Science.gov

Sample records for dual purpose compton

  1. Dual color x-rays from Thomson or Compton sources

    NASA Astrophysics Data System (ADS)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Ferrario, M.; Maroli, C.; Rau, J. V.; Ronsivalle, C.; Serafini, L.; Vaccarezza, C.; Venturelli, M.

    2015-05-01

    We analyze the possibility of producing two color X or γ radiation by Thomson/Compton back-scattering between a high intensity laser pulse and a two-energy level electron beam, constituted by a couple of beamlets separated in time and/or energy obtained by a photoinjector with comb laser techniques and linac velocity bunching. The parameters of the Thomson source at SPARC_LAB have been simulated, proposing a set of values for a realistic experiments.

  2. Dual color x rays from Thomson or Compton sources

    NASA Astrophysics Data System (ADS)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Ferrario, M.; Gatti, G.; Maroli, C.; Rau, J. V.; Ronsivalle, C.; Serafini, L.; Vaccarezza, C.; Venturelli, M.

    2014-02-01

    We analyze the possibility of producing two-color x or γ radiation by Thomson/Compton backscattering between a high intensity laser pulse and a two-energy level electron beam, constituted by a couple of beamlets separated in time and/or energy obtained by a photoinjector with comb laser techniques and linac velocity bunching. The parameters of the Thomson source at SPARC_LAB have been simulated, proposing a set of realistic experiments.

  3. A magnetic shield/dual purpose mission

    NASA Technical Reports Server (NTRS)

    Watkins, Seth; Albertelli, Jamil; Copeland, R. Braden; Correll, Eric; Dales, Chris; Davis, Dana; Davis, Nechole; Duck, Rob; Feaster, Sandi; Grant, Patrick

    1994-01-01

    The objective of this work is to design, build, and fly a dual-purpose payload whose function is to produce a large volume, low intensity magnetic field and to test the concept of using such a magnetic field to protect manned spacecraft against particle radiation. An additional mission objective is to study the effect of this moving field on upper atmosphere plasmas. Both mission objectives appear to be capable of being tested using the same superconducting coil. The potential benefits of this magnetic shield concept apply directly to both earth-orbital and interplanetary missions. This payload would be a first step in assessing the true potential of large volume magnetic fields in the U.S. space program. Either converted launch systems or piggyback payload opportunities may be appropriate for this mission. The use of superconducting coils for magnetic shielding against solar flare radiation during manned interplanetary missions has long been contemplated and was considered in detail in the years preceding the Apollo mission. With the advent of new superconductors, it has now become realistic to reconsider this concept for a Mars mission. Even in near-earth orbits, large volume magnetic fields produced using conventional metallic superconductors allow novel plasma physics experiments to be contemplated. Both deployed field-coil and non-deployed field-coil shielding arrangements have been investigated, with the latter being most suitable for an initial test payload in a polar orbit.

  4. Dual-Channel Multi-Purpose Telescope

    NASA Technical Reports Server (NTRS)

    Howard, Joseph M.; Content, David

    2009-01-01

    A dual-channel telescope allows for a wide-field telescope design wit h a good, narrow field channel of fewer surfaces for shorter-wavelen gth or planet-finding applications. The design starts with a Korsch three-mirror-anastigmat (TMA) telescope that meets the mission criter ia for image quality over a wide field of view. The internal image a t the Cassegrain focus is typically blurry due to the aberration bala ncing among the three mirrors. The Cassegrain focus is then re-optim ized on the axis of the system where the narrow field channel instru ment is picked off by bending the primary mirror.

  5. Using dual-purpose crops in sheep-grazing systems.

    PubMed

    Dove, Hugh; Kirkegaard, John

    2014-05-01

    The utilisation of dual-purpose crops, especially wheat and canola grown for forage and grain production in sheep-grazing systems, is reviewed. When sown early and grazed in winter before stem elongation, later-maturing wheat and canola crops can be grazed with little impact on grain yield. Recent research has sought to develop crop- and grazing-management strategies for dual-purpose crops. Aspects examined have been grazing effects on crop growth, recovery and yield development along with an understanding of the grazing value of the crop fodder, its implications for animal nutrition and grazing management to maximise live-weight gain. By alleviating the winter 'feed gap', the increase in winter stocking rate afforded by grazing crops allows crop and livestock production to be increased simultaneously on the same farm. Integration of dual-purpose wheat with canola on mixed farms provides further systems advantages related to widened operational windows, weed and disease control and risk management. Dual-purpose crops are an innovation that has potential to assist in addressing the global food-security challenge. PMID:24323974

  6. System-Level Logistics for Dual Purpose Canister Disposal

    SciTech Connect

    Kalinina, Elena A.

    2014-06-03

    The analysis presented in this report investigated how the direct disposal of dual purpose canisters (DPCs) may be affected by the use of standard transportation aging and disposal canisters (STADs), early or late start of the repository, and the repository emplacement thermal power limits. The impacts were evaluated with regard to the availability of the DPCs for emplacement, achievable repository acceptance rates, additional storage required at an interim storage facility (ISF) and additional emplacement time compared to the corresponding repackaging scenarios, and fuel age at emplacement. The result of this analysis demonstrated that the biggest difference in the availability of UNF for emplacement between the DPC-only loading scenario and the DPCs and STADs loading scenario is for a repository start date of 2036 with a 6 kW thermal power limit. The differences are also seen in the availability of UNF for emplacement between the DPC-only loading scenario and the DPCs and STADs loading scenario for the alternative with a 6 kW thermal limit and a 2048 start date, and for the alternatives with a 10 kW thermal limit and 2036 and 2048 start dates. The alternatives with disposal of UNF in both DPCs and STADs did not require additional storage, regardless of the repository acceptance rate, as compared to the reference repackaging case. In comparison to the reference repackaging case, alternatives with the 18 kW emplacement thermal limit required little to no additional emplacement time, regardless of the repository start time, the fuel loading scenario, or the repository acceptance rate. Alternatives with the 10 kW emplacement thermal limit and the DPCs and STADs fuel loading scenario required some additional emplacement time. The most significant decrease in additional emplacement time occurred in the alternative with the 6 kW thermal limit and the 2036 repository starting date. The average fuel age at emplacement ranges from 46 to 88 years. The maximum fuel age at

  7. A Process for Designing and Implementing a Dual Purpose Evaluation System. CSE Resource Paper No. 7.

    ERIC Educational Resources Information Center

    Aschbacher, Pamela; Burry, James

    This paper offers a guide for a dual purpose evaluation plan that can provide information for local program managers and simultaneously serve the accountability and reporting needs of a state legislature, district office, or other policy making body. The dual focus approach has two advantages: (1) it provides a common information base for…

  8. Inverse Compton for Compton

    NASA Astrophysics Data System (ADS)

    Suortti, Pekka

    2016-04-01

    A novel concept for a high resolution Compton spectrometer is introduced. 88 keV radiation from an Inverse Compton Compact Source is focused using crossed cylindrically bent Laue-type Si perfect crystals, and dispersed on the sample with a constant energy gradient. Dispersion is compensated exactly at a Ge crystal analyzer, so that the same wavelength shift is observed for all wavelengths of the incident beam. The ThomX source is used as a concrete example. Detailed dimensions and flux estimates at successive locations of the spectrometer are given, and the performance is compared with the dispersion compensating spectrometer at ID15 of the ESRF. The momentum resolution is better than 0.1 atomic units in both cases. The intensity of scattering with the compact source is an order of magnitude smaller, but still adequate for high resolution Compton profile measurements.

