sampled during the experiment. Lastly, we present the results obtained for relating the light output equivalence between electrons and protons/deuterons.

  9. Magnifying lens for 800 MeV proton radiography

    SciTech Connect

    Merrill, F. E.; Campos, E.; Espinoza, C.; Hogan, G.; Hollander, B.; Lopez, J.; Mariam, F. G.; Morley, D.; Morris, C. L.; Murray, M.; Saunders, A.; Schwartz, C.; Thompson, T. N.

    2011-10-15

    This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.

  10. Measurement of the Wolfenstein parameters for proton-proton and proton-neutron scattering at 500 MeV

    SciTech Connect

    Marshall, J.A.

    1984-07-01

    Using liquid hydrogen and liquid deuterium targets respectively, forward angle (ten degrees to sixty degrees in the center of Mass) free proton-proton and quasielastic proton-proton and proton-neutron triple scattering data at 500 MeV have been obtained using the high resolution spectrometer at the Los Alamos Meson Physics Facility. The data are in reasonable agreement with recent predictions from phase shift analyses, indicating that the proton-nucleon scattering amplitudes are fairly well determined at 500 MeV. 32 references.

  11. Proton Polarimeter Calibration between 82 and 217 MeV

    SciTech Connect

    Glister, J; Lee, B; Beck, A; Brash, E; Camsonne, A; Choi, S; Dumas, J; Feuerbach, R; Gilman, R; Higinbotham, D W; Jiang, X; Jones, M K; May-Tal Beck, S; McCullough, E; Paolone, M; Piasetzky, E; Roche, J; Rousseau, Y; Sarty, A J; Sawatzky, B; Strauch, S

    2009-07-01

    The proton analyzing power in carbon has been measured for energies of 82 to 217 MeV and proton scattering angles of 5 to 41 degrees. The measurements were carried out using polarized protons from the elastic scattering H(pol. e, pol. p) reaction and the Focal Plane Polarimeter (FPP) in Hall A of Jefferson Lab. A new parameterization of the FPP p-C analyzing power was fit to the data, which is in good agreement with previous parameterizations and provides an extension to lower energies and larger angles. The main conclusions are that all polarimeters to date give consistent measurements of the carbon analyzing power, independently of the details of their construction and that measuring on a larger angular range significantly improves the polarimeter figure of merit at low energies.

  12. MeV proton flux predictions near Saturn's D ring

    NASA Astrophysics Data System (ADS)

    Kollmann, P.; Roussos, E.; Kotova, A.; Cooper, J. F.; Mitchell, D. G.; Krupp, N.; Paranicas, C.

    2015-10-01

    Radiation belts of MeV protons have been observed just outward of Saturn's main rings. During the final stages of the mission, the Cassini spacecraft will pass through the gap between the main rings and the planet. Based on how the known radiation belts of Saturn are formed, it is expected that MeV protons will be present in this gap and also bounce through the tenuous D ring right outside the gap. At least one model has suggested that the intensity of MeV protons near the planet could be much larger than in the known belts. We model this inner radiation belt using a technique developed earlier to understand Saturn's known radiation belts. We find that the inner belt is very different from the outer belts in the sense that its intensity is limited by the densities of the D ring and Saturn's upper atmosphere, not by radial diffusion and satellite absorption. The atmospheric density is relatively well constrained by EUV occultations. Based on that we predict an intensity in the gap region that is well below that of the known belts. It is more difficult to do the same for the region magnetically connected to the D ring since its density is poorly constrained. We find that the intensity in this region can be comparable to the known belts. Such intensities pose no hazard to the mission since Cassini would only experience these fluxes on timescales of minutes but might affect scientific measurements by decreasing the signal-to-contamination ratio of instruments.

  13. Shielding measurements for a 230 MeV proton beam

    SciTech Connect

    Siebers, J.V.

    1990-01-01

    Energetic secondary neutrons produced as protons interact with accelerator components and patients dominate the radiation shielding environment for proton radiotherapy facilities. Due to the scarcity of data describing neutron production, attenuation, absorbed dose, and dose equivalent values, these parameters were measured for 230 MeV proton bombardment of stopping length Al, Fe, and Pb targets at emission angles of 0{degree}, 22{degree}, 45{degree}, and 90{degree} in a thick concrete shield. Low pressure tissue-equivalent proportional counters with volumes ranging from 1 cm{sup 3} to 1000 cm{sup 3} were used to obtain microdosimetric spectra from which absorbed dose and radiation quality are deduced. Does equivalent values and attenuation lengths determined at depth in the shield were found to vary sharply with angle, but were found to be independent of target material. Neutron dose and radiation length values are compared with Monte Carlo neutron transport calculations performed using the Los Alamos High Energy Transport Code (LAHET). Calculations used 230 MeV protons incident upon an Fe target in a shielding geometry similar to that used in the experiment. LAHET calculations overestimated measured attenuation values at 0{degree}, 22{degree}, and 45{degree}, yet correctly predicted the attenuation length at 90{degree}. Comparison of the mean radiation quality estimated with the Monte Carlo calculations with measurements suggest that neutron quality factors should be increased by a factor of 1.4. These results are useful for the shielding design of new facilities as well as for testing neutron production and transport calculations.

  14. Predicting solar energetic proton events (E > 10 MeV)

    NASA Astrophysics Data System (ADS)

    NúñEz, Marlon

    2011-07-01

    A high level of proton radiation exposure can be dangerous to astronauts, satellite equipment, and air passengers/crew flying along polar routes. The presented solar energetic proton (SEP) event forecaster is based on a dual-model approach for predicting the time interval within which the integral proton flux is expected to meet or surpass the Space Weather Prediction Center threshold of J (E > 10 MeV) = 10 pr cm-2 sr-1 s-1 and the intensity of the first hours of well- and poorly connected SEP events. This forecaster analyzes flare and near-Earth space environment data (soft X-ray, differential and integral proton fluxes). The purpose of the first model is to identify precursors of well-connected events by empirically estimating the magnetic connectivity from the associated CME/flare process zone to the near-Earth environment and identifying the flare temporally associated with the phenomenon. The goal of the second model is to identify precursors of poorly connected events by using a regression model that checks whether the differential proton flux behavior is similar to that in the beginning phases of previous historically poorly connected SEP events and thus deduce similar consequences. An additional module applies a higher-level analysis for inferring additional information about the situation by filtering out inconsistent preliminary forecasts and estimating the intensity of the first hours of the predicted SEP events. The high-level module periodically retrieves solar data and, in the case of well-connected events, automatically identifies the associated flare and active region. For the events of solar cycles 22 and 23 of the NOAA/SWPC SEP list, the presented dual-model system, called UMASEP, has a probability of detection of all well- and poorly connected events of 80.72% (134/166) and a false alarm rate of 33.99% (69/203), which outperforms current automatic forecasters in predicting >10 MeV SEP events. The presented forecaster has an average warning time

  15. Flare vs. Shock Acceleration of >100 MeV Protons in Large Solar Particle Events

    NASA Astrophysics Data System (ADS)

    Cliver, Edward W.

    2016-05-01

    Recently several studies have presented correlative evidence for a significant-to-dominant role for a flare-resident process in the acceleration of high-energy protons in large solar particle events. In one of these investigations, a high correlation between >100 MeV proton fluence and 35 GHz radio fluence is obtained by omitting large proton events associated with relatively weak flares; these outlying events are attributed to proton acceleration by shock waves driven by coronal mass ejections (CMEs). We argue that the strong CMEs and associated shocks observed for proton events on the main sequence of the scatter plot are equally likely to accelerate high-energy protons. In addition, we examine ratios of 0.5 MeV electron to >100 MeV proton intensities in large SEP events, associated with both well-connected and poorly-connected solar eruptions, to show that scaled-up versions of the small flares associated with classical impulsive SEP events are not significant accelerators of >100 MeV protons.

  16. First experimental results from 2MeV proton tandem accelerator for neutron productiona)

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, A.; Belchenko, Yu.; Burdakov, A.; Davydenko, V.; Ivanov, A.; Khilchenko, A.; Konstantinov, S.; Krivenko, A.; Kuznetsov, A.; Mekler, K.; Sanin, A.; Shirokov, V.; Sorokin, I.; Sulyaev, Yu.; Tiunov, M.

    2008-02-01

    A 2MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction Li7(p,n)Be7 for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724MeV resonance gamma, which are produced via reaction C13(p,γ)N14, absorption in nitrogen.

  17. Radiation shielding for 250 MeV protons

    SciTech Connect

    Awschalom, M.

    1987-04-01

    This paper is targetted at personnel who have the responsibility of designing the radiation shielding against neutron fluences created when protons interact with matter. Shielding of walls and roofs are discussed, as well as neutron dose leakage through labyrinths. Experimental data on neutron flux attenuation are considered, as well as some calculations using the intranuclear cascade calculations and parameterizations.

  18. Medical Application of the SARAF-Proton/Deuteron 40 MeV Superconducting Linac

    SciTech Connect

    Halfon, Shlomi

    2007-11-26

    The Soreq Applied Research Accelerator Facility (SARAF) is based on a superconducting linear accelerator currently being built at the Soreq research center (Israel). The SARAF is planned to generate a 2 mA 4 MeV proton beam during its first year of operation and up to 40 MeV proton or deuteron beam in 2012. The high intensity beam, together with the linac ability to adjust the ion energy provides opportunities for medical research, such as Boron Neutron Capture Therapy (BNCT) and the production of medical radioisotopes, for instance {sup 103}Pd for prostate brachytherapy.

  19. 1000 MeV Proton beam therapy facility at Petersburg Nuclear Physics Institute Synchrocyclotron

    NASA Astrophysics Data System (ADS)

    Abrosimov, N. K.; Gavrikov, Yu A.; Ivanov, E. M.; Karlin, D. L.; Khanzadeev, A. V.; Yalynych, N. N.; Riabov, G. A.; Seliverstov, D. M.; Vinogradov, V. M.

    2006-05-01

    Since 1975 proton beam of PNPI synchrocyclotron with fixed energy of 1000 MeV is used for the stereotaxic proton therapy of different head brain diseases. 1300 patients have been treated during this time. The advantage of high energy beam (1000 MeV) is low scattering of protons in the irradiated tissue. This factor allows to form the dose field with high edge gradients (20%/mm) that is especially important for the irradiation of the intra-cranium targets placed in immediate proximity to the life critical parts of the brain. Fixation of the 6 0mm diameter proton beam at the isodose centre with accuracy of ±1.0 mm, two-dimensional rotation technique of the irradiation provide a very high ratio of the dose in the irradiation zone to the dose at the object's surface equal to 200:1. The absorbed doses are: 120-150 Gy for normal hypophysis, 100-120 Gy for pituitary adenomas and 40-70 Gy for arterio-venous malformation at the rate of absorbed dose up to 50 Gy/min. In the paper the dynamics and the efficiency of 1000 MeV proton therapy treatment of the brain deceases are given. At present time the feasibility study is in progress with the goal to create a proton therapy on Bragg peak by means of the moderation of 1000 MeV proton beam in the absorber down to 200 MeV, energy required for radiotherapy of deep seated tumors.

  20. Spectral measurements of neutrons produced by 52 MeV protons with activation detectors

    NASA Astrophysics Data System (ADS)

    Shin, Kazuo; Saito, Takatsugu; Fujii, Masahiko; Nakamura, Takashi

    The accuracy of the neutron spectral measurement of energy up to ˜40 MeV with activation detectors was examined using high energy neutrons from thick targets bombarded by 52 MeV protons. The measured activation rates were unfolded with the modified SAND-II code and compared with the neutron spectra measured by the NE-213 scintillator. Quite good agreement in absolute values was obtained between the spectra recorded by these two different detectors. The activation detector was shown to be useful for neutron spectroscopy at energies higher than ˜ 10 MeV.

  1. The Single Event Upset (SEU) response to 590 MeV protons

    NASA Technical Reports Server (NTRS)

    Nichols, D. K.; Price, W. E.; Smith, L. S.; Soli, G. A.

    1984-01-01

    The presence of high-energy protons in cosmic rays, solar flares, and trapped radiation belts around Jupiter poses a threat to the Galileo project. Results of a test of 10 device types (including 1K RAM, 4-bit microP sequencer, 4-bit slice, 9-bit data register, 4-bit shift register, octal flip-flop, and 4-bit counter) exposed to 590 MeV protons at the Swiss Institute of Nuclear Research are presented to clarify the picture of SEU response to the high-energy proton environment of Jupiter. It is concluded that the data obtained should remove the concern that nuclear reaction products generated by protons external to the device can cause significant alteration in the device SEU response. The data also show only modest increases in SEU cross section as proton energies are increased up to the upper limits of energy for both the terrestrial and Jovian trapped proton belts.

  2. 200 MeV Proton Radiography Studies with a Hand Phantom Using a Prototype Proton CT Scanner

    PubMed Central

    Plautz, Tia; Bashkirov, V.; Feng, V.; Hurley, F.; Johnson, R.P.; Leary, C.; Macafee, S.; Plumb, A.; Rykalin, V.; Sadrozinski, H.F.-W.; Schubert, K.; Schulte, R.; Schultze, B.; Steinberg, D.; Witt, M.; Zatserklyaniy, A.

    2014-01-01

    Proton radiography has applications in patient alignment and verification procedures for proton beam radiation therapy. In this paper, we report an experiment which used 200 MeV protons to generate proton energy-loss and scattering radiographs of a hand phantom. The experiment used the first-generation proton CT scanner prototype, which was installed on the research beam line of the clinical proton synchrotron at Loma Linda University Medical Center (LLUMC). It was found that while both radiographs displayed anatomical details of the hand phantom, the energy-loss radiograph had a noticeably higher resolution. Nonetheless, scattering radiography may yield more contrast between soft and bone tissue than energy-loss radiography, however, this requires further study. This study contributes to the optimization of the performance of the next-generation of clinical proton CT scanners. Furthermore, it demonstrates the potential of proton imaging (proton radiography and CT), which is now within reach of becoming available as a new, potentially low-dose medical imaging modality. PMID:24710156

  3. 200 MeV proton radiography studies with a hand phantom using a prototype proton CT scanner.

    PubMed

    Plautz, Tia; Bashkirov, V; Feng, V; Hurley, F; Johnson, R P; Leary, C; Macafee, S; Plumb, A; Rykalin, V; Sadrozinski, H F-W; Schubert, K; Schulte, R; Schultze, B; Steinberg, D; Witt, M; Zatserklyaniy, A

    2014-04-01

    Proton radiography has applications in patient alignment and verification procedures for proton beam radiation therapy. In this paper, we report an experiment which used 200 MeV protons to generate proton energy-loss and scattering radiographs of a hand phantom. The experiment used the first-generation proton computed tomography (CT) scanner prototype, which was installed on the research beam line of the clinical proton synchrotron at Loma Linda University Medical Center. It was found that while both radiographs displayed anatomical details of the hand phantom, the energy-loss radiograph had a noticeably higher resolution. Nonetheless, scattering radiography may yield more contrast between soft and bone tissue than energy-loss radiography, however, this requires further study. This study contributes to the optimization of the performance of the next-generation of clinical proton CT scanners. Furthermore, it demonstrates the potential of proton imaging (proton radiography and CT), which is now within reach of becoming available as a new, potentially low-dose medical imaging modality. PMID:24710156

  4. Proton irradiation of conventional and lithium solar cells - 11-37 MeV

    NASA Technical Reports Server (NTRS)

    Anspaugh, B. E.; Carter, J. R.

    1974-01-01

    Conventional n/p and lithium solar cells were irradiated with 11- to 37-MeV protons. The energy dependence of the solar cell degradation, calculated from electrical parameters and lifetime measurements, is shown to be very slight. Damage coefficients for the n/p cells are calculated. Annealing characteristics of both the lithium cells and the n/p cells are presented.

  5. Dose distribution outside the target volume for 170-MeV proton beam.

    PubMed

    Pachnerová Brabcová, K; Ambrožová, I; Kubančák, J; Puchalska, M; Vondráček, V; Molokanov, A G; Sihver, L; Davídková, M

    2014-10-01

    Dose delivered outside the proton field during radiotherapy can potentially lead to secondary cancer development. Measurements with a 170-MeV proton beam were performed with passive detectors (track etched detectors and thermoluminescence dosemeters) in three different depths along the Bragg curve. The measurement showed an uneven decrease of the dose outside of the beam field with local enhancements. The major contribution to the delivered dose is due to high-energy protons with linear energy transfer (LET) up to 10 keV µm(-1). However, both measurement and preliminary Monte Carlo calculation also confirmed the presence of particles with higher LET. PMID:24759915

  6. Calculations of neutron shielding data for 10-100 MeV proton accelerators.

    PubMed

    Chen, C C; Sheu, R J; Jian, S H

    2005-01-01

    The characteristics of neutron sources and their attenuation in concrete were investigated in detail for protons with energies ranging from 10 to 100 MeV striking on target materials of C, N, Al, Fe, Cu and W. A two-step approach was adopted: thick-target double-differential neutron yields were first calculated from the (p, xn) cross sections recommended in the ICRU Report 63; further, transport simulations of those neutrons in concrete were performed by using the FLUKA Monte Carlo code. The purpose of this study is to provide reasonably accurate parameters for shielding design for 10-100 MeV proton accelerators. Source terms and the corresponding attenuation lengths in concrete for several target materials are given as a function of proton energies and neutron emission angles. PMID:16604637

  7. The response of CR-39 nuclear track detector to 1-9 MeV protons

    DOE PAGESBeta

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Johnson, M. Gatu; Seguin, F. H.; Frenje, J. A.; et al

    2011-10-28

    The response of CR-39 nuclear track detector (TasTrak®) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. The effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather thanmore » the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.« less

  8. Analysing powers and spin correlations in deuteron-proton charge exchange at 726 MeV

    NASA Astrophysics Data System (ADS)

    Dymov, S.; Azaryan, T.; Bagdasarian, Z.; Barsov, S.; Carbonell, J.; Chiladze, D.; Engels, R.; Gebel, R.; Grigoryev, K.; Hartmann, M.; Kacharava, A.; Khoukaz, A.; Komarov, V.; Kulessa, P.; Kulikov, A.; Kurbatov, V.; Lomidze, N.; Lorentz, B.; Macharashvili, G.; Mchedlishvili, D.; Merzliakov, S.; Mielke, M.; Mikirtychyants, M.; Mikirtychyants, S.; Nioradze, M.; Ohm, H.; Prasuhn, D.; Rathmann, F.; Serdyuk, V.; Seyfarth, H.; Shmakova, V.; Ströher, H.; Tabidze, M.; Trusov, S.; Tsirkov, D.; Uzikov, Yu.; Valdau, Yu.; Weidemann, C.; Wilkin, C.

    2015-05-01

    The charge exchange of vector polarised deuterons on a polarised hydrogen target has been studied in a high statistics experiment at the COSY-ANKE facility at a deuteron beam energy of Td = 726 MeV. By selecting two fast protons at low relative energy Epp, the measured analysing powers and spin correlations are sensitive to interference terms between specific neutron-proton charge-exchange amplitudes at a neutron kinetic energy of Tn ≈1/2Td = 363 MeV. An impulse approximation calculation, which takes into account corrections due to the angular distribution in the diproton, describes reasonably the dependence of the data on both Epp and the momentum transfer. This lends broad support to the current neutron-proton partial wave solution that was used in the estimation.

  9. A new proton fluence model for E greater than 10 MeV

    NASA Technical Reports Server (NTRS)

    Feynman, Joan; Armstrong, T. P.; Dao-Gibner, L.; Silverman, S.

    1988-01-01

    Researchers describe a new engineering model for the fluence of protons with energies greater than 10 MeV. The data set used is a combination of observations made primarily from the Earth's surface between 1956 and 1963 and observations made from spacecraft in the vicinity of Earth between 1963 and 1985. With this data set we find that the distinction between ordinary proton events and anomalously large proton events made in earlier work disappears. The greater than 10 MeV fluences at 1 AU calculated with the new model are about twice those expected on the basis of models now in use. In contrast to earlier models, results do not depend critically on the fluence from any one event.

  10. The response of CR-39 nuclear track detector to 1-9 MeV protons

    SciTech Connect

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Johnson, M. Gatu; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.

    2011-10-28

    The response of CR-39 nuclear track detector (TasTrak®) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. The effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather than the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.

  11. Filamentation control and collimation of laser accelerated MeV protons

    NASA Astrophysics Data System (ADS)

    Ramakrishna, B.; Tayyab, M.; Bagchi, S.; Mandal, T.; Upadhyay, A.; Weng, S. M.; Murakami, M.; Cowan, T. E.; Chakera, J. A.; Naik, P. A.; Gupta, P. D.

    2015-12-01

    We demonstrate experimentally that the proton beam filamentation in dense plasma can be controlled in multi-layered (Al-CH-Al) sandwich targets. We observe up to three-fold reduction in the MeV proton beam divergence (~12°) from these targets as a result of decrease in filamentary structures in the proton beam profile. Strong self-generated resistive magnetic fields in targets with a high-Z transport layer are mainly responsible for this observed effect. Enhancement in the proton flux and energy is also observed from these targets. Supported by a matching 2D particle-in-cell (PIC) simulation and theoretical considerations, we suggest that these targets can be very effectively implemented to collimate proton beams useful for ion oncology applications or advanced fast igniter approach of inertial confinement fusion (ICF).

  12. Neutron transition densities for 48Ca from proton scattering at 200 and 318 MeV

    NASA Astrophysics Data System (ADS)

    Feldman, A. E.; Kelly, J. J.; Flanders, B. S.; Khandaker, M. A.; Seifert, H.; Boberg, P.; Hyman, S. D.; Karen, P. H.; Norum, B. E.; Welch, P.; Chen, Q.; Bacher, A. D.; Berg, G. P.; Stephenson, E. J.; Nanda, S.; Saha, A.; Scott, A.

    1994-04-01

    Differential cross sections and analyzing powers for scattering of 200 and 318 MeV protons have been measured for states of 48Ca up to 7 MeV of excitation. The data cover c.m. momentum transfers from approximately 0.4 to 3.0 fm-1. Neutron transition densities were extracted for the 2+1,3-1,3-2,4+2, and 5-1 states using density-dependent empirical effective interactions previously calibrated upon elastic and inelastic scattering data for 16O and 40Ca. The corresponding proton transition densities were obtained from electron scattering data and held fixed during the analysis. Fits performed to the data for either energy provide excellent predictions for the other. Neutron densities fitted to data for either energy independently agree very well with each other and with the densities fitted to both data sets simultaneously. These densities are also consistent with earlier data for 500 MeV protons. The energy-independence of the extracted transition densities demonstrates that residual errors in the reaction model are compatible with the error bands estimated by the fitting procedure. Several additional tests of the model dependence of the results were performed also. The proton and neutron transition densities are compared with calculations based upon the extended random phase approximation, which includes 2p2h correlations. These calculations are most successful for densities dominated by 1p1h configurations, whereas densities requiring substantial 2p2h contributions tend to be underestimated.

  13. Experimental evidence of the superfocusing effect for axially channeled MeV protons

    NASA Astrophysics Data System (ADS)

    Motapothula, M.; Petrović, S.; Nešković, N.; Breese, M. B. H.

    2016-08-01

    Sub-Ångström focusing of megaelectronvolt (MeV) ions within axial channels was predicted over 10 years ago, but evidence proved elusive. We present experimental angular distributions of axially channeled MeV protons in a 55-nm-thick (001) silicon membrane through which multiple scattering is negligible. Fine angular structure is in excellent agreement with Monte Carlo simulations based on three interaction potentials, providing indirect evidence of the existence of the superfocusing effect with flux enhancement of around 800 within a focused beam width of ˜20 pm .

  14. First experimental results from 2 MeV proton tandem accelerator for neutron production

    SciTech Connect

    Kudryavtsev, A.; Belchenko, Yu.; Burdakov, A.; Davydenko, V.; Ivanov, A.; Khilchenko, A.; Konstantinov, S.; Krivenko, A.; Kuznetsov, A.; Mekler, K.; Sanin, A.; Shirokov, V.; Sorokin, I.; Sulyaev, Yu.; Tiunov, M.

    2008-02-15

    A 2 MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction {sup 7}Li(p,n){sup 7}Be for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724 MeV resonance gamma, which are produced via reaction {sup 13}C(p,{gamma}){sup 14}N, absorption in nitrogen.

  15. Effects of 3 MeV proton irradiation on the mechanical properties of polyimide films

    NASA Astrophysics Data System (ADS)

    Hill, David J. T.; Hopewell, Jefferson L.

    1996-11-01

    The effects of 3 MeV proton irradiation on the elongation to break, fracture energy and Young's Modulus have been investigated for films of Kapton and Ultem over the dose range 0-75 MGy at ambient temperature. The results have been compared with those reported by other workers for irradiation by 60Co gamma rays and 2 MeV electron beams under similar conditions, and little difference was found between the damage to the mechanical properties of the films induced by these three beam types.

  16. First experimental results from 2 MeV proton tandem accelerator for neutron production.

    PubMed

    Kudryavtsev, A; Belchenko, Yu; Burdakov, A; Davydenko, V; Ivanov, A; Khilchenko, A; Konstantinov, S; Krivenko, A; Kuznetsov, A; Mekler, K; Sanin, A; Shirokov, V; Sorokin, I; Sulyaev, Yu; Tiunov, M

    2008-02-01

    A 2 MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction (7)Li(p,n)(7)Be for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724 MeV resonance gamma, which are produced via reaction (13)C(p,gamma)(14)N, absorption in nitrogen. PMID:18315262

  17. Absolute polarimeter for the proton-beam energy of 200 MeV

    SciTech Connect

    Zelenski, A. N.; Atoian, G.; Bogdanov, A. A.; Nurushev, S. B.; Pylaev, F. S.; Raparia, D.; Runtso, M. F.; Stephenson, E.

    2013-12-15

    A polarimeter is upgraded and tested in a 200-MeV polarized-proton beam at the accelerator-collider facility of the Brookhaven National Laboratory. The polarimeter is based on the elastic polarizedproton scattering on a carbon target at an angle of 16.2°, in which case the analyzing power is close to unity and was measured to a very high degree of precision. It is shown that, in the energy range of 190–205 MeV, the absolute polarization can be measured to a precision better than ±0.5%.

  18. Transport mechanism of MeV protons in tapered glass capillaries

    SciTech Connect

    Hasegawa, Jun; Oguri, Yoshiyuki; Jaiyen, Sarawut; Polee, Chalermpong; Chankow, Nares

    2011-08-15

    To investigate the transport mechanism of MeV protons in tapered glass capillaries, spatially resolved energy spectra were measured for proton microbeams focused by 20-{mu}m-outlet capillaries having various taper angles. Three-dimensional Monte Carlo (MC) simulations were also performed to support the experiments and trace each particle in the capillary in more detail. The dependence of the proton energy distribution on the outgoing angle proved that the capillary-focused proton beam consists of two different components, protons traveling straight through the capillary without colliding with the capillary wall and protons scattered by the capillary inner wall. Moreover, the focusing effect of the tapered glass capillary was found to be mainly due to the scattered beam component. The MC simulations well reproduced the experimental results and showed that beam focusing ratios of 1.6-2.4 are possible with capillaries having a convex inner wall. The flight distance of the scattered proton in the capillary glass body was found to play an important role in determining transport efficiency of the protons through the capillary.

  19. The dependence of single event upset on proton energy /15-590 MeV/

    NASA Technical Reports Server (NTRS)

    Nichols, D. K.; Price, W. E.; Andrews, J. L.

    1982-01-01

    Low earth orbit satellite and Jupiter orbiter probe semiconductor devices may incur soft errors or single event upsets, manifested as bit flips, during exposure to such nuclear particles or heavy ions as trapped protons with energies ranging up to 1000 MeV. Experimental data is given on the average proton fluence needed to cause a bit flip as a function of proton energy for isoplanar bipolar TTL RAMs. Error dependence data shape and threshold energy can be related to the existing body of theoretical data on energy deposition following proton nuclear reactions. Experimental data also show that the relative cross sectional amplitude for functionally identical devices can be related to the device's power consumption.

  20. Preliminary shielding assessment for the 100 MeV proton linac (KOMAC).

    PubMed

    Lee, Young-Ouk; Cho, Y S; Chang, J

    2005-01-01

    The Proton Engineering Frontier Project is building the Korea Multipurpose Accelerator Complex facilities from 2002 to 2012, which consists of a high-current 100 MeV proton linear accelerator and various beam-lines. This paper provides a preliminary estimate of the shielding required for the 20 mA proton linac and the beam-dump. For an accurate information on secondary neutron production from the guiding magnet and primary heat sink of the beam dump, proton-induced 63Cu and 65Cu cross section data were evaluated and applied to shielding calculations. The required thickness of the concrete was assessed by a simple line-of-sight model for the lateral shielding of the beam-line and the full shielding of the beam dump. Monte Carlo simulations were also performed using the MCNPX code to obtain the source term and attenuation coefficients for the three-dimensional lateral shielding model of the beam-line. PMID:16381787

  1. Radiation pressure acceleration of protons to 93 MeV with circularly polarized petawatt laser pulses

    NASA Astrophysics Data System (ADS)

    Kim, I. Jong; Pae, Ki Hong; Choi, Il Woo; Lee, Chang-Lyoul; Kim, Hyung Taek; Singhal, Himanshu; Sung, Jae Hee; Lee, Seong Ku; Lee, Hwang Woon; Nickles, Peter V.; Jeong, Tae Moon; Kim, Chul Min; Nam, Chang Hee

    2016-07-01

    The radiation pressure acceleration (RPA) of charged particles has been a challenging task in laser-driven proton/ion acceleration due to its stringent requirements in laser and target conditions. The realization of radiation-pressure-driven proton acceleration requires irradiating ultrathin targets with an ultrahigh contrast and ultraintense laser pulses. We report the generation of 93-MeV proton beams achieved by applying 800-nm 30-fs circularly polarized laser pulses with an intensity of 6.1 × 10 20 W / cm 2 to 15-nm-thick polymer targets. The radiation pressure acceleration was confirmed from the obtained optimal target thickness, quadratic energy scaling, polarization dependence, and three-dimensional particle-in-cell simulations. We expect this clear demonstration of RPA to facilitate the realization of laser-driven proton/ion sources delivering energetic and short-pulse particle beams for novel applications.

  2. Radiation accompanying the absorption of 2-MeV protons in various materials

    NASA Astrophysics Data System (ADS)

    Kasatov, D. A.; Makarov, A. N.; Taskaev, S. Yu.; Shchudlo, I. M.

    2015-11-01

    For the development of boron neutron-capture therapy of malignant tumors, a source of epithermal neutrons on the basis of a tandem accelerator with a vacuum insulation and a lithium target was created and launched. With the aim of optimizing the neutron-producing target, various structure materials were irradiated with a proton beam. The results obtained bymeasuring the dose rate and radiation spectrum upon the absorption of 2-MeV protons are presented, and the choice of tantalum for an optimum material of the target substrate was explained.

  3. Isotopic production cross sections in proton-nucleus collisions at 200 MeV

    SciTech Connect

    Machner, H.; Aschman, D.G.; Steyn, D.; Baruth-Ram, K.; Carter, J.; Sideras-Haddad, E.; Sellschop, J.P.F.; Cowley, A.A.; Goldenbaum, F.; Nangu, B.M.; Spoelstra, B.; Pilcher, J.V.; Smit, F.D.

    2006-04-15

    Intermediate-mass fragments from the interaction of {sup 27}Al, {sup 59}Co, and {sup 197}Au with 200-MeV protons were measured in an angular range from 20 deg. to 120 deg. in the laboratory system. The fragments, ranging from isotopes of helium up to isotopes of carbon, were isotopically resolved. Double-differential cross sections, energy-differential cross sections, and total cross sections were extracted.

  4. Effects of 22 MeV protons on single junction and silicon controlled rectifiers

    NASA Technical Reports Server (NTRS)

    Beatty, M. E., III

    1972-01-01

    The effects of 22-MeV protons on various types of silicon single junction and silicon controlled rectifiers were investigated. The results show that low-leakage devices and silicon controlled rectifiers are the most susceptable to radiation damage. There are also differences noted between single junction rectifiers of the same type made by different manufacturers, which emphasizes the need for better selection of devices used in spacecraft.

  5. RF phase stability in the 100-MeV proton linac operation

    NASA Astrophysics Data System (ADS)

    Seol, Kyung-Tae

    2015-02-01

    The 100-MeV proton linac of the Korea multi-purpose accelerator complex (KOMAC) has been operated to provide a proton beam to users. The 100-MeV linac consists of a 3-MeV radio-frequency quadrupole accelerator (RFQ), four 20-MeV drift-tube linac (DTL) tanks, two medium-energy beam-transmitter (MEBT) tanks, and seven 100-MeV DTL tanks. The requirements of the field stability are within ±1% in RF amplitude and ±1 degree in RF phase. The RF phase stability is influenced by a RF reference line, RF transmission lines, and a RF control system. The RF reference signal is chosen to be a 300-MHz local oscillator (LO) signal, and a rigid copper coaxial line with temperature control was installed for an RF reference distribution. A phase stability of ±0.1 degrees was measured under a temperature change of ±0.1 °C. A digital feedback control system with a field-programmable gate-array (FPGA) module was adopted for a high RF stability. The RF phase was maintained within ±0.1 degrees with a dummy cavity and was within ±0.3 degrees at RFQ operation. In the case of the 20-MeV DTL tanks, one klystron drives 4 tanks, and the input phases of 4 tanks were designed to be in phase. The input phases of 4 tanks were fixed within ±1 degree by adjusting a phase shifter in each waveguide.