  9. Source book for planning nuclear dual-purpose electric/distillation desalination plants

    SciTech Connect

    Reed, S.A.

    1981-02-01

    A source book on nuclear dual-purpose electric/distillation desalination plants was prepared to assist government and other planners in preparing broad evaluations of proposed applications of dual-purpose plants. The document is divided into five major sections. Section 1 presents general discussions relating to the benefits of dual-purpose plants, and spectrum for water-to-power ratios. Section 2 presents information on commercial nuclear plants manufactured by US manufacturers. Section 3 gives information on distillation desalting processes and equipment. Section 4 presents a discussion on feedwater pretreatment and scale control. Section 5 deals with methods for coupling the distillation and electrical generating plants to operate in the dual mode.

  10. Grazing initiation timing affects net rturn to dual-purpose wheat systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Limited experimental data are available to allow direct evaluation of the effects of grazing initiation timing on net returns to dual-purpose wheat systems. The objectives were to simulate the effect of grazing initiation dates on net returns to a wheat (Triticum aestivum L.) – cattle (Bos taurus) ...

  11. Dakota Trailblazer: A new, dual-purpose russet cultivar with Verticillium wilt resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dakota Trailblazer, a new, full-season, dual-purpose cultivar was released in 2009 by the North Dakota Agricultural Experiment Station. It has medium russet skin, white to creamy flesh, and long and blocky tuber type. Dakota Trailblazer originated from the cross of A89163-3LS x A8914-4, parental s...

  12. Spectra of clinical CT scanners using a portable Compton spectrometer

    SciTech Connect

    Duisterwinkel, H. A.; Abbema, J. K. van; Kawachimaru, R.; Paganini, L.; Graaf, E. R. van der; Brandenburg, S.; Goethem, M. J. van

    2015-04-15

    Purpose: Spectral information of the output of x-ray tubes in (dual source) computer tomography (CT) scanners can be used to improve the conversion of CT numbers to proton stopping power and can be used to advantage in CT scanner quality assurance. The purpose of this study is to design, validate, and apply a compact portable Compton spectrometer that was constructed to accurately measure x-ray spectra of CT scanners. Methods: In the design of the Compton spectrometer, the shielding materials were carefully chosen and positioned to reduce background by x-ray fluorescence from the materials used. The spectrum of Compton scattered x-rays alters from the original source spectrum due to various physical processes. Reconstruction of the original x-ray spectrum from the Compton scattered spectrum is based on Monte Carlo simulations of the processes involved. This reconstruction is validated by comparing directly and indirectly measured spectra of a mobile x-ray tube. The Compton spectrometer is assessed in a clinical setting by measuring x-ray spectra at various tube voltages of three different medical CT scanner x-ray tubes. Results: The directly and indirectly measured spectra are in good agreement (their ratio being 0.99) thereby validating the reconstruction method. The measured spectra of the medical CT scanners are consistent with theoretical spectra and spectra obtained from the x-ray tube manufacturer. Conclusions: A Compton spectrometer has been successfully designed, constructed, validated, and applied in the measurement of x-ray spectra of CT scanners. These measurements show that our compact Compton spectrometer can be rapidly set-up using the alignment lasers of the CT scanner, thereby enabling its use in commissioning, troubleshooting, and, e.g., annual performance check-ups of CT scanners.

  13. Dual purpose optical instrument capable of simultaneously acting as spectrometer and diffractometer

    NASA Technical Reports Server (NTRS)

    Dasgupta, K.; Schnopper, H. W.; Metzger, A. E. (Inventor)

    1969-01-01

    A dual purpose optical instrument is described capable of simultaneously acting as a spectrometer and diffractometer to respectively perform elemental and structural analysis of an unknown sample. The diffractometer portion of the instrument employs a modified form of Seeman-Bohlin focusing which involves providing a line source of X-rays, a sample, and a detector, all on the same focal circle. The spectrometer portion of the instrument employs a fixedly mounted X-ray energy detector mounted outside of the plane of the focal circle.

  14. Nano-casted Metal Oxide Aerogels as Dual Purpose Structural Components for Space Exploration

    NASA Technical Reports Server (NTRS)

    Vassilaras, Plousia E.

    2004-01-01

    NASA missions and space exploration rely on strong, ultra lightweight materials. Such materials are needed for building up past and present space vehicles such as the Sojourner Rover (1997) or the two MERs (2003), but also for a number of components and/or systems including thermal insulators, Solar Sails, Rigid Aeroshells, and Ballutes. The purpose of my internship here at Glenn Research Center is to make dual purpose materials; materials that in addition to being lightweight have electronic, photophysical and magnetic properties and, therefore, act as electronic components and sensors as well as structural components. One type of ultra lightweight material of great interest is aerogels, which have densities ranging from 0.003 g/cc to 0.8 g/cc . However, aerogels are extremely fragile and, as a result, have limited practical applications. Recently, Glenn Research Center has developed a process of nano-casting polymers onto the inorganic network of silica-based aerogels increasing the strength 300 fold while only increasing the density 3 fold. By combining the process of nano-casting polymers with inorganic oxide networks other than silica, we are actively pursuing lightweight dual purpose materials. To date, thirty different inorganic oxide aerogels have been prepared using either standard sol-gel chemistry or a non-alkoxide method involving metal chloride precursors and an epoxide; epichlorohydrin, propylene oxide or trimethylene oxide, as proton scavengers. More importantly, preliminary investigations show that the residual surface hydroxyl groups on each of these inorganic oxide aerogels can be successfully crosslinked with urethane. In addition to characterizing physical and mechanical properties such as density, strength and flexibility, each of these metal oxide aerogels are being characterized for thermal and electronic conductivity and magnetic and optical properties.

  15. Genetic Evaluation of Dual-Purpose Buffaloes (Bubalus bubalis) in Colombia Using Principal Component Analysis.

    PubMed

    Agudelo-Gómez, Divier; Pineda-Sierra, Sebastian; Cerón-Muñoz, Mario Fernando

    2015-01-01

    Genealogy and productive information of 48621 dual-purpose buffaloes born in Colombia between years 1996 and 2014 was used. The following traits were assessed using one-trait models: milk yield at 270 days (MY270), age at first calving (AFC), weaning weight (WW), and weights at the following ages: first year (W12), 18 months (W18), and 2 years (W24). Direct additive genetic and residual random effects were included in all the traits. Maternal permanent environmental and maternal additive genetic effects were included for WW and W12. The fixed effects were: contemporary group (for all traits), sex (for WW, W12, W18, and W24), parity (for WW, W12, and MY270). Age was included as covariate for WW, W12, W18 and W24. Principal component analysis (PCA) was conducted using the genetic values of 133 breeding males whose breeding-value reliability was higher than 50% for all the traits in order to define the number of principal components (PC) which would explain most of the variation. The highest heritabilities were for W18 and MY270, and the lowest for AFC; with 0.53, 0.23, and 0.17, respectively. The first three PCs represented 66% of the total variance. Correlation of the first PC with meat production traits was higher than 0.73, and it was -0.38 with AFC. Correlations of the second PC with maternal genetic component traits for WW and W12 were above 0.75. The third PC had 0.84 correlation with MY270. PCA is an alternative approach for analyzing traits in dual-purpose buffaloes and reduces the dimension of the traits. PMID:26230093

  16. Genetic Evaluation of Dual-Purpose Buffaloes (Bubalus bubalis) in Colombia Using Principal Component Analysis

    PubMed Central

    Agudelo-Gómez, Divier; Pineda-Sierra, Sebastian; Cerón-Muñoz, Mario Fernando

    2015-01-01

    Genealogy and productive information of 48621 dual-purpose buffaloes born in Colombia between years 1996 and 2014 was used. The following traits were assessed using one-trait models: milk yield at 270 days (MY270), age at first calving (AFC), weaning weight (WW), and weights at the following ages: first year (W12), 18 months (W18), and 2 years (W24). Direct additive genetic and residual random effects were included in all the traits. Maternal permanent environmental and maternal additive genetic effects were included for WW and W12. The fixed effects were: contemporary group (for all traits), sex (for WW, W12, W18, and W24), parity (for WW, W12, and MY270). Age was included as covariate for WW, W12, W18 and W24. Principal component analysis (PCA) was conducted using the genetic values of 133 breeding males whose breeding-value reliability was higher than 50% for all the traits in order to define the number of principal components (PC) which would explain most of the variation. The highest heritabilities were for W18 and MY270, and the lowest for AFC; with 0.53, 0.23, and 0.17, respectively. The first three PCs represented 66% of the total variance. Correlation of the first PC with meat production traits was higher than 0.73, and it was -0.38 with AFC. Correlations of the second PC with maternal genetic component traits for WW and W12 were above 0.75. The third PC had 0.84 correlation with MY270. PCA is an alternative approach for analyzing traits in dual-purpose buffaloes and reduces the dimension of the traits. PMID:26230093

  17. Dual Purpose Landscaping Tools: Small Extra Dimensions in AdS/CFT

    SciTech Connect

    Polchinski, Joseph; Silverstein, Eva; /Santa Barbara, KITP /UC, Santa Barbara /SLAC /Stanford U., Phys. Dept.

    2010-08-26

    We propose a class of AdS/CFT dual pairs which have small internal dimensions on the gravity side. Starting from known Freund-Rubin AdS/CFT dual pairs, we use 7-branes to nearly cancel the curvature energy of the internal dimensions while maintaining their stabilization. This leads to a new corner of the landscape - a class of AdS solutions with a hierarchically large AdS radius - with a dual field theory given (implicitly) by the infrared limit of a concrete brane construction involving D3-branes, 7-branes, and curvature. We first construct a class of hierarchical AdS5/CFT4 dual pairs with a simple formula for the number of degrees of freedom which we interpret in the dual QFT. We then generalize these to AdS4/CFT3 duals, and suggest extensions of the method to obtain de Sitter solutions.

  18. A microfluidic, dual-purpose sensor for in vitro detection of Enterobacteriaceae and biotinylated antibodies.

    PubMed

    Kokkinis, G; Plochberger, B; Cardoso, S; Keplinger, F; Giouroudi, I

    2016-03-23

    In this paper, we present a versatile, dual-purpose sensor for in vitro detection of Enterobacteriaceae (e.g. Escherichia coli) and biotinylated antibodies (e.g. IgG rabbit polyclonal antibodies), based on different detection principles for each bioanalyte. These bioanalytes are tagged individually with functionalized magnetic microparticles, suspended into a static fluid and injected into a microfluidic channel. Without the need for bulk or complicated pumping systems, the functionalized microparticles are set in motion by a magnetic force exerted on them by integrated microconductors. The fundamental detection principle is the decrease in the velocity of the microparticles that are loaded with the respective bioanalyte, due to factors inhibiting their motion. The velocity of the unloaded, bare microparticles is used as a reference. We discovered a novel mechanism on which the constrained particle motion is based; in the case of E. coli, the inhibiting factor is the enhanced Stokes' drag force due to the greater volume and altered hydrodynamic shape, whereas in the case of biotinylated antibodies, it is the increased friction force at the interface between the modified microparticle and the biosensor's surface. Friction force is for the first time employed in a scheme for resolving biomolecules. Integrated magnetic microsensors are used for the velocity measurements by detecting the microparticles' stray field. Moreover, we developed a biocompatible, easy to implement and reliable surface modification that practically diminishes the problem of bioadhesion on the sensor's surface. PMID:26939996

  19. Crossbreeding dual-purpose cattle for beef production in tropical regions.

    PubMed

    Rodriguez-Voigt, A; Noguera, E; Rodriguez, H L; Huerta-Leidenz, N O; Morón-Fuenmayor, O; Rincón-Urdaneta, E

    1997-11-01

    Six breed types groups of six steer calves each were used to observe differences in growth and carcass traits: F1 Brown Swiss (F1BS), F1 Holstein (F1HO), F2 Brahman (F2BR), F2 Criollo Rio Limon (F2CRL), purebred Criollo Rio Limon (CRL), and Perija Mosaic (PMO). After 404 days of grazing, the heaviest F1BS and F2BR steers were different from F1HO and CRL counterparts (p < 0.05) in slaughter weight. F2BR dressed higher and had better muscle conformation scores than F1BS, F1HO, F2CRL and CRL (p < 0.05). F1BS had the thickest backfat (0.5 cm) but only differed (p < 0.05) from F1HO (0.3 cm). Rib eye area, marbling score, carcass maturity, quality or yield grade, boneless cut percentages, bone percentage or percent trimmable fat did not vary among breed types. All steers were within the A maturity level and graded Standard. Results indicate the importance of feeding dual-purpose steers to heavier weights to please industry preferences. PMID:22062732

  20. 'Duster' wheat: A durable, dual-purpose cultivar adapted to the southern great plains of the USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter wheat (Triticum aestivum L.) cultivars which gain broad commercial acceptance in Oklahoma and surrounding states of the U.S. southern Great Plains must produce a definitive grain yield advantage, and they must demonstrate season-long dependability in dual purpose management systems, effective...