  6. Occurrence of brain tumors in rhesus monkeys exposed to 55-MeV protons

    NASA Astrophysics Data System (ADS)

    Wood, D. H.; Yochmowitz, M. G.; Hardy, K. A.; Salmon, Y. L.

    Twenty-year observation of monkeys exposed to single doses of high energy protons simulating solar particles revealed that the most prevalent fatal cancers were brain tumors in the group of animals exposed to 55-MeV protons. Of 72 animals (50 males and 22 females) receiving 0.25 to 8.0 Gy total body surface dose, nine developed fatal tumors classified as grade IV astrocytoma or glioblastoma multiforme. The latent period for tumor development ranged from 14 months to 20 years, with a median of 5 years. Doses associated with the tumors were 4.0 to 8.0 Gy. Eight males and one female were affected. Depth-dose determinations suggest that the high incidence of cerebral neoplasia is associated with the Bragg Peak energy distribution of the 55-MeV protons. Comparison of the tumor incidence with that in humans with brain exposures incidental to radiotherapy indicates a high biological effectiveness compared with gamma radiation. Studies are in progress to attempt to replicate the results in rodents and establish a dose-response curve for proton-induced brain tumors.

  7. A statistical survey of 5-MeV proton events at transient interplanetary shocks

    NASA Astrophysics Data System (ADS)

    Kallenrode, May-Britt

    1996-11-01

    Between 1974 and 1985 the two Helios spacecraft observed 351 transient interplanetary shocks. For 5-MeV protons the particle events associated with these shocks can be divided into three groups: (1) events without intensity increase above quiet time or increased background (47%), (2) solar and interplanetary particle (SIP) events consisting of particles accelerated on or close to the Sun (solar or near-Sun component) as well as at the interplanetary shock (24%), and (3) pure interplanetary particle (PIP) events (29%) which consist of particles accelerated at the shock in interplanetary space but do not show evidence for significant or even excess particle acceleration on the Sun. This classification shows that (1) only about half of the shocks accelerate MeV protons in interplanetary space and (2) MeV protons accelerated on the Sun are neither a necessary nor a sufficient condition for the acceleration of MeV protons in interplanetary space. Shock parameters such as speed or shock strength alone do not give an indication for the class of the associated particle event, because in the parameter range which covers most of the shocks, all three classes are distributed rather evenly. However, the shocks strongest in these parameters tend to accelerate particles. The intensity at the time of shock-passage, which can be used as a crude measure for the local acceleration efficiency, is correlated with the local shock speed and the magnetic compression. The correlation coefficients are small but statistically significant, indicating that (1) the correlations are real and (2) the intensity is influenced by additional parameters, which are not necessarily shock inherent. As an example I will show that the local acceleration at the shock decreases roughly symmetrically with increasing distance from the nose of the shock with a median e-folding angle of 10°. Occasionally, larger e-folding angles are observed close to the nose of the shock. The question of how the shock

  8. Modification of radiobiological effects of 171 MeV protons by elements of physical protection

    NASA Astrophysics Data System (ADS)

    Bulinina, Taisia; Shurshakov, Vyacheslav; Ivanov, Alexander; Molokanov, Alexander

    2016-07-01

    Space radiation includes protons of various energies. Physical protection is effective in the case of low energy protons (50-100 MeV) and becomes insufficient for radiation with a high part of high-energy protons. In the experiment performed on outbred mice, the purpose of the study was to evaluate the radiobiological effect of 171 MeV protons and protons modified by elements of physical protection of the spacecraft, on a complex of indicators of the functional condition of the system hematopoiesis and the central nervous system in 24 hours after irradiation at 20 cGy dose. The spacecraft radiation protection elements used in the experiment were a construction of wet hygiene wipes called a «protective curtain», and a glass plate imitating an ISS window. Mass thickness of the " protective curtain" in terms of water equivalent was ̴ 6,2 g/cm2. Physical shielding along the path of 171 MeV protons increases their linear energy transfer leading to the absorbed dose elevation and strengthening of the radiobiological effect. In the experiment, the two types of shielding together raised the absorbed dose from 20 to 23.2 cGy. Chemically different materials (glass and water in the wipes) were found to exert unequal modifying effects on physical and biological parameters of the proton-irradiated mice. There was a distinct dose-dependent reduction of bone marrow cellularity within the dose range from 20 cGy to 23.2 cGy in 24 hours after exposure. No modifying effect of the radiation protection elements on spontaneous motor activity was discovered when compared with entrance protons. The group of animals protected by the glass plate exhibited normal orientative-trying reactions and weakened grip with the forelimbs. The effects observed in the experiment indicate the necessity to carry out comprehensive radiobiological researches (physical, biological and mathematical) in assessing the effects of physical protection, that are actual for ensuring radiation safety of crews in

  9. Radiation effects induced in pin photodiodes by 40- and 85-MeV protons

    NASA Technical Reports Server (NTRS)

    Becher, J.; Kernell, R. L.; Reft, C. S.

    1985-01-01

    PIN photodiodes were bombarded with 40- and 85-MeV protons to a fluence of 1.5 x 10 to the 11th power p/sq cm, and the resulting change in spectral response in the near infrared was determined. The photocurrent, dark current and pulse amplitude were measured as a function of proton fluence. Changes in these three measured properties are discussed in terms of changes in the diode's spectral response, minority carrier diffusion length and depletion width. A simple model of induced radiation effects is presented which is in good agreement with the experimental results. The model assumes that incident protons produce charged defects within the depletion region simulating donor type impurities.

  10. Anomalous effects in silicon solar cell irradiated by 1-MeV protons

    NASA Technical Reports Server (NTRS)

    Kachare, R.; Anspaugh, B. E.

    1989-01-01

    Several silicon solar cells having thicknesses of approximately 63 microns, with and without back-surface fields (BSF), were irradiated with 1-MeV protons having fluences between 10 to the 10th and 10 to the 12th sq cm. The irradiations were performed using both normal and isotropic incidence on the rear surfaces of the cells. It was observed that after irradiation with fluences greater than 10 to the 11th protons/sq cm, all BSF cells degraded at a faster rate than cells without BSF. The irradiation results are analyzed using a model in which irradiation-induced defects in the BSF region are taken into account. Tentatively, it is concluded that an increase in defect density due to the formation of aluminum and proton complexes in BSF cells is responsible for the higher-power loss in the BSF cells compared to the non-BSF cells.

  11. Results of hybrid photodiode irradiation by 200 MeV protons

    SciTech Connect

    Baumbaugh A. et al.

    2001-12-03

    Hybrid Photodiodes (HPD, [1]) will be used as the photodetector for the Compact Muon Solenoid (CMS) Hadron Calorimeter (HCAL) readout [2]. The HPDs are required to operate in a high radiation environment, where the HCAL detector will receive a total ionizing dose of about 330 rads and a fluence of 4 x 10{sup 11} n/cm{sup 2} over a 10 year running period [3]. Effects of HPD irradiation by low energy neutrons were studied and reported previously [1]. In these studies, high energy protons are used to study possible effects of single event burnout [4], since high energy protons are more likely to induce large energy transfer within the HPD silicon. The HPDs were irradiated by 200 MeV protons at the Indiana University Cyclotron Facility [IUCF, 5]. The results of the study are presented.

  12. Response of Cellulose detectors to different doses of 62 MeV protons

    NASA Astrophysics Data System (ADS)

    Tripathy, S. P.; Mishra, R.; Dwivedi, K. K.; Ghosh, S.; Fink, D.; Khathing, D. T.

    2003-08-01

    Optical and thermal responses of two cellulose detectors, Cellulose triacetate (Triafol-TN) and Cellulose acetate butyrate (Triafol-BN), to four different doses of 62 MeV protons were studied using spectroscopic, thermal and track-etching techniques. The spectroscopic analysis revealed that though the optical band-gap in the polymers was affected by proton irradiation, the polymers showed high resistance against any major structural modification by radiation. The thermal stability of the polymers was found to be affected by proton irradiation. The activation energy of etching was found to be almost constant for both the polymers even after irradiation. It is hoped that the findings in this work would be of significant relevance to material science and applications of polymers.

  13. Single event upsets calculated from new ENDF/B-VI proton and neutron data up to 150 MeV

    SciTech Connect

    Chadwick, M.B.; Normand, E.

    1999-06-01

    Single-event upsets (SEU) in microelectronics are calculated from newly-developed silicon nuclear reaction recoil data that extend up to 150 MeV, for incident protons and neutrons. Calculated SEU cross sections are compared with measured data.

  14. A 100 MeV Multi-Tank Drift Tube Linac for the Linear Proton Accelerator of the Energy Amplifier

    NASA Astrophysics Data System (ADS)

    D'Auria, Gerardo; Rossi, Carlo

    1997-05-01

    For the acceleration of protons from the exit of the RFQ at about 6 MeV up to 100 MeV, a Multi-Tank Drift Tube Linac (MTDTL) has been proposed with the goal of being technologically simple, compact, efficient and economical. Theoretical design studies and first measurements on a prototype tank are presented.

  15. Proton-nucleus total inelastic cross sections - An empirical formula for E greater than 10 MeV

    NASA Technical Reports Server (NTRS)

    Letaw, J. R.; Silberberg, R.; Tsao, C. H.

    1983-01-01

    An empirical formula for the total inelastic cross section of protons on nuclei with charge greater than 1 is presented. The formula is valid with a varying degree of accuracy down to proton energies of 10 MeV. At high energies (equal to or greater than 2 GeV) the formula reproduces experimental data to within reported errors (about 2%).

  16. An 800-MeV proton radiography facility for dynamic experiments

    SciTech Connect

    King, N.S.P.; Adams, K.; Ables, E.

    1998-12-01

    The capability has been successfully developed at the Los Alamos Nuclear Science Center (LANSCE) to utilize a spatially and temporally prepared 800-MeV proton beam to produce proton radiographs. A series of proton bursts are transmitted through a dynamically varying object and transported, via a unique magnetic lens system, to an image plane. The magnetic lens system permits correcting for the effects of multiple coulomb scattering which would otherwise completely blur the spatially transmitted information at the image plane. The proton radiographs are recorded on either a time integrating film plate or with a recently developed multi-frame electronic imaging camera system. The latter technique permits obtaining a time dependent series of proton radiographs with time intervals (modulo 358 ns) up to many microseconds and variable time intervals between images. One electronically shuttered, intensified, CCD camera is required per image. These cameras can detect single protons interacting with a scintillating fiber optic array in the image plane but also have a dynamic range which permits recording radiographs with better than 5% statistics for observation of detailed density variations in the object. A number of tests have been carried out to characterize the quality of the proton radiography system for absolute mass determination, resolution, and dynamic range. Initial dynamic experiments characterized the temporal and spatial behavior of shock propagation in high explosives with up to six images per experiment. Based on experience with the prototype system, a number of upgrades are being implemented including the anticipated capability for enhanced mass discrimination through differential multiple coulomb scattering radiographs and more images with improved imaging techniques.

  17. Beam optics of the 2 MeV proton injection line at the LLUMC proton accelerator

    NASA Astrophysics Data System (ADS)

    Coutrakon, G.; Hubbard, J.; Sanders, E.

    2005-12-01

    Simulations of the beam optics of the LLUMC proton accelerator injection line have been modeled using the computer codes Parmila [Los Alamos Nat'l Lab, Internal Report LA-UR-98-4478, Los Alamos Accelerator Code Group, Los Alamos, NM] and Trace 3D [Distributed by AccelSoft Inc, P.O. Box 2813. Del Mar, CA 92014, United States]. These simulations give reasonable agreement with the known accelerator dispersion, beam energy spread and optimal debuncher setting. The purpose of this paper is to understand the beam losses and show where improvements can be made, if required, in the future. It has previously been found [G. Coutrakon et al., J. Med. Phys. 20 (11) (1994) 1691] that most intensity losses in the synchrotron can be ascribed to the narrow energy acceptance of the synchrotron. While the present intensity of the accelerator is quite adequate for patient treatments, future plans to treat larger fields will make higher intensity more desirable. A simulation has been performed which adds a second debuncher, or energy compactor, which shows a reduction in energy spread by a factor of two yielding a factor of two increase in the available intensity. The present intensity of 2.5 × 1010 protons per pulse with 34% of the injected intensity captured in the ring can possibly be improved to 5 × 1010 protons per pulse by capturing 68% of the injected beam intensity. These results are discussed in this paper.

  18. Design study for a superconducting proton linac from 20 to 100 MeV

    SciTech Connect

    Wangler, T.P.; Garnett, R.; Krawczyk, F.; Billen, J.; Bultman, N.; Christensen, K.; Fox, W.; Wood, R.

    1993-07-01

    Advances in superconducting radiofrequency technology during the past 15 years have made possible the large-scale application of superconducting niobium accelerators. So far this development has been restricted to rather low-current electron and heavy-ion accelerators. In addition to the power savings, the improved capability of superconducting cavities to provide acceleration of high currents with low beam losses, which follows from the ability to use larger beam apertures without a large economic penalty from increased rf losses, could make superconducting proton linacs very attractive for high-intensity applications, where activation of the accelerator is a major concern. During the past year, at Los Alamos, the authors have been looking at a possible upgrade to the 800-MeV LAMPF proton accelerator, to provide higher intensity injection into a new storage ring for a new high-intensity pulsed neutron source. As part of this upgrade to the LAMPF accelerator, the entire linac below 100 MeV would be rebuilt to provide improved beam quality, improved reliability, and to include funneling at 20 MeV for higher beam currents. Both a room-temperature and a superconducting option are being considered for the section from 20 to 100 MeV. At present, this section is a 201.25 MHz room-temperature copper drift-tube linac (DTL). For this new upgrade scenario the frequency from 20 to 100 MeV was fixed at 805 MHz. The new duty factor is assumed to be 7.2%, and the authors show some results at two currents, 30 mA and 150 mA, that span the range of interest. Their superconducting linac concept consists of individual multicell cavities, each driven by a klystrode. Focusing would be provided by superconducting quadrupole lenses between cavities. In the remainder of the paper they describe their study to evaluate the potential of a superconducting proton linac section for this application, and address some of the many design choices.

  19. Neutron-proton spin-correlation parameter A sub z z at 68 MeV

    SciTech Connect

    Hammans, M.; Brogli-Gysin, C.; Burzynski, S.; Campbell, J.; Haffter, P.; Henneck, R.; Lorenzon, W.; Pickar, M.A.; Sick, I. ); Konter, J.A.; Mango, S.; van den Brandt, B. )

    1991-05-06

    We report a first measurement of the spin-correlation parameter {ital A}{sub {ital z}{ital z}} in neutron-proton scattering at 67.5 MeV. The results, obtained in the angular range 105{degree}{le}{theta}{sub c.m.}{le}170{degree} with typical accuracies of 0.008, are highly sensitive to the {sup 3}{ital S}{sub 1}-{sup 3}{ital D}{sub 1} mixing parameter {epsilon}{sub 1}. A phase-shift analysis based on the current world data yields a value of {epsilon}{sub 1} significantly higher than predicted by modern potential models.

  20. Nuclear excitation functions from 40 to 200 MeV proton irradiation of terbium

    NASA Astrophysics Data System (ADS)

    Engle, Jonathan W.; Mashnik, Stepan G.; Parker, Lauren A.; Jackman, Kevin R.; Bitteker, Leo J.; Ullmann, John L.; Gulley, Mark S.; Pillai, Chandra; John, Kevin D.; Birnbaum, Eva R.; Nortier, Francois M.

    2016-01-01

    Nuclear formation cross sections are reported for 26 radionuclides, measured with 40-200 MeV proton irradiations of terbium foils. These data provide the basis for the production of medically relevant radionuclides (e.g., 152Tb, 155Tb, 155Eu, and 156Eu) and 153Gd, a potential source used in ongoing efforts to characterize stellar nucleosynthesis routes. Computational predictions from the ALICE2011, CEM03.03, Bertini, and INCL + ABLA codes are compared with newly measured data to contribute to the ongoing process of code development, and yields are calculated for selected radionuclides using measured data.

  1. Parity Nonconservation in Proton-water Scattering at 800 MeV

    DOE R&D Accomplishments Database

    Nagle, D. E.; Bowman, J. D.; Carlini, R.; Mischke, R. E.; Frauenfelder, H.; Harper, R. W.; Yuan, V.; McDonald, A. B.; Talaga, R.

    1982-01-01

    A search has been made for parity nonconservation in the scattering of 800 MeV polarized protons from an unpolarized water target. The result is for the longitudinal asymmetry, A{sub L} = +(6.6 +- 3.2) x 10{sup -7}. Control runs with Pb, using a thickness which gave equivalent beam broadening from Coulomb multiple scattering, but a factor of ten less nuclear interactions than the water target, gave A{sub L} = -(0.5 +- 6.0) x 10{sup -7}.

  2. Phenomenological optical potential analysis of proton-carbon elastic scattering at 200 MeV

    NASA Technical Reports Server (NTRS)

    Bidasaria, H. B.; Townsend, L. W.

    1982-01-01

    Differential cross sections for 200 MeV protons elastically scattered from C-12 were analyzed utilizing a local, complex, spin-dependent optical potential with a harmonic well radial dependence. Analyses were performed using the WKB and eikonal approximations. For the latter, first-order corrections to he phase shifts were incorporated to account for the spin-orbit contribution. Large disagreement between theory and experiment was observed when the usual Thomas form for the spin-orbit potential was utilized. Substantial improvement was obtained by allowing the parameters in the central and spin-orbit potential terms to vary independently.

  3. Charged pions from the isotopes sup 58,64 Ni by 201 MeV protons

    SciTech Connect

    Palmeri, A.; Aiello, S.; Badala, A.; Barbera, R.; Pappalardo, G.S. ); Bimbot, L. ); Reide, F. ); Willis, N.; Oeschler, H.

    1989-08-01

    Charged pion production induced by 201 MeV protons on {sup 58}Ni and {sup 64}Ni has been studied. The double differential cross sections have been measured over a wide angular range. Different behavior of the angular distribution is observed for low and high energy pions. The yield of positive pions shows a pronounced forward peaked component. The deduced total production yields are about the same for ({ital p},{pi}{sup +}) on both isotopes whereas that for {sup 64}Ni({ital p},{pi}{sup {minus}}) is twice as large as for {sup 58}Ni({ital p},{pi}{sup {minus}}).

  4. Performance of GaAs and silicon concentrator cells under 37 MeV proton irradiation

    NASA Technical Reports Server (NTRS)

    Curtis, Henry B.; Swartz, Clifford K.

    1987-01-01

    Gallium arsenide concentrator cells from three sources and silicon concentrator cells from one source were exposed to 37 MeV protons at fluences up to 2.8 x 10 to the 12th protons/sq cm. Performance data were taken after several fluences, at two temperatures (25 and 80 C), and at concentration levels from 1 to about 150 x AMO. Data at one sun and 25 C were taken with an X-25 xenon lamp solar simulator. Data at concentration were taken using a pulsed solar simulator with the assumption of a linear relationship between short circuit current and irradiance. The cells are 5 x 5 mm with a 4-mm diameter illuminated area.

  5. Activation cross sections of proton induced nuclear reactions on gold up to 65MeV.

    PubMed

    Ditrói, F; Tárkányi, F; Takács, S; Hermanne, A

    2016-07-01

    Activation cross sections of proton induced reactions on gold for production of (197m,197g,195m,195g, 193m,193g,192)Hg, (196m,196g(cum),195g(cum),194,191(cum))Au, (191(cum))Pt and (192)Ir were measured up to 65MeV proton energy, some of them for the first time. The new data are in acceptably good agreement with the recently published earlier experimental data in the overlapping energy region. The experimental data are compared with the predictions of the TALYS 1.6 (results in TENDL-2015 on-line library) and EMPIRE 3.2 code. PMID:27156194

  6. Cross Sections and Analyzing Powers of Nitrogen -15(PROTON, NEUTRON)OXYGEN-15 at 200 Mev and 494 Mev.

    NASA Astrophysics Data System (ADS)

    Ciskowski, Douglas Edward

    Differential cross sections and analyzing powers have been measured for the ^{15} N(p,n)^{15}O(g.s.) reaction at bombarding energies of 200 MeV and 494 MeV. The 494 MeV data were obtained at the LAMPF Neutron Time-Of -Flight Facility on an 82 m flight path with a resolution of about 2.7 MeV. The 200 MeV data were obtained at IUCF on a 76 m flight path with a resolution of about 1.1 MeV. At both energies, the measured analyzing power is small, the magnitude is less than.2 for momentum transfers of less than 1 fm^{-1}. In contrast, both Relativistic and standard DWIA calculations predict a maximum of A = -.7 near q = 0.7 fm ^{-1}.

  7. Anomalous effects in silicon solar cell irradiated by 1-MeV protons

    SciTech Connect

    Kachare, R.; Anspaugh, B.E. )

    1989-09-15

    Several silicon solar cells having thicknesses of approximately 63 {mu}m, with and without back-surface fields (BSF), were irradiated with 1-MeV protons having fluences between 10{sup 10} and 10{sup 12} protons/cm{sup 2}. The irradiations were performed using both normal and isotropic incidence on the rear surfaces of the cells. It was observed that after irradiation with fluences greater than 10{sup 11} protons/cm{sup 2}, all BSF cells degraded at a faster rate than cells without BSF. The irradiation results are analyzed using a model in which irradiation-induced defects in the BSF region are taken into account. A number of other possibilities for BSF cell degradation are considered. Tentatively, it is concluded that an increase in defect density due to the formation of aluminum and proton complexes in BSF cells is responsible for the higher-power loss in the BSF cells compared to the non-BSF cells.

  8. Experimental study of ion-beam self-pinched transport for MeV protons

    SciTech Connect

    Neri, J.M.; Young, F.C.; Stephanakis, S.J.; Ottinger, P.F.; Rose, D.V.; Hinshelwood, D.D.; Weber, B.V.

    1999-07-01

    A 100-kA, 1.2-MeV proton beam from a pinch-reflex ion diode on the Gamble II accelerator is used to test the concept of self-pinched ion transport. Self-pinched transport (SPT) uses the self-generated magnetic field from the ion beam to radially confine the ion beam. A proton beam is injected through a 3-cm radius aperture covered with a 2-{micro}m thick polycarbonate foil into a 10-cm radius transport region. The transport region is filled with helium at pressures of 30--250 mTorr, vacuum (10{sup {minus}4} Torr), or 1-Torr air. The beam is diagnosed with witness plates, multiple-pinhole-camera imaging onto radiochromic film, time- and space-resolved proton-scattering, and with prompt-{gamma} and nuclear-activation from LiF targets. Witness-plates and the multiple-pinhole-camera are used to determine the size, location, and uniformity of the beam at different distances from the injection aperture. A beam global divergence of 200 mrad is measured at 15 cm. At 50 cm, the beam fills the transport region. At 110 cm and 100- to 200-mTorr helium, there is evidence of beam filamentation. The measured increase in protons is consistent with the physical picture for SPT, and comparisons with IPROP simulations are in qualitative agreement with the measurements.

  9. Stochastic spatial energy deposition profiles for MeV protons and keV electrons

    NASA Astrophysics Data System (ADS)

    Udalagama, C.; Bettiol, A. A.; Watt, F.

    2009-12-01

    With the rapid advances being made in novel high-energy ion-beam techniques such as proton beam writing, single-ion-event effects, ion-beam-radiation therapy, ion-induced fluorescence imaging, proton/ion microscopy, and ion-induced electron imaging, it is becoming increasingly important to understand the spatial energy-deposition profiles of energetic ions as they penetrate matter. In this work we present the results of comprehensive yet straightforward event-by-event Monte Carlo calculations that simulate ion/electron propagation and secondary electron ( δ ray) generation to yield spatial energy-deposition data. These calculations combine SRIM/TRIM features, EEDL97 data and volume-plasmon-localization models with a modified version of one of the newer δ ray generation models, namely, the Hansen-Kocbach-Stolterfoht. The development of the computer code DEEP (deposition of energy due to electrons and protons) offers a unique means of studying the energy-deposition/redistribution problem while still retaining the important stochastic nature inherent in these processes which cannot be achieved with analytical modeling. As an example of an application of DEEP we present results that compare the energy-deposition profiles of primary MeV protons and primary keV electrons in polymethymethacrylate. Such data are important when comparing proximity effects in the direct write lithography processes of proton-beam writing and electron-beam writing. Our calculations demonstrate that protons are able to maintain highly compact spatial energy-deposition profiles compared with electrons.

  10. Compact superconducting 250 MeV proton cyclotron for the PSI PROSCAN proton therapy project

    NASA Astrophysics Data System (ADS)

    Schillo, M.; Geisler, A.; Hobl, A.; Klein, H. U.; Krischel, D.; Meyer-Reumers, M.; Piel, C.; Blosser, H.; Kim, J.-W.; Marti, F.; Vincent, J.; Brandenburg, S.; Beijers, J. P. M.

    2001-12-01

    A cyclotron for proton therapy has to fulfill many requirements set by the specific operational and safety needs of a medical facility and the medical environment. These are for instance high extraction efficiency, high availability and reliability, simple and robust operation. ACCEL Instruments GmbH has refined the design concept of a medical cyclotron for the PSI PROSCAN project with the objective to use this cyclotron as the standard accelerator in complete proton therapy facilities, which ACCEL intends to market. Starting from the design in [1], we have carried out further detail clarifications, optimizations and adaptations to the needs of PSI [2]. The work was performed in a collaboration between ACCEL, NSCL and KVI in view of the requirements from the PSI PROSCAN project. An overview on the design will be given touching on subjects such as the 3D structural analysis of the coil, detailed magnetic modeling for optimization of the inner region and the spiral, optimization of the RF power, optimization of the cryogenic design based on available cryocoolers instead of a liquefaction plant and Monte Carlo simulations to estimate the heat balance produced by neutrons at 4K components.

  11. A novel source of MeV positron bunches driven by energetic protons for PAS application

    NASA Astrophysics Data System (ADS)

    Tan, Zongquan; Xu, Wenzhen; Liu, Yanfen; Xiao, Ran; Kong, Wei; Ye, Bangjiao

    2014-11-01

    This paper proposes a novel methodology of MeV positrons generation for PAS application. Feasibility of this proposal analyzed by G4Beamline and Transport have shown reasonable success. Using 2 Hz, 1.6 GeV, 100 ns and 1.5 μC/bunch proton bunches for bombarding a graphite target, about 100 ns e+ bunches are generated. Quasi-monochromatic positrons in the range of 1-10 MeV included in these bunches have a flux of >107/s, peak brightness of 1014/s. A magnetic-confinement beamline is utilized to transport the positrons and a "Fast Beam Chopper" is unprecedentedly extended to chop those relativistic bunches. The positron beam can be finally characterized by the energy range of 1-10 MeV and bunch width from one hundred ps up to 1 ns. Such ultrashort bunches can be useful in tomography-type positron annihilation spectroscopy (PAS) as well as other applications.

  12. A Monte Carlo Model for LET Spectra of 200 MeV Protons Used for Microelectronic Testing

    NASA Technical Reports Server (NTRS)

    O'Neill, Patrick M.; Culpepper, William X.

    2003-01-01

    The direct ionization Linear Energy Transfer (LET) for 200 MeV protons in silicon is much smaller than that for higher charged particles since LET increases as the square of the ion charge. However, occasionally the proton interacts with the silicon nuclei and produces a shower of fragments and a recoiling nucleus. When this happens, the LET produced is much greater than the direct ionization LET. Testing the single event effect susceptibility of components using energetic (200 MeV) protons is often the only viable option for system level testing commercial-off-the-shelf (COTS) avionics that have not been designed for space environments. However, the question of how a system tested with protons will perform in a heavy ion environment arises. Here the concern is not only with prediction of on-orbit upset rate, but also about possibility of on-orbit failures that were not observed during proton testing.

  13. Inclusive proton spectra and total reaction cross sections for proton-nucleus scattering at 800 MeV

    SciTech Connect

    McGill, J.A.

    1981-08-01

    Current applications of multiple scattering theory to describe the elastic scattering of medium energy protons from nuclei have been shown to be quite successful in reproducing the experimental cross sections. These calculations use the impulse approximation, wherein the scattering from individual nucleons in the nucleus is described by the scattering amplitude for a free nucleon. Such an approximation restricts the inelastic channels to those initiated by nucleon-nucleon scattering. As a first step in determining the nature of p + nucleus scattering at 800 MeV, both total reaction cross sections and (p,p') inclusive cross sections were measured and compared to the free p + p cross sections for hydrogen, deuterium, calcium 40, carbon 12, and lead 208. It is concluded that as much as 85% of all reactions in a nucleus proceed from interactions with a single nucleon in the nucleus, and that the impulse approximation is a good starting point for a microscopic description of p + nucleus interactions at 800 MeV.

  14. Comparison between calculation and measurement of energy deposited by 800 MeV protons

    SciTech Connect

    Loewe, W.E.

    1980-04-03

    The High Energy Transport Code, HETC, was obtained from the Radiation Shielding Information Center (RSIC) at Oak Ridge National Laboratory and altered as necessary to run on a CDC 7600 using the LTSS software in use at LLNL. HETC was then used to obtain calculated estimates of energy deposited, for comparison with a series of benchmark experiments done by LLNL. These experiments used proton beams of various energies incident on well-defined composite targets in good geometry. In this report, two aspects of the comparison between calculated and experimental energy depositions from an 800 MeV proton beam are discussed. Both aspects involve the fact that workers at SAI had previously used their version of HETC to calculate this experiment and reported their comparison with the measured data. The first aspect addressed is that their calculated data and LLNL calculations do not agree, suggesting an error in the conversion process from the RSIC code. The second aspect is not independent of the first, but is of sufficient importance to merit separate emphasis. It is that the SAI calculations agree well with experiments at the detector plate located some distance from the shower plate, whereas the LLNL calculations show a clearcut discrepancy there in comparison with the experiment. A contract was let in January 1980 by LLNL with SAI in order to obtain full details on the two cited aspects of the comparison between calculated and experimental energy depositions from an 800 MeV proton beam. The ensuing discussion is based on the final report of that contracted work.

  15. Radiation protection studies for a high-power 160 MeV proton linac

    NASA Astrophysics Data System (ADS)

    Mauro, Egidio; Silari, Marco

    2009-07-01

    CERN is presently designing a new chain of accelerators to replace the present Proton Synchrotron (PS) complex: a 160 MeV room-temperature H - linac (Linac4) to replace the present 50 MeV proton linac injector, a 3.5 GeV Superconducting Proton Linac (SPL) to replace the 1.4 GeV PS Booster (PSB) and a 50 GeV synchrotron (named PS2) to replace the 26 GeV PS. Linac4 has been funded and the civil engineering work started in October 2008, whilst the SPL is in an advanced stage of design. Beyond injecting into the future 50 GeV PS, the ultimate goal of the SPL is to generate a 4 MW beam for the production of intense neutrino beams. The radiation protection design is driven by the latter requirement. This work summarizes the radiation protection studies conducted for Linac4. FLUKA Monte Carlo simulations, complemented by analytical estimates, were performed to evaluate the propagation of neutrons through the waveguide, ventilation and cable ducts placed along the accelerator, to estimate the radiological impact of the accelerator in its low-energy section, where the access area is located, and to calculate the induced radioactivity in the air and in the components of the accelerator. The latter study is particularly important for maintenance interventions and final disposal of radioactive waste. Two possible layouts for the CCDTL section of the machine were considered in order to evaluate the feasibility, from the radiological standpoint, of replacing electromagnetic quadrupoles with permanent magnet quadrupoles with a high content of cobalt.

  16. Independent isotopic yields in 25 MeV and 50 MeV proton-induced fission of natU

    NASA Astrophysics Data System (ADS)

    Penttilä, H.; Gorelov, D.; Elomaa, V.-V.; Eronen, T.; Hager, U.; Hakala, J.; Jokinen, A.; Kankainen, A.; Karvonen, P.; Moore, I. D.; Parkkonen, J.; Peräjärvi, K.; Pohjalainen, I.; Rahaman, S.; Rinta-Antila, S.; Rissanen, J.; Rubchenya, V. A.; Saastamoinen, A.; Simutkin, V.; Sonoda, T.; Weber, C.; Voss, A.; Äystö, J.