  1. Molasses supplementation for dual-purpose cows during the dry season in subtropical Mexico.

    PubMed

    Salvador-Loreto, Isela; Arriaga-Jordán, Carlos Manuel; Estrada-Flores, Julieta Gertrudis; Vicente-Mainar, Fernando; García-Martínez, Anastacio; Albarrán-Portillo, Benito

    2016-03-01

    The effect of including 9 % of molasses in supplements offered to dual purpose cows, during dry season in subtropical Mexico was determined. Forage availability in pastures during the dry season is reduced and of low quality. Molasses is a readily available source of energy that may improve forage utilization and could have a positive effect on cow's milk production and calves daily weight gain (CDWG). Twelve multiparous Brown Swiss cows (409 ± 33 kg of body weight and 136 ± 73 days in milk), and their calves were randomly assigned to two supplements (six cows per treatment). Control supplement (COS) consisted of cracked maize ears (CME), soybean meal and urea (14 % CP), and experimental supplement in which 9 % of CME was replaced by molasses (MOS). Cows received 4.5 kg/cow/day dry matter (DM) of supplement. Experiment lasted 10 weeks divided in five experimental periods (EP). Animal responses (milk yield, milk composition, body weight, body condition score and CDWG) were recorded at the end of every EP. A linear mixed model was used to analyse the data as a complete random design. Net profits from milk and beef due to supplements were estimated using partial budget approach. Average milk yield was 7 (kg/cow/day) with 30.6, 30.4 and 42.5 (g/kg milk) of fat, protein and lactose, respectively. Average cow weight was 422 kg and CDWG was 0.8 kg/day. No significant responses on animal production variables were found when 9 % of MOS was included in the supplement; however, total net income increased on 4 %, due to higher CDWG. PMID:26885986

  2. Safety Analysis of Dual Purpose Metal Cask Subjected to Impulsive Loads due to Aircraft Engine Crash

    NASA Astrophysics Data System (ADS)

    Shirai, Koji; Namba, Kosuke; Saegusa, Toshiari

    In Japan, the first Interim Storage Facility of spent nuclear fuel away from reactor site is being planned to start its commercial operation around 2010, in use of dual-purpose metal cask in the northern part of Main Japan Island. Business License Examination for safety design approval has started since March, 2007. To demonstrate the more scientific and rational performance of safety regulation activities on each phase for the first license procedure, CREPEI has executed demonstration tests with full scale casks, such as drop tests onto real targets without impact limiters(1) and seismic tests subjected to strong earthquake motions(2). Moreover, it is important to develop the knowledge for the inherent security of metal casks under extreme mechanical-impact conditions, especially for increasing interest since the terrorist attacks from 11th September 2001(3)-(6). This paper presents dynamic mechanical behavior of the metal cask lid closure system caused by direct aircraft engine crash and describes calculated results (especially, leak tightness based on relative dynamic displacements between metallic seals). Firstly, the local penetration damage of the interim storage facility building by a big passenger aircraft engine crash (diameter 2.7m, length 4.3m, weight 4.4ton, impact velocity 90m/s) has been examined. The reduced velocity is calculated by the local damage formula for concrete structure with its thickness of 70cm. The load vs. time function for this reduced velocity (60m/s) is estimated by the impact analysis using Finite Element code LS-DYNA with the full scale engine model onto a hypothetically rigid target. Secondly, as the most critical scenarios for the metal cask, two impact scenarios (horizontal impact hitting the cask and vertical impact onto the lid metallic seal system) are chosen. To consider the geometry of all bolts for two lids, the gasket reaction forces and the inner pressure of the cask cavity, the detailed three dimensional FEM models are

  3. Genetic principal components for reproductive and productive traits in dual-purpose buffaloes in Colombia.

    PubMed

    Agudelo-Gómez, D A; Pelicioni Savegnago, R; Buzanskas, M E; Ferraudo, A S; Prado Munari, D; Cerón-Muñoz, M F

    2015-08-01

    A multitrait model (MC) and 5 reduced-rank models with principal component structure (components PC, PC, PC, PC, and PC) were compared. The objectives were to determine the most appropriate model for estimating genetic parameters and to evaluate the genetic progress of dual-purpose buffaloes in Colombia using that model. The traits evaluated were weaning weight (WW), yearling weight (W12), weight at 18 mo of age (W18), weight at 2 yr of age (W24), age at first calving (AFC), and milk yield at 270 d of first lactation (MY270). Genealogy and productive information from 34,326 buffaloes born in Colombia between 1997 and 2014 were used. Colombian Association of Buffalo Breeders (ACB) provided the data. Direct additive genetic and residual random effects were included for all the traits. In addition, the maternal additive genetic effect and permanent environmental random effect were included for WW, while a maternal additive genetic effect was included for W12. The fixed effects were contemporary group (farm, year, and calving season: January to April, May to August, or September to December; for all traits) and sex (for WW, W12, W18, and W24). Additionally, parity was included as a fixed effect for WW and W12. Age at weighing was used as a covariate for WW, W12, W18, and W24. Genetic progress of all traits was analyzed using a generalized smooth model (GAM). According to the Akaike information criteria (AIC), the best model was the one with reduced rank and first 3 principal components (PC). This model maintained 100% of the original variance. Genetic parameters estimated with this model were similar to those estimated by MC, but with smaller standard errors. Heritability for weight-related traits ranged between 0.23 and 0.44. Heritabilities for AFC and MY270 were 0.14 and 0.24, respectively. The genetic correlations obtained between all weights (WW, W12, W18, and W24) were positive and high. Correlations between all weights with AFC were negative and moderate

  4. Economic values for health and feed efficiency traits of dual-purpose cattle in marginal areas.

    PubMed

    Krupová, Z; Krupa, E; Michaličková, M; Wolfová, M; Kasarda, R

    2016-01-01

    Economic values of clinical mastitis, claw disease, and feed efficiency traits along with 16 additional production and functional traits were estimated for the dairy population of the Slovak Pinzgau breed using a bioeconomic approach. In the cow-calf population (suckler cow population) of the same breed, the economic values of feed efficiency traits along with 15 further production and functional traits were calculated. The marginal economic values of clinical mastitis and claw disease incidence in the dairy system were -€ 70.65 and -€ 26.73 per case per cow and year, respectively. The marginal economic values for residual feed intake were -€ 55.15 and -€ 54.64/kg of dry matter per day for cows and breeding heifers in the dairy system and -€ 20.45, -€ 11.30, and -€ 6.04/kg of dry matter per day for cows, breeding heifers, and fattened animals in the cow-calf system, respectively, all expressed per cow and year. The sums of the relative economic values for the 2 new health traits in the dairy system and for residual feed intake across all cattle categories in both systems were 1.4 and 8%, respectively. Within the dairy production system, the highest relative economic values were for milk yield (20%), daily gain of calves (20%), productive lifetime (10%), and cow conception rate (8%). In the cow-calf system, the most important traits were weight gain of calves from 120 to 210 d and from birth to 120 d (19 and 14%, respectively), productive lifetime (17%), and cow conception rate (13%). Based on the calculation of economic values for traits in the dual-purpose Pinzgau breed, milk production and growth traits remain highly important in the breeding goal, but their relative importance should be adapted to new production and economic conditions. The economic importance of functional traits (especially of cow productive lifetime and fertility) was sufficiently high to make the inclusion of these traits into the breeding goal necessary. An increased interest

  5. Improvement of operational safety of dual-purpose transport packaging set for naval SNF in storage

    SciTech Connect

    Guskov, Vladimir; Korotkov, Gennady; Barnes, Ella; Snipes, Randy

    2007-07-01

    Available in abstract form only. Full text of publication follows: In recent ten years a new technology of management of irradiated nuclear fuel (SNF) at the final stage of fuel cycle has been intensely developing on a basis of a new type of casks used for interim storage of SNF and subsequent transportation therein to the place of processing, further storage or final disposal. This technology stems from the concept of a protective cask which provides preservation of its content (SNF) and fulfillment of all other safety requirements for storage and transportation of SNF. Radiation protection against emissions and non-distribution of activity outside the cask is ensured by physical barriers, i.e. all-metal or composite body, shells, inner cavities for irradiated fuel assemblies (SFA), lids with sealing systems. Residual heat release of SFA is discharged to the environment by natural way: through emission and convection of surrounding air. By now more than 100 dual purpose packaging sets TUK-108/1 are in operation in the mode of interim storage and transportation of SNF from decommissioned nuclear powered submarines (NPS). In accordance with certificate, spent fuel is stored in TUK-108/1 on the premises of plants involved in NPS dismantlement for 2 years, whereupon it is transported for processing to PO Mayak. At one Far Eastern plant Zvezda involved in NPS dismantlement there arose a complicated situation due to necessity to extend period of storage of SNF in TUK- 108/1. To ensure safety over a longer period of storage of SNF in TUK-108/1 it is essential to modify conditions of storage by removing of residual water and filling the inner cavity of the cask with an inert gas. Within implementation of the international 1.1- 2 project Development of drying technology for the cask TUK-108/1 intended for naval SNF under the Program, there has been developed the technology of preparation of the cask for long-term storage of SNF in TUK-108/1, the design of a mobile TUK-108

  6. The Compton Observatory Science Workshop

    NASA Technical Reports Server (NTRS)

    Shrader, Chris R. (Editor); Gehrels, Neil (Editor); Dennis, Brian (Editor)

    1992-01-01

    The Compton Observatory Science Workshop was held in Annapolis, Maryland on September 23-25, 1991. The primary purpose of the workshop was to provide a forum for the exchange of ideas and information among scientists with interests in various areas of high energy astrophysics, with emphasis on the scientific capabilities of the Compton Observatory. Early scientific results, as well as reports on in-flight instrument performance and calibrations are presented. Guest investigator data products, analysis techniques, and associated software were discussed. Scientific topics covered included active galaxies, cosmic gamma ray bursts, solar physics, pulsars, novae, supernovae, galactic binary sources, and diffuse galactic and extragalactic emission.

  7. Conducting a Statewide Dual-Purpose Program for Pesticide Applicators and County Extension Agents

    ERIC Educational Resources Information Center

    Fishel, Fred; Liu, Guodong David

    2014-01-01

    The University of Florida Cooperative Extension conducted a statewide program with a dual role during 2013 and 2014 to enhance efficiency. The program provided in-service training to county Extension agents and provided continuing education to meet requirements needed by licensed pesticide applicators. Using Polycom distance technology, the event…

  8. Overlap in genomic variation associated with milk fat composition in Holstein Friesian and Dutch native dual-purpose breeds.

    PubMed

    Maurice-Van Eijndhoven, M H T; Bovenhuis, H; Veerkamp, R F; Calus, M P L

    2015-09-01

    The aim of this study was to identify if genomic variations associated with fatty acid (FA) composition are similar between the Holstein-Friesian (HF) and native dual-purpose breeds used in the Dutch dairy industry. Phenotypic and genotypic information were available for the breeds Meuse-Rhine-Yssel (MRY), Dutch Friesian (DF), Groningen White Headed (GWH), and HF. First, the reliability of genomic breeding values of the native Dutch dual-purpose cattle breeds MRY, DF, and GWH was evaluated using single nucleotide polymorphism (SNP) effects estimated in HF, including all SNP or subsets with stronger associations in HF. Second, the genomic variation of the regions associated with FA composition in HF (regions on Bos taurus autosome 5, 14, and 26), were studied in the different breeds. Finally, similarities in genotype and allele frequencies between MRY, DF, GWH, and HF breeds were assessed for specific regions associated with FA composition. On average across the traits, the highest reliabilities of genomic prediction were estimated for GWH (0.158) and DF (0.116) when the 8 to 22 SNP with the strongest association in HF were included. With the same set of SNP, GEBV for MRY were the least reliable (0.022). This indicates that on average only 2 (MRY) to 16% (GWH) of the genomic variation in HF is shared with the native Dutch dual-purpose breeds. The comparison of predicted variances of different regions associated with milk and milk fat composition showed that breeds clearly differed in genomic variation within these regions. Finally, the correlations of allele frequencies between breeds across the 8 to 22 SNP with the strongest association in HF were around 0.8 between the Dutch native dual-purpose breeds, whereas the correlations between the native breeds and HF were clearly lower and around 0.5. There was no consistent relationship between the reliabilities of genomic prediction for a specific breed and the correlation between the allele frequencies of this breed

  9. Advanced development in phytochemicals analysis of medicine and food dual purposes plants used in China (2011-2014).

    PubMed

    Zhao, Jing; Ge, Li-Ya; Xiong, Wei; Leong, Fong; Huang, Lu-Qi; Li, Shao-Ping

    2016-01-01

    In 2011, we wrote a review for summarizing the phytochemical analysis (2006-2010) of medicine and food dual purposes plants used in China (Zhao et al., J. Chromatogr. A 1218 (2011) 7453-7475). Since then, more than 750 articles related to their phytochemical analysis have been published. Therefore, an updated review for the advanced development (2011-2014) in this topic is necessary for well understanding the quality control and health beneficial phytochemicals in these materials, as well as their research trends. PMID:26385085

  10. Assessment of the sustainability of dual-purpose farms by the IDEA method in the subtropical area of central Mexico.

    PubMed

    Salas-Reyes, Isela Guadalupe; Arriaga-Jordán, Carlos Manuel; Rebollar-Rebollar, Samuel; García-Martínez, Anastacio; Albarrán-Portillo, Benito

    2015-08-01

    The objective of this study was to assess the sustainability of 10 dual-purpose cattle farms in a subtropical area of central Mexico. The IDEA method (Indicateurs de Durabilité des Exploitations Agricoles) was applied, which includes the agroecological, socio-territorial and economic scales (scores from 0 to 100 points per scale). A sample of 47 farms from a total of 91 registered in the local livestock growers association was analysed with principal component analysis and cluster analysis. From results, 10 farms were selected for the in-depth study herein reported, being the selection criterion continuous milk production throughout the year. Farms had a score of 88 and 86 points for the agroecological scale in the rainy and dry seasons. In the socio-territorial scale, scores were 73 points for both seasons, being the component of employment and services the strongest. Scores for the economic scale were 64 and 56 points for the rainy and dry seasons, respectively, when no economic cost for family labour is charged, which decreases to 59 and 45 points when an opportunity cost for family labour is considered. Dual-purpose farms in the subtropical area of central Mexico have a medium sustainability, with the economic scale being the limiting factor, and an area of opportunity. PMID:25958175

  11. Compton tomography system

    DOEpatents

    Grubsky, Victor; Romanoov, Volodymyr; Shoemaker, Keith; Patton, Edward Matthew; Jannson, Tomasz

    2016-02-02

    A Compton tomography system comprises an x-ray source configured to produce a planar x-ray beam. The beam irradiates a slice of an object to be imaged, producing Compton-scattered x-rays. The Compton-scattered x-rays are imaged by an x-ray camera. Translation of the object with respect to the source and camera or vice versa allows three-dimensional object imaging.