    2016-04-01

    Independent isotopic yields for elements from Zn to La in the 25 MeV proton-induced fission of {}^{nat}U were determined with the JYFLTRAP facility. In addition, isotopic yields for Zn, Ga, Rb, Sr, Zr, Pd and Xe in the 50 MeV proton-induced fission of {}^{nat}U were measured. The deduced isotopic yield distributions are compared with a Rubchenya model, the GEF model with universal parameters and the semi-empirical Wahl model. Of these, the Rubchenya model gives the best overall agreement with the obtained data. Combining the isotopic yield data with mass yield data to obtain the absolute independent yields was attempted. The result depends on the mass yield distribution.

  17. Characterization of MeV proton acceleration from double pulse irradiation of foil targets

    NASA Astrophysics Data System (ADS)

    Kerr, S.; Mo, M. Z.; Masud, R.; Tiedje, H. F.; Tsui, Y.; Fedosejevs, R.; Link, A.; Patel, P.; McLean, H. S.; Hazi, A.; Chen, H.; Ceurvorst, L.; Norreys, P.

    2014-10-01

    We report on the experimental characterization of proton acceleration from double-pulse irradiation of um-scale foil targets. Temporally separated sub-picosecond pulses have been shown to increase the conversion efficiency of laser energy to MeV protons. Here, two 700 fs, 1 ω pulses were separated by 1 to 5 ps; total beam energy was 100 J, with 5-20% of the total energy contained within the first pulse. In contrast to the ultraclean beams used in previous experiments, prepulse energies on the order of 10 mJ were present in the current experiments which appear to have a moderating effect on the enhancement. Proton beam measurements were made with radiochromic film stacks, as well as magnetic spectrometers. The effect on electron generation was measured using Kα emission from buried Cu tracer layers, while specular light diagnostics (FROG, reflection spectralon) indicated the laser coupling efficiency into the target. The results obtained will be presented and compared to PIC simulations. Work by LLNL was performed under the auspices of U.S. DOE under contract DE-AC52-07NA27344.

  18. Comparison of radiobiological effective depths in 65-MeV modulated proton beams.

    PubMed Central

    Tang, J. T.; Inoue, T.; Inoue, T.; Yamazaki, H.; Fukushima, S.; Fournier-Bidoz, N.; Koizumi, M.; Ozeki, S.; Hatanaka, K.

    1997-01-01

    To assess the achievement of uniformity of radiobiological effectiveness at different depths in the proton spread-out Bragg peak (SOBP), Chinese hamster ovary (CHO) cells were exposed to 65-MeV modulated proton beams at the Research Center for Nuclear Physics (RCNP) of Osaka University. We selected four different irradiation positions: 2 mm depth, corresponding to the entrance, and 10, 18 and 23 mm depths, corresponding to different positions in the SOBP. Cell survival curves were generated with the in vitro colony formation method and fitted to the linear-quadratic model. With 137Cs gamma-rays as the reference irradiation, the relative biological effectiveness (RBE) values for a surviving fraction (SF) level of 0.1 are 1.05, 1.10, 1.12 and 1.19 for depths of 2, 10, 18 and 23 mm respectively. A significant difference was found between the survival curves at 10 and 23 mm (P < 0.05), but not between 18 and 10 mm or between 18 and 23 mm. There was a significant dependence of RBE on depths in modulated proton beams at the 0.1 surviving fraction level (P < 0.05). Moreover, the rise of RBEs significantly depended on increasing SF level or decreased approximately in correspondence with irradiation dose (P = 0.0001). To maintain uniformity of radiobiological effectiveness for the target volume, careful attention should be paid to the influence of depth of beam and irradiation dose. PMID:9231922

  19. Relative biological effectiveness and microdosimetry of a mixed energy field of protons up to 200 MeV

    NASA Astrophysics Data System (ADS)

    Robertson, J. B.; Eaddy, J. M.; Archambeau, J. O.; Coutrakon, G. B.; Miller, D. W.; Moyers, M. F.; Siebers, J. V.; Slater, J. M.; Dicello, J. F.

    1994-10-01

    We have studied radiation effects utilizing the new 250 MeV Synchrotron at Loma Linda University Medical Center. In this paper we present the data collected for the survival of Chinese hamster lung (V79) cells, that were irradiated with a beam of mixed energy protons up to 200 MeV. The RBE for protons, when compared to 60Co gamma rays, ranged from a low of 1.2 at the high energy portion of the field to 1.3+ at the low energy portion of the field. These results are consistent with the measured lineal energy (microdosimetric) spectra.

  20. Relative biological effectiveness and microdosimetry of a mixed energy field of protons up to 200 MeV.

    PubMed

    Robertson, J B; Eaddy, J M; Archambeau, J O; Coutrakon, G B; Miller, D W; Moyers, M F; Siebers, J V; Slater, J M; Dicello, J F

    1994-10-01

    We have studied radiation effects utilizing the new 250 MeV Synchrotron at Loma Linda University Medical Center. In this paper we present the data collected for the survival of Chinese hamster lung (V79) cells, that were irradiated with a beam of mixed energy protons up to 200 MeV. The RBE for protons, when compared to 60Co gamma rays, ranged from a low of 1.2 at the high energy portion of the field to 1.3+ at the low energy portion of the field. These results are consistent with the measured lineal energy (microdosimetric) spectra. PMID:11539961

  1. Near realtime forecasting of MeV protons on the basis of sub relativistic electrons

    NASA Astrophysics Data System (ADS)

    Labrenz, Johannes; Heber, Bernd; Kuehl, Patrick; Sarlanis, Christos; Malandraki, Olga; Posner, Arik

    2016-04-01

    A major impact on human and robotic space exploration activities is the sudden and prompt occurrence of solar energetic ion events. In order to provide up to an hour warning before these particles arrive at Earth, relativistic electron and below 50 MeV proton data from the Electron Proton Helium Instrument (EPHIN) on SOHO were used to implement the 'Relativistic Electron Alert System for Exploration (REleASE)'. It has been demonstrated that the analysis of relativistic electron time profiles provides a low miss and false alarm rate. High Energy Solar Particle Events foRecastIng and Analysis (HESPERIA) is a project funded within the European Union's Horizon 2020 research and innovation programme (PROTEC-1-2014 Call: Space Weather). Within this project the REleASE forecasting scheme was rewritten in the open access programming language PYTHON and will be made public. As a next step, we have analyzed the possibility to also use, along with relativistic electrons (v > 0.9 c) provided by SOHO, near-relativistic (v <0.8 c) electron measurements from other instruments like the Electron Proton Alpha Monitor (EPAM) aboard the Advanced Composition Explorer (ACE). This would prove to be particularly useful during periods that SOHO does not provide continuous near real-time data. We show that the ACE/EPAM observations can be adapted to the REleASE forecasting scheme to provide reliable SEP forecasts. A comparison of measured and forecast proton intensities by SOHO/EPHIN and ACE/EPAM will be presented. In addition we investigated the false alarm rate and detection probability of solar ion events. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324.

  2. Radiative capture of polarized neutrons by polarized protons at Tn=183 MeV

    NASA Astrophysics Data System (ADS)

    Xu, G.; Pate, S. F.; Bloch, C.; Vigdor, S. E.; Bowyer, S. M.; Bowyer, T. W.; Jacobs, W. W.; Meyer, H. O.; Pierce, E.; Sowinski, J.; Whiddon, C.; Wissink, S. W.; Jolivette, P. L.; Pickar, M. A.

    1995-12-01

    In order to provide a quantitative test of theoretical calculations incorporating meson-exchange currents and intermediate Δ resonances, we measure the normal-component spin correlation coefficient CNN, the differential cross section dσ/dΩ, and the neutron and proton analyzing powers An and Ap, each as a function of angle, for n-->p-->-->dγ at Tn=183 MeV. Our n-->p-->-->dγ results, combined with the previous cross section and photon asymmetry data collected in the past decade, place quite strong constraints on model calculations. Our data are in excellent agreement with theoretical predictions by Jaus and Woolcock that incorporate meson-exchange and isobar current effects and relativistic corrections, signifying great recent progress in our understanding of these effects in the nucleon-nucleon system.

  3. Mutation effect of MeV protons on bioflocculant bacteria Bacillus cereus

    NASA Astrophysics Data System (ADS)

    Yang, Y. N.; Ren, N.; Xue, J. M.; Yang, J.; Rong, B. L.

    2007-09-01

    A 3.2 MeV proton beam was used to irradiate bioflocculant bacteria (Bacillus cereus) to achieve mutation. The ion fluence ranged from 1011 to 1014/cm2. Most of the bacteria were killed when the ion fluence reached 1012 ions/cm2. The survival ratio drops in an exponential way on further increasing the ion fluence. The flocculating activity of 7 samples out of 51 showed a positive change, and a perfect mutant C7-23 with a stable high capacity of bioflocculant production was found. RAPD measurements showed that a new lane appears in this sample. The flocculating activity of the C7-23 bacteria increased by factors of 22%, 54% and 217% under pH values of 4, 7 or 10, respectively.

  4. Activation cross sections of proton induced nuclear reactions on palladium up to 80MeV.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Csikai, J; Hermanne, A; Uddin, M S; Baba, M

    2016-08-01

    Activation cross sections of proton induced nuclear reactions on palladium were measured up to 80MeV by using the stacked foil irradiation technique and gamma ray spectrometry. The beam intensity, the incident energy and the energy degradation were controlled by a method based on flux constancy via normalization to the excitation functions of monitor reactions measured in parallel. Excitation functions for direct and cumulative cross-sections were measured for the production of (104m,104g,105g,106m,110m)Ag, (100,101)Pd, (99m,99g,100,101m,101g,102m,102g,105)Rh and (103,97)Ru radioisotopes. The cross section data were compared with the theoretical predictions of TENDL-2014 and -2015 libraries. For practical applications thick target yields were derived from the measured excitation functions. Application in the field of medical radionuclide production is shortly discussed. PMID:27235887

  5. Track nanodosimetry of 20-MeV protons at 20 nm.

    PubMed

    Conte, V; Colautti, P; De Nardo, L; Ferretti, A; Poggi, M; Moro, D; Lombardi, M; Tornielli, G; Grosswendt, B

    2011-02-01

    Track nanodosimetry is the theoretical and experimental research which studies the stochastic aspects of ionisation yield produced by ionising particles in nanometric target volumes, positioned at different distances from the primary particle track. The STARTRACK experimental set-up, mounted on the +50° beam line at the Tandem-Alpi particle accelerator of Legnaro National Laboratories, has been conceived to give an experimental basis to nanodosimetric calculations. STARTRACK is a detection system able to measure the ionisation cluster-size distributions in a 20 nm propane site, by counting the electrons set in motion by different ion tracks, with the resolution of one electron. The 'sensitive volume' SV can be moved at different distances from the primary particle track (different impact parameter). Distributions of 20-MeV protons have been measured and compared with Monte Carlo calculations. PMID:21127036

  6. Study of 180 Mev Proton Inelastic Scattering from SILICON-28 and SILICON-30.

    NASA Astrophysics Data System (ADS)

    Chen, Quan

    This thesis reports the measurement of cross section and analyzing power angular distribution of elastic and inelastic scattering of 180 MeV proton for ^ {28}Si and ^{30} Si. Measurements were carried out using the proton beam available at the Indiana University Cyclotron Facility. The scattered protons were detected using the QDDM magnetic spectrometer. The DWIA framework, in which most inelastic proton scattering observables are analyzed, has three ingredients, (1) NN-effective interaction, (2) transition density, and (3) distorted waves. The procedure used here to obtain effective NN-interaction empirically is that first suggested by J. J. Kelly. It models effective NN-interaction guided by the nuclear matter theory(G-matrix) and employs the local density approximation(LDA). By using the transitions, for which transition densities are known, it fits the inelastic observable to determine the parameters used to model the momentum transfer(q) and density(k_{F }) dependence of the effective interaction (here reference to as empirical interaction). The distorted waves are calculated in a self-consistent manner from the model empirical interaction. The salient results are: (1) It is observed that, although the data base was increased by combining the ^{16}O observable with those of ^{28}Si, it still was not large enough to determine all the parameters without ambiguity in terms of which the effective NN-interaction was modeled. (2) The model prediction of cross section and analyzing power in terms of DWIA, using both the Paris -g and empirical interaction, with the observed are compared. It is clear that the results and the technique used to obtain effective NN-interaction shows that there is substantial potential to gain both qualitative and quantitative insight into how the interaction between two nucleons is modified within the nuclear medium. In particular, at low-q effective interaction is reduced and at high-q repulsion is enhanced compared to free interaction

  7. Utilization of new 150-MeV neutron and proton evaluations in MCNP

    SciTech Connect

    Little, R.C.; Frankle, S.C.; Hughes, H.G. III; Prael, R.E.

    1997-10-01

    MCNP{trademark} and LAHET{trademark} are two of the codes included in the LARAMIE (Los Alamos Radiation Modeling Interactive Environment) code system. Both MCNP and LAHET are three-dimensional continuous-energy Monte Carlo radiation transport codes. The capabilities of MCNP and LAHET are currently being merged into one code for the Accelerator Production of Tritium (APT) program at Los Alamos National Laboratory. Concurrently, a significant effort is underway to improve the accuracy of the physics in the merged code. In particular, full nuclear-data evaluations (in ENDF6 format) for many materials of importance to APT are being produced for incident neutrons and protons up to an energy of 150-MeV. After processing, cross-section tables based on these new evaluations will be available for use fin the merged code. In order to utilize these new cross-section tables, significant enhancements are required for the merged code. Neutron cross-section tables for MCNP currently specify emission data for neutrons and photons only; the new evaluations also include complete neutron-induced data for protons, deuterons, tritons, and alphas. In addition, no provision in either MCNP or LAHET currently exists for the use of incident charged-particle tables other than for electrons. To accommodate the new neutron-induced data, it was first necessary to expand the format definition of an MCNP neutron cross-section table. The authors have prepared a 150-MeV neutron cross-section library in this expanded format for 15 nuclides. Modifications to MCNP have been implemented so that this expanded neutron library can be utilized.

  8. Interlock system for machine protection of the KOMAC 100-MeV proton linac

    NASA Astrophysics Data System (ADS)

    Song, Young-Gi

    2015-02-01

    The 100-MeV proton linear accelerator of the Korea Multi-purpose Accelerator Complex (KOMAC) has been developed. The beam service started this year after performing the beam commissioning. If the very sensitive and essential equipment is to be protected during machine operation, a machine interlock system is required, and the interlock system has been implemented. The purpose of the interlock system is to shut off the beam when the radio-frequency (RF) and ion source are unstable or a beam loss occurs. The interlock signal of the KOMAC linac includes a variety of sources, such as the beam loss, RF and high-voltage converter modulator faults, and fast closing valves of the vacuum window at the beam lines and so on. This system consists of a hardware-based interlock system using analog circuits and a software-based interlock system using an industrial programmable logic controller (PLC). The hardware-based interlock system has been fabricated, and the requirement has been satisfied with the results being within 10 µs. The software logic interlock system using the PLC has been connected to the framework of with the experimental physics and industrial control system (EPICS) to integrate a variety of interlock signals and to control the machine components when an interlock occurs. This paper will describe the design and the construction of the machine interlock system for the KOMAC 100-MeV linac.

  9. Comparing Solar-Flare Acceleration of >-20 MeV Protons and Electrons Above Various Energies

    NASA Technical Reports Server (NTRS)

    Shih, Albert Y.

    2010-01-01

    A large fraction (up to tens of percent) of the energy released in solar flares goes into accelerated ions and electrons, and studies indicate that these two populations have comparable energy content. RHESSI observations have shown a striking close linear correlation between the 2.223 MeV neutron-capture gamma-ray line and electron bremsstrahlung emission >300 keV, indicating that the flare acceleration of >^20 MeV protons and >300 keV electrons is roughly proportional over >3 orders of magnitude in fluence. We show that the correlations of neutron-capture line fluence with GOES class or with bremsstrahlung emission at lower energies show deviations from proportionality, primarily for flares with lower fluences. From analyzing thirteen flares, we demonstrate that there appear to be two classes of flares with high-energy acceleration: flares that exhibit only proportional acceleration of ions and electrons down to 50 keV and flares that have an additional soft, low-energy bremsstrahlung component, suggesting two separate populations of accelerated electrons. We use RHESSI spectroscopy and imaging to investigate a number of these flares in detail.

  10. Proton-proton correlations at small relative momentum in neon-nucleus collisions at E/A=400 and 800 MeV

    NASA Technical Reports Server (NTRS)

    Dupieux, P.; Alard, J. P.; Augerat, J.; Babinet, R.; Bastid, N.; Brochard, F.; Charmensat, P.; De Marco, N.; Fanet, H.; Fodor, Z.; Fraysse, L.; Girard, J.; Gorodetzky, P.; Gosset, J.; Laspalles, C.; Lemaire, M. C.; L'Hote, D.; Lucas, B.; Marroncle, J.; Montarou, G.; Parizet, M. J.; Poitou, J.; Qassoud, D.; Racca, C.; Schimmerling, W.

    1988-01-01

    Proton-proton small angle correlations have been measured in neon-nucleus collisions, using the 4 pi detector Diogene, at 400 and 800 MeV per nucleon incident energies. Values of the size of the emitting region are obtained by comparison with the Koonin formula, taking into account the biases of the apparatus. The dependence of the density on target mass and incident energy is also analysed.

  11. Shielding variation effects for 250 MeV protons on tissue targets.

    PubMed

    Brandl, A; Hranitzky, C; Rollet, S

    2005-01-01

    This paper provides results of computer simulation studies with the goal to analyse issues regarding radiation protection for personnel, patients and third persons involved in hadron therapy treatment. The treatment room and the patient are modelled by simple cylindrical geometries at incident proton energies of 250 MeV. Monte Carlo simulations of the energy and angular dependence of proton, neutron and photon radiation fields and resulting ambient dose equivalent distributions outside the shielding walls are performed. In order to investigate systematic uncertainties due to the shielding materials and inherent to the computer models, various concrete compositions, densities and water contents are modelled, and the influence of simulation parameters on the results obtained is determined. Generally, good agreement is found between results provided by MCNPX and FLUKA computer codes. Variations in neutron ambient dose attenuation from -50 to +/-30% are found due to varying concrete composition. Changes in the water content of the concrete in the order of 8% may cause variations up to 20%. PMID:16381711

  12. Dynamic Pressure of Liquid Mercury Target During 800-MeV Proton Thermal Shock Tests

    SciTech Connect

    Allison, S.W.; Andriulli, J.B.; Cates, M.R.; Earl. D.D.; Haines, J.R.; Morrissey, F.X.; Tsai, C.C.; Wender, S.

    2000-02-01

    Described here are efforts to diagnose transient pressures generated by a short-pulse (about 0.5 microseconds) high intensity proton ({approximately} 2 * 10 14 per pulse) beam. Proton energy is 800-MeV. The tests were performed at the Los Alamos Neutron Science Center - Weapons Neutron Research (LANSCE-WNR). Such capability is required for understanding target interaction for the Spallation Neutron Source project as described previously at this conference.1-4 The main approach to effect the pressure measurements utilized the deflection of a diaphragm in intimate contact with the mercury. There are a wide variety of diaphragm-deflection methods used in scientific and industrial applications. Many deflection-sensing approaches are typically used, including, for instance, capacitive and optical fiber techniques. It was found, however, that conventional pressure measurement using commercial pressure gages with electrical leads was not possible due to the intense nuclear radiation enviro nment. Earlier work with a fiber optic strain gauge demonstrated the viability of using fiber optics for this environment.

  13. Production of radionuclides in artificial meteorites irradiated isotropically with 600 MeV protons

    NASA Technical Reports Server (NTRS)

    Michel, R.; Dragovitsch, P.; Englert, P.; Herpers, U.

    1986-01-01

    The understanding of the production of cosmogenic nuclides in small meteorites (R is less than 40 cm) still is not satisfactory. The existing models for the calculation of depth dependent production rates do not distinguish between the different types of nucleons reacting in a meteorite. They rather use general depth dependent particle fluxes to which cross sections have to be adjusted to fit the measured radionuclide concentrations. Some of these models can not even be extended to zero meteorite sizes without logical contradictions. Therefore, a series of three thick target irradiations was started at the 600 MeV proton beam of the CERN isochronuous cyclotron in order to study the interactions of small stony meteorites with galactic protons. The homogeneous 4 pi irradiation technique used provides a realistic meteorite model which allows a direct comparison of the measured depth profiles with those in real meteorites. Moreover, by the simultaneous measurement of thin target production cross sections one can differentiate between the contributions of primary and secondary nucleons over the entire volume of the artificial meteorite.

  14. Limits on the antiproton/proton ratio in the cosmic radiation from 100 MeV to 1580 MeV

    NASA Technical Reports Server (NTRS)

    Salamon, M. H.; Mckee, S.; Musser, J. A.; Tarle, G.; Tomasch, A.

    1990-01-01

    A search for antiprotons (p-bars) in the cosmic radiation with energies below 1580 MeV at the top of the atmosphere was performed using the PBAR balloon-borne magnetic spectrometer. No antiprotons were observed in 124,000 proton events. For the energy interval 100-640 MeV, an upper limit is reported to the p-bar/p ratio of 2.8 x 10 to the -5th at the top of the atmosphere, after correcting for instrumental efficiencies and contributions from secondary particles. No antiproton was observed in the energy interval 640-1580 MeV, which yields an upper limit to the p-bar/p ratio of 6.1 x 10. By combining both data sets, the limits on the p-bar/p ratio can be improved to 2.0 x 10 to the -5th. The detector performance and instrumental efficiencies of the individual detector components are discussed. A detail Monte Carlo calculation was used to evaluate the instrumental efficiency for both antiprotons and protons as a function of momentum.

  15. Proton beam of 2 MeV 1.6 mA on a tandem accelerator with vacuum insulation

    NASA Astrophysics Data System (ADS)

    Kasatov, D.; Kuznetsov, A.; Makarov, A.; Shchudlo, I.; Sorokin, I.; Taskaev, S.

    2014-12-01

    A source of epithermal neutrons based on a tandem accelerator with vacuum insulation for boron neutron capture therapy of malignant tumors was proposed and constructed. Stationary proton beam with 2 MeV energy, 1.6 mA current, 0.1% energy monochromaticity and 0.5% current stability has just been obtained.

  16. Internuclear cascade-evaporation model for LET spectra of 200 MeV protons used for parts testing

    SciTech Connect

    O`Neill, P.M.; Badhwar, G.D.; Culpepper, W.X.

    1998-12-01

    The Linear Energy Transfer (LET) spectrum produced in microelectronic components during testing with 200 MeV protons is calculated with an internuclear cascade-evaporation code. This spectrum is compared to the natural space heavy ion environment for various earth orbits. This comparison is used to evaluate the results of proton testing in terms of determining a firm upper bound to the on-orbit heavy ion upset rate and the risk of on-orbit heavy ion failures that would not be detected with protons.

  17. Development of the integrated control system for the microwave ion source of the PEFP 100-MeV proton accelerator

    NASA Astrophysics Data System (ADS)

    Song, Young-Gi; Seol, Kyung-Tae; Jang, Ji-Ho; Kwon, Hyeok-Jung; Cho, Yong-Sub

    2012-07-01

    The Proton Engineering Frontier Project (PEFP) 20-MeV proton linear accelerator is currently operating at the Korea Atomic Energy Research Institute (KAERI). The ion source of the 100-MeV proton linac needs at least a 100-hour operation time. To meet the goal, we have developed a microwave ion source that uses no filament. For the ion source, a remote control system has been developed by using experimental physics and the industrial control system (EPICS) software framework. The control system consists of a versa module europa (VME) and EPICS-based embedded applications running on a VxWorks real-time operating system. The main purpose of the control system is to control and monitor the operational variables of the components remotely and to protect operators from radiation exposure and the components from critical problems during beam extraction. We successfully performed the operation test of the control system to confirm the degree of safety during the hardware performance.

  18. Short term prediction of E greater than or equal to 10 MeV proton fluxes from solar flares

    NASA Technical Reports Server (NTRS)

    Kuck, G. A.

    1972-01-01

    Both the anisotropic and isotropic diffusion theories can be used to extrapolate proton fluxes for E greater than or equal to 10 meV for over 50% of the particle events. The isotropic diffusion theory uses a diffusion coefficient: D = Mr sup beta. It was found that M and beta tended to be functions of flare position on the solar disk. A measurement of the interplanetary flux in near earth space gives a good indication of the polar cap fluxes. It was found that the 30 MHz absorption over the poles during a PCA is proportional to the square root of the integral proton flux E greater than or equal to 11 meV in interplanetary space, J = KA squared, with K = 8 plus or minus 2 and J in protons/sq cm-sec-ster.

  19. COPPER-64 Production Studies with Natural Zinc Targets at Deuteron Energy up to 19 Mev and Proton Energy from 141 Down to 31 Mev

    NASA Astrophysics Data System (ADS)

    Bonardi, Mauro L.; Birattari, Claudio; Groppi, Flavia; Song Mainard, Hae; Zhuikov, Boris L.; Kokhanyuk, Vladimir M.; Lapshina, Elena V.; Mebel, Michail V.; Menapace, Enzo

    2004-07-01

    High specific activity no-carrier-added 64Cu is a β-/β+ emitting radionuclide of increasing interest for PET imaging, as well as systemic and targeted radioimmunotherapy of tumors. Its peculiarity of intense Auger emitter is still under investigation. The cross-sections for production of 64Cu from Zn target of natural isotopic composition were measured in the deuteron energy range from threshold up to 19 MeV and proton energy range from 141 down to 31 MeV. The stacked-foil technique was used at both K=38 cyclotron of JRC-Ispra of CEC, Italy and 160 MeV intersection point of INR proton-LINAC in Troitsk, Russia. Several Ga, Zn, Cu, Ni, Co, V, Fe and Mn radionuclides were detected in Zn targets at the EOB. Optimized irradiation conditions are reported as a function of deuteron energy and energy loss into the Zn target, as well as target irradiation time and cooling time after radiochemistry. The activity of n.c.a. 64Cu was measured through its only γ emission of 1346 keV (i.e. 0.473 % intensity) both by instrumental and radiochemical methods, due to the non-specificity of annihilation radiation at 511 keV. To this last purpose, it was necessary to carry out a selective radiochemical separation of GaIII radionuclides by liquid/liquid extraction from the bulk of irradiated Zn targets and other spallation products, which remained in the 7 M HCl aqueous phase. Anion exchange chromatography tests had been carried out to separate the 64Cu from all others radionuclides in n.c.a. form. Theoretical calculations of cross-sections were performed with codes EMPIRE II and PENELOPE for deuteron reactions and CEF model and HMS-ALICE hybrid model for proton reactions. The theoretical results are presented and compared with the experimental values.

  20. Hydrogen release from 800 MeV proton-irradiated tungsten

    NASA Astrophysics Data System (ADS)

    Oliver, B. M.; Venhaus, T. J.; Causey, R. A.; Garner, F. A.; Maloy, S. A.

    2002-12-01

    Tungsten irradiated in spallation neutron sources, such as those proposed for the accelerator production of tritium (APT) project, will contain large quantities of generated helium and hydrogen gas. Tungsten used in proposed fusion reactors will also be exposed to neutrons, and the generated protium will be accompanied by deuterium and tritium diffusing in from the plasma-facing surface. The release kinetics of these gases during various off-normal scenarios involving loss of coolant and after heat-induced rises in temperature are of particular interest for both applications. To determine the release kinetics of hydrogen from tungsten, tungsten rods irradiated with 800 MeV protons in the Los Alamos Neutron Science Center (LANSCE) to high exposures as part of the APT project have been examined. Hydrogen evolution from the tungsten has been measured using a dedicated mass-spectrometer system by subjecting the specimens to an essentially linear temperature ramp from ˜300 to ˜1500 K. Release profiles are compared with predictions obtained using the Tritium Migration Analysis Program (TMAP4). The measurements show that for high proton doses, the majority of the hydrogen is released gradually, starting at about 900 K and reaching a maximum at about 1400 K, where it drops fairly rapidly. Comparisons with TMAP show quite reasonable agreement using a trap energy of 1.4 eV and a trap density of ˜7%. There is a small additional release fraction occurring at ˜550 K, which is believed to be associated with low-energy trapping at or near the surface, and, therefore, was not included in the bulk TMAP model.

  1. Proton-induced fragmentation of carbon at energies below 100 MeV

    NASA Technical Reports Server (NTRS)

    Schmitz, M.; Streibel, T.; Roecher, H.; Dreute, J.; Hirzebruch, S. E.; Huentrup, G.; Heinrich, Wolfgang

    1994-01-01

    Radiation effects caused by single cosmic ray particles have been studied for many years in radiobiological experiments for different biological objects and biological end-points. Additionally, single event effects in microelectronic devices have gained large interest. There are two fundamental mechanisms by which a single particle can cause radiation effects. On the one hand, a cosmic ray ion with high linear energy transfer can deposit a high dose along its path. On the other hand, in a nuclear collision, a high dose can be deposited by short range particles emitted from the target nucleus. In low earth orbits a large contribution to target fragmentation events originates from trapped protons which are encountered in the South Atlantic Anomaly. These protons have energies up to a few hundred MeV. We study the fragmentation of C, O and Si nuclei - the target nuclei of biological material and microelectronic devices - in nuclear collisions. Our aim is to measure production cross sections, energy spectra, emission directions and charge correlations of the emitted fragments. The present knowledge concerning these data is rather poor. M. Alurralde et al. have calculated cross sections and average energies of fragments produced from Si using the cascade-evaporation model. D.M. Ngo et al. have used the semiempirical cross section formula of Silberberg and Tsao to calculate fragment yields and the statistical model of Goldhaber to describe the reaction kinematics. Cross sections used in these models have uncertainties within a factor of two. Our data will help to test and improve existing models especially for energies below 300 MeV/nucleon. Charge correlations of fragments emitted in the same interaction are of particular importance, since high doses can be deposited if more than one heavy fragment with a short range is produced.

  2. High intensity proton beam transportation through fringe field of 70 MeV compact cyclotron to beam line targets

    NASA Astrophysics Data System (ADS)

    Zhang, Xu; Li, Ming; Wei, Sumin; Xing, Jiansheng; Hu, Yueming; Johnson, Richard R.; Piazza, Leandro; Ryjkov, Vladimir

    2016-06-01

    From the stripping points, the high intensity proton beam of a compact cyclotron travels through the fringe field area of the machine to the combination magnet. Starting from there the beams with various energy is transferred to the switching magnet for distribution to the beam line targets. In the design of the extraction and transport system for the compact proton cyclotron facilities, such as the 70 MeV in France and the 100 MeV in China, the space charge effect as the beam crosses the fringe field has not been previously considered; neither has the impact on transverse beam envelope coupled from the longitudinal direction. Those have been concerned much more with the higher beam-power because of the beam loss problem. In this paper, based on the mapping data of 70 MeV cyclotron including the fringe field by BEST Cyclotron Inc (BEST) and combination magnet field by China Institute of Atomic Energy (CIAE), the beam extraction and transport are investigated for the 70 MeV cyclotron used on the SPES project at Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (INFN-LNL). The study includes the space charge effect and longitudinal and transverse coupling mentioned above, as well as the matching of beam optics using the beam line for medical isotope production as an example. In addition, the designs of the ±45° switching magnets and the 60° bending magnet for the extracted beam with the energy from 35 MeV to 70 MeV have been made. Parts of the construction and field measurements of those magnets have been done as well. The current result shows that, the design considers the complexity of the compact cyclotron extraction area and fits the requirements of the extraction and transport for high intensity proton beam, especially at mA intensity levels.

  3. Design and operation of a proton microscope for radiography at 800 MEV

    SciTech Connect

    Mottershead, C. T.; Barlow, D. B.; Blind, B.; Hogan, G. E.; Jason, A. J.; Merrill, F. E.; Morley, Kevin B.; Morris, C.; Saunders, A.; Valdiviez, R.

    2003-01-01

    A high-magnification high-resolution option is desirable for the study of small-scale dynamic experiments at the LANSCE 800-MeV Proton Radiography Facility. Magnification is achievable by either repowering the existing imaging-lens quadrupoles, using new high-gradient quadrupoles, or some hybrid combination of the two. The large and complex parameter space of magnetic optics solutions was studied extensively with the 3rd order optics code MARYLIE. Some of the hybrid solutions achieve magnifications up to 150, but at the price of high chromatic aberrations. In the end, a design using only new high-gradient permanent-magnet quadrupoles was selected and built at the design parameters that minimized chromatic aberration per unit magnification. The design has a moderate magnification of 7.1 and 15.8 at the two existing image stations. First-beam commissioning results exceeded expectations. Image contrast is produced by multiple Coulomb scattering in the thin objects. Early experimental objectives are to optimize this contrast by collimator design and by adjusting the correlation in the illuminating beam, as well as to characterize the (quite high) resolution limits of the system.

  4. Test of charge symmetry in neutron-proton elastic scattering at 477 MeV

    SciTech Connect

    Abegg, R.; Bandyopadhyay, D.; Birchall, J.; Cairns, E.W.; Coombes, H.; Davis, C.A.; Davison, N.E.; Delheij, P.P.J.; Green, P.W.; Greeniaus, L.G.; Gubler, H.P.; Healy, D.C.; Lapointe, C.; Lee, W.P.; McDonald, W.J.; Miller, C.A.; Moss, G.A.; Plattner, G.R.; Poffenberger, P.R.; Ramsay, W.D.; Roy, G.; Soukup, J.; Svenne, J.P.; Tkachuk, R.; van Oers, W.T.H.; Wait, G.D.; Zhang, Y.P.

    1986-06-16

    An experiment resulting in the first measurement of the isospin-mixing, charge-symmetry violating component of the n-italic-p-italic interaction has been performed. The experiment determined the difference in the angles of the zero crossing of the neutron and proton analyzing powers A-italic/sub n-italic/ and A-italic/sub p-italic/ at 477 MeV. In terms of the laboratory scattering angle of the neutron, the measured difference t-italich-italice-italict-italica-italic/sub 0//sub n-italic/(A/sub n/)= -t-italich-italice-italict-italica-italic/sub 0//sub n-italic/(A/sub p/) = +0.13X(de +- 0.06 X(de( +- 0.03X(de) where the second error is a worst case estimate of systematic error. The resulting difference in the analyzing powers at the zero-crossing angle A-italic/sub n-italic/-A/sub p/ = +0.0037 +- 0.0017( +- 0 .0008).

  5. {sup 7}Li(p,n) NUCLEAR DATA LIBRARY FOR INCIDENT PROTON ENERGIES TO 150 MEV

    SciTech Connect

    S. MASHNIK; ET AL

    2000-11-01

    Researchers at Los Alamos National Laboratory are considering the possibility of using the Low Energy Demonstration Accelerator (LEDA), constructed at LANSCE for the Accelerator Production of Tritium program (APT), as a neutron source. Evaluated nuclear data are needed for the p+{sup 7}Li reaction, to predict neutron production from thin and thick lithium targets. In this report we describe evaluation methods that make use of experimental data, and nuclear model calculations, to develop an ENDF-formatted data library for incident protons with energies up to 150 MeV. The important {sup 7}Li(p,n{sub 0}) and {sup 7}Li(p,n{sub 1}) reactions are evaluated from the experimental data, with their angular distributions represented using Lengendre polynomial expansions. The decay of the remaining reaction flux is estimated from GNASH nuclear model calculations. This leads to the emission of lower-energy neutrons and other charged particles and gamma-rays from preequilibrium and compound nucleus decay processes. The evaluated ENDF-data are described in detail, and illustrated in numerous figures. We also illustrate the use of these data in a representative application by a radiation transport simulation with the code MCNPX.

  6. Assessment of nuclear-reaction codes for proton-induced reactions on light nuclei below 250 MeV

    NASA Astrophysics Data System (ADS)

    Braunn, Benjamin; Boudard, Alain; David, Jean-Christophe; Koning, Arjan J.; Leprince, Anne; Leray, Sylvie; Mancusi, Davide

    2015-07-01

    We assess the suitability of nuclear-reaction codes for the generation of accurate cross-section libraries targeted at the simulation of the transport of high-energy protons (up to 250 MeV) in the human body, or in any material containing light nuclides. To this end we present an extensive study of elastic, reaction and fragmentation cross sections for proton-induced reactions on several nuclides. We compare TALYS evaluations against experimental data and, wherever applicable, against the predictions of the INCL/ABLA07 nuclear-reaction model. The TALYS evaluations have been cast in the form of a new cross-section library, which also includes evaluated proton-proton cross sections based on the NN-OnLine tool.

  7. Commissioning of a compact laser-based proton beam line for high intensity bunches around 10Â MeV

    NASA Astrophysics Data System (ADS)

    Busold, S.; Schumacher, D.; Deppert, O.; Brabetz, C.; Kroll, F.; Blažević, A.; Bagnoud, V.; Roth, M.

    2014-03-01

    We report on the first results of experiments with a new laser-based proton beam line at the GSI accelerator facility in Darmstadt. It delivers high current bunches at proton energies around 9.6 MeV, containing more than 109 particles in less than 10 ns and with tunable energy spread down to 2.7% (ΔE/E0 at FWHM). A target normal sheath acceleration stage serves as a proton source and a pulsed solenoid provides for beam collimation and energy selection. Finally a synchronous radio frequency (rf) field is applied via a rf cavity for energy compression at a synchronous phase of -90 deg. The proton bunch is characterized at the end of the very compact beam line, only 3 m behind the laser matter interaction point, which defines the particle source.

  8. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV.

    PubMed

    Sjue, S K L; Mariam, F G; Merrill, F E; Morris, C L; Saunders, A

    2016-01-01

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model's accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets. PMID:26827356

  9. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV

    NASA Astrophysics Data System (ADS)

    Sjue, S. K. L.; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A.

    2016-01-01

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model's accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.

  10. 225Ac and 223Ra production via 800 MeV proton irradiation of natural thorium targets.

    PubMed

    Weidner, J W; Mashnik, S G; John, K D; Ballard, B; Birnbaum, E R; Bitteker, L J; Couture, A; Fassbender, M E; Goff, G S; Gritzo, R; Hemez, F M; Runde, W; Ullmann, J L; Wolfsberg, L E; Nortier, F M

    2012-11-01

    Cross sections for the formation of (225,227)Ac, (223,225)Ra, and (227)Th via the proton bombardment of natural thorium targets were measured at a nominal proton energy of 800 MeV. No earlier experimental cross section data for the production of (223,225)Ra, (227)Ac and (227)Th by this method were found in the literature. A comparison of theoretical predictions with the experimental data shows agreement within a factor of two. Results indicate that accelerator-based production of (225)Ac and (223)Ra is a viable production method. PMID:22944532

  11. Development of a gaseous proton-recoil detector for fission cross section measurements below 1 MeV neutron energy

    NASA Astrophysics Data System (ADS)

    Marini, P.; Mathieu, L.; Aïche, M.; Czajkowski, S.; Jurado, B.; Tsekhanovich, I.

    2016-03-01

    The elastic H(n,p) reaction is sometimes used to measure neutron flux, in order to produce high precision measurements. The use of this technique is not straightforward to use below incident neutron energy of 1 MeV, due to a high background in the detected proton spectrum. Experiments have been carried out at the AIFIRA facility to investigate such background and determine its origin and components. Based on these investigations, a gaseous proton-recoil detector has been designed, with a reduced low energy background.

  12. Stopping powers of polycarbonate for 0.36-5.94-MeV protons and 1.0-24.0-MeV α particles

    NASA Astrophysics Data System (ADS)

    Räisänen, J.; Trzaska, W. H.; Alanko, T.; Lyapin, V.; Porter, L. E.

    2003-08-01

    The stopping powers of polycarbonate for protons of energy 0.6-5.9 MeV and α particles of energy 2.0-24.0 MeV have been measured in a transmission experiment employing thin-foil targets. The essence of the novel experimental method employed in the present measurements is to record both projectile energy and time of flight while constantly alternating measurements with and without the target foil in place. The accuracies of the proton data and α-particle data range from 2.0% to 3.0% and 2.2% to 2.7%, respectively. All of the resulting measurements were analyzed in terms of modified Bethe-Bloch theory in order to extract values of the target mean excitation energy (I) and Barkas-effect parameter (b). The composite results for the two projectiles are that I=71.52 eV and b=1.13, the former value lying about one standard deviation below the additivity value and the latter value lying about one standard deviation below the expected value of 1.4±0.1. Previous measurements of the stopping power of polycarbonate for 7Li ions were analyzed by the same method, but with the inclusion of an effective charge parameter (λ). The proton and α-particle data, with a few lower-energy points included, were analyzed for a three-parameter fit, also. Results for the three projectiles studied indicate both internal consistency and agreement with expectations based on modified Bethe-Bloch theory.

  13. Stopping powers of havar for 0.63 5.9 MeV protons and 2.6 24 MeV alpha particles

    NASA Astrophysics Data System (ADS)

    Porter, L. E.; Trzaska, W. H.; Räisänen, J.; Lyapin, V.

    2004-11-01

    A transmission experiment utilizing thin foil targets has been conducted in order to establish the stopping powers of the cobalt-base alloy, havar, for 0.6-5.9 MeV protons and 2.6-24 MeV alpha particles. The basic technique of the novel experimental method used was to record both the projectile energy and the time of flight while alternating measurements with and without the target in place. The uncertainties of the proton and alpha particle data sets ranged from 1.4 to 2.3% and 1.1 to 1.5%, respectively. Modified Bethe-Bloch theory was applied to the measurements in order to ascertain values of the target mean excitation energy (I) and Barkas-effect parameter (b) for each projectile. The extracted values were I = 304.3 ± 2.4 eV and b = 1.37 ± 0.04 for the case of protons, and I = 306.3 ± 2.3 eV and b = 1.47 ± 0.03 for the case of alpha particles. The I-values are somewhat higher than the additivity-based expectation of 295.7 eV, whereas the b-values are clearly consistent with the expected range of 1.4 ± 0.1. The parameter values extracted from the measurements are appraised for compatibility with recently observed trends in values of I and of b with increasing projectile atomic number.

  14. Observational Search for >10 MeV Electrons in the Inner Magnetosphere Using the Van Allen Probes Relativistic Proton Spectrometer

    NASA Astrophysics Data System (ADS)

    Mazur, J. E.; Looper, M. D.; O'Brien, T. P., III; Blake, J. B.

    2015-12-01

    Any detection of ultra-relativistic electrons (>10 MeV) trapped in the inner magnetosphere is potentially a sensitive indicator of a unique particle acceleration process or of a unique particle source. The 24 March 1991 shock injection of >15 MeV electrons is a classic example of the former, while the latter includes measurements in low Earth orbit of >100 MeV electrons and positrons from cosmic ray interactions with the atmosphere. In this paper we use new instrumentation on the Van Allen Probes to survey the inner magnetosphere for signatures of ultra-relativistic electrons. The Relativistic Proton Spectrometer, designed primarily for spectroscopy of 60 to 2000 MeV protons in the inner belt, nonetheless is capable of detecting minimum-ionizing electrons in a silicon detector stack. More critical to this survey is the instrument's Cherenkov radiator subsystem whose response to incident electrons ranges from a threshold near 10 MeV and reaches light saturation above 50 MeV. Together with the silicon detector system we are able to explore an energy range that has not been routinely studied in the context of the Earth's magnetosphere. We will report on quiet-time and storm-time signatures in regions of the inner magnetosphere that heretofore have not been explored with an orbit like that of Van Allen Probes. We will also quantitatively compare our electron energy spectra, or flux limits, with other measurements from Van Allen Probes and prior glimpses of high-energy electrons from low Earth orbit.

  15. Routine production of copper-64 using 11.7MeV protons

    SciTech Connect

    Jeffery, C. M.; Smith, S. V.; Asad, A. H.; Chan, S.; Price, R. I.

    2012-12-19

    Reliable production of copper-64 ({sup 64}Cu) was achieved by irradiating enriched nickel-64 ({sup 64}Ni, >94.8%) in an IBA 18/9 cyclotron. Nickel-64 (19.1 {+-} 3.0 mg) was electroplated onto an Au disc (125{mu}m Multiplication-Sign 15mm). Targets were irradiated with 11.7 MeV protons for 2 hours at 40{mu}A. Copper isotopes ({sup 60,61,62,64}Cu) were separated from target nickel and cobalt isotopes ({sup 55,57,61}Co) using a single ion exchange column, eluted with varying concentration of low HCl alcohol solutions. The {sup 64}Ni target material was recovered and reused. The {sup 64}Cu production rate was 1.46{+-}0.3MBq/{mu}A.hr/mg{sup 64}Ni(n = 10) (with a maximum of 2.6GBq of {sup 64}Cu isolated after 2hr irradiation at 40uA. Radionuclidic purity of the {sup 64}Cu was 98.7 {+-} 1.6 % at end of separation. Cu content was < 6mg/L (n = 21). The specific activity of {sup 64}Cu was determined by ICP-MS and by titration with Diamsar to be 28.9{+-}13.0GBq/{mu}mol[0.70{+-}0.35Ci/{mu}mol]/({mu}A.hr/mg{sup 64}Ni)(n = 10) and 13.1{+-}12.0GBq/{mu}mol[0.35{+-}0.32Ci/{mu}mol]/({mu}A.hr/mg{sup 64}Ni)(n 9), respectively; which are in agreement, however, further work is required.

  16. Response functions of Fuji imaging plates to monoenergetic protons in the energy range 0.6-3.2 MeV

    SciTech Connect

    Bonnet, T.; Denis-Petit, D.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Aleonard, M. M.

    2013-01-15

    We have measured the responses of Fuji MS, SR, and TR imaging plates (IPs) to protons with energies ranging from 0.6 to 3.2 MeV. Monoenergetic protons were produced with the 3.5 MV AIFIRA (Applications Interdisciplinaires de Faisceaux d'Ions en Region Aquitaine) accelerator at the Centre d'Etudes Nucleaires de Bordeaux Gradignan (CENBG). The IPs were irradiated with protons backscattered off a tantalum target. We present the photo-stimulated luminescence response of the IPs together with the fading measurements for these IPs. A method is applied to allow correction of fading effects for variable proton irradiation duration. Using the IP fading corrections, a model of the IP response function to protons was developed. The model enables extrapolation of the IP response to protons up to proton energies of 10 MeV. Our work is finally compared to previous works conducted on Fuji TR IP response to protons.

  17. Absolute calibration of photostimulable image plate detectors used as (0.5-20 MeV) high-energy proton detectors.

    PubMed

    Mancić, A; Fuchs, J; Antici, P; Gaillard, S A; Audebert, P

    2008-07-01

    In this paper, the absolute calibration of photostimulable image plates (IPs) used as proton detectors is presented. The calibration is performed in a wide range of proton energies (0.5-20 MeV) by exposing simultaneously the IP and calibrated detectors (radiochromic films and solid state detector CR39) to a source of broadband laser-accelerated protons, which are spectrally resolved. The final result is a calibration curve that enables retrieving the proton number from the IP signal. PMID:18681694

  18. An Observational Test of the Stability of Inner Belt Protons Above 60 Mev Using Measurements Separated By 41 Years

    NASA Astrophysics Data System (ADS)

    Mazur, J. E.; O'Brien, T. P., III; Looper, M. D.; Blake, J. B.; George, J. S.

    2014-12-01

    The relative stability of protons trapped in the inner Van Allen radiation belt is a unique signature of the near-Earth radiation environment. While the outer electron belt changes its topography and intensity on timescales of less than a day, calculations indicate that protons in the deepest portions of the inner belt can remain on drift shells for centuries. The long lifetimes for equatorially mirroring protons have never been experimentally verified because few missions traverse this challenging environment, and those that have attempted to quantify the proton flux there have faced potentially large backgrounds from penetrating protons outside the instrument field of view. Today, the Relativistic Proton Spectrometer (RPS) investigation on board the Van Allen Probes offers a background-free reference and hence a unique opportunity to compare the present state of inner belt protons with prior measurements. In this study we revisit one relatively clean, and possibly the most accurate historical dataset: a Cherenkov proton spectrometer that operated in a highly inclined 132x1932 km orbit in 1971. The OV1-20P proton spectrometer covered the energy range of ~65-550 MeV (completely within the RPS energy range), had good background rejection because of a fast scintillator coincidence requirement, but operated off of a flight battery for only 10 days. The short lifetime of the OV1-20P mission is the primary reason it did not have significant impact on subsequent studies of the inner belt. At the meeting we will report on a comparison of OV1-20P and RPS fluxes at the same magnetic field coordinates. Our 41-year measurement baseline is not anywhere near a continuous record of course, but it is rare in space science that we have the opportunity to measure a trapped radiation environment on the timescale of decades.

  19. Optically stimulated luminescence from Al 2O 3:C irradiated with 10-60 MeV protons

    NASA Astrophysics Data System (ADS)

    Edmund, J. M.; Andersen, C. E.; Greilich, S.; Sawakuchi, G. O.; Yukihara, E. G.; Jain, M.; Hajdas, W.; Mattsson, S.

    2007-09-01

    We investigated the potential use of Al 2O 3:C for medical proton dosimetry. Detector crystals coupled to fiber-optic cables were irradiated in proton beams with energies from 10 to 60 MeV. The key finding is that the initial intensity of the optically stimulated luminescence (OSL) signal is energy independent for small detectors (<0.5 mm) and relatively small doses (<0.3 Gy). This feature is related to the supralinearity of the detectors dose-response to low linear energy transfer (LET) radiation. The results show that our system can be used in medical proton dosimetry without LET-dependent correction factors in the dose and energy interval investigated.

  20. Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets

    SciTech Connect

    Morris, Christopher L.; Bourke, Mark A.; Byler, Darrin D.; Chen, Ching-Fong; Hogan, Gary E.; Hunter, James F.; Kwiatkowski, Kris K.; Mariam, Fesseha G.; McClellan, Kenneth J.; Merrill, Frank E.; Morley, Deborah J.; Saunders, Alexander

    2013-02-11

    We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. Also, we show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods has been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 μm has been demonstrate, 20 μm seems feasible with minor changes) for tomography on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 μm resolution but further development of sources, collimation and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods.

  1. High order magnetic optics for high dynamic range proton radiography at a kinetic energy 800 MeV

    DOE PAGESBeta

    Sjue, Sky K. L.; Morris, Christopher L.; Merrill, Frank Edward; Mariam, Fesseha Gebre; Saunders, Alexander

    2016-01-14

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the protonimaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane.more » Furthermore, comparison with a series of static calibrationimages demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.« less

  2. 2.6 MeV proton irradiation effects on the surface integrity of depleted UO2

    NASA Astrophysics Data System (ADS)

    Pakarinen, J.; He, L.; Gupta, M.; Gan, J.; Nelson, A.; El-Azab, A.; Allen, T. R.

    2014-01-01

    The effect of low temperature proton irradiation in depleted uranium dioxide was examined as a function of fluence. With 2.6 MeV protons, the fluence limit for preserving a good surface quality was found to be relatively low, about 1.4 and 7.0 × 1017 protons/cm2 for single and poly crystalline samples, respectively. Upon increasing the fluence above this threshold, severe surface flaking and disintegration of samples was observed. Based on scanning electron microscopy (SEM) and X-ray diffraction (XRD) observations the causes of surface failure were associated to high H atomic percent at the peak damage region due to low solubility of H in UO2. The resulting lattice stress is believed to exceed the fracture stress of the crystal at the observed fluencies. The oxygen point defects from the displacement damage may hinder the H diffusion and further increase the lattice stress, especially at the peak damage region.

  3. Most probable charge of fission products in 24 MeV proton induced fission of {sup 238}U

    SciTech Connect

    Kudo, H.; Maruyama, M.; Tanikawa, M.; Shinozuka, T.; Fujioka, M.

    1998-01-01

    The charge distributions of fission products in 24 MeV proton-induced fission of {sup 238}U were measured by the use of an ion-guide isotope separator on line. The most probable charge (Z{sub p}) of the charge distribution was discussed in view of the charge polarization in the fission process. It was found that Z{sub p} mainly lies on the proton-rich side in the light mass region and on the proton-deficient side in the heavy mass region compared with the postulate of the unchanged charge distribution. The charge polarization was examined with respect to production Q values. {copyright} {ital 1998} {ital The American Physical Society}

  4. Measurement of the free neutron-proton analyzing power and spin transfer parameters in the charge exchange region at 790 MeV

    SciTech Connect

    Ransome, R.D.

    1981-07-01

    The free neutron-proton analyzing power and the spin transfer parameters (K/sub NN/, K/sub SS/, K/sub SL/, and K/sub LL/) were measured at the Los Alamos Meson Physics Facility at 790 MeV between 165/sup 0/ and 180/sup 0/ center of mass. A 40% polarized neutron beam incident on a liquid hydrogen target was used. The recoil protons were momentum analyzed with a magnetic spectrometer to isolate elastic scatters. A large solid angle carbon polarimeter was used to measure the proton polarization. The measurements are the first at this energy and are in basic agreement with pre-existing phase shift solutions. The proton-carbon analyzing power was measured between 500 and 750 MeV. An empirical fit to the proton-carbon analyzing power between 100 and 750 MeV was done.

  5. Electrophilic FLUORIDE-18 from AN 11 Mev Proton Cyclotron for Radiolabeling of Presynaptic Dopaminergic PET Tracers

    NASA Astrophysics Data System (ADS)

    Sunderland, John Joseph

    1990-01-01

    The reliable production of (^{18 }F) F_2 from an 11 MeV proton cyclotron has been achieved through the implementation of two accelerator targets built to exploit the copious ^{18}O(p,n)^ {18}F cross-section. Yields of electrophilic (^{18}F) F_2 from the targets reached deciCurie levels with specific activities approaching 3 Ci/mmole with 75 minute irradiations at 10 muA. Higher specific activities are expected with longer bombardments and increased beam current. The targets, one nickel, the other with a gold -plated target chamber, have been tested for (^ {18}F) F_2 production efficiency under two bombardment protocols. An economic two-step protocol cryogenically reclaims the precious enriched ^{18}O_{2 } target material following ^ {18}F production, followed by a second (^{18}F) F_2 recovery irradiation of Kr + F_2 . Studies of target performance using this protocol under variable irradiation conditions suggest a five compartment model governing the in-target kinetics. Similarly, the (^{18}F) F_2 yields have been tested using a single irradiation protocol consisting of bombardment of ^{18}O_{2} + F _2. Theoretical descriptions of beam induced phenomena in the irradiated target are also presented. The behavior of these targets cannot be judged solely on the amount of reactive ^{18 }F which elutes from the target; successful radiochemical synthesis utilizing this ^ {18}F activity in a model reaction is the true test. Synthesis of 6- (^{18 }F) fluoro-L-DOPA (6-FD) by the fluoro-demercuration method of Luxen served this purpose, testing the eletrophilic (^{18}F) F_2 gas from the two targets and two irradiation protocols. Elution of Kr + (^{18}F) F _2 from the two-step method achieved the expected 12% radiochemical yields from (^ {18}F) F_2, while experience with ^{18}F activity eluted with oxygen from the single irradiation protocol suffered lower yields. Solutions to problems associated with 6-FD studies for Positron Emission Tomography (PET) are addressed. A

  6. Irradiation of strontium chloride targets at proton energies above 35 MeV to produce PET radioisotope Y-86

    SciTech Connect

    Medvedev D. G.; Mausner, L.F.; Srivastava, S.C.

    2011-12-01

    Proton irradiation of natural and enriched SrCl{sub 2} targets was used to produce PET radioisotope {sup 86}. The proton energy was degraded from the incident 117.8 MeV to induce the {sup 88}Sr(p,3n) reaction. For the irradiation three pellets made of {sup nat}SrCl{sub 2} (6.61 and 74.49 g) and {sup 88}SrCl{sub 2} (5.02 g) were pressed and individually encapsulated in stainless steel target bodies. The two smaller targets were irradiated for 0.5-1 h at the energy - 46 {yields} 37 MeV to take advantage of the peak in the excitation function of the {sup 88}Sr(p,3n) reaction. The larger target was irradiated at 66.4 {yields} 44.6 MeV. The irradiated pellets were chemically processed to selectively separate {sup 86}Y radioisotope using Eichrom DGA (N,N,N{prime},N{prime}-tetra-n-octyldiglycolamide) resin. The production yields of {sup 86}Y were determined to be 10-13 mCi/{mu}A h. Coproduction of {sup 87m}Y in the final product was 34% for {sup nat}SrCl{sub 2} and 54% for {sup 88}SrCl{sub 2} target. The chemical separation yield of yttrium reached 88-92%. The developed chemical procedure allows for the same day processing and shipment of the isotope to users.

  7. Design study of the ESS-Bilbao 50 MeV proton beam line for radiobiological studies

    NASA Astrophysics Data System (ADS)

    Huerta-Parajon, M.; Martinez-Ballarin, R.; Abad, E.

    2015-02-01

    The ESS-Bilbao proton accelerator facility has been designed fulfilling the European Spallation Source (ESS) specifications to serve as the Spanish contribution to the ESS construction. Furthermore, several applications of the ESS-Bilbao proton beam are being considered in order to contribute to the knowledge in the field of radiobiology, materials and aerospace components. Understanding of the interaction of radiation with biological systems is of vital importance as it affects important applications such as cancer treatment with ion beam therapy among others. ESS-Bilbao plans to house a facility exclusively dedicated to radiobiological experiments with protons up to 50 MeV. Beam line design, optimisation and initial calculations of flux densities and absorbed doses were undertaken using the Monte Carlo simulation package FLUKA. A proton beam with a flux density of about 106 protons/cm2 s reaches the water sample with a flat lateral distribution of the dose. The absorbed dose at the pristine Bragg peak calculated with FLUKA is 2.4 ± 0.1 Gy in 1 min of irradiation time. This value agrees with the clinically meaningful dose rates, i.e. around 2 Gy/min, used in hadrontherapy. Optimisation and validation studies in the ESS-Bilbao line for radiobiological experiments are detailed in this article.

  8. Anisotropies in the interplanetary intensity of solar protons with energies greater than 0.3 MeV.

    NASA Technical Reports Server (NTRS)

    Innanen, W. G.; Van Allen, J. A.

    1973-01-01

    By using Explorer 35 interplanetary observations of solar protons with energies greater than 0.3 MeV during ten selected solar events (1967-1970) the tine dependence of intensity and of the angular distribution of intensity has been studied for the first time in the sub-MeV range of energy. The respective contributions of diffusive and convective transport are resolved. Results are qualitatively similar to those of McCracken et al. (1968, 1971) in the energy range from 7.5to 45 MeV; but, as was expected, convective transport is found to be relatively more important at the lower energies. The convective component of the anisotropy vector yields values of the solar wind velocity in good agreement with directly measured values.

  9. Excitation functions of (nat)Zn(p,x) nuclear reactions with proton beam energy below 18 MeV.

    PubMed

    Asad, Ali H; Chan, Sun; Morandeau, Laurence; Cryer, David; Smith, Suzanne V; Price, Roger I

    2014-12-01

    We measured the excitation functions of (nat)Zn (p,x) reactions up to 17.6MeV, using the stacked-foils activation technique. High-purity natural zinc (and copper) foils were irradiated with proton beams generated by an 18MeV isochronous cyclotron. Activated foils were measured using high-purity Ge gamma spectroscopy to quantify the radionuclides (61)Cu, (66)Ga, (67)Ga, and (65)Zn produced from the reactions. Thick-target integral yields were also deduced from the measured excitation functions of the produced radioisotopes. These results were compared with the published literature and were found to be in good agreement with most reports, particularly those most recently compiled. PMID:25108597

  10. Proton-induced cross sections relevant to production of 225Ac and 223Ra in natural thorium targets below 200 MeV.

    PubMed

    Weidner, J W; Mashnik, S G; John, K D; Hemez, F; Ballard, B; Bach, H; Birnbaum, E R; Bitteker, L J; Couture, A; Dry, D; Fassbender, M E; Gulley, M S; Jackman, K R; Ullmann, J L; Wolfsberg, L E; Nortier, F M

    2012-11-01

    Cross sections for (223,)(225)Ra, (225)Ac and (227)Th production by the proton bombardment of natural thorium targets were measured at proton energies below 200 MeV. Our measurements are in good agreement with previously published data and offer a complete excitation function for (223,)(225)Ra in the energy range above 90 MeV. Comparison of theoretical predictions with the experimental data shows reasonable-to-good agreement. Results indicate that accelerator-based production of (225)Ac and (223)Ra below 200 MeV is a viable production method. PMID:22940414

  11. Calculations of Neutron- and Proton-Induced Reactions up to 200 MeV for Target 238U

    SciTech Connect

    Yu Hongwei; Zhao Zhixiang; Cai Chonghai

    2005-05-24

    The calculations of neutron- and proton-induced reaction up to 200 MeV for target 238U are performed; the calculated results are generally in good agreement with experimental data, and the physics is rational. The theoretical framework consists of the spherical optical model, intranuclear cascade mechanism for nucleon emission based on empirical formula, preequilibrium emission theory based on exciton model, evaporation model, and Hauser-Feshbach statistical theory with a width fluctuation correction. The fission widths are calculated using the Bohr-Wheeler formula.

  12. Dynamic Strain on Thin Diaphragms of a Mercury Target During 800-MeV Proton Thermal Shock Tests

    SciTech Connect

    Allison, S.W.; Andriulli, J.B.; Cates, M.R.; Earl, D.D.; Haines, J.R.; Morrissey, F.X.; Tsai, C.C.; Wender, S.

    1999-11-13

    Extrinsic Fabry-Perot Interferometric fiber optic sensors were used to measure dynamic strains on thin diaphragms of a liquid mercury target, which was subjected to intense 800-MeV proton thermal shock tests. The mercury target is engineered with very thin end plates or diaphragms (either 0.6 mm or 1.9 mm) for studying large strain effects. During thermal shock tests, the mercury in the target interacted with an intense pulsed beam of 2.4x10{sup 13 protons}. The resulting pressure waves lead to large strains exceeding 250 microstrains on a 0.6-mm diaphragm. Significant factors relative to the accuracy of strain measurements are emphasized, such as the sensor air gap, alignment of sensors, and frequency response of the strain instrument. In this paper, dynamic strains measured on thin diaphragms are described and discussed.

  13. Application of a PAGAT/MgCl2 gel for dose measurements in a 150 MeV proton beam

    NASA Astrophysics Data System (ADS)

    Tominaga, T.; Hayashi, S.; Usui, S.; Kawamura, H.; Katahira, K.

    2013-06-01

    The purpose of this study is to evaluate the dose response of polyacrylamide-based gel (PAGAT) when irradiated with clinical proton beams. Recently inorganic salt additive in gel has been reported to improve dose sensitivity substantially. We attempted to add MgCl2 (0.5M) to regular PAGAT gel in order to compensate its lower radiation sensitivity. The spin-spin relaxation rates (R2) as dose readout was calculated from MR imaging after irradiation with 150MeV proton beam. The dose sensitivity was discussed from the slope at dose-R2 response curve. As the result, the sensitivity of the gel with MgCl2 is approximately 3 times higher than that of regular PAGAT gel without spoiling dose response stability under the various irradiation conditions such as dose rate and dose integration.

  14. The radiation dosimetry of a quartz viewer irradiated with a 4.5 MeV proton beam

    NASA Astrophysics Data System (ADS)

    Ouyasathian, Kalong

    The present dissertation describes a procedure to measure the radiation dose received by an accelerator operator who uses a quartz viewer to locate an ion beam. This procedure consists of the following steps: (i) A solid-state gamma radiation detector was calibrated to determine its efficiency and its energy scale. (ii) The calibrated detector was used to measure the gamma energy spectrum obtained when bombarding the viewer with the ion beam. This measurement was normalized, that is, beam current and measurement duration were determined. (iii) Individual gamma energy lines were extracted from the gamma spectrum and the respective energies and emission rates were obtained. Energies were checked with known transitions in silicon and oxygen, to ensure correct identification. (iv) The Compton gamma energy spectrum generated by the primary gamma rays was determined using a Compton code. (v) Finally the charged-ion bremsstrahlung spectrum was obtained using the formalism of Alder et. al. In this dissertation several prospective contributors to the radiation dose have been checked and were found to be insignificant. They were: the radiation dose due to x-rays generated by Compton electrons and the radiation dose generated by electrons produced by collisions with the incident ions. With a proton energy of 4.5 MeV the eye dose equivalent was determined at 0 and 90 degrees to the proton beam. At 0 degree with a proton fluence rate of 8.9 x 1011 protons/s the dose was 8.7 x 10-3 rem/hr. At 90 degrees with a proton fluence rate of 1.1 x 1012 protons/s the dose was 8.1 x 10-3 rem/hr.

  15. Variations in the Processing of DNA Double-Strand Breaks Along 60-MeV Therapeutic Proton Beams

    PubMed Central

    Chaudhary, Pankaj; Marshall, Thomas I.; Currell, Frederick J.; Kacperek, Andrzej; Schettino, Giuseppe; Prise, Kevin M.

    2016-01-01

    Purpose To investigate the variations in induction and repair of DNA damage along the proton path, after a previous report on the increasing biological effectiveness along clinically modulated 60-MeV proton beams. Methods and Materials Human skin fibroblast (AG01522) cells were irradiated along a monoenergetic and a modulated spread-out Bragg peak (SOBP) proton beam used for treating ocular melanoma at the Douglas Cyclotron, Clatterbridge Centre for Oncology, Wirral, Liverpool, United Kingdom. The DNA damage response was studied using the 53BP1 foci formation assay. The linear energy transfer (LET) dependence was studied by irradiating the cells at depths corresponding to entrance, proximal, middle, and distal positions of SOBP and the entrance and peak position for the pristine beam. Results A significant amount of persistent foci was observed at the distal end of the SOBP, suggesting complex residual DNA double-strand break damage induction corresponding to the highest LET values achievable by modulated proton beams. Unlike the directly irradiated, medium-sharing bystander cells did not show any significant increase in residual foci. Conclusions The DNA damage response along the proton beam path was similar to the response of X rays, confirming the low-LET quality of the proton exposure. However, at the distal end of SOBP our data indicate an increased complexity of DNA lesions and slower repair kinetics. A lack of significant induction of 53BP1 foci in the bystander cells suggests a minor role of cell signaling for DNA damage under these conditions. PMID:26452569

  16. Further results in the search for the direct two-proton decay of ^94Ag^m (J^π= 21^+, 6.7 MeV)

    NASA Astrophysics Data System (ADS)

    Cerny, J.; Lee, D. W.; Perajarvi, K.; Moltz, D. M.; Barquest, B. R.; Grossman, L. E.; Jeong, W.; Jewett, C. C.