  12. Dual purpose microalgae-bacteria-based systems that treat wastewater and produce biodiesel and chemical products within a biorefinery.

    PubMed

    Olguín, Eugenia J

    2012-01-01

    Excess greenhouse gas emissions and the concomitant effect on global warming have become significant environmental, social and economic threats. In this context, the development of renewable, carbon-neutral and economically feasible biofuels is a driving force for innovation worldwide. A lot of effort has been put into developing biodiesel from microalgae. However, there are still a number of technological, market and policy barriers that are serious obstacles to the economic feasibility and competitiveness of such biofuels. Conversely, there are also a number of business opportunities if the production of such alternative biofuel becomes part of a larger integrated system following the Biorefinery strategy. In this case, other biofuels and chemical products of high added value are produced, contributing to an overall enhancement of the economic viability of the whole integrated system. Additionally, dual purpose microalgae-bacteria-based systems for treating wastewater and production of biofuels and chemical products significantly contribute to a substantial saving in the overall cost of microalgae biomass production. These types of systems could help to improve the competitiveness of biodiesel production from microalgae, according to some recent Life Cycle Analysis studies. Furthermore, they do not compete for fresh water resources for agricultural purposes and add value to treating the wastewater itself. This work reviews the most recent and relevant information about these types of dual purpose systems. Several aspects related to the treatment of municipal and animal wastewater with simultaneous recovery of microalgae with potential for biodiesel production are discussed. The use of pre-treated waste or anaerobic effluents from digested waste as nutrient additives for weak wastewater is reviewed. Isolation and screening of microalgae/cyanobacteria or their consortia from various wastewater streams, and studies related to population dynamics in mixed cultures

  13. Compton Sources of Electromagnetic Radiation

    SciTech Connect

    Geoffrey Krafft,Gerd Priebe

    2011-01-01

    When a relativistic electron beam interacts with a high-field laser beam, intense and highly collimated electromagnetic radiation will be generated through Compton scattering. Through relativistic upshifting and the relativistic Doppler effect, highly energetic polarized photons are radiated along the electron beam motion when the electrons interact with the laser light. For example, X-ray radiation can be obtained when optical lasers are scattered from electrons of tens-of-MeV beam energy. Because of the desirable properties of the radiation produced, many groups around the world have been designing, building, and utilizing Compton sources for a wide variety of purposes. In this review article, we discuss the generation and properties of the scattered radiation, the types of Compton source devices that have been constructed to date, and the prospects of radiation sources of this general type. Due to the possibilities of producing hard electromagnetic radiation in a device that is small compared to the alternative storage ring sources, it is foreseen that large numbers of such sources may be constructed in the future.

  14. Dual purpose system that treats anaerobic effluents from pig waste and produce Neochloris oleoabundans as lipid rich biomass.

    PubMed

    Olguín, Eugenia J; Castillo, Omar S; Mendoza, Anilú; Tapia, Karla; González-Portela, Ricardo E; Hernández-Landa, Víctor J

    2015-05-25

    Dual purpose systems that treat wastewater and produce lipid rich microalgae biomass have been indicated as an option with great potential for production of biodiesel at a competitive cost. The aim of the present work was to develop a dual purpose system for the treatment of the anaerobic effluents from pig waste utilizing Neochloris oleoabundans and to evaluate its growth, lipid content and lipid profile of the harvested biomass and the removal of nutrients from the media. Cultures of N. oleoabundans were established in 4 L flat plate photobioreactors using diluted effluents from two different types of anaerobic filters, one packed with ceramic material (D1) and another one packed with volcanic gravel (D2). Maximum biomass concentration in D1 was 0.63 g L(-1) which was significantly higher than the one found in D2 (0.55 g L(-1)). Cultures were very efficient at nutrient removal: 98% for NNH4(+) and 98% for PO4(3-). Regarding total lipid content, diluted eflluents from D2 promoted a biomass containing 27.4% (dry weight) and D1 a biomass containing 22.4% (dry weight). Maximum lipid productivity was also higher in D2 compared to D1 (6.27±0.62 mg L(-1) d(-1) vs. 5.12±0.12 mg L(-1) d(-1)). Concerning the FAMEs profile in diluted effluents, the most abundant one was C18:1, followed by C18:2 and C16:0. The profile in D2 contained less C18:3 (linolenic acid) than the one in D1 (4.37% vs. 5.55%). In conclusion, this is the first report demonstrating that cultures of N. oleoabundans treating anaerobic effluents from pig waste are very efficient at nutrient removal and a biomass rich in lipids can be recovered. The maximum total lipid content and the most convenient FAMEs profile were obtained using effluents from a digester packed with volcanic gravel. PMID:25556121

  15. TGC36 a dual purpose cask for the transport and interim storage of compacted waste (CSD-C)

    SciTech Connect

    Oldiges, O.; Boniface, J.M.

    2008-07-01

    According to contractual and international obligations, the German Utilities have to return the residues resulting from the reprocessing of nuclear fuel assemblies (compacted hulls and ends) to Germany. The new dual purpose cask TGC36 is a joint product from the two leading companies in the field development and manufactory of nuclear casks in Europe, GNS and TN International, is intended for the transport to the interim storage facility Ahaus and to be stored there for up several years. For the development and the delivery of the TGC36 cask, GNS and TN International formed the AGC Consortium based on German law to combine the special know how of both partners in the most efficient way. The design and the licensing strategy of the TGC36 are introduced in this paper. In conclusions: GNS and TNI have formed a consortium named AGC to design, license and manufacture an innovative cask for the transport and the interim storage of the compacted wastes resulting from the reprocessing of the German spent fuel. This cask has been optimized in order to offer a high capacity of loading, and allows a payload of 36 canisters, leading to a total mass of approximately 116 Mg in transport configuration. The success of this project requires a special effort from both partner companies, members of the consortium, and implies also an efficient management of simultaneous tasks during the licensing period and the manufacturing time of the first items of the cask. (authors)

  16. Economic analysis of alternative nutritional management of dual-purpose cow herds in central coastal Veracruz, Mexico.