    2008-10-01

    Both direct one-proton decay and direct two-proton decay of ^94Ag^m from this 0.4 s isomeric state have been reported in experiments utilizing the GSI on-line mass separator [1]. In the latter decay, coincident events between silicon E detectors with a threshold energy of 0.4 MeV and a summed decay energy of 1.9±0.1 MeV were observed with a yield of 350±210 pb in coincidence with γ-decays in the ^92Rh daughter. We utilized our helium-jet system at the LBNL 88-inch cyclotron to repeat this experiment, again employing the ^58Ni(^40Ca,p3n) reaction at 197 MeV. Reaction products were transported via a capillary to a detection area and collected on a slowly rotating wheel in front of an assembly of 24 δEgas-δEgas-ESi detector telescopes with a threshold of 0.4 MeV for identifying protons. Five of these telescopes observe the 0.79 MeV single proton decay from ^94Ag^m at the reported yield of 1.3 nb. In the 240/276 identified proton detector combinations with low background, no proton-proton coincidences have been observed. Data from the remaining 36 detector combinations require a separate analysis, which is in progress. Monte Carlo analyses of our anticipated proton-proton coincidences for both sets of detector combinations will be presented. ^ 1Mukha et al., Nature 439, 298 (2006).

  17. Activation calculations for trapped protons below 200 MeV: Appendix

    NASA Technical Reports Server (NTRS)

    Laird, C. E.

    1991-01-01

    Tables are given displaying of the results of the activation calculations of metal samples and other material aboard the Long Duration Exposure Facility-1 (LDEF-1) and Spacelab-2 with the computer program, PTRAP4. The computer printouts give the reaction, the reactant product, the proton reaction cross sections as a function of the energy of the incident protons, and the activation as a function of distance into the sample from the exposed surface.

  18. Validity of the relativistic impulse approximation for elastic proton-nucleus scattering at energies lower than 200 MeV

    SciTech Connect

    Li, Z. P.; Hillhouse, G. C.; Meng, J.

    2008-07-15

    We present the first study to examine the validity of the relativistic impulse approximation (RIA) for describing elastic proton-nucleus scattering at incident laboratory kinetic energies lower than 200 MeV. For simplicity we choose a {sup 208}Pb target, which is a spin-saturated spherical nucleus for which reliable nuclear structure models exist. Microscopic scalar and vector optical potentials are generated by folding invariant scalar and vector scattering nucleon-nucleon (NN) amplitudes, based on our recently developed relativistic meson-exchange model, with Lorentz scalar and vector densities resulting from the accurately calibrated PK1 relativistic mean field model of nuclear structure. It is seen that phenomenological Pauli blocking (PB) effects and density-dependent corrections to {sigma}N and {omega}N meson-nucleon coupling constants modify the RIA microscopic scalar and vector optical potentials so as to provide a consistent and quantitative description of all elastic scattering observables, namely, total reaction cross sections, differential cross sections, analyzing powers and spin rotation functions. In particular, the effect of PB becomes more significant at energies lower than 200 MeV, whereas phenomenological density-dependent corrections to the NN interaction also play an increasingly important role at energies lower than 100 MeV.

  19. Characterization of radiation damage caused by 23 MeV protons in Multi-Pixel Photon Counter (MPPC)

    NASA Astrophysics Data System (ADS)

    Li, Zhengwei; Xu, Yupeng; Liu, Congzhan; Gu, Yudong; Xie, Fei; Li, Yanguo; Hu, Hongliang; Zhou, Xu; Lu, Xuefeng; Li, Xufang; Zhang, Shuo; Chang, Zhi; Zhang, Juan; Xu, Zhenling; Zhang, Yifei; Zhao, Jianling

    2016-06-01

    A automatic gain control system (AGC) is designed to continuously monitor and automatically control the gain of the phoswich detectors onboard the Hard X-ray Modulation Telescope (HXMT). It consists of a Am241 radioactive source and a photo-detector. The Am241 radioactive source is tagged within a plastic scintillator (BC440M). The scintillating photons produced by the decayed alpha particles from the radioactive source is readout by the photo-detector. The Multi-Pixel Photon Counter (MPPC) produced by Hamamatsu is used as the photo-detector for AGC. To verify the feasibility of its application in space environment, four MPPCs (S10362-33-050C) were irradiated by a beam of 23 MeV protons. The integrated proton fluence that exposed to the four MPPC samples are 1.0 ×108 p cm-2 , 2.0 ×108 p cm-2 , 4.0 ×108 p cm-2 and 1.0 ×1010 p cm-2 respectively. It is found that the increment leakage current of the MPPC samples caused by irradiation damage increase linearly with the integrated fluence. The pulse-height resolution of the MPPC has deteriorated hardly after irradiation. When irradiated up to 1.1 ×109cm-2 1 MeV equivalent neutrons, the MPPC completely lost its photon-counting capability but could still work as a photo-detector for AGC. The MPPC fails as a photo-detector for the AGC when the irradiated 1 MeV neutron equivalent fluences is up to 2.7 ×1010cm-2 .

  20. Reinvestigation of the Direct Two-proton Decay of the Long-lived Isomer 94Agm [0.4 s, 6.7 MeV, (21+)

    SciTech Connect

    Cerny, J.; Moltz, D. M.; Lee, D. W.; Perajarvi, K.; Barquest, B. R.; Grossman, L. E.; Jeong, W.; Jewett, C.

    2009-03-05

    An attempt to confirm the reported direct one-proton and two-proton decays of the (21+) isomer at 6.7(5) MeV in 94Ag has been made. The 0.39(4) s half-life of the isomer permitted use of a helium-jet system to transport reaction products from the 40Ca + natNi reaction at 197 MeV to a low-background area; 24 gas Delta E-(Si) E detector telescopes were used to identify emitted protons down to 0.4 MeV. No evidence was obtained for two-proton radioactivity with a summed energy of 1.9(1) MeV and a branching ratio of 0.5(3)percent. Two groups of one-proton radioactivity from this isomer had also been reported; our data confirm the lower energy group at 0.79(3) MeV with its branching ratio of 1.9(5)percent.

  1. Chromosome aberrations in human lymphocytes induced by 250 MeV protons: effects of dose, dose rate and shielding

    NASA Astrophysics Data System (ADS)

    George, K.; Willingham, V.; Wu, H.; Gridley, D.; Nelson, G.; Cucinotta, F. A.

    Although the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm 2 aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples.

  2. Validation of nuclear models in Geant4 using the dose distribution of a 177 MeV proton pencil beam

    NASA Astrophysics Data System (ADS)

    Hall, David C.; Makarova, Anastasia; Paganetti, Harald; Gottschalk, Bernard

    2016-01-01

    A proton pencil beam is associated with a surrounding low-dose envelope, originating from nuclear interactions. It is important for treatment planning systems to accurately model this envelope when performing dose calculations for pencil beam scanning treatments, and Monte Carlo (MC) codes are commonly used for this purpose. This work aims to validate the nuclear models employed by the Geant4 MC code, by comparing the simulated absolute dose distribution to a recent experiment of a 177 MeV proton pencil beam stopping in water. Striking agreement is observed over five orders of magnitude, with both the shape and normalisation well modelled. The normalisations of two depth dose curves are lower than experiment, though this could be explained by an experimental positioning error. The Geant4 neutron production model is also verified in the distal region. The entrance dose is poorly modelled, suggesting an unaccounted upstream source of low-energy protons. Recommendations are given for a follow-up experiment which could resolve these issues.

  3. Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets

    DOE PAGESBeta

    Morris, Christopher L.; Bourke, Mark A.; Byler, Darrin D.; Chen, Ching-Fong; Hogan, Gary E.; Hunter, James F.; Kwiatkowski, Kris K.; Mariam, Fesseha G.; McClellan, Kenneth J.; Merrill, Frank E.; et al

    2013-02-11

    We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. Also, we show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods has been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 μm has been demonstrate, 20 μm seems feasible with minor changes) for tomographymore » on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 μm resolution but further development of sources, collimation and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods.« less

  4. Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets.

    PubMed

    Morris, C L; Bourke, M; Byler, D D; Chen, C F; Hogan, G; Hunter, J F; Kwiatkowski, K; Mariam, F G; McClellan, K J; Merrill, F; Morley, D J; Saunders, A

    2013-02-01

    We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. We also show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods have been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 μm has been demonstrate, 20 μm seems feasible with minor changes) for tomography on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 μm resolution but further development of sources, collimation, and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods. PMID:23464222

  5. Neutron yield and induced radioactivity: a study of 235-MeV proton and 3-GeV electron accelerators.

    PubMed

    Hsu, Yung-Cheng; Lai, Bo-Lun; Sheu, Rong-Jiun

    2016-01-01

    This study evaluated the magnitude of potential neutron yield and induced radioactivity of two new accelerators in Taiwan: a 235-MeV proton cyclotron for radiation therapy and a 3-GeV electron synchrotron serving as the injector for the Taiwan Photon Source. From a nuclear interaction point of view, neutron production from targets bombarded with high-energy particles is intrinsically related to the resulting target activation. Two multi-particle interaction and transport codes, FLUKA and MCNPX, were used in this study. To ensure prediction quality, much effort was devoted to the associated benchmark calculations. Comparisons of the accelerators' results for three target materials (copper, stainless steel and tissue) are presented. Although the proton-induced neutron yields were higher than those induced by electrons, the maximal neutron production rates of both accelerators were comparable according to their respective beam outputs during typical operation. Activation products in the targets of the two accelerators were unexpectedly similar because the primary reaction channels for proton- and electron-induced activation are (p,pn) and (γ,n), respectively. The resulting residual activities and remnant dose rates as a function of time were examined and discussed. PMID:25628454

  6. Chromosome aberrations in human lymphocytes induced by 250 MeV protons: effects of dose, dose rate and shielding

    NASA Technical Reports Server (NTRS)

    George, K.; Willingham, V.; Wu, H.; Gridley, D.; Nelson, G.; Cucinotta, F. A.

    2002-01-01

    Although the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm2 aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  7. Chromosome aberrations in human lymphocytes induced by 250 MeV protons: effects of dose, dose rate and shielding.

    PubMed

    George, K; Willingham, V; Wu, H; Gridley, D; Nelson, G; Cucinotta, F A

    2002-01-01

    Although the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm2 aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples. PMID:12539753

  8. 2.6 MeV Proton Irradiation Effects on the Surface Integrity of Depleted UO2

    SciTech Connect

    Pakarinen, Janne; He, Lingfeng; Gupta, Mahima; Gan, Jian; Nelson, Andrew; El-Azab, Anter; Allen, Todd

    2014-01-01

    The effect of low temperature proton irradiation in depleted uranium dioxide was examined as a function of fluence. With 2.6 MeV protons, the fluence limit for preserving a good surface quality was found to be relatively low, about 1.4 and 7.0 x 1017 protons/cm2 for single and poly crystalline samples, respectively. Upon increasing the fluence above this threshold, severe surface flaking and disintegration of samples was observed. Based on scanning electron microscopy (SEM) and X-ray diffraction (XRD) observations the causes of surface failure were associated to high H atomic percent at the peak damage region due to low solubility of H in UO2. The resulting lattice stress is believed to exceed the fracture stress of the crystal at the observed fluencies. The oxygen point defects from the displacement damage may hinder the H diffusion and further increase the lattice stress, especially at the peak damage region.

  9. Proton Radiography of Field Distributions in Ultra-Intense-Laser Plasma Interactions with Pulse of MeV Proton Beams

    NASA Astrophysics Data System (ADS)

    Nakamura, Hirotaka; Kodama, Ryosuke; Tampo, Motonobu; Borghesi, Marco; Romagnani, Lorenzo; Fuchs, Julien; Amin, Munib; Pipahl, Ariane; Willi, Oswald; Michibata, Takuya; Mima, Kunioki; Azechi, Hiroshi

    2008-11-01

    Proton radiography has been used to observe transient electric and magnetic fields in laser plasma interactions. We report an experimental investigation of a transient electric field generated around a laser-irradiated-plasma-fiber attached on a tip of a cone-geometry target. The electric field guided and collimated energetic electrons generated by the laser-plasma interactions in the fiber. The front of these fields propagated along the fiber with the energetic electrons at almost the light velocity. Simulation with the Geant4 Monte Carlo code shows the electric field above a few TV/m were excited around the fiber.

  10. Mechanisms of mutagenesis in human cells exposed to 55 MeV protons

    NASA Technical Reports Server (NTRS)

    Gauny, S.; Wiese, C.; Kronenberg, A.

    2001-01-01

    Protons represent the major type of charged particle radiation in spaceflight environments. The purpose of this study was to assess mutations arising in human lymphoid cells exposed to protons. Mutations were quantitated at the thymidine kinase (TK1) locus in cell lines derived from the same donor: TK6 cells (wt TP53) and WTK1 cells (mutant TP53). WTK1 cells were much more susceptible to mutagenesis following proton exposure than TK6 cells. Intragenic deletions were observed among early-arising TK1 mutants in TK6 cells, but not in WTK1 cells where all of the mutants arose by LOH. Deletion was the predominant mode of LOH in TK6 cells, while allelic recombination was the major mode of LOH in WTK1 cells. Deletions were of variable lengths, from <1 cM to 64 cM, while mutations that arose by allelic recombination often extended to the telomere. In summary, proton exposures elicited many types of mutations at an autosomal locus in human cells. Most involved large scale loss of genetic information, either through deletion or by recombination.

  11. Proton beam studies with a 1.25 MeV, cw radio frequency quadrupole linac

    SciTech Connect

    Bolme, G.O.; Hardek, T.W.; Hansborough, L.D.

    1998-12-31

    A high-current, cw linear accelerator has been proposed as a spallation neutron source driver for tritium production. Key features of this accelerator are high current (100 mA), low emittance-growth beam propagation, cw operation, high efficiency, and minimal maintenance downtime. A 268 MHz, cw radio frequency quadrupole (RFQ) LINAC section and klystrode based rf system were obtained from the Chalk River Laboratories and were previously installed at LANL to support systems development and advanced studies in support of cw, proton accelerators. A variation of the Low Energy Demonstration Accelerator (LEDA) proton injector, modified to operate at 50 keV, was mated to the RFQ and was operated to support advance developments for the Accelerator Production of Tritium (APT) program. High current, proton beam studies were completed which focused on the details of injector-RFQ integration, development of beam diagnostics, development of operations procedures, and personnel and equipment safety systems integration. This development led to acceleration of up to 100 mA proton beam.

  12. Real-time prediction of the occurrence and intensity of the first hours of >100 MeV solar energetic proton events

    NASA Astrophysics Data System (ADS)

    Núñez, Marlon

    2015-11-01

    A new model for predicting the occurrence of >100 MeV solar energetic proton (SEP) events and the first hours of the >100 MeV integral proton flux is presented. This model uses a novel approach based on the lag correlation between strong positive derivatives of X-ray flux and proton flux. The new model has been validated with data from January 1994 to September 2013, obtaining a probability of detection of all >100 MeV SEP events of 80.85%, a false alarm ratio of 29.62%, and an average warning time of 1 h and 6 min. The model identifies the associated flare and active region. Currently, there is no other automatic empirical or physics-based system able to predict SEP events of energies in the interval of 100 MeV to ~430 MeV (lower GLE cutoff according to Clem and Dorman (2000)). This paper also proposes the combined use of the new prediction model and the existing one for predicting >10 MeV SEP events. The combined SEP prediction models have been developed to improve mitigation of adverse effects on near-Earth and interplanetary missions.

  13. Experimental cross-sections for proton induced nuclear reactions on mercury up to 65 MeV

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Tárkányi, F.; Takács, S.; Ditrói, F.; Szücs, Z.; Brezovcsik, K.

    2016-07-01

    Cross-sections for formation of activation products induced by protons on natural mercury targets were measured. Results for 196m,196g,197g(cum), 198m,198g,199g(cum), 200g(cum), 201,202Tl, 194g(cum), 195g(cum), 196g(cum), 198m,199g(cum) Au and 195m,197m,203Hg are presented up to 65 MeV incident particle energy, many of these for the first time. The experimental data are compared with literature values and with the predictions of the TALYS 1.6 code (results taken from TENDL-2015 on-line library), thick target yields were derived and possible applications in biomedical sciences are discussed.

  14. Activation cross-sections of proton induced reactions on natSm up to 65 MeV

    NASA Astrophysics Data System (ADS)

    Tárkányi, F.; Hermanne, A.; Takács, S.; Ditrói, F.; Ignatyuk, A. V.

    2015-03-01

    Activation cross sections for proton induced reactions on Sm are presented for the first time for natSm(p,xn)154,152m2,152m1,152g,150m,150g,149,148,147,146,145Eu, natSm(p,x)153,145Sm, natSm(p,x)151,150,149,148g,148m,146,144,143Pm and natSm(p,x)141Nd up to 65 MeV. The cross sections were measured via activation method by using a stacked-foil irradiation technique and high resolution gamma ray spectroscopy. The results were compared with results of the nuclear reaction codes ALICE, EMPIRE and TALYS (results taken from TENDL libraries). Integral yields of the activation products were calculated from the excitation functions.

  15. Results of 1 MeV proton irradiation of front and back surfaces of silicon solar cells

    NASA Technical Reports Server (NTRS)

    Anspaugh, B. E.; Kachare, R.; Weizer, V. G.

    1987-01-01

    Several silicon solar cells with and without back surface fields (BSF), having thicknesses of 200 microns and 63 microns were irradiated with 1 MeV protons having fluences between 1 times 10 to the 10th power and 1 times 10 to the 12th power p/square cm. The irradiation was performed using both normal and isotropic incidence on the front as well as back surfaces of the solar cells. The results of the back surface irradiations are analyzed using a model in which irradiation induced defects across the high-low (BSF) junction are considered. It is concluded that degradation of the high-low junction is responsible for the severe performance loss in thinner cells when irradiated from the rear.

  16. Activation cross-sections of proton induced reactions on vanadium in the 37-65 MeV energy range

    NASA Astrophysics Data System (ADS)

    Ditrói, F.; Tárkányi, F.; Takács, S.; Hermanne, A.

    2016-08-01

    Experimental excitation functions for proton induced reactions on natural vanadium in the 37-65 MeV energy range were measured with the activation method using a stacked foil irradiation technique. By using high resolution gamma spectrometry cross-section data for the production of 51,48Cr, 48V, 48,47,46,44m,44g,43Sc and 43,42K were determined. Comparisons with the earlier published data are presented and results predicted by different theoretical codes (EMPIRE and TALYS) are included. Thick target yields were calculated from a fit to our experimental excitation curves and compared with the earlier experimental yield data. Depth distribution curves to be used for thin layer activation (TLA) are also presented.

  17. Spectroscopic determination of hypochlorous acid, in chloride brine solutions, featuring 5 MeV proton beam line experiments

    NASA Astrophysics Data System (ADS)

    Hartmann, Thomas; Paviet-Hartmann, Patricia; Wetteland, Christopher; Lu, Ningping

    2003-04-01

    The irradiation effects of 4.9 MeV protons on salt repository related brines are investigated spectrophotometrically. The induced formation of hypochlorous acid is determined up to doses of 11 kGy in 3.7 M MgCl 2·6H 2O and in a multicomponent brine of high concentration: Brine G. The build-up of hypochlorous acid to a steady-state concentration is found to be independent on the chloride concentration. The ultimate objective of this experiment is the estimation of the G value for HOCl in which meaningful predictions of long-term redox conditions in a nuclear repository strongly depend on. This paper describes our first steps towards the determination of HOCl.

  18. MECHANICAL PROPERTIES AND MICROSTRUCTURE IN LOW ACTIVATION MARTENSITIC STEELS F82H AND OPTIMAX AFTER 800 MEV PROTON IRRADIATION

    SciTech Connect

    Y. DAI; ET AL

    1999-10-01

    Low-activation martensitic steels, F82H (mod.) and Optimax-A, have been irradiated with 800-MeV protons up to 5.9 dpa. The tensile properties and microstructure have been studied. The results show that radiation hardening increases continuously with irradiation dose. F82H has lesser irradiation hardening as compared to Optimax-A in the present work and DIN1.4926 from a previous study. The irradiation embrittlement effects are evident in the materials since the uniform elongation is reduced sharply to less than 2%. However, all the irradiated samples ruptured in a ductile-fracture mode. Defect clusters have been observed. The size and the density of defect clusters increase with the irradiation dose. Precipitates are amorphous after irradiation.

  19. Stopping power of palladium for protons in the energy range 0.300-3.100 MeV

    NASA Astrophysics Data System (ADS)

    Miranda, P. A.; Sepúlveda, A.; Morales, J. R.; Rodriguez, T.; Burgos, E.; Fernández, H.

    2014-01-01

    The stopping power of palladium for protons has been measured using the transmission method with an overall uncertainty of around 5% over the energy range Ep=(0.300-3.100) MeV. These stopping power data are then compared to stopping power values calculated by the SRIM-2010 code and to those derived from a model based on the dielectric formalism. Subsequently, and within the framework of the modified Bethe-Bloch theory, this stopping power data were used for extracting Pd target mean excitation and ionization potential, (I = 468 ± 5 eV), and Barkas effect parameter, (b = 1.51 ± 0.06). A good agreement is found between the obtained results and values reported in literature.

  20. Measurement of excitation functions in proton induced reactions on natural copper from their threshold to 43 MeV

    NASA Astrophysics Data System (ADS)

    Shahid, Muhammad; Kim, Kwangsoo; Naik, Haladhara; Zaman, Muhammad; Yang, Sung-Chul; Kim, Guinyun

    2015-01-01

    We have measured the production cross-sections of the residual radionuclides from proton-induced reactions of natCu by using a stacked-foil activation and off-line γ-ray spectrometric technique in the energy range from their respective threshold to 43 MeV at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Sciences. The measured results were compared with the earlier reported data as well as with the theoretical values obtained from the TENDL-2013 library based on the TALYS 1.6 code. The integral yields for thick target of the investigated radio-nuclides were calculated from the measured excitation function and the stopping power of natCu.

  1. Elastic scattering and breakup of 11Be on protons at 26.9 A MeV

    NASA Astrophysics Data System (ADS)

    Chen, J.; Lou, J. L.; Ye, Y. L.; Li, Z. H.; Ge, Y. C.; Li, Q. T.; Li, J.; Jiang, W.; Sun, Y. L.; Zang, H. L.; Aoi, N.; Ideguchi, E.; Ong, H. J.; Ayyad, Y.; Hatanaka, K.; Tran, D. T.; Yamamoto, T.; Tanaka, M.; Suzuki, T.; Tho, N. T.; Rangel, J.; Moro, A. M.; Pang, D. Y.; Lee, J.; Wu, J.; Liu, H. N.; Wen, C.

    2016-03-01

    The elastic scattering and breakup of the halo nucleus 11Be on protons at an incident energy of 26.9 A MeV have been measured. The 11Be+p elastic scattering cross sections at various energies, including the present one, are systematically analyzed with the Chapel Hill 89 (CH89) and Koning-Delaroche (KD) global optical model potentials (OMPs), and the corresponding normalization factors are obtained. An extended version of the continuum-discretized coupled-channels (XCDCC) formalism, including dynamic core excitation effects, is applied to analyze the elastic scattering and breakup data. It is found that the core excitation plays a moderate role in the elastic scattering and breakup reaction of the halo nucleus 11Be, being consistent with previous results at higher energies.

  2. Calculating Variations in Biological Effectiveness for a 62 MeV Proton Beam

    PubMed Central

    Carante, Mario Pietro; Ballarini, Francesca

    2016-01-01

    A biophysical model of radiation-induced cell death and chromosome aberrations [called BIophysical ANalysis of Cell death and chromosome Aberrations (BIANCA)] was further developed and applied to therapeutic protons. The model assumes a pivotal role of DNA cluster damage, which can lead to clonogenic cell death following three main steps: (i) a DNA “cluster lesion” (CL) produces two independent chromosome fragments; (ii) fragment mis-rejoining within a threshold distance d gives rise to chromosome aberrations; (iii) certain aberration types (dicentrics, rings, and large deletions) lead to clonogenic inactivation. The yield of CLs and the probability, f, that a chromosome fragment remains un-rejoined even if other fragment(s) are present within d, were adjustable parameters. The model, implemented as a MC code providing simulated dose–responses directly comparable with experimental data, was applied to pristine and modulated Bragg peaks of the proton beam used to treat eye melanoma at INFN-LNS in Catania, Italy. Experimental survival curves for AG01522 cells exposed to the Catania beam were reproduced, supporting the model assumptions. Furthermore, cell death and chromosome aberrations at different depths along a spread-out Bragg peak (SOBP) dose profile were predicted. Both endpoints showed an increase along the plateau, and high levels of damage were found also beyond the distal dose fall-off, due to low-energy protons. Cell death and chromosome aberrations were also predicted for V79 cells, in the same irradiation scenario as that used for AG01522 cells. In line with other studies, this work indicated that assuming a constant relative biological effectiveness (RBE) along a proton SOBP may be sub-optimal. Furthermore, it provided qualitative and quantitative evaluations of the dependence of the beam effectiveness on the considered endpoint and dose. More generally, this work represents an example of therapeutic beam characterization avoiding the use of

  3. Calculating Variations in Biological Effectiveness for a 62 MeV Proton Beam.

    PubMed

    Carante, Mario Pietro; Ballarini, Francesca

    2016-01-01

    A biophysical model of radiation-induced cell death and chromosome aberrations [called BIophysical ANalysis of Cell death and chromosome Aberrations (BIANCA)] was further developed and applied to therapeutic protons. The model assumes a pivotal role of DNA cluster damage, which can lead to clonogenic cell death following three main steps: (i) a DNA "cluster lesion" (CL) produces two independent chromosome fragments; (ii) fragment mis-rejoining within a threshold distance d gives rise to chromosome aberrations; (iii) certain aberration types (dicentrics, rings, and large deletions) lead to clonogenic inactivation. The yield of CLs and the probability, f, that a chromosome fragment remains un-rejoined even if other fragment(s) are present within d, were adjustable parameters. The model, implemented as a MC code providing simulated dose-responses directly comparable with experimental data, was applied to pristine and modulated Bragg peaks of the proton beam used to treat eye melanoma at INFN-LNS in Catania, Italy. Experimental survival curves for AG01522 cells exposed to the Catania beam were reproduced, supporting the model assumptions. Furthermore, cell death and chromosome aberrations at different depths along a spread-out Bragg peak (SOBP) dose profile were predicted. Both endpoints showed an increase along the plateau, and high levels of damage were found also beyond the distal dose fall-off, due to low-energy protons. Cell death and chromosome aberrations were also predicted for V79 cells, in the same irradiation scenario as that used for AG01522 cells. In line with other studies, this work indicated that assuming a constant relative biological effectiveness (RBE) along a proton SOBP may be sub-optimal. Furthermore, it provided qualitative and quantitative evaluations of the dependence of the beam effectiveness on the considered endpoint and dose. More generally, this work represents an example of therapeutic beam characterization avoiding the use of

  4. Polarized-target asymmetry in pion-proton bremsstrahlung at 298 MeV

    SciTech Connect

    Bosshard, A.; Amsler, C.; Bistirlich, J.A.; van den Brandt, B.; Crowe, K.M.; Doebeli, M.; Doser, M.; Haddock, R.P.; Konter, J.A.; Ljungfelt, S.; Loude, J.F.; Mango, S.; Meyer, C.A.; Perroud, J.P.; Riedlberger, J.; Renker, D.; Schaad, M.; Sober, D.I.; Truoel, P.; Weymuth, P. Lawrence Berkeley Laboratory, University of California at Berkeley, Berkeley California 94720 Paul Scherrer Institut, 5232 Villigen, Paul Scherrer Institut, Department of Physics, University of California at Los Angeles, Los Angeles, California 90024 Institut de Physique Nucleaire, Universite de Lausanne, 1015 Lausanne, Department of Physics, Catholic University of America, Washington, D.C. 10024 )

    1990-05-28

    First data are presented for the polarized-target asymmetry in the reaction {pi}{sup +}{ital p}{r arrow}{pi}{sup +}{ital p}{gamma} at an incident pion energy of 298 MeV. The geometry was chosen to maximize the sensitivity to the radiation of the magnetic dipole moment {mu}{sub {Delta}} of the {Delta}{sup ++}(1232 MeV). A fit of the asymmetry in the cross section {ital d}{sup 5}{sigma}/{ital d}{Omega}{sub {pi}} {ital d}{Omega}{sub {gamma}} {ital dk} as a function of the photon energy {ital k} to predictions from a recent isobar-model calculation with {mu}{sub {Delta}} as the only free parameter yields {mu}{sub {Delta}}=1.64({plus minus}0.19exp{Delta},{plus minus}0.14 theor){mu}{sub {ital p}}. Though this value agrees with bag-model corrections to the SU(6) prediction {mu}{sub {Delta}}=2{mu}{sub {ital p}}, further clarifications on the model dependence of the result are needed, in particular since the isobar model fails to describe both the cross section and the asymmetry at the highest photon energies.

  5. Characterization of the proton beam at the output of the 6.7MeV LEDA RFQ.

    SciTech Connect

    Allen, C. K.; Colestock, P. L. ,; Gilpatrick, J. D.; Lysenko, W. P.; Rybarcyk, L. J.; Schneider, J. D.; Sheffield, R. L.; Smith, H. V.; Wangler, Thomas P.,; Crandall, K. R.; Chan, D.; Garnett, R. W.; Schulze, M. E.

    2001-01-01

    The present configuration of the Low-Energy Demonstration Accelerator (LEDA) consists of a 75-keV proton injector, a 6.7-MeV 350-MHz cw radio-frequency quadrupole (RFQ) with associated high-power and lowlevel rf systems, a 52-magnet periodic lattice followed by a short high-energy beam transport (HEBT) and highpower (670-kW cw) beam stop. The rms beam emittance was measured prior to the installation of the 52-magnet lattice, based on wire-scanner measurements of the beam profile at a single location in the HEBT. New measurements with additional diagnostic hardware have been performed to determine the rms transverse beam properties of the beam at the output of the 6.7-MeV LEDA RFQ. The 52-magnet periodic lattice also includes ten beam position monitors (BPMs) evenly spaced in pairs of two. The BPMs provide a measure of the bunched beam current that exhibits nulls at different locations in the lattice. Model predictions of the locations of the nulls and the strength of the bunched beam current are made to determine what information this data can provide regarding the longitudinal beam emittance.

  6. Forward-angle neutron-proton scattering at 96 MeV

    SciTech Connect

    Johansson, C.; Blomgren, J.; Atac, A.; Bergenwall, B.; Hildebrand, A.; Klug, J.; Mermod, P.; Pomp, S.; Oesterlund, M.; Dangtip, S.; Tippawan, U.; Elmgren, K.; Jonsson, O.; Prokofiev, A.V.; Renberg, P.-U.; Nadel-Turonski, P.; Nilsson, L.; Olsson, N.

    2005-02-01

    The differential np scattering cross section has been measured at 96 MeV in the angular range {theta}{sub c.m.}=20 deg. -76 deg. Together with an earlier data set at the same energy, covering the angles {theta}{sub c.m.}=74 deg. -180 deg., a new data set has been formed in the angular range {theta}{sub c.m.}=20 deg. - 180 deg. This extended data set has been normalized to the experimental total np cross section, resulting in a renormalization of the earlier data of 0.7%, which is well within the reported normalization uncertainty for that experiment. A novel normalization technique has been investigated. The results on forward np scattering are in reasonable agreement with theory models and partial wave analyses and have been compared with data from the literature.

  7. Interplanetary protons (E/sub p/ approx. 1 MeV) 1973-1986 and out to 22. 4 AU

    SciTech Connect

    Van Allen, J.A.; Decker, R.B.

    1988-03-01

    This reprint uses annual mean counting rate data from detectors on two long-lived spacecraft, Pioneer 11 and IMP 8, to study the temporal and and heliocentric radial distance variations of the intensity of interplanetary protons (E/sub p/ about = 1 MeV) over solar activity cycle 21. The Pioneer 11 data cover the time period April 1973 through 1986 and the heliocentric radial distance range 1.0 < r < 22.4 AU. IMP 8, in an approximately circular geocentric orbit of semimajor axis 35 earth radii, provides comparable data at 1 AU over the time period 1974-1986. The combination of two bodies of data shows that the annual mean intensity of such protons varies as the inverse square of the distance from the sun, i.e., as r to the -alpha power with alpha = 2.0 (+ or - 0.2), irrespective of solar activity as measured by the annual mean sunspot number S. Also it is found (a) that the annual mean intensity at 1 AU is approximately proportional to S, except for anomalously low values in 1979 and 1980 and (b) that the product of the annual mean intensity at Pioneer 11 by r-square is also approximately proportional to S, except for anomalously low values in 1979, 1980 (in particular), and 1981. The common 1980 anomaly is attributed to gross changes in interplanetary conditions associated with the reversal of the polarity of the sun's polar magnetic field.

  8. Cross-field diffusion of energetic (100 keV to 2 MeV) protons in interplanetary space

    SciTech Connect

    Costa Jr, Edio da; Tsurutani, Bruce T.; Alves, Maria Virgínia; Echer, Ezequiel; Lakhina, Gurbax S. E-mail: costajr.e@gmail.com

    2013-12-01

    Magnetic field magnitude decreases (MDs) are observed in several regions of the interplanetary medium. In this paper, we characterize MDs observed by the Ulysses spacecraft instrumentation over the solar south pole by using magnetic field data to obtain the empirical size, magnetic field MD, and frequency of occurrence distribution functions. The interaction of energetic (100 keV to 2 MeV) protons with these MDs is investigated. Charged particle and MD interactions can be described by a geometrical model allowing the calculation of the guiding center shift after each interaction. Using the distribution functions for the MD characteristics, Monte Carlo simulations are used to obtain the cross-field diffusion coefficients as a function of particle kinetic energy. It is found that the protons under consideration cross-field diffuse at a rate of up to ≈11% of the Bohm rate. The same method used in this paper can be applied to other space regions where MDs are observed, once their local features are well known.

  9. Measurement of a 200 MeV proton beam using a polyurethane dosimeter

    NASA Astrophysics Data System (ADS)

    Heard, Malcolm; Adamovics, John; Ibbott, Geoffrey

    2006-12-01

    PRESAGETM (Heuris Pharma LLC, Skillman, NJ) is a three-dimensional polyurethane dosimeter containing a leuco dye that generates a color change when irradiated. The dosimeter is solid and does not require a container to maintain its shape. The dosimeter is transparent before irradiation and the maximum absorbance of the leuco dye occurs at 633 nm which is compatible with the OCT-OPUSTM laser CT scanner (MGS Research, Inc., Madison, CT). The purpose of this study was to investigate the response of PRESAGETM to proton beam radiotherapy.

  10. Two-Proton Intensity Interferometry for Impact - Selected ARGON-36 + SCANDIUM-45 Collisions at E/a = 80, 120 and 160 Mev.

    NASA Astrophysics Data System (ADS)

    Handzy, Damian Orest

    1995-01-01

    Impact-parameter selected two-proton intensity interferometry is used to study the space-time characteristics of emitting sources formed in medium-energy heavy-ion collisions. Building on a previous study for the same system at a lower energy, a high-resolution 56-element Si-CsI(Tl) hodoscope was used to collect single- and two-proton yields, for collisions of ^{36}Ar + ^{45}Sc at E/A = 120 MeV and 160 MeV. Coincident measurements of other charged particles emitted in the reaction were made with the MSU 4pi Array, providing information about the impact-parameter of the collision. The Boltzmann-Uehling-Uhlenbeck (BUU) equation is used to predict the emission of protons from the reaction zone created in heavy-ion collisions. The Koonin-Pratt formalism is then used to calculate theoretical correlation functions from the predicted single-particle phase space probability density. Dependencies of predicted longitudinal and transverse correlation functions on source velocity are examined for central and peripheral ^ {36}A + ^{45} Sc collisions at E/A = 80 MeV, and are compared to previously measured values. The usefulness of the correlation function to distinguish exotically shaped sources, predicted by microscopic transport models at this energy, is investigated. Consistent with previous measurements, proton correlations are shown to have larger peaks for more energetic protons, regardless of impact-parameter. However, the measured correlations are shown to decrease as beam energy increases from E/A = 80 to 160 MeV, indicating that proton -emitting sources formed in more energetic collisions appear to have larger space-time extents. For central collisions at E/A = 160 MeV, the correlation function shows no dependence on the momentum of the proton pair, suggesting that the source emits fast and slow protons on similar time scales. The BUU theory is shown to over predict the magnitude of the measured correlations for the reactions at E/A = 120 and 160 MeV, possibly because

  11. Elastic scattering of polarized protons on helium three at 800 MeV

    SciTech Connect

    Azizi, A.

    1985-07-01

    A set of spin dependent parameters and cross sections has been measured for polarized p-/sup 3/He elastic scattering over the range of q .7 to 4.2 fm/sup -1/. The experiment was done at the Los Alamos Meson Physics Facility (LAMPF) using the High Resolution Spectrometer (HRS) with a polarized proton beam at .8 GeV. The focal plane polarimeter of the HRS was used to determine the spin direction of the scattered proton. Since /sup 3/He is one of the simplest nuclei, polarized p-/sup 3/He scattering provides a very sensitive test of multiple scattering theories. The theoretical analysis was done by using two different wave functions for /sup 3/He as input to the multiple scattering theory. The theoretical calculations and experimental data together will give us useful information about nucleon-nucleon amplitudes and also help us to obtain a better understanding of the scattering process. 68 refs., 55 figs., 9 tabs.

  12. Performance of timing Resistive Plate Chambers with protons from 200 to 800 MeV

    NASA Astrophysics Data System (ADS)

    Machado, J.; Adamczewski-Musch, J.; Blanco, A.; Boretzky, K.; Cabanelas, P.; Cartegni, L.; Ferreira Marques, R.; Fonte, P.; Fruehauf, J.; Galaviz, D.; Heil, M.; Henriques, A.; . Ickert, G.; Körper, D.; Lopes, L.; Palka, M.; Pereira, A.; Rossi, D.; Simon, H.; Teubig, P.; Traxler, M.; Velho, P.; Altstadt, S.; Atar, L.; Aumann, T.; Bemmerer, D.; Caesar, C.; Charpy, A.; Elekes, Z.; Fiori, E.; Gasparic, I.; Gerbig, J.; Göbel, K.; Heftrich, T.; Heine, M.; Heinz, A.; Holl, M.; Ignatov, A.; Isaak, J.; Johansson, H.; Kelic-Heil, A.; Lederer, C.; Lindberg, S.; Löher, B.; Marganiec, J.; Martensson, M.; Nilsson, T.; Panin, V.; Paschalis, S.; Petri, M.; Plag, R.; Pohl, M.; Rastrepina, G.; Reifarth, R.; Reinhardt, T. P.; Röder, M.; Savran, D.; Scheit, H.; Schrock, P.; Silva, J.; Stach, D.; Strannerdahl, F.; Thies, R.; Wagner, A.; Wamers, F.; Weigand, M.

    2015-01-01

    A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic protons produced from a deuteron beam of varying energy (200 to 800 AMeV) in experiment S406 at GSI, Darmstadt, Germany. The aim of the experiment is to characterize the response of the prototype to protons in this energy range, which deposit from 1.75 to 6 times more energy than minimum ionizing particles. Each layer, with an active area of about 2000 × 500 mm2, is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C2H2F4 and 10% SF6. The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Results show an uniform efficiency close to 100% along with a timing resolution of around 60 ps on the entire 2000 × 500 mm2 area.

  13. An application of GafChromic MD-55 film for 67.5 MeV clinical proton beam dosimetry.

    PubMed

    Daftari, I; Castenadas, C; Petti, P L; Singh, R P; Verhey, L J

    1999-11-01

    The purpose of this study is to explore the use of GafChromic MD-55 (RC) film for 67.5 MeV clinical proton beam dosimetry at the Crocker Nuclear Laboratory, University of California, Davis. Several strips of RC film 6 cm x 6 cm in dimension were irradiated at a depth of 18.2 mm corresponding to the middle of a 24 mm spread-out Bragg peak (SOBP). The films were irradiated to a proton dose in the range of 0.5 Gy to 100 Gy. The beam profiles were also measured at the middle of the 24 mm SOBP. The Bragg peak was measured by using a wedge shaped phantom made of Lucite. The Bragg peak measured with RC film was compared with diode and ionization chamber measurements. After background subtraction, the calibration of the dose response of RC film showed, to a maximum deviation of 10%, a linear increase of optical density (OD) with dose from 0.5 to 100 Gy. The uniformity of OD over a single sheet of film showed a variation of +/-6%. The distal-fall off between 90% and 20% measured with GafChromic film for the Bragg peak was 1.3 mm as compared to 1.1 mm for a diode measurement and 1.4 mm for an ionization chamber measurement. The FWHM of the Bragg peak was 7.5 mm when measured with GafChromic film, 5.3 mm when measured with a diode and 8.1 mm as measured by an ionization chamber. The peak/plateau ratio with GafChromic film was 3.3 as compared to 3.7 with a diode and 3.2 with an ionization chamber. In conclusion, GafChromic MD-55 film may be a useful and convenient detector for dose measurement and quality assurance programmes of proton beams. PMID:10588281

  14. Simultaneous quiet time observations of energetic radiation belt protons and helium ions - The equatorial alpha/p ratio near 1 MeV

    NASA Technical Reports Server (NTRS)

    Fritz, T. A.; Spjeldvik, W. N.

    1979-01-01

    Simultaneous monitoring of energetic helium ions and protons in the earth's radiation belts has been conducted with Explorer 45 in the immediate vicinity of the equatorial plane. Protons were measured from less than 1 keV to 1.6 MeV and also above 3.3 MeV in a channel responsive up to 22 MeV; helium ions were monitored in three passbands: 910 keV to 3.15 MeV, 590 to 910 keV, and 2.0 to 3.99 MeV. Alpha/proton flux ratios were found to vary significantly with energy and location in the radiation belts. At equal energy per nucleon a range of variability for alpha/p from 0.0001 to well above 0.001 was found, and at equal energy per ion the corresponding variability was from 0.001 to above 10. The latter findings emphasize the relative importance of the very energetic helium ions in the overall radiation belt ion populations.

  15. RBE and genetic susceptibility of mouse and rat spermatogonial stem cells to protons, heavy charged particles and 1.5 MeV neutrons

    NASA Astrophysics Data System (ADS)

    Vaglenov, A.; Fedorenko, B.; Kaltenboeck, B.

    The main purpose of the present study is to provide data on RBE and genetic susceptibility in the mouse and the rat when exposed to protons, HZE particles and neutrons. Genetic damage from exposure to 50 MeV and 9 GeV protons, 4 GeV/nucleon helium ions, 4 GeV/nucleon carbon ions and 1.5 MeV neutrons was studied in adult (CBA × C57Bl/6J) F1 mice. Damage from 9 GeV protons and 4 GeV helium ions was studied in adult Wistar rats. The incidence of reciprocal translocations (RT) induced in the spermatogonial stem cells of each species was recorded. RBE values were derived by comparing linear regression coefficients from dose-responses within the same dose-range for each of the radiation types tested and 60Co γ-rays or by means of a direct nonparametric method. RT yields measured after mouse and rat spermatogonial irradiation with protons, heavy charged particles and neutrons fit the linear model of the dose-response relationship. Relative to 60Co γ-rays, RBE values are as follows for mouse spermatogonia: 0.9 for 50 MeV protons; 1.3 for 9 GeV protons; 0.7 for 4 GeV helium ions; and 1.3 for 4 GeV carbon ions. For rat spermatogonia, values were: 1.7 for 9 GeV protons and 1.3 for helium ions. Compared to mice irradiated using the same experimental design, rats were more susceptible to high-LET radiations, with susceptibility assessed by genetic damage to their spermatogonial stem cells. The RBE of 1.5 MeV neutron is about 6.6.

  16. Noise performance of 0.35-(mu)m SOI CMOS devices and micropower preamplifier following 63-MeV, 1-Mrad (Si) proton irradiation

    NASA Technical Reports Server (NTRS)

    Binkley, D. M.; Hopper, C. E.; Cressler, J. D.; Mojarradi, M. M.; Blalock, B. J.

    2004-01-01

    This paper presents measured noise for 0.35(mu)m, silicon-on-insulator devices and a micropower preamplifier following 63-MeV, 1-Mrad (Si) proton irradiation. Flicker noise voltage, important for gyros having low frequency output, increases less than 32% after irradiation.

  17. Calculation of proton total reaction cross sections for some target nuclei in incident energy range of 10-600 MeV

    SciTech Connect

    Bueyuekuslu, H.; Kaplan, A.; Aydin, A.; Tel, E.; Yildirim, G.

    2010-10-15

    In this study, proton total reaction cross sections have been investigated for some isotopes such as {sup 12}C, {sup 27}Al, {sup 9}Be, {sup 16}O, {sup 181}Ta, {sup 197}Au, {sup 6}Li, and {sup 14}N by a proton beam up to 600 MeV. Calculation of the proton total cross sections has been carried out by the analytic expression formulated by M.A. Alvi by using Coulomb-modified Glauber theory with the Helm model nuclear form factor. The obtained results have been discussed and compared with the available experimental data and found to be in agreement with each other.

  18. Energy loss of MeV protons specularly reflected from metal surfaces

    SciTech Connect

    Juaristi, J.I.

    1996-05-01

    A parameter-free model is presented to study the energy loss of fast protons specularly reflected from metal surfaces. The contributions to the energy loss from excitation of valence-band electrons and ionization of localized target-atom electronic states are calculated separately. The former is calculated from the induced surface wake potential using linear response theory and the specular-reflection model, while the latter is calculated in the first Born approximation. The results obtained are in good agreement with available experimental data. However, the experimental qualitative trend of the energy loss as a function of the angle of incidence is obtained when the valence-band electron model is replaced by localized target atom electron states, though with a worse quantitative agreement. {copyright} {ital 1996 The American Physical Society.}

  19. Hugoniot Measurements at Low Pressures in Tin Using 800 MeV proton Radiography

    SciTech Connect

    Schwartz, Cynthia; Hogan, Gary E; King, Nicholas S. P.; Kwiathowski, Kris K.; Mariam, Fesseha G.; Marr-Lyon, Mark; McNeil, Wendy Vogan; Merrill, Frank E.; Morris, Christopher; Rightley, Paul; Saunders, Alexander

    2009-08-05

    A 2cm long 8 mm diameter cylindrical tin target has been shocked to a pressure in the region of the {beta} {yields} {gamma} phase change using a small, low density PETN charge mounted on the opposite side of a stainless steel diaphragm. The density jump and shock velocity were measured radiographically as the shock wave moved through the sample and the pressure dropped, using the proton radiography facility at LANL. This provided a quasi-continuous record of the equations of state along the Hugoniot for the P1 wave from a shock velocity of 3.25 km/sec down to near the sound speed. Edge release effects were removed from the data using tomographic techniques. The data show evidence for a phase transition that extends over a broad pressure range. The data and analysis will be presented.

  20. Microscopic description of proton scattering at 295 MeV from Pb isotopes

    SciTech Connect

    Rafi, Syed; Pachouri, Dipti; Sharma, Manjari; Haider, W.; Bhagwat, A.; Gambhir, Y. K.

    2011-09-15

    Microscopic analysis of the recently reported 295-MeV-proton scattering data from Pb isotopes and {sup 58}Ni is presented within the framework of the Brueckner-Hartree-Fock theory. The effective interaction (g matrix) has been calculated using three Hamiltonians with Urbana v-14, Argonne v-18, and Ried93 internucleon potentials. The microscopic optical potential is calculated by folding the effective interactions over nucleon density distributions obtained in the relativistic mean field framework. The Argonne v-18 and Ried93 interactions have been used for the first time to calculate the nucleon-nucleus optical potential. The calculations reproduce the experiment well thus revalidating the use of microscopic optical potential in such analyses.

  1. Cross-field transport of less than 1 MeV protons in energetic particle events

    NASA Technical Reports Server (NTRS)

    Zwickl, R. D.; Roelof, E. C.; Gold, R. E.

    1980-01-01

    A systematic analysis of hourly averaged low-energy anisotropy data (0.3-0.5 MeV) has been carried out with the JHU/APL detectors onboard the IMP-7 and 8 spacecraft from 1972-1975. The energetic particle events were divided into two major groups: flare-associated or nonimpulsive. Resolving the anistropy vectors into components parallel and perpendicular to the measured magnetic field leads directly to the following model-independent conclusions: (1) the average perpendicular anisotropy component is entirely accounted for in terms of the ExB drift, and hence transverse diffusion is negligible at these energies; application of the diffusion model to the nonimpulsive data set implies a ratio of the diffusion mean free paths parallel and perpendicular to the magnetic field much less than 0.051; (2) the parallel anisotropy component averages nearly to zero in the nonimpulsive data set, indicating virtually no net streaming along the field at 1 AU, averaged over all events.

  2. The Elemental Analysis of Biological and Environmental Materials Using a 2MEV Proton Beam

    NASA Astrophysics Data System (ADS)

    Arshed, Waheed

    Available from UMI in association with The British Library. A programme has been developed to simulate the proton induced x-ray emission (PIXE) spectra and its uses have been described. The PIXE technique has been applied to the analysis of new biological reference materials which consist of IAEA human diet samples and NIST leaf samples. Homogeneity of these and two existing reference materials, IAEA soil -7 and Bowen's kale, has also been determined at the mug scale. A subsample representative of a material is ascertained by determination of sampling factors for the elements detected in the material. Proton induced gamma-ray emission (PIGE) analysis in conjunction with PIXE has been employed to investigate F and other elemental concentrations found in human teeth samples. The mean F concentration in enamel and dentine parts of teeth followed an age dependent model. Concentrations of Ca and P were found to be higher in the enamel than in the dentine. Analysis of blood and its components in the study of elemental models in sickle cell disease in Nigerians has been carried out. Comparisons revealed that Cl, Ca and Cu were at higher levels whereas K, Fe, Zn and Rb were at lower levels in the whole blood of the sicklers compared to controls. Similar results were obtained for the erythrocytes except that Br was found at higher concentration in erythrocytes of the sicklers. Higher concentrations of Cl, K, Fe and Cu were also observed in plasma of the sicklers compared to controls. PIXE and scanning electron microscopy (SEM) were used in the characterization of the Harmattan dust particulates collected at Kano and Ife. Most of the elements were found to be at higher concentrations as compared to those found in Recife (Brazil) and Toronto (Canada). The value of total suspended particulate was above the relevant national air quality standards. PIXE in conjunction with Rutherford backscattering spectrometry and instrumental neutron activation analysis was employed in the

  3. Stopping of 236 keV - 3.019 MeV protons in mylar and polypropylene films

    NASA Astrophysics Data System (ADS)

    Damache, S.; Ouichaoui, S.; Belhout, A.; Medouni, A.; Toumert, I.

    2004-10-01

    The stopping powers of polypropylene and mylar polymers for protons have been accurately measured over the energy intervals Ep=(0.352-3.009) MeV and Ep=(0.236-3.019) MeV, respectively. Ab initio calculations using the Sigmund-Schinner binary collision theory for electronic stopping yielded S( E) values fairly consistent with the measured data that show no noticeable deviations from the Bragg-Kleeman additivity rule. The data have also been analyzed in the framework of the modified Bethe-Bloch theory assuming additivity. Values of the mean excitation and ionization potential, I, and of the Barkas parameter, b, have been deduced for the two polymers and for their (C, O) atomic constituents by adopting values of these parameters recommended in the ICRU-49 report for the H element. Thus, the respective I-values {(56.90 ± 0.72) eV, (79.92 ± 1.30) eV} for the two polymers and the same b-value 1.39 for their (C, O) atomic constituents have been determined by adopting for H the value b=1.8, while the I-values {(81.73 ± 1.38) eV, (109.46 ± 6.55) eV} have been deduced for the (C, O) constituents by adopting for H the value I=19.2 eV. Priorily, the shell, Barkas and Bloch corrections to the calculated S( E) values have been evaluated for both polymers over the explored respective energy ranges. The obtained results are discussed in comparison with previous ones when reported in the literature to our knowledge.

  4. Thorium and uranium M-shell x-ray production cross sections for 0.4--4.0 MeV protons, 0.4--6.0 MeV helium ions, 4.5--11.3 mev carbon ions, and 4.5--13.5 MeV oxygen ions

    NASA Astrophysics Data System (ADS)

    Phinney, Lucas C.

    The M-shell x-ray production cross section for thorium and uranium have been determined for protons of energy 0.4--4.0 MeV, helium ions of energy 0.4--6.0 MeV, carbon ions of energy 4.5--11.3 MeV and oxygen ions of energy 4.5--13.5 MeV. The total cross sections and the cross sections for individual x-ray peaks in the spectrum, consisting of the following transitions Mz (M4-N2, M5-N3, M4-N3), Ma (M5-N6,7), Mb (M4-N6, M5-O3, M4-O2), and Mg (M4-O3, M5-P3, M3-N4, M3-N5), were compared to the theoretical values determined from the PWBA + OBKN and ECUSAR. The theoretical values for the carbon and oxygen ions were also modified to take into account the effects of multiple ionizations of the target atom by the heavier ions. It is shown that the results of the ECUSAR theory tend to provide better agreement with the experimental data.

  5. The depth-dependent radiation response of human melanoma cells exposed to 65 MeV protons.

    PubMed

    Courdi, A; Brassart, N; Hérault, J; Chauvel, P

    1994-08-01

    Radiation therapy with positively charged particles implies that the Bragg peak be spread out to deliver a homogeneous dose to the tumour. The spread-out Bragg peak (SOBP) has a higher linear energy transfer (LET) than the entrance beam. In addition, there is an LET gradient from proximal to distal SOBP. The aim of this study is to find out whether these small LET variations lead to differences in radiation response. Human melanoma cells (CAL4) were exposed to 65 MeV proton beams produced by the cyclotron Medicyc at five different positions: 2 mm depth corresponding to the entrance, 15, 20, 25 and 26.8 mm depth corresponding to four different positions in the half-modulated SOBP. Survival curves were generated using the in vitro colony method and fitted with the linear-quadratic model. Survival differences were observed at high doses; they were statistically significant at a dose of 8 Gy. With respect to the entrance position (2 mm), the relative biological effectiveness (RBE) at 1% survival was 1.09, 1.12, 1.19 and 1.27 at 15, 20, 25 and 26.8 mm in the SOBP, respectively. Whereas RBE values in the SOBP greater than 1.0 relative to the entrance beam represent a small biological advantage to be added to the well-known physical advantage of high energy proton beams; the RBE gradient along the SOBP would imply that the distal end of the tumour would receive a higher biologically equivalent dose than the proximal end, despite a homogeneous physical dose, especially at the high doses per fraction given in ocular melanomas. Although the increase in effectiveness with depth is mild, it should be kept in mind during eye treatment planning, in case a critical target is present at the extreme end of the SOBP. PMID:8087487

  6. Evaluation of 10MeV proton irradiation on 5.5 Mpixel scientific CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Vu, Paul; Fowler, Boyd; Rodricks, Brian; Balicki, Janusz; Mims, Steve..; Li, Wang

    2010-10-01

    We evaluate the effects of 10 MeV proton irradiation on the performance of a 5.5 Mpixel scientific grade CMOS image sensor based on a 5T pixel architecture with pinned photodiode and transfer gate. The sensor has on-chip dual column level amplifiers and 11-bit single slope analog to digital converters (ADC) for high speed readout and wide dynamic range. The operation of the sensor is programmable and controlled by on-chip digital control modules. Since the image sensor features two identical halves capable of operating independently, we used a mask to expose only one half of the sensor to the proton beam, leaving the other half intact to serve as a reference. In addition, the pixel array and the digital logic control section were irradiated separately, at dose rates varying from 4 rad/s to 367 rad/s, for a total accumulated dose of 146 krad(Si) to assess the radiation effects on these key components of the image sensor. We report the resulting damage effects on the performance of the sensor including increase in dark current, temporal noise, dark spikes, transient effects and latch-up. The dark signal increased by about 55 e-/pixel after exposure to 14 krad (Si) and the dark noise increased from about 2.75e- to 6.5e-. While the number of hot pixels increased by 6 percent and the dark signal non uniformity degraded, no catastrophic failure mechanisms were observed during the tests, and the sensor did not suffer from functional failures.

  7. Measurement of Dynamic Strain on a Mercury Target Vessel During 800-MeV Proton Thermal Shock Tests

    SciTech Connect

    Cates, M.R.

    2001-01-11

    A mercury target vessel, designed to simulate some aspects of the eventual target design for the proposed Spallation Neutron Source (SNS) to be built in Oak Ridge by the Department of Energy, was used in a test at the Los Alamos Neutron Science Center (LANSCE) to study the strain induced from thermal shock of bombarding protons. In the SNS, intense thermal shock loads are expected to cause an enormous rate of temperature rise ({approximately}10{sup 7} K/s), with resulting pressure waves in the mercury that may lead to large stresses on the thin walls of the mercury target. To guide the mercury target design and to benchmark the computer design codes, transient strain was measured using fiber optic Fabry-Perot sensors. Twenty strain sensors were attached in various axial and transverse orientations to a cylindrical stainless steel target vessel containing mercury. The vessel was 10 cm in diameter, about 15 cm long, and with a 5-cm radius hemispherical shell welded to the forward end. The test was done at the LANSCE Weapons Neutron Research (WNR) beam facility on 30-31 January 1999. The sensors were attached with gauge lengths of about two centimeters, and were located in pairs in most areas, for redundancy and facilitation of data analysis. The 800-MeV proton deposition of 0.5--2.3 x 10{sup 13} over a full-width at half maximum beam size of {approximately}25 mm, produced axial strains peaking at a few microstrains, with transverse (hoop) strains more than an order of magnitude higher. We describe the experiments, including the sensors and measurement configuration, and discuss the strain data analysis.

  8. [BIOLOGICAL EFFECTIVENESS OF FISSION SPECTRUM NEUTRONS AND PROTONS WITH ENERGIES OF 60-126 MEV DURING ACUTE AND PROLONGED IRRADIATION].

    PubMed

    Shafirkin, A V

    2015-01-01

    Neutrons of the fission spectrum are characterized by relatively high values of linear energy transfer (LET). Data about their effects on biological objects are used to evaluate the risk of delayed effects of accelerated ions within the same LET range that serve as an experimental model of the nuclei component of galactic cosmic rays (GCR). Additionally, risks of delayed consequences to cosmonaut's health and average lifetime from certain GCR fluxes and secondary neutrons can be also prognosticated. The article deals with comparative analysis of the literature on reduction of average lifespan (ALS) of animals exposed to neutron reactor spectrum, 60-126 MeV protons, and X- and γ-rays in a broad range of radiation intensity and duration. It was shown that a minimal lifespan reduction by 5% occurs due to a brief exposure to neutrons with the absorbed dose of 5 cGy, whereas same lifespan reduction due to hard X- and γ-radiation occurs after absorption of a minimal dose of 100 cGy. Therefore, according to the estimated minimal ALS reduction in mice, neutron effectiveness is 20-fold higher. Biological effectiveness of protons as regards ALS reduction is virtually equal to that of standard types of radiation. Exposure to X- and γ-radiation with decreasing daily doses, and increasing number of fractions and duration gives rise to an apparent trend toward a less dramatic ALS reduction in mice; on the contrary, exposure to neutrons of varying duration had no effect on threshold doses for the specified ALS reductions. Factors of relative biological effectiveness of neutrons reached 40. PMID:26934784

  9. Generation of energetic (>15 MeV) neutron beams from proton- and deuteron-driven nuclear reactions using short pulse lasers

    NASA Astrophysics Data System (ADS)

    Petrov, G. M.; Higginson, D. P.; Davis, J.; Petrova, Tz B.; McGuffey, C.; Qiao, B.; Beg, F. N.

    2013-10-01

    A roadmap is proposed for the production of high-energy (>15 MeV) neutrons using short pulse lasers. Different approaches are suggested for the two limiting cases of small (E1 ≪ Q) and large (E1 ≫ Q) projectile energies E1 depending on the Q-value of the nuclear reaction. The neutron fluence from many converter materials is evaluated for two projectiles: protons and deuterons. We found profound differences between proton- and deuteron-driven reactions with regard to both converter material and generated neutron fluence. The optimum converter material for deuteron-driven reactions is low-Z elements such as Li and Be, while for proton-driven reactions the converter material is not critical. For a projectile energy of 50 MeV the deuteron-driven reactions are two orders of magnitude more efficient compared to the proton-driven reactions. Two-dimensional particle-in-cell simulations have been performed for laser pulses with peak intensity 3 × 1020 W cm-2, pulse duration 40 fs, spot size 5 µm and energy 3 J interacting with ultrathin (0.1 µm) CD foil. The calculated deuteron beam is highly directional along the laser propagation direction with maximum energy of 45 MeV. The interaction of the deuteron beam with a lithium converter and the production of neutrons is modeled using a Monte Carlo code. The computed neutron spectra show that a forward directed neutron beam is generated with an opening angle of ˜1 sr, maximum energy of 60 MeV and a fluence in the forward direction 1.8 × 108 n sr-1, ˜20% of which are with energy above 15 MeV.

  10. Neutron spectra produced by 30, 35 and 40 MeV proton beams at KIRAMS MC-50 cyclotron with a thick beryllium target

    NASA Astrophysics Data System (ADS)

    Shin, Jae Won; Bak, Sang-In; Ham, Cheolmin; In, Eun Jin; Kim, Do Yoon; Min, Kyung Joo; Zhou, Yujie; Park, Tae-Sun; Hong, Seung-Woo; Bhoraskar, V. N.

    2015-10-01

    Neutrons over a wide range of energies are produced by bombarding a 1.05 cm thick beryllium target with protons of different energies delivered by the MC-50 Cyclotron of the Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux Φ(En) versus neutron energy En, produced by protons of 30, 35, and 40 MeV energies, was obtained by using the GEANT4 code with a data-based hadronic model. For the experimental validation of the simulated neutron spectra, a number of pure aluminum and iron oxide samples were irradiated with the neutrons produced by 30, 35, and 40 MeV protons at 20 μA beam current. The gamma-ray activities of 24Na and 56Mn produced, respectively, through 27Al(n,α)24Na and 56Fe(n,p)56Mn reactions were measured by a HPGe detector. The neutron flux Φ(En) at each neutron energy from the simulation was multiplied with the evaluated cross-sections σ(En) of the respective nuclear reaction, and the summation ∑ Φ(En) σ(En) was calculated over the neutron spectrum for each proton energy of 30, 35, and 40 MeV. The measured gamma-ray activities of 24Na and 56Mn were found in good agreement with the activities estimated by using the summed values of ∑ Φ(En) σ(En) along with other parameters in a neutron activation method.

  11. Measurement of neutron spectra generated from bombardment of 4 to 24 MeV protons on a thick {sup 9}Be target and estimation of neutron yields

    SciTech Connect

    Paul, Sabyasachi; Sahoo, G. S.; Tripathy, S. P. E-mail: tripathy@barc.gov.in; Sunil, C.; Bandyopadhyay, T.; Sharma, S. C.; Ramjilal,; Ninawe, N. G.; Gupta, A. K.

    2014-06-15

    A systematic study on the measurement of neutron spectra emitted from the interaction of protons of various energies with a thick beryllium target has been carried out. The measurements were carried out in the forward direction (at 0° with respect to the direction of protons) using CR-39 detectors. The doses were estimated using the in-house image analyzing program autoTRAK-n, which works on the principle of luminosity variation in and around the track boundaries. A total of six different proton energies starting from 4 MeV to 24 MeV with an energy gap of 4 MeV were chosen for the study of the neutron yields and the estimation of doses. Nearly, 92% of the recoil tracks developed after chemical etching were circular in nature, but the size distributions of the recoil tracks were not found to be linearly dependent on the projectile energy. The neutron yield and dose values were found to be increasing linearly with increasing projectile energies. The response of CR-39 detector was also investigated at different beam currents at two different proton energies. A linear increase of neutron yield with beam current was observed.

  12. A comparison of 4 MeV Proton and Co-60 gamma irradiation induced degradation in the electrical characteristics of N-channel MOSFETs

    NASA Astrophysics Data System (ADS)

    Anjum, Arshiya; Vinayakprasanna, N. H.; Pradeep, T. M.; Pushpa, N.; Krishna, J. B. M.; Gnana Prakash, A. P.

    2016-07-01

    N-channel depletion MOSFETs were irradiated with 4 MeV Proton and Co-60 gamma radiation in the dose range of 100 krad(Si) to 100 Mrad(Si). The electrical characteristics of MOSFET such as threshold voltage (Vth), density of interface trapped charges (ΔNit), density of oxide trapped charges (ΔNot), transconductance (gm), mobility (μ), leakage current (IL) and drain saturation current (ID Sat) were studied as a function of dose. A considerable increase in ΔNit and ΔNot and decrease in Vth,gm, μ, and ID Sat was observed after irradiation. The results of 4 MeV Proton irradiation were compared with that of Co-60 gamma radiation and it is found that the degradation is more for the devices irradiated with 4 MeV Protons when compared with the Co-60 gamma radiation. This indicates that Protons induce more trapped charges in the field oxide region when compared to the gamma radiation.