    PubMed

    Absalón-Medina, Victor Antonio; Nicholson, Charles F; Blake, Robert W; Fox, Danny Gene; Juárez-Lagunes, Francisco I; Canudas-Lara, Eduardo G; Rueda-Maldonado, Bertha L

    2012-08-01

    Market information was combined with predicted input-output relationships in an economic analysis of alternative nutritional management for dual-purpose member herds of the Genesis farmer organization of central coastal Veracruz, Mexico. Cow productivity outcomes for typical management and alternative feeding scenarios were obtained from structured sets of simulations in a companion study of productivity limitations and potentials using the Cornell Net Carbohydrate and Protein System model (Version 6.0). Partial budgeting methods and sensitivity analysis were used to identify economically viable alternatives based on expected change in milk income over feed cost (change in revenues from milk sales less change in feed costs). Herd owners in coastal Veracruz have large economic incentives, from $584 to $1,131 in predicted net margin, to increase milk sales by up to 74% across a three-lactation cow lifetime by improving diets based on good quality grass and legume forages. This increment is equal to, or exceeds, in value the total yield from at least one additional lactation per cow lifetime. Furthermore, marginal rates of return (change in milk income over feed costs divided by change in variable costs when alternative practices are used) of 3.3 ± 0.8 indicate clear economic incentives to remove fundamental productivity vulnerabilities due to chronic energy deficits and impeded growth of immature cows under typical management. Sensitivity analyses indicate that the economic outcomes are robust for a variety of market conditions. PMID:22193940

  17. A fuzzy-logic based dual-purpose adaptive circuit for vibration control and energy harvesting using piezoelectric transducer

    NASA Astrophysics Data System (ADS)

    Liu, Zhe Peng; Li, Qing

    2013-04-01

    Due to their two-way electromechanical coupling effect, piezoelectric transducers can be used to synthesize passive vibration control schemes, e.g., RLC circuit with the integration of inductance and resistance elements that is conceptually similar to damped vibration absorber. Meanwhile, the wide usage of wireless sensors has led to the recent enthusiasm of developing piezoelectric-based energy harvesting devices that can convert ambient vibratory energy into useful electrical energy. It can be shown that the integration of circuitry elements such as resistance and inductance can benefit the energy harvesting capability. Here we explore a dual-purpose circuit that can facilitate simultaneous vibration suppression and energy harvesting. It is worth noting that the goal of vibration suppression and the goal of energy harvesting may not always complement each other. That is, the maximization of vibration suppression doesn't necessarily lead to the maximization of energy harvesting, and vice versa. In this research, we develop a fuzzy-logic based algorithm to decide the proper selection of circuitry elements to balance between the two goals. As the circuitry elements can be online tuned, this research yields an adaptive circuitry concept for the effective manipulation of system energy and vibration suppression. Comprehensive analyses are carried out to demonstrate the concept and operation.

  18. Clearwater Russet: A dual-purpose potato cultivar with cold sweetening resistance, high protein content, and low incidence of external defects and sugar ends

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clearwater Russet is a russet-skinned potato cultivar suitable for processing or fresh pack. It is notable for having a low incidence of external defects that contributes to its high U.S. No 1 yield relative to the dual-purpose industry standard, Russet Burbank. Clearwater Russet also has exceptio...

  19. The Role of Student Outcomes in Dual Purpose Teacher Evaluation Systems: A Model for Meeting Top Down and Bottom Up Needs.

    ERIC Educational Resources Information Center

    Redfield, Doris L.; And Others

    A model is presented for including student outcome measures on teacher evaluation systems when there are needs for both formative and summative evaluation data. The experiences of Kentucky and Georgia provided bases for the development of the dual purpose assessment model. Pilot tests in Kentucky and Georgia were specific to the top-down…

  20. 30 CFR 206.181 - How do I establish processing costs for dual accounting purposes when I do not process the gas?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false How do I establish processing costs for dual accounting purposes when I do not process the gas? 206.181 Section 206.181 Mineral Resources MINERALS... be deemed to be denied and subject to appeal to the MMS Director under 30 CFR part 290....

  1. Prohexadione-calcium improves the establishment and yield of alfalfa interseeded as a dual purpose cover-forage crop into silage corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interseeded alfalfa could serve as a dual purpose crop for providing groundcover during silage corn production and forage during subsequent years of production, but this system has been unworkable because competition between the co-planted crops often leads to stand failure of interseeded alfalfa an...

  2. Compton Community College Information Notebook, Fall 1995.

    ERIC Educational Resources Information Center

    Camacho, Julian S.

    This notebook serves the purpose of informing the Compton Community College District about the student body population, faculty and classified employees in reference to gender, race/ethnicity and age. Findings from an analysis of the period from fall 1991 to fall 1995 included the following: (1) over the period, the enrollment of Black students…

  3. Timelike Compton Scattering

    SciTech Connect

    T. Horn, Y. Illieva, F. J. Klein, P. Nadel‐Turonski, R. Paremuzyan, S. Stepanyan

    2011-10-01

    Generalized Parton Distributions (GPDs) have become a key concept in our studies of hadron structure in QCD. The measurement of suitable experimental observables and the extraction of GPDs from these data is one of the high priority 12 GeV programs at Jefferson Lab. Deeply Virtual Compton Scattering (DVCS) is generally thought of as the most promising channel for probing GPDs in the valence quark region. However, the inverse process, Timelike Compton Scattering (TCS) can provide an important complementary measurement, in particular of the real part of the Compton amplitude and power corrections at intermediate values of Q2. The first studies of TCS using real tagged and quasi-real untagged photons were performed in Hall B at Jefferson Lab.

  4. The Compton generator revisited

    NASA Astrophysics Data System (ADS)

    Siboni, S.

    2014-09-01

    The Compton generator, introduced in 1913 by the US physicist A H Compton as a relatively simple device to detect the Earth's rotation with respect to the distant stars, is analyzed and discussed in a general perspective. The paper introduces a generalized definition of the generator, emphasizing the special features of the original apparatus, and provides a suggestive interpretation of the way the device works. To this end, an intriguing electromagnetic analogy is developed, which turns out to be particularly useful in simplifying the calculations. Besides the more extensive description of the Compton generator in itself, the combined use of concepts and methods coming from different fields of physics, such as particle dynamics in moving references frames, continuum mechanics and electromagnetism, may be of interest to both teachers and graduate students.

  5. Dual-Purpose Bioreactors to Monitor Noninvasive Physical and Biochemical Markers of Kidney and Liver Scaffold Recellularization.