  13. Radiation performance of GaAs concentrator cells for 0.4 to 12 MeV electrons and 0.1 to 37 MeV protons

    NASA Technical Reports Server (NTRS)

    Curtis, Henry B.; Anspaugh, Bruce

    1991-01-01

    Gallium arsenide concentrator cells have been irradiated with both electrons and protons with a wide variety of energies. The cells are made using OM-VPE growth process with a junction depth of a half micron. All data are taken with bare cells without coverglasses or shielding. Performance data are given at the designed concentration level of 100X AMO. Results are presented in a number of ways, including performance of electrical parameters (Pmax, Isc, and Voc) as a function of fluence for different electron and proton energies. Critical fluences (defined at a degradation of 25 percent in Pmax) are calculated for each energy level and presented for both electron and proton irradiations.

  14. Stopping powers of havar for protons from 0.45 to 3.0 MeV

    NASA Astrophysics Data System (ADS)

    Shiomi-Tsuda, N.; Sakamoto, N.; Ogawa, H.; Saitoh, M.; Kitoba, U.

    1998-02-01

    Stopping powers of havar (a cobalt based alloy) for protons from 0.45 to 3.0 MeV have been measured with an uncertainty of ±0.35% using the accelerator at Nara Women's University. The results agree fairly well with experimental data reported by Duder et al. [J.C. Duder, J.F. Clare, H. Naylor, Nucl. Instr. and Meth. 123 (1975) 89] within the uncertainties. The results also have been compared with the calculated stopping power values obtained by Bragg's additivity rule using the stopping power values for constituent elements calculated by Janni [J.F. Janni, At. Data Nucl. Data Tables 27 (1982) 147] and by Andersen and Ziegler's formula [H.H. Andersen, J.F. Ziegler, Hydrogen Stopping Powers and Ranges in All Elements, Pergamon Press, New York, 1977]. Applying the modified Bethe-Bloch formula for the stopping power of compounds assuming the validity of Bragg's additivity rule, we extracted an effective mean excitation energy, I value, for havar from the stopping power data.

  15. Annealing characteristics of amorphous silicon alloy solar cells irradiated with 1.00 MeV protons

    NASA Technical Reports Server (NTRS)

    Abdulaziz, Salman S.; Woodyard, James R.

    1991-01-01

    Amorphous Si:H and amorphous Si sub x, Ge sub (1-x):H solar cells were irradiated with 1.00 MeV proton fluences in the range of 1.00E14 to 1.25E15 cm (exp -2). Annealing of the short circuit current density was studied at 0, 22, 50, 100, and 150 C. Annealing times ranged from an hour to several days. The measurements confirmed that annealing occurs at 0 C and the initial characteristics of the cells are restored by annealing at 200 C. The rate of annealing does not appear to follow a simple nth order reaction rate model. Calculations of the short-circuit current density using quantum efficiency measurements and the standard AM1.5 global spectrum compare favorably with measured values. It is proposed that the degradation in J sub sc with irradiation is due to carrier recombination through the fraction of D (o) states bounded by the quasi-Fermi energies. The time dependence of the rate of annealing of J sub sc does appear to be consistent with the interpretation that there is a thermally activated dispersive transport mechanism which leads to the passivation of the irradiation induced defects.

  16. New excitation functions for proton induced reactions on natural titanium, nickel and copper up to 70 MeV

    NASA Astrophysics Data System (ADS)

    Garrido, E.; Duchemin, C.; Guertin, A.; Haddad, F.; Michel, N.; Métivier, V.

    2016-09-01

    New excitation functions for proton induced nuclear reactions on natural titanium, nickel and copper were measured, using the stacked-foil technique and gamma spectrometry, up to 70 MeV. The experimental cross sections were measured using the Ti-nat(p,x) V-48, Ni-nat(p,x) Ni-57 and Cu-nat(p,x) Zn-62,Co-56 monitor reactions recommended by the International Atomic Energy Agency (IAEA), depending on the investigated energy range. Data have been extracted for the Ti-nat(p,x) Sc-43,44m,46,47,48, V-48, K-42,43, Ni-nat(p,x) Ni-56,57, Co-55,56,57,58, Mn-52,54, Cu-nat(p,x) Cu-61,64, Ni-57, Co-56,57,58,60, Zn-62,65, Mn-54 reactions. Our results are discussed and compared to the existing ones as well as with the TALYS code version 1.6 calculations using default models. Our experimental data are in overall good agreement with the literature. TALYS is able to reproduce, in most cases, the experimental trend. Our new experimental results allow to expand our knowledge on these excitation functions, to confirm the existing trends and to give additional values on a large energy range. This work is in line with the new Coordinated Research Project (CRP) launched by the IAEA to expand the database of monitor reactions.

  17. Secondary neutron spectrum from 250-MeV passively scattered proton therapy: Measurement with an extended-range Bonner sphere system

    SciTech Connect

    Howell, Rebecca M.; Burgett, E. A.

    2014-09-15

    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

  18. MeV proton beams generated by 3 mJ ultrafast laser pulses at 0.5 kHz

    SciTech Connect

    Hou Bixue; Nees, John; Easter, James; Thomas, Alexander; Krushelnick, Karl; Davis, Jack; Petrov, George

    2009-09-07

    Well-collimated proton beams are generated from bulk glass along the target normal direction by tightly focused 55 fs, 3 mJ pulses from a laser operating at 0.5 kHz repetition rate. Proton beams with energies of >265 keV have an emission angle of about 16 deg. full width at half maximum. Spectral measurements indicate proton energies exceeding 0.5 MeV with a flux of 3.2x10{sup 9} s{sup -1} sr{sup -1} and the flux of measured protons with energies of greater than 90 keV is 8.5x10{sup 11} s{sup -1} sr{sup -1} on center.

  19. Investigation of the Stability and 1.0 MeV Proton Radiation Resistance of Commercially Produced Hydrogenated Amorphous Silicon Alloy Solar Cells

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth R., II; Walters, Michael R.; Woodyard, James R.

    1994-01-01

    The radiation resistance of commercial solar cells fabricated from hydrogenated amorphous silicon alloys is reported. A number of different device structures were irradiated with 1.0 MeV protons. The cells were insensitive to proton fluences below 1E12 sq cm. The parameters of the irradiated cells were restored with annealing at 200 C. The annealing time was dependent on proton fluence. Annealing devices for one hour restores cell parameters for fluences below 1E14 sq cm fluences above 1E14 sq cm require longer annealing times. A parametric fitting model was used to characterize current mechanisms observed In dark I-V measurements. The current mechanism were explored with irradiation fluence, and voltage and light soaking times. The thermal generation current density and quality factor increased with proton fluence. Device simulation shows the degradation in cell characteristics may be explained by the reduction of the electric field in the intrinsic layer.

  20. Light response of YAP:Ce and LaBr3:Ce scintillators to 4-30 MeV protons for applications to Telescope Proton Recoil neutron spectrometers

    NASA Astrophysics Data System (ADS)

    Cazzaniga, C.; Cremona, A.; Nocente, M.; Rebai, M.; Rigamonti, D.; Tardocchi, M.; Croci, G.; Ericsson, G.; Fazzi, A.; Hjalmarsson, A.; Mazzocco, M.; Strano, E.; Gorini, G.

    2016-06-01

    The light response of two thin inorganic scintillators based on YAP:Ce and LaBr3:Ce crystals has been measured with protons in the 4-8 MeV energy range at the Uppsala tandem accelerator and in the 8-26 MeV energy range at the Legnaro tandem accelerator. The crystals have been calibrated in situ with 137Cs and 60Co γ-ray sources. The relative light yields of protons with respect to gammas have been measured and are here reported to be (96±2)% and (80±2)% for YAP:Ce and LaBr3:Ce, respectively. The results open up to the development of a Telescope Proton Recoil spectrometer based on either of the two crystals as alternative to a silicon based spectrometer for applications to high neutron fluxes.

  1. Measured and simulated transport of 1.9 MeV laser-accelerated proton bunches through an integrated test beam line at 1 Hz

    NASA Astrophysics Data System (ADS)

    Nishiuchi, M.; Sakaki, H.; Hori, T.; Bolton, P. R.; Ogura, K.; Sagisaka, A.; Yogo, A.; Mori, M.; Orimo, S.; Pirozhkov, A. S.; Daito, I.; Kiriyama, H.; Okada, H.; Kanazawa, S.; Kondo, S.; Shimomura, T.; Tanoue, M.; Nakai, Y.; Sasao, H.; Wakai, D.; Daido, H.; Kondo, K.; Souda, H.; Tongu, H.; Noda, A.; Iseki, Y.; Nagafuchi, T.; Maeda, K.; Hanawa, K.; Yoshiyuki, T.; Shirai, T.

    2010-07-01

    A laser-driven repetition-rated 1.9 MeV proton beam line composed of permanent quadrupole magnets (PMQs), a radio frequency (rf) phase rotation cavity, and a tunable monochromator is developed to evaluate and to test the simulation of laser-accelerated proton beam transport through an integrated system for the first time. In addition, the proton spectral modulation and focusing behavior of the rf phase rotation cavity device is monitored with input from a PMQ triplet. In the 1.9 MeV region we observe very weak proton defocusing by the phase rotation cavity. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code. The transmitted proton beam duration of 6 ns corresponds to an energy spread near 5% for which the transport efficiency is simulated to be 10%. The predictive capability of PARMILA suggests that it can be useful in the design of future higher energy transport beam lines as part of an integrated laser-driven ion accelerator system.

  2. Pitch Angle Distributions of 0.6-1.8 MeV Protons Observed by Voyager 1 at 85-87 AU

    SciTech Connect

    Decker, R.B.; Krimigis, S.M.; Roelof, E.C.; Burlaga, L.F.; Ness, N.F.

    2004-09-15

    We combined daily averages of magnetic field vector data and 0.6-1.8 MeV proton angular intensity data to construct 32 pitch angle distributions (PADs) for measurements made by Voyager 1 (V1) at 85-87 AU. The PADs were observed during the period 2002.6-2003.1, when energetic particle instruments on V1 measured unusually high intensities. The angular data show large, mainly unidirectional beaming of protons most often in the -T direction, i.e., away from the sun in the sense of a spiral magnetic field. The mean anisotropy amplitude based on the 32 samples is 0.55{+-}0.21.

  3. Measurement of LET (linear energy transfer) spectra using CR-39 at different depths of water irradiated by 171 MeV protons: A comparison with Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Sahoo, G. S.; Tripathy, S. P.; Molokanov, A. G.; Aleynikov, V. E.; Sharma, S. D.; Bandyopadhyay, T.

    2016-05-01

    In this work, we have used CR-39 detectors to estimate the LET (linear energy transfer) spectrum of secondary particles due to 171 MeV proton beam at different depths of water including the Bragg peak region. The measured LET spectra were compared with those obtained from FLUKA Monte Carlo simulation. The absorbed dose (DLET), dose equivalent (HLET) were estimated using the LET spectra. The values of DLET and HLET per incident proton fluence were found to increase with the increase in depth of water and were maximum at Bragg peak.

  4. Cross-section for proton tritium scattering from 1.4 to 3.4 MeV at the laboratory angle of 165°

    NASA Astrophysics Data System (ADS)

    Xia, X. J.; Ding, W.; Zhang, B.; Long, X. G.; Luo, S. Z.; Peng, S. M.; Hutton, R.; Shi, L. Q.

    2008-03-01

    The elastic scattering cross-section for proton scattering from tritium was measured at a laboratory angle of 165° and over an incident proton energy range from 1.4 to 3.4 MeV. A thin solid target containing 1.62 × 1017 T atoms/cm2 was prepared by absorption of tritium into a film of titanium on aluminium foil backing. The cross-section increases almost linearly with decreasing energy in the higher energy region of 2-3.4 MeV. The currently measured cross-section data are compared with data available in the literature values and they show a similarly linear trend in a similar higher energy range. The maximum difference in the cross-section at almost the same scattering angle between current data and the previous results is no worse than 2.3%.

  5. Traceable stopping cross sections of Al and Mo elemental targets for 0.9-3.6-MeV protons

    NASA Astrophysics Data System (ADS)

    Moro, M. V.; Silva, T. F.; Mangiarotti, A.; Guimarães-Filho, Z. O.; Rizzutto, M. A.; Added, N.; Tabacniks, M. H.

    2016-02-01

    Accurate knowledge about the energy loss of ions in matter is essential in many problems, ranging from fundamental to applied nuclear physics. Indeed, there is a recent and increasing demand for new data on stopping cross sections measured with high accuracy and with a rigorous budget of their uncertainty sources. In the present paper we describe an accurate and traceable approach to determine the stopping cross sections in pure elemental materials—aluminum and molybdenum—for protons in the energy range of 0.9-3.6 MeV by the transmission method. The main sources of uncertainties here considered are (i) (random) the uncertainty in the peak positions and in the Gaussian fits and (ii) (systematic) the presence of thickness nonuniformity (a special procedure has been developed to correct it as far as possible). The accuracy in the final stopping cross section is 0.63 % (0.32 % random and 0.54 % systematic) for Al and 1.5 % (0.44 % random and 1.4 % systematic) for Mo, both mainly limited by the quality and homogeneity of the foils. For Al, this high accuracy represents an improvement compared to previous publications and serves as a benchmark for our procedure. For Mo, even though the uncertainty is somewhat higher, our results will help in improving the few data currently available in the energy range here considered. The data were also compared to the most commonly employed theoretical models (srim 1985, srim 2013, pstar, and casp 5.2) and Monte Carlo codes (geant 3 and geant 4). The experimental results are electronically available as supplemental material.

  6. 0.5 - 165 MeV proton and 102 - 312 keV electron injections during the 2006 December 13 SEP event

    NASA Astrophysics Data System (ADS)

    Aran, A.; Agueda, N.; Jacobs, C.; Lario, D.; Sanahuja, B.; Poedts, S.; Marsden, R. G.

    2010-12-01

    The last large solar energetic particle event of solar cycle 23 was observed on 2006 December 13. The origin of this event was associated with a X3.4 flare from AR10930 at S06W23 and a fast (> 1700 km/s) halo CME. A long-lasting type III and a metric type II radio burst were also recorded. We combine proton observations from ACE/EPAM, SOHO/ERNE and STEREO/IMPACT (24 energy channels from 0.5 to 165 MeV) to model the proton differential intensities measured during this event. We simulate both the propagation of the CME-driven shock (from 4 solar radii to 1 AU) and the transport of shock-accelerated protons along the upstream interplanetary magnetic field lines. Near-relativistic (102 - 312 keV) electron observations by ACE/EPAM during the early phase of the event are used to constrain the electron transport conditions along the field lines and deduce, via a Monte Carlo transport model, the electron injection profile close to the Sun. The best-fit electron injection profile shows one prompt component consistent with the timing and duration of both the radio type III and the hard X-ray bursts and a second delayed injection component timely associated with the type II radio burst. From the proton modelling we quantify the injection rate of shock accelerated protons and show that most of the > 50 MeV protons are injected when the shock is still close to the Sun (i.e. within 42 solar radii). We compare the inferred electron and proton injections and discuss the possible contribution of flare-related particles in the early phase of the event.

  7. Measurements of proton induced γ-ray emission cross-sections on Mg from 1.0 to 3.0 MeV

    NASA Astrophysics Data System (ADS)

    Sharifzadeh, N.; Kakuee, O.; Mohammadi, S.

    2016-04-01

    Differential cross-section of proton induced γ-ray emission from the reactions 24Mg(p,p‧γ)24Mg (Eγ = 1369 keV), 25Mg(p,p‧γ)25Mg (Eγ = 390, 585, 975 keV) and 26Mg(p,γ)27Al (Eγ = 1014 keV) were measured for proton energies from 1 to 3 MeV using a 60 μg/cm2 Mg target evaporated on a 40 μg/cm2 Ag thin film. The γ-rays were collected by a 50% relative efficiency HPGe detector placed at an angle of 90° with respect to the beam direction, while the backscattered protons were collected by an ion implanted Si detector placed at a scattering angle of 165°. Simultaneous collection of γ-ray and RBS spectra is a great advantage of this approach which makes differential cross-section measurements independent on the collected beam charge. Measured cross-section values were compared with the previously reported data in the literature. Absolute γ-ray differential cross-sections were obtained with an overall systematic uncertainty of about ±6% and statistical uncertainty of less than ±5% for proton energies higher than 2.24 MeV.

  8. Search for narrow structure in proton-antiproton annihilation cross sections from 1900 to 1960 MeV

    SciTech Connect

    Lowenstein, D.I.; Pealsee, D.C.; Miller, R.J.; Lewis, R.A.; Oh, B.Y.; Smith, G.A.; Whitmore, J.; Brando, T.; Daftari, I.; deGuzman, A.

    1985-01-01

    The anti pp annihilation cross section has been measured with good resolution (approx.2 MeV rms) in the mass range 1900-1960 MeV. No narrow structures are seen, the 90% confidence level upper limit being 8-12 mb-MeV for the integrated area of a resonance in this mass range. However, we do not rule out a very narrow bump-dip structure seen in an earlier experiment in the 1935-1941 MeV mass interval. The data also do not support the existence of a broad structure previously reported at 1937 MeV.

  9. Recovery of the chemical ordering in L1{sub 0} MnAl epitaxial thin films irradiated by 2 MeV protons

    SciTech Connect

    Anuniwat, Nattawut; Cui, Yishen; Wolf, Stuart A.; Lu, Jiwei; Weaver, Bradley D.

    2013-03-11

    Epitaxial MnAl films with a high chemical ordering were synthesized and characterized during a series of irradiations by 2 MeV protons (H{sup +}). The chemical ordering was first reduced to a minimum at a total fluence (TF) of 1 Multiplication-Sign 10{sup 15} H{sup +}/cm{sup 2}, and consequently was recovered at the final total fluence of 2 Multiplication-Sign 10{sup 15} H{sup +}/cm{sup 2}. We attributed the recovery of chemical ordering to thermal effects and the enhanced diffusion caused by the high energy protons. In addition, the damages by the protons have little effect on the magnetic scattering processing in MnAl characterized by the anomalous Hall effect.

  10. Radiation tolerance characterization of dual band InAs/GaSb type-II strain-layer superlattice pBp detectors using 63 MeV protons

    SciTech Connect

    Cowan, V. M.; Morath, C. P.; Hubbs, J. E.; Myers, S.; Plis, E.; Krishna, S.

    2012-12-17

    The radiation tolerance characterization of dual band InAs/GaSb type-II strain-layer superlattice pBp detectors of varying size using 63 MeV proton irradiation is presented. The detectors' mid-wave infrared performance degraded with increasing proton fluence {Phi}{sub P} up to 3.75 Multiplication-Sign 10{sup 12} cm{sup -2} or, equivalently, a total ionizing dose = 500 kRad (Si). At this {Phi}{sub P}, an {approx}31% drop in quantum efficiency {eta}, {approx}2 order increase in dark current density J{sub D}, and consequently, >1 order drop in calculated detectivity D* were observed. Proton damage factors were determined for {eta} and D*. Arrhenius-analysis of temperature-dependent J{sub D} measurements reflected significant changes in the activation energies following irradiation.

  11. Geant4 Monte Carlo simulation of absorbed dose and radiolysis yields enhancement from a gold nanoparticle under MeV proton irradiation

    NASA Astrophysics Data System (ADS)

    Tran, H. N.; Karamitros, M.; Ivanchenko, V. N.; Guatelli, S.; McKinnon, S.; Murakami, K.; Sasaki, T.; Okada, S.; Bordage, M. C.; Francis, Z.; El Bitar, Z.; Bernal, M. A.; Shin, J. I.; Lee, S. B.; Barberet, Ph.; Tran, T. T.; Brown, J. M. C.; Nhan Hao, T. V.; Incerti, S.

    2016-04-01

    Gold nanoparticles have been reported as a possible radio-sensitizer agent in radiation therapy due to their ability to increase energy deposition and subsequent direct damage to cells and DNA within their local vicinity. Moreover, this increase in energy deposition also results in an increase of the radiochemical yields. In this work we present, for the first time, an in silico investigation, based on the general purpose Monte Carlo simulation toolkit Geant4, into energy deposition and radical species production around a spherical gold nanoparticle 50 nm in diameter via proton irradiation. Simulations were preformed for incident proton energies ranging from 2 to 170 MeV, which are of interest for clinical proton therapy.

  12. Analyses of stopping power measurements for 0.90-2.50 MeV protons and deuterons traversing Al 2O 3 targets

    NASA Astrophysics Data System (ADS)

    Porter, L. E.

    2000-09-01

    Recently reported measurements of the stopping power of Al 2O 3 for 0.90-2.50 MeV protons and deuterons have been analyzed in terms of modified Bethe-Bloch theory. Values of the mean excitation energy ( I) and Barkas-effect parameter ( b) have been extracted from the data, yielding results for I and b, respectively, of 176.8 eV and 0.83 for protons, and of 182.7 eV and 1.02 for deuterons. These values of I exceed the additivity-based value by 32% for proton data and by 36% for deuteron data. Moreover, both extracted values of b lie well below the expected interval of 1.3-1.5.

  13. Investigation of the stability and 1.0 MeV proton radiation resistance of commercially produced hydrogenated amorphous silicon alloy solar cells

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth R., II; Walters, Michael R.; Woodyard, James R.

    1994-01-01

    The radiation resistance of commercial solar cells fabricated from hydrogenated amorphous silicon alloys is reported. A number of different device structures were irradiated with 1.0 MeV protons. The cells were annealing at 200 C. The annealing time was dependent on proton fluence. Annealing devices for one hour restores cell parameters or fluences below 1(exp 14) cm(exp -2); fluences above 1(exp 14) cm(exp -2) require longer annealing times. A parametric fitting model was used to characterize current mechanisms observed in dark I-V measurements. The current mechanisms were explored with irradiation fluence, and voltage and light soaking times. The thermal generation current density and quality factor increased with proton fluence. Device simulation shows the degradation in cell characteristics may be explained by the reduction of the electric field in the intrinsic layer.

  14. Cross sections for proton induced high energy γ -ray emission (PIGE) in reaction 19 F(p, αγ)16 O at incident proton energies between 1.5 and 4 MeV

    NASA Astrophysics Data System (ADS)

    Cabanelas, P.; Cruz, J.; Fonseca, M.; Henriques, A.; Lourenço, F.; Luís, H.; Machado, J.; Pires Ribeiro, J.; Sánchez-Benítez, A. M.; Teubig, P.; Velho, P.; Zarza-Moreno, M.; Galaviz, D.; Jesus, A. P.

    2016-08-01

    We have studied the high energy gamma-rays produced in the reaction 19 F(p, αγ)16 O for incident proton energies from 1.5 to 4.0 MeV over NaF/Ag and CaF2/Ag thin targets in two different sets of data. Gamma-rays were detected with a High Purity Ge detector with an angle of 130° with respect to the beam axis. The cross-sections for the high energy gamma-rays of 6.129, 6.915 and 7.115 MeV have been measured for the whole group between 5 and 7.2 MeV with accuracy better than 10%. A new energy range was covered and more points are included in the cross-sections data base expanding the existing set of data. Results are in agreement with previous measurements in similar conditions.

  15. Implementation of water calorimetry in a 180 MeV scanned pulsed proton beam including an experimental determination of kQ for a Farmer chamber

    NASA Astrophysics Data System (ADS)

    Medin, Joakim

    2010-06-01

    Water calorimetric measurements have been performed in a 180 MeV scanned pulsed proton beam and the absorbed dose determined has been compared with the results obtained using two NE2571 Farmer chambers and the IAEA TRS-398 code of practice. The depth of measurement in water corresponded to a residual range of Rres = 16.5 cm, corresponding to a mean energy of about 150 MeV. Ionization chambers were calibrated in terms of the absorbed dose to water in 60Co at the Swedish Secondary Standard Dosimetry Laboratory, directly traceable to Bureau International des Poids et Mesures. The present experimental investigation has shown that water calorimetry is feasible in a high-energy scanned pulsed proton beam. When comparing the results obtained with water calorimetry and ionometry, the beam quality correction factor, kQ, could be determined for the two NE2571 ionization chambers used. The kQ-factor was found to be 1.032 ± 0.013, which is in good agreement with the factor tabulated in IAEA TRS-398 for this chamber type (1.039 ± 0.018). The present result has also been compared with a previously obtained result in a passively scattered proton beam having similar energy. This comparison yielded a 1.1% deviation, which is not significant considering the combined uncertainties of the two experimental determinations of kQ. The dominating contribution to the combined uncertainty stems from the correction factor for ion recombination in the scanned proton beam (1%), and further studies are required in order to reduce this uncertainty and reveal any possible differences in the kQ-factor between these two proton beam delivery techniques.

  16. Changes of structure and electrical conductivity of multi-walled carbon nanotubes film caused by 3 MeV proton irradiation

    NASA Astrophysics Data System (ADS)

    Yang, Jianqun; Li, Xingji; Liu, Chaoming; Ma, Guoliang

    2015-01-01

    The effects of 3 MeV proton irradiation for fluences of 3.5 × 1010 cm-2 to 3.1 × 1012 cm-2 on structure and electrical conductivity of multi-walled carbon nanotubes (MWCNTs) film were investigated. The pristine and the irradiated MWCNTs films were characterized using scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and electron paramagnetic resonance (EPR) spectroscopy in order to investigate the effects of irradiation on their structure. Electrical conductivity of the MWCNTs films was characterized before and after irradiation. SEM analysis reveals that the proton irradiation for the high fluence (more than 3.6 × 1011 cm-2) leads to evident changes in morphology of the MWCNTs film, such as forming uneven film surface, curve, shrinkage and fragmentation of nanotubes. Based on Raman, XPS, FTIR and EA analyses, it is confirmed that the 3 MeV protons with high fluence (more than 3.6 × 1011 cm-2) can damage the structure of the MWCNTs, including increase of the disorder and the formation of functional groups. EPR spectroscopy shows that the electrons delocalized over carbon nanotubes increase with increasing irradiation fluence, implying that the MWCNTs film might be sensitive to ionizing radiation to some extent. With increasing the irradiation fluence, the electrical conductivity of the MWCNTs film decreases due to the structural and morphological damage.

  17. Estimate of the radiation source term for 18F production via thick H218O targets bombarded with 18 MeV protons

    NASA Astrophysics Data System (ADS)

    Cruzate, Juan Ángel

    2015-12-01

    The positron-emitting radionuclide most important from the point of view of radiation protection is 18F. This isotope is usually produced by bombarding 18O-enriched water with protons. Currently there are few experimental data on the radiation source term generated during these reactions. In addition, presently there is no theoretical estimates of this source term, for use in radiation protection, validated by experimental data. Up till now this term is calculated by using nuclear interactions' simulation codes, such as ALICE91. An estimate of the energy spectra for neutrons and photons, induced by 18 MeV protons on H218O target, have been calculated by using MCNPX code with cross sections from release 0 of ENDF/B VII library for all materials except 18O, for which TENDL-2012 library was used. This estimate was validated against a recent experiment carried out at the Japan Atomic Energy Agency (JAEA). The calculated spectra have generally well reproduced experiments. The results show that the calculated radiation source term may be used to estimate the neutron activation of the accelerator components and the cyclotron building, to calculate the cyclotron shielding, and to carry out radiation protection evaluations in general, for the case of cyclotrons producing 18F by means of the 18O(p,n)18F nuclear reactions, for proton energies up to 18 MeV.

  18. Measurement of the stochastic radial dose distribution for a 30-MeV proton beam using a wall-less tissue-equivalent proportional counter.

    PubMed

    Tsuda, S; Sato, T; Ogawa, T

    2016-02-01

    The frequency distribution of the lineal energy, y, of a 30-MeV proton beam was measured as a function of the radial distance from the beam path, and the dosed mean of [Formula: see text] was obtained to investigate the radial dependence of [Formula: see text] A wall-less tissue-equivalent proportional counter, in a cylindrical volume with simulated diameters of 0.36, 0.72 and 1.44 µm was used for the measurement of y distributions, yf(y). The measured values of yf(y) summed in the radial direction agreed fairly well with the corresponding data taken from the microdosimetric calculations using the PHITS code. The [Formula: see text] value of the 30-MeV proton beam presented its smallest value at r = 0.0 and gradually increased with radial distance, and the [Formula: see text] values of heavy ions such as iron showed rapid decrease with radial distance. This experimental result demonstrated that the stochastic deposited energy distribution of high-energy protons in the microscopic region is rather constant in the core as well as in the penumbra region of the track structure. PMID:25956785

  19. RBE for late somatic effects in mice irradiated with 60 MeV protons relative to X-rays.

    NASA Technical Reports Server (NTRS)

    Darden, E. B., Jr.; Clapp, N. K.; Bender, R. S.; Jernigan, M. C.; Upton, A. C.

    1971-01-01

    Investigation of the relative biological effectiveness of energetic protons for the induction of somatic effects in a mammal (mice) following whole body irradiation. The proton energy used approximates the mean energy for proton spectra accompanying solar events. The effects on longevity and the incidence of major neoplastic diseases are summarized. The results obtained suggest that medium energy proton irradiation is no more effective, and on the whole, probably less effective, than conventional X radiation for the induction of late radiation effects in the mouse.

  20. Stopping powers and energy loss straggling for (0.9-3.4) MeV protons in a kapton polyimide thin film

    NASA Astrophysics Data System (ADS)

    Damache, S.; Djaroum, S.; Ouichaoui, S.; Amari, L.; Moussa, D.

    2016-09-01

    The energy loss and energy loss straggling widths have been measured in transmission for Ep ≈ (0.9-3.4) MeV protons traversing a thin kapton polyimide foil. In a prior step, the thickness and non-uniformity of the target foil were carefully investigated. The overall relative uncertainties in the stopping power and energy loss straggling variance data amount, respectively, to less than 2% and 8%. The S(E) experimental data show to be in excellent agreement with available previous ones and with those compiled in the ICRU-49 report. They are fully consistent with the predictions of Sigmund-Schinner's binary collision theory of electronic stopping over the whole proton energy range explored. An average deviation of ∼2.5% relative to values calculated by the SRIM-2008 code, likely due to effects of valence electrons involving the Csbnd H, Cdbnd C and Cdbnd O bonds, is however observed at low proton velocities. The measured energy loss straggling data, which are unique to our knowledge, are found to be in good agreement with values derived by the classical Bohr formula for Ep ≳ 1300 keV but they significantly exceed Bohr's collisional energy loss straggling at lower proton velocities where target electrons can no longer be considered as free. They also show to be consistent with the predictions of the Bethe-Livingston and Sigmund-Schinner theories over the low proton velocity region (Ep < 1300 keV). However, they are significantly overestimated by these theories over the intermediate and high proton velocity regions, which may be due to bunching effect by inner shell electrons of the polymer target. Besides, our energy loss straggling data are in better overall consistency with the Yang, O'Connor and Wang empirical formula for Ep > 1300 keV, while deviations above the latter amounting up to ∼18% are observed at lower proton velocities.

  1. Proton beam simulation with MCNPX: Gallium metal activation estimates below 30 MeV relevant to the bulk production of 68Ge and 65Zn

    NASA Astrophysics Data System (ADS)

    Fassbender, M.; Arzumanov, A.; Jamriska, D. J.; Lyssukhin, S. N.; Trellue, H.; Waters, L. S.

    2007-08-01

    Several gallium metal targets containing Ga metal encapsulated in Nb shells were irradiated in a 30 MeV cyclotron beam. Proton and secondary neutron beam fluences as well as radionuclide activity formation were modeled using MCNP-X in combination with CINDER90. Targets were chemically processed using two anion exchange steps. Good agreement between measured radiochemical yields and MCNPX/CINDER estimates was observed. The separation principle introduced in this work was utilized for a small 68Ge/Ga generator column for 68Ga labeling purposes.

  2. A study of gamma-ray and neutron radiation in the interaction of a 2 MeV proton beam with various materials.

    PubMed

    Kasatov, D; Makarov, A; Shchudlo, I; Taskaev, S

    2015-12-01

    Epithermal neutron source based on a tandem accelerator with vacuum insulation and lithium target has been proposed, developed and operated in Budker Institute of Nuclear Physics. The source is regarded as a prototype of a future compact device suitable for carrying out BNCT in oncology centers. In this work the measurements of gamma-ray and neutron radiation are presented for the interaction of a 2 MeV proton beam with various materials (Li, C, F, Al, V, Ti, Cu, Mo, stainless steel, and Ta). The obtained results enabled the optimization of the neutron-generating target and the high energy beam transportation path. PMID:26298434

  3. Characterization techniques for fixed-field alternating gradient accelerators and beam studies using the KURRI 150 MeV proton FFAG

    NASA Astrophysics Data System (ADS)

    Sheehy, S. L.; Kelliher, D. J.; Machida, S.; Rogers, C.; Prior, C. R.; Volat, L.; Haj Tahar, M.; Ishi, Y.; Kuriyama, Y.; Sakamoto, M.; Uesugi, T.; Mori, Y.

    2016-07-01

    In this paper we describe the methods and tools used to characterize a 150 MeV proton scaling fixed field alternating gradient (FFAG) accelerator at Kyoto University Research Reactor Institute. Many of the techniques used are unique to this class of machine and are thus of relevance to any future FFAG accelerator. For the first time we detail systematic studies undertaken to improve the beam quality of the FFAG. The control of beam quality in this manner is crucial to demonstrating high power operation of FFAG accelerators in future.

  4. K-MM radiative Auger effect in solid Ca, Ti and Cr targets after ionization with 0.7-1.5 MeV protons

    NASA Astrophysics Data System (ADS)

    Budnar, M.; Mühleisen, A.; Hribar, M.; Janžekovič, H.; Ravnikar, M.; Šmit, Ž.; Žitnik, M.

    1992-03-01

    Radiative Auger (RAE) X-ray spectra were measured for the first time on Ca, Cr, and Ti targets after ionization by 0.7-1.5 MeV protons. The energies of the RAE X-ray transitions were compared with the energies obtained from the Auger transitions. The RAE intensities relative to the diagram K β13 line were deduced and compared with the available data from X-ray fluorescence and electron capture ionization. The relative yields obtained for Ca, Ti, and Cr were (3.14 ± 0.47), (2.44 ± 0.37) and (2.91 ± 0.58)%, respectively.

  5. Holmium-161 produced using 11.6 MeV protons: A practical source of narrow-band X-rays.

    PubMed

    Stephens, Bryan J; Mendenhall, Marcus H

    2010-10-01

    We present a novel technique to produce narrow-band X-rays by preparing (161)Ho from the bombardment of dysprosium foil by 11.6 MeV protons. The activated foil produces predominantly 45-55 keV X-rays, which are suitable for activating iodinated radio-sensitizing agents (e.g. IUdR) for oncological therapy. We demonstrate that clinically useful quantities of the nuclide are easily produced with a medical cyclotron which is far from the current state of the art. PMID:20554211

  6. Comparison of the (p,xn) cross sections from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1982-01-01

    We have measured absolute cross sections for (p,xn) reactions (x ranges from 0 to 8) from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons at the Brookhaven AGS Linac injector. Chemical yields were determined by using /sup 239/Np and /sup 233/Pa as tracers. Yield patterns obtained in this work can be compared to the experimental results and theoretical calculations from earlier work, and they are consistent within the framework of intranuclear cascade followed by neutron evaporation and fission competition.

  7. Activation cross-sections of proton induced nuclear reactions on thulium in the 20-45 MeV energy range.

    PubMed

    Tárkányi, F; Hermanne, A; Takács, S; Ditrói, F; Spahn, I; Ignatyuk, A V

    2012-01-01

    Cross-sections of proton induced nuclear reactions on (169)Tm were measured in the 20-45MeV energy range using the standard stacked-foil irradiation technique and high resolution gamma-ray spectroscopy. Experimental cross-sections and derived integral yields are reported for the production of (169,167,166)Yb and (168,167,166)Tm radioisotopes. The experimental data are analysed and compared to results of the earlier measurements and the theoretical model codes ALICE-IPPE, EMPIRE and TALYS. Application of the new cross-sections to the production of the (167)Tm medical radioisotope is discussed. PMID:21920768

  8. Oxidation of SO2 and formation of water droplets under irradiation of 20 MeV protons in N2/H2O/SO2

    NASA Astrophysics Data System (ADS)

    Tomita, Shigeo; Nakai, Yoichi; Funada, Shuhei; Tanikawa, Hideomi; Harayama, Isao; Kobara, Hitomi; Sasa, Kimikazu; Pedersen, Jens Olaf Pepke; Hvelplund, Preben

    2015-12-01

    We have performed an experiment on charged droplet formation in a humidified N2 gas with trace SO2 concentration and induced by 20 MeV proton irradiation. It is thought that SO2 reacts with the chemical species, such as OH radicals, generated through the reactions triggered by N2+ production. Both droplet number and droplet size increased with SO2 consumption for the proton irradiation. The total charged droplet numbers entering the differential mobility analyzer per unit time were proportional to the 0.68 power of the SO2 consumption. These two findings suggest that coagulation among the small droplets contributes to the formation of the droplets. The charged droplet volume detected per unit time is proportional to the SO2 consumption, which indicates that a constant amount of sulfur atoms is contained in a unit volume of droplet, regardless of different droplet-size distributions depending on the SO2 consumption.

  9. The streaming of 1.3 - 2.3 MeV cosmic-ray protons during periods between prompt solar particle events. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Marshall, F. E.

    1977-01-01

    The anisotropy of 1.3 to 2.3 MeV protons in interplanetary space was measured using the Caltech electron/isotope spectrometer aboard IMP-7 for 317 6 hour periods from 72/273 to 74/2. Periods dominated by prompt solar particle events are not included. The convective and diffusive anisotropies were determined from the observed anisotropy using concurrent solar wind speed measurements and observed energy spectra. The diffusive flow of particles was found to be typically toward the sun, indicating a positive radial gradient in the particle density. This anisotropy was inconsistent with previously proposed sources of low energy proton increases seen at 1 AU which involve continual solar acceleration. The typical properties of this new component of low-energy cosmic rays were determined for this period which is near solar minimum.

  10. Selenium-72 formation via nat Br(p,x) induced by 100 MeV protons: steps towards a novel 72Se/72As generator system.

    PubMed

    Ballard, B; Wycoff, D; Birnbaum, E R; John, K D; Lenz, J W; Jurisson, S S; Cutler, C S; Nortier, F M; Taylor, W A; Fassbender, M E

    2012-04-01

    Selenium-72 production by the proton bombardment of a natural NaBr target has been successfully demonstrated at the Los Alamos National Laboratory Isotope Production Facility (LANL-IPF). Arsenic-72 (half life 26 h) is a medium-lived positron emitting radionuclide with the major advantage of being formed as the daughter of another "generator" radioisotope (Se-72, 8.5 d). A (72)Se/(72)As generator would be the preferred mechanism for clinical utilization of (72)As for positron emission tomography (PET). No portable (72)Se/(72)As generator system has been demonstrated for convenient, repeated (72)As elution ("milking"). In this work, we describe (72)Se production and recovery from irradiated NaBr targets using a 100 MeV proton beam. We also introduce an (72)As generator principle based on (72)Se chelation followed by liquid-liquid extraction, which will be transferred to a solid-phase sorption/elution system. PMID:22326368

  11. Investigation of the radiation resistance of triple-junction a-Si:H alloy solar cells irradiated with 1.00 MeV protons

    NASA Technical Reports Server (NTRS)

    Lord, Kenneth R., II; Walters, Michael R.; Woodyard, James R.

    1993-01-01

    The effect of 1.00 MeV proton irradiation on hydrogenated amorphous silicon alloy triple-junction solar cells is reported for the first time. The cells were designed for radiation resistance studies and included 0.35 cm(sup 2) active areas on 1.0 by 2.0 cm(sup 2) glass superstrates. Three cells were irradiated through the bottom contact at each of six fluences between 5.10E12 and 1.46E15 cm(sup -2). The effect of the irradiations was determined with light current-voltage measurements. Proton irradiation degraded the cell power densities from 8.0 to 98 percent for the fluences investigated. Annealing irradiated cells at 200 C for two hours restored the power densities to better than 90 percent. The cells exhibited radiation resistances which are superior to cells reported in the literature for fluences less than 1E14 cm(sup -2).

  12. Experimental determination of beam quality factors, kQ, for two types of Farmer chamber in a 10 MV photon and a 175 MeV proton beam

    NASA Astrophysics Data System (ADS)

    Medin, Joakim; Ross, Carl K.; Klassen, Norman V.; Palmans, Hugo; Grusell, Erik; Grindborg, Jan-Erik

    2006-03-01

    Absorbed doses determined with a sealed water calorimeter operated at 4 °C are compared with the results obtained using ionization chambers and the IAEA TRS-398 code of practice in a 10 MV photon beam (TPR20,10 = 0.734) and a 175 MeV proton beam (at a depth corresponding to the residual range, Rres = 14.7 cm). Three NE 2571 and two FC65-G ionization chambers were calibrated in terms of absorbed-dose-to-water in 60Co at the Swedish secondary standard dosimetry laboratory, directly traceable to the BIPM. In the photon beam quality, calorimetry was found to agree with ionometry within 0.3%, confirming the kQ values tabulated in TRS-398. In contrast, a 1.8% deviation was found in the proton beam at 6 g cm-2 depth, suggesting that the TRS-398 tabulated kQ values for these two ionization chamber types are too high. Assuming no perturbation effect in the proton beam for the ionization chambers, a value for (wair/e)Q of 33.6 J C-1 ± 1.7% (k = 1) can be derived from these measurements. An analytical evaluation of the effect from non-elastic nuclear interactions in the ionization chamber wall indicates a perturbation effect of 0.6%. Including this estimated result in the proton beam would increase the determined (wair/e)Q value by the same amount.

  13. Analysis of gamma-ray spectra from foils activated in a range-thick lead target by 800-MeV protons. Final technical report

    SciTech Connect

    Laird, C.E.; Mullins, D.H.

    1995-06-12

    Approximately 400 gamma-ray spectra have been analyzed to obtain the types and quantities of radioisotopes produced when 800-MeV protons interact with a range-thick lead target. These spectra were obtained from the radioactive decay of product isotopes in lead disks placed at various depths and radial positions within the target. These spectra were analyzed with the computer code HYPERMET and the photopeak areas were reduced to nuclei produced per incident proton per cubic centimeter of material. Product nuclei ranged from atomic mass 160 to mass 206 and over a range of half lives from a few minutes to several weeks. The results of this analysis have been outlined in this report and transmitted on computer disk to Los Alamos National Laboratory. The consistency of these analyses have been confirmed by a comparison of photopeak areas obtained at LANL with the computer code GAMANAL with those from HYPERMET for two gamma-ray spectra. Also, the nuclear production per proton per cm{sub 3} obtained from these two spectra analyzed both at LANL and at EKU have been found to agree to within the statistical accuracy of the peak-fitting programs. This analysis of these 400 gamma-ray spectra has determined the nuclear production per incident proton per cm{sub 3} at five regularly-spaced radial positions and depths up to 40 cm into a range-thick lead target.

  14. Response of CR-39 to 0.9-2.5 MeV protons for KOH and NaOH etching solutions

    NASA Astrophysics Data System (ADS)

    Bahrami, F.; Mianji, F.; Faghihi, R.; Taheri, M.; Ansarinejad, A.

    2016-03-01

    In some circumstances passive detecting methods are the only or preferable measuring approaches. For instance, defining particles' energy profile inside the objects being irradiated with heavy ions and measuring fluence of neutrons or heavy particles in space missions are the cases covered by these methods. In this paper the ability of polyallyl diglycol carbonate (PADC) track detector (commercially known as CR-39) for passive spectrometry of proton particles is studied. Furthermore, the effect of KOH and NaOH as commonly used chemical etching solutions on the response of the detector is investigated. The experiments were carried out with protons in the energy range of 0.94-2.5 MeV generated by a Van de Graaff accelerator. Then, the exposed track dosimeters were etched in the two aforementioned etchants through similar procedure with the same normality of 6.25 N and the same temperature of 85 °C. Formation of the tracks was precisely investigated and the track diameters were recorded following every etching step for each solution using a multistage etching process. The results showed that the proposed method can be efficiently used for the spectrometry of protons over a wider dynamic range and with a reasonable accuracy. Moreover, NaOH and KOH outperformed each other over different regions of the proton energy range. The detection efficiency of both etchants was approximately 100%.

  15. Experimental determination of beam quality factors, kQ, for two types of Farmer chamber in a 10 MV photon and a 175 MeV proton beam.

    PubMed

    Medin, Joakim; Ross, Carl K; Klassen, Norman V; Palmans, Hugo; Grusell, Erik; Grindborg, Jan-Erik

    2006-03-21

    Absorbed doses determined with a sealed water calorimeter operated at 4 degrees C are compared with the results obtained using ionization chambers and the IAEA TRS-398 code of practice in a 10 MV photon beam (TPR(20,10) = 0.734) and a 175 MeV proton beam (at a depth corresponding to the residual range, R(res) = 14.7 cm). Three NE 2571 and two FC65-G ionization chambers were calibrated in terms of absorbed-dose-to-water in (60)Co at the Swedish secondary standard dosimetry laboratory, directly traceable to the BIPM. In the photon beam quality, calorimetry was found to agree with ionometry within 0.3%, confirming the k(Q) values tabulated in TRS-398. In contrast, a 1.8% deviation was found in the proton beam at 6 g cm(-2) depth, suggesting that the TRS-398 tabulated k(Q) values for these two ionization chamber types are too high. Assuming no perturbation effect in the proton beam for the ionization chambers, a value for (w(air)/e)(Q) of 33.6 J C(-1) +/- 1.7% (k = 1) can be derived from these measurements. An analytical evaluation of the effect from non-elastic nuclear interactions in the ionization chamber wall indicates a perturbation effect of 0.6%. Including this estimated result in the proton beam would increase the determined (w(air)/e)(Q) value by the same amount. PMID:16510959

  16. Exclusive studies of 130-270 MeV {sup 3}He- and 200-MeV proton-induced reactions on {sup 27}Al, {sup nat}Ag, and {sup 197}Au

    SciTech Connect

    Ginger, D. S.; Kwiatkowski, K.; Wang, G.; Hsi, W.-C.; Hudan, S.; Cornell, E.; Souza, R. T. de; Viola, V. E.; Korteling, R. G.

    2008-09-15

    Exclusive light-charged-particle and IMF spectra have been measured with the ISiS detector array for bombardments of {sup 27}Al, {sup nat}Ag, and {sup 197}Au nuclei with 130-270-MeV {sup 3}He and 200-MeV protons. The results are consistent with previous interpretations based on inclusive data that describe the global yield of complex fragments in terms of a time-dependent process. The emission mechanism for energetic nonequilibrium fragments observed at forward angles with momenta up to twice the beam momentum is also investigated. This poorly understood mechanism, for which the angular distributions indicate formation on a time scale comparable to the nuclear transit time, are accompanied primarily by thermal-like emissions. The data are most consistent with a schematic picture in which nonequilibrium fragments are formed in a localized region of the target nucleus at an early stage in the energy-dissipation process, where the combined effects of high energy density and Fermi motion produce the observed suprathermal spectra.

  17. K-shell ionization probability in close collisions of 7--12-MeV protons with targets of Z = 24 --83

    SciTech Connect

    Dost, M.; Hoppenau, S.; Kising, J.; Roehl, S.; Schorn, P.

    1981-08-01

    K-shell ionization probabilities were measured by the particle--x-ray coincidence technique for 7-MeV protons of 15 to 39 fm impact parameter on 24 targets from Cr to Bi. For 22 of these targets, total K-shell ionization cross sections are also reported. Additional K-shell ionization probabilities were measured for 7-, 10-, and 12-MeV protons on Mo, Cd, and Sn, at impact parameters down to 2 fm. While the total K-shell cross sections closely follow relativistic semiclassical (RSCA) calculations supplemented by minor binding-plus-polarization corrections, significant discrepancies of up to 70% occur for the K-shell ionization probabilities at small impact parameters, particularly for the targets from Cr to Zr. They can be traced back to the use of hydrogenic wave functions in the RSCA calculation, whereas nuclear recoil may account only for a few percent of the discrepancies. The data on both K-shell total cross sections and ionization probabilities exhibit the pattern characteristic for small distortions of the K-electron binding energy by the projectile charge: adiabatic binding for xi/sub K/<1 and nonadiabatic polarization for xi/sub K/>1. The perturbed-stationary-state approximation somewhat underestimates these distortion effects.

  18. Effect of irradiation with MeV protons and electrons on the conductivity compensation and photoluminescence of moderately doped p-4H-SiC (CVD)

    SciTech Connect

    Kozlovski, V. V.; Lebedev, A. A. Bogdanova, E. V.; Seredova, N. V.

    2015-09-15

    The compensation of moderately doped p-4H-SiC samples grown by the chemical vapor deposition (CVD) method under irradiation with 0.9-MeV electrons and 15-MeV protons is studied. The experimentally measured carrier removal rates are 1.2–1.6 cm{sup –1} for electrons and 240–260 cm{sup –1} for protons. The dependence of the concentration of uncompensated acceptors and donors, measured in the study, demonstrates a linear decrease with increasing irradiation dose to the point of complete compensation. This run of the dependence shows that compensation of the samples is due to the transition of carriers to deep centers formed by primary radiation-induced defects. It is demonstrated that, in contrast to n-SiC (CVD), primary defects in the carbon sublattice of moderately doped p-SiC (CVD) only cannot account for the compensation process. In p-SiC, either primary defects in the silicon sublattice, or defects in both sublattices are responsible for conductivity compensation. Also, photoluminescence spectra are examined in relation to the irradiation dose.

  19. Global magnetohydrodynamic simulation of the 15 March 2013 coronal mass ejection event—Interpretation of the 30-80 MeV proton flux

    NASA Astrophysics Data System (ADS)

    Wu, Chin-Chun; Liou, Kan; Vourlidas, Angelos; Plunkett, Simon; Dryer, Murray; Wu, S. T.; Mewaldt, Richard A.

    2016-01-01

    The coronal mass ejection (CME) event on 15 March 2013 is one of the few solar events in Cycle 24 that produced a large solar energetic particle (SEP) event and severe geomagnetic activity. Observations of SEP from the ACE spacecraft show a complex time-intensity SEP profile that is not easily understood with current empirical SEP models. In this study, we employ a global three-dimensional (3-D) magnetohydrodynamic (MHD) simulation to help interpret the observations. The simulation is based on the H3DMHD code and incorporates extrapolations of photospheric magnetic field as the inner boundary condition at a solar radial distance (r) of 2.5 solar radii. A Gaussian-shaped velocity pulse is imposed at the inner boundary as a proxy for the complex physical conditions that initiated the CME. It is found that the time-intensity profile of the high-energy (>10 MeV) SEPs can be explained by the evolution of the CME-driven shock and its interaction with the heliospheric current sheet and the nonuniform solar wind. We also demonstrate in more detail that the simulated fast-mode shock Mach number at the magnetically connected shock location is well correlated (rcc ≥ 0.7) with the concurrent 30-80 MeV proton flux. A better correlation occurs when the 30-80 MeV proton flux is scaled by r-1.4(rcc = 0.87). When scaled by r-2.8, the correlation for 10-30 MeV proton flux improves significantly from rcc = 0.12 to rcc = 0.73, with 1 h delay. The present study suggests that (1) sector boundary can act as an obstacle to the propagation of SEPs; (2) the background solar wind is an important factor in the variation of IP shock strength and thus plays an important role in manipulation of SEP flux; (3) at least 50% of the variance in SEP flux can be explained by the fast-mode shock Mach number. This study demonstrates that global MHD simulation, despite the limitation implied by its physics-based ideal fluid continuum assumption, can be a viable tool for SEP data analysis.

  20. Production of (28)Mg by bombardment of (nat)Cl with 200MeV protons: Proof-of-concept study for a stacked LiCl target.

    PubMed

    van der Meulen, N P; Steyn, G F; Vermeulen, C; van Rooyen, T J

    2016-09-01

    A stacked target consisting of ten Al-encapsulated LiCl discs, for producing (28)Mg via the (nat)Cl(p,X)(28)Mg process in the energy region 50-200MeV, is described. This target was irradiated with a 200MeV beam at an intensity of 100nA, providing information on both yield and outscattering losses. Results of a Monte Carlo modelling of the beam and target, by means of the code MCNPX, are also presented. Similar Al-encapsulated LiCl discs were individually irradiated with 66MeV proton beams of 65 and 90μA, respectively, to study their behaviour under high-intensity bombardment. Once removed from the Al encapsulation, the (28)Mg can be separated from the LiCl target material efficiently, using a 12.5cm x 1cm(2) column containing Purolite S950 chelating resin. The eluate contains (7)Be but no other measurable radio-contaminants. The removal of the (7)Be contaminant is performed by cation exchange chromatography in malate media, with (28)Mg being retained by the resin and (7)Be eluted. PMID:27372806

  1. Relative Biological Effectiveness Variation Along Monoenergetic and Modulated Bragg Peaks of a 62-MeV Therapeutic Proton Beam: A Preclinical Assessment

    SciTech Connect

    Chaudhary, Pankaj; Marshall, Thomas I.; Perozziello, Francesca M.; Manti, Lorenzo; Currell, Frederick J.; Hanton, Fiona; McMahon, Stephen J.; Kavanagh, Joy N.; Cirrone, Giuseppe Antonio Pablo; Romano, Francesco; Prise, Kevin M.; Schettino, Giuseppe

    2014-09-01

    Purpose: The biological optimization of proton therapy can be achieved only through a detailed evaluation of relative biological effectiveness (RBE) variations along the full range of the Bragg curve. The clinically used RBE value of 1.1 represents a broad average, which disregards the steep rise of linear energy transfer (LET) at the distal end of the spread-out Bragg peak (SOBP). With particular attention to the key endpoint of cell survival, our work presents a comparative investigation of cell killing RBE variations along monoenergetic (pristine) and modulated (SOBP) beams using human normal and radioresistant cells with the aim to investigate the RBE dependence on LET and intrinsic radiosensitvity. Methods and Materials: Human fibroblasts (AG01522) and glioma (U87) cells were irradiated at 6 depth positions along pristine and modulated 62-MeV proton beams at the INFN-LNS (Catania, Italy). Cell killing RBE variations were measured using standard clonogenic assays and were further validated using Monte Carlo simulations and the local effect model (LEM). Results: We observed significant cell killing RBE variations along the proton beam path, particularly in the distal region showing strong dose dependence. Experimental RBE values were in excellent agreement with the LEM predicted values, indicating dose-averaged LET as a suitable predictor of proton biological effectiveness. Data were also used to validate a parameterized RBE model. Conclusions: The predicted biological dose delivered to a tumor region, based on the variable RBE inferred from the data, varies significantly with respect to the clinically used constant RBE of 1.1. The significant RBE increase at the distal end suggests also a potential to enhance optimization of treatment modalities such as LET painting of hypoxic tumors. The study highlights the limitation of adoption of a constant RBE for proton therapy and suggests approaches for fast implementation of RBE models in treatment planning.

  2. Delayed entry of solar protons (E/p/ over 0.3 MeV) into the earth's magnetotail

    NASA Technical Reports Server (NTRS)

    Van Allen, J. A.; Saflekos, N. A.; Sarris, E. T.

    1987-01-01

    The delayed entry of solar protons into the earth's magnetotail is studied using simultaneous observations from three earth-orbiting spacecraft of a number of interplanetary proton events which exhibited abrupt and relatively large discontinuities in intensity associated with magnetic field discontinuities. It is found that such protons have immediate access to the magnetosheath and that delay times increase discontinuously from essentially zero in the magnetosheath to tens of minutes as an observing point moves inward across the magnetopause. Well-defined delay times from 30 to 160 min occur for points interior to the magnetotail. The inferred entry points lie at downstream distances of 80-500 R(E). No discernible relationship is found between the direction and sense of the interplanetary magnetic field and the entry times in the northern and southern lobes of the magnetotail or the entry tiems at various distances from its central axis. These results favor some form of an open model of the magnetotail.

  3. 1.5 MeV proton irradiation effects on electrical and structural properties of TiO2/n-Si interface

    NASA Astrophysics Data System (ADS)

    Ishfaq, M.; Rizwan Khan, M.; Bhopal, M. F.; Nasim, F.; Ali, A.; Bhatti, A. S.; Ahmed, I.; Bhardwaj, Sunil; Cepek, Cinzia

    2014-05-01

    In this paper, we report the effect of 1.5 MeV proton beam irradiation dose on the structural and electrical properties of TiO2 thin films deposited on n-Si substrates. The formation and transformation of different TiO2 phases in the irradiated thin films were characterized by X-ray diffraction and X-ray photoelectron spectroscopy (XPS). X-ray diffraction measurements revealed that the as grown film was rich in Ti5O9 phase and then converted to mixed phases of TiO2 (rutile and anatase) after exposure with radiation doses up to 5 × 1014 cm-2. The XPS results revealed the formation of oxygen vacancy (negative) traps in the exposed TiO2 films, which showed strong dependence on the dose. The C-V measurements showed that proton radiations also damaged the Si substrate and created deep level defects in the substrate, which caused a shift of 0.26 ± 0.01 V in the flat band voltage (VFB). I-V measurements showed that the ideality factor increased and the rectification ratio dropped with the increase in the radiation dose. The present study showed the stability of TiO2/Si interface and TiO2 film as an oxide layer against proton radiations.

  4. Investigation of activation cross-sections of proton induced nuclear reactions on natMo up to 40 MeV: New data and evaluation

    NASA Astrophysics Data System (ADS)

    Tárkányi, F.; Ditrói, F.; Hermanne, A.; Takács, S.; Ignatyuk, A. V.

    2012-06-01

    Cross-sections of proton induced nuclear reactions on natural molybdenum have been studied in the frame of a systematic investigation of charged particle induced nuclear reactions on metals for different applications. The excitation functions of 93mTc, 93gTc(m+), 94mTc, 94gTc, 95mTc, 95gTc, 96gTc(m+), 99mTc, 90Mo(cum), 93mMo, 99Mo(cum), 90Nb(cum), 92mNb, 95mNb, 95gNb, 96Nb and 88Zr(cum), 89Zr(cum) were measured up to 40 MeV proton energy by a using stacked foil technique and activation method. The main goals of this work were to study the production possibility of the medically important 99mTc and its 99Mo parent nucleus, to get experimental data for accelerator technology, for monitoring of proton beam, for thin layer activation technique and for testing nuclear reaction theories. The experimental data were compared with critically analysed published data and with the results of model calculations, obtained by using the ALICE-IPPE, EMPIRE-II and TALYS codes.

  5. Effects of high-dose 40 MeV proton irradiation on the electroluminescent and electrical performance of InGaN light-emitting diodes

    SciTech Connect

    Khanna, Rohit; Allums, K.K.; Abernathy, C.R.; Pearton, S.J.; Kim, Jihyun; Ren, F.; Dwivedi, R.; Fogarty, T.N.; Wilkins, R.

    2004-10-11

    InGaN multi-quantum-well light-emitting diodes (LEDs) in the form of unpackaged die with emission wavelengths from 410 to 525 nm were irradiated with 40 MeV protons to doses of 5x10{sup 9}-5x10{sup 10} cm{sup -2}. The highest dose is equivalent to more than 100 years in low-earth orbit. The projected range of these protons is >50 {mu}m in GaN and thus they traverse the entire active region. The electroluminescent intensity from the LEDs decreased by only 15%-25% even for the highest doses and the reverse breakdown voltage increased by 1-2 V from their control values of {approx}21-29 V. The percentage change in breakdown voltage and electroluminescence intensity was independent of the initial emission wavelength over the range investigated, within experimental error. The GaN LEDs exhibit extremely good stability to these high-energy proton irradiations with no measurable change in contact resistance or contact morphology.

  6. Elastic and inelastic scattering of polarized protons from carbon-12 at 400, 600, and 700 MeV

    SciTech Connect

    Jones, K.W.

    1984-04-01

    Good resolution cross section and analyzing power (p vector, p') data for many states in /sup 12/C up to an excitation energy of 21 MeV and spanning a momentum transfer range of 0.3 to 2.1 fm/sup -1/ were obtained using the High Resolution Spectrometer at the Clinton P. Anderson Meson Physics Facility at incident beam energies of 398, 597, and 698 MeV. Optical model potentials were obtained from the elastic scattering data. Inelastic data were analyzed in the Distorted Wave Impulse Approximation using the Love-Franey effective nucleon-nucleon interaction. The energy dependent isoscalar natural parity cross sections were underestimated, while phase difficulties were encountered in fitting analyzing powers. The energy independent isovector natural parity cross sections were reasonably reproduced, but analyzing powers were not, the calculations yielding positive trends whereas the data are of opposite sign. The energy independent isoscalar and isovector unnatural parity cross sections were quite well reproduced up to moderate momentum transfers, and striking successes were observed for some analyzing power data. Systematics of energy dependence together with the results of the DWIA calculations permitted the assignment of spin, parity and isospin quantum numbers to states in the 18-21 MeV excitation region. 64 references.

  7. Acceleration of protons to above 6 MeV using H{sub 2}O 'snow' nanowire targets

    SciTech Connect

    Pomerantz, I.; Schleifer, E.; Nahum, E.; Eisenmann, S.; Botton, M.; Gordon, D.; Sprangel, P.; Zigler, A.

    2012-07-09

    A scheme is presented for using H{sub 2}O 'snow' nanowire targets for the generation of fast protons. This novel method may relax the requirements for very high laser intensities, thus reducing the size and cost of laser based ion acceleration system.

  8. SU-E-T-554: Monte Carlo Calculation of Source Terms and Attenuation Lengths for Neutrons Produced by 50–200 MeV Protons On Brass

    SciTech Connect

    Ramos-Mendez, J; Faddegon, B; Paganetti, H

    2015-06-15

    Purpose: We used TOPAS (TOPAS wraps and extends Geant4 for medical physicists) to compare Geant4 physics models with published data for neutron shielding calculations. Subsequently, we calculated the source terms and attenuation lengths (shielding data) of the total ambient dose equivalent (TADE) in concrete for neutrons produced by protons in brass. Methods: Stage1: The Bertini and Binary nuclear models available in Geant4 were compared with published attenuation at depth of the TADE in concrete and iron. Stage2: Shielding data of the TADE in concrete was calculated for 50– 200 MeV proton beams on brass. Stage3: Shielding data from Stage2 was extrapolated for 235 MeV proton beams. This data was used in a point-line-source analytical model to calculate the ambient dose per unit therapeutic dose at two locations inside one treatment room at the Francis H Burr Proton Therapy Center. Finally, we compared these results with experimental data and full TOPAS simulations. Results: At larger angles (∼130o) the TADE in concrete calculated with the Bertini model was about 9 times larger than that calculated with the Binary model. The attenuation length in concrete calculated with the Binary model agreed with published data within 7%±0.4% (statistical uncertainty) for the deepest regions and 5%±0.1% for shallower regions. For iron the agreement was within 3%±0.1%. The ambient dose per therapeutic dose calculated with the Binary model, relative to the experimental data, was a ratio of 0.93±0.16 and 1.23±0.24 for two locations. The analytical model overestimated the dose by four orders of magnitude. These differences are attributed to the complexity of the geometry. Conclusion: The Binary and Bertini models gave comparable results, with the Binary model giving the best agreement with published data at large angle. Shielding data we calculated using the Binary model is useful for fast shielding calculations with other analytical models. This work was supported by

  9. Measurement of the total photoabsorption cross section on a proton in the energy range 600-1500 MeV at the GRAAL

    SciTech Connect

    Bartalini, O.; Bellini, V.; Bocquet, J. P.; Calvat, P.; D'Angelo, A.; Didelez, J.-P.; Di Salvo, R.; Fantini, A.; Ghio, F.; Girolami, B.; Guidal, M.; Giusa, A.; Hourany, E.; Ignatov, A. S.; Kunne, R.; Lapik, A. M.; Sandri, P. Levi; Lleres, A.; Moricciani, D.; Mushkarenkov, A. N.; and others

    2008-01-15

    The total photoabsorption cross section on a free proton was measured at the GRAAL facility in the energy range E{sub {gamma}} = 600-1500 MeV. The large-aperture LAGRAN{gamma}E detector and a liquid hydrogen target were used in the experiment performed with a back-scattered Compton gamma beam. To improve the accuracy, two alternative methods were employed. First, a subtraction method of using empty-target measurements allowed the cross section {sigma}{sub tot} to be evaluated directly because of a low level of the electromagnetic background. Second, an algorithm for evaluating {sigma}{sub tot} on the basis of summing the dominating partial cross sections was developed. Experimental results obtained for {sigma}{sub tot} by the two methods are compared with existing data.

  10. Production cross sections of products in the proton induced reactions on natNd in the energy region up to 45 MeV

    NASA Astrophysics Data System (ADS)

    Yang, Sung-Chul; Kim, Kwangsoo; Song, Tae-Yung; Lee, Young-Ouk; Kim, Guinyun

    2015-11-01

    The production cross sections of 141,143,144,146,148m,148g,149,150Pm, 139m,147,149Nd, 138m,142gPr, and 139gCe in the natNd(p,x) reactions were determined by a stacked-foil activation technique for the proton energy range up to 45 MeV using the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences. The measured cross sections were compared with literature data as well as data from the TENDL-2014 library based on TALYS 1.6. The production cross sections of the above radionuclides are slightly higher than the literature data but are in general agreement with values in TENDL-2014 library except for 148mPm, 148gPm, 139mNd, and 142gPr. The thick target integral yields of the produced radionuclides were also deducted from the measured cross sections.