    PubMed

    Uzarski, Joseph S; Bijonowski, Brent M; Wang, Bo; Ward, Heather H; Wandinger-Ness, Angela; Miller, William M; Wertheim, Jason A

    2015-10-01

    Analysis of perfusion-based bioreactors for organ engineering and a detailed evaluation of physical and biochemical parameters that measure dynamic changes within maturing cell-laden scaffolds are critical components of ex vivo tissue development that remain understudied topics in the tissue and organ engineering literature. Intricately designed bioreactors that house developing tissue are critical to properly recapitulate the in vivo environment, deliver nutrients within perfused media, and monitor physiological parameters of tissue development. Herein, we provide an in-depth description and analysis of two dual-purpose perfusion bioreactors that improve upon current bioreactor designs and enable comparative analyses of ex vivo scaffold recellularization strategies and cell growth performance during long-term maintenance culture of engineered kidney or liver tissues. Both bioreactors are effective at maximizing cell seeding of small-animal organ scaffolds and maintaining cell survival in extended culture. We further demonstrate noninvasive monitoring capabilities for tracking dynamic changes within scaffolds as the native cellular component is removed during decellularization and model human cells are introduced into the scaffold during recellularization and proliferate in maintenance culture. We found that hydrodynamic pressure drop (ΔP) across the retained scaffold vasculature is a noninvasive measurement of scaffold integrity. We further show that ΔP, and thus resistance to fluid flow through the scaffold, decreases with cell loss during decellularization and correspondingly increases to near normal values for whole organs following recellularization of the kidney or liver scaffolds. Perfused media may be further sampled in real time to measure soluble biomarkers (e.g., resazurin, albumin, or kidney injury molecule-1) that indicate degree of cellular metabolic activity, synthetic function, or engraftment into the scaffold. Cell growth within bioreactors is

  6. Deeply virtual Compton scattering

    NASA Astrophysics Data System (ADS)

    Marukyan, Hrachya

    2015-11-01

    This paper reviews the experimental measurements in the field of deeply virtual Compton scattering and related theoretical efforts aimed for the extraction of generalized parton distributions, objects, describing the three-dimensional structure of nucleons and nuclei. The future experiments and theoretical expectations are also considered.

  7. Nucleon Compton Scattering

    SciTech Connect

    Bogdan Wojtsekhowski

    2006-06-04

    Review of Nucleon Compton Scattering in wide angle regime is presented. JLab experimental data strongly support dominance of handbag mechanism in the RCS process. The approved ALLRCS experiment with polarized target and future plans with 12 GeV beam are discussed.

  8. Compton scattering overview

    SciTech Connect

    Hartemann, F V

    2008-12-01

    An overview of linear and nonlinear Compton scattering is presented, along with a comparison with Thomson scattering. Two distinct processes play important roles in the nonlinear regime: multi-photon interactions, leading to the generation of harmonics, and radiation pressure, yielding a downshift of the radiated spectral features. These mechanisms, their influence on the source brightness, and different modeling strategies are also briefly discussed.

  9. Virtual Compton Scattering

    SciTech Connect

    Helene Fonvieille

    2003-05-01

    Virtual Compton Scattering off the proton: {gamma}^+p --> {gamma}p is a new field of investigation of nucleon structure. Several dedicated experiments have been performed at low c.m. energy and various momentum transfers, yielding specific information on the proton. This talk reviews the concept of nucleon Generalized Polarizabilities and the present experimental status.

  10. Bull exposure and an increased within-day milking to suckling interval reduced postpartum anoestrus in dual purpose cows.

    PubMed

    Pérez-Hernández, P; García-Winder, M; Gallegos-Sánchez, J

    2002-12-16

    It is hypothesized that the combined effects of suckling and milking in the dual purpose cows is one of the main suppressors of reproductive efficiency in this production system. The experiment described here examined whether managing the interval between milking and suckling could reduce the postpartum anoestrous period and whether the presence of a teaser bull could enhance the effects of these managements. The experiment involved 39 Bos taurus x Bos indicus cows which had an average weight of 523.0 +/- 12.8 kg (mean +/- S.E.M.) and body condition score of 5-7 (scale 1-9) at calving. The cows and calves grazed separate pastures and the cows were supplemented with 2 kg 17% CP concentrates and 1 kg molasses per cow per day. The experiment was conducted over the first 100 days postpartum. Cows were hand-milked once per day in the presence of the calf to stimulate milk release. The factors in the 2 x 2 design were the milking to suckling interval (0 h, control suckling; CS versus 8 h prolonged-delay suckling; PDS) and no exposure versus exposure to a teaser bull (B). Cows were assigned at random within calving date to the four treatments: CS (n = 10), PDS (n = 10), CS-B (n = 9) and PDS-B (n = 10). Cows on treatments CS and CS-B had three-quarters of the udder milked and one-quarter was not milked. The entire udder was milked on those treatments where there was an interval between milking and suckling. The bull was introduced 7 days after calving in treatments where the cows were exposed to a teaser bull. Body weights of cows and calves and cow milk yield were recorded. Weekly blood samples were collected for plasma progesterone assay. Data were analyzed by ANOVA in a 2 x 2 factorial design and by chi(2)-test. There were no statistically significant differences between treatments in cow body weight at calving and at 100 days postpartum, nor in milk yield (overall mean 6.0 +/- 1.1 kg per day). Calf daily gain was 598 +/- 25 g for treatments CS and CS-B in which

  11. Quantitation of selected terpenoids and mercaptans in the dual-purpose hop varieties Amarillo, Citra, Hallertau Blanc, Mosaic, and Sorachi Ace.

    PubMed

    Cibaka, Marie-Lucie Kankolongo; Gros, Jacques; Nizet, Sabrina; Collin, Sonia

    2015-03-25

    Free terpenoids and both free and bound polyfunctional thiols were investigated in five selected dual-purpose hop cultivars. Surprisingly, the dual-purpose Sorachi Ace variety was found to contain higher amounts of farnesene (2101 mg/kg) than aromatic hops such as Saaz but only traces of 3-methylbutylisobutyrate, a compound that usually distinguishes all bitter varieties. All five cultivars investigated here showed an exceptional citrus-like potential explained by either monoterpenic alcohols or polyfunctional thiols. Among the monoterpenic alcohols, β-citronellol at concentrations above 7 mg/kg distinguished Amarillo, Citra, Hallertau Blanc, Mosaic, and Sorachi Ace from Nelson Sauvin and Tomahawk, two previously investigated dual-purpose hops, while linalool (312 mg/kg) and geraniol (211 mg/kg) remained good discriminating compounds for Nelson Sauvin and Tomahawk, respectively. Regarding polyfunctional thiols, higher amounts of 3-sulfanylhexyl acetate (27 μg/kg) characterized the Citra variety. Free 4-sulfanyl-4-methylpentan-2-one proved discriminant for Sorachi Ace, while the bound form is predominant in Nelson Sauvin. On the other hand, an S-conjugate of 3-sulfanylhexan-1-ol was found in Sorachi Ace at levels not far from those previously reported for Cascade, although the free form was undetected here. Both free and bound grapefruit-like 3-sulfanyl-4-methylpentan-1-ol (never evidenced before the present work) emerged as discriminating compounds for the Hallertau Blanc variety. The apotryptophanase assay also allowed us to evidence for the first time an S-conjugate of 2-sulfanylethan-1-ol. PMID:25780945

  12. The Compton Gamma Ray Observatory

    NASA Astrophysics Data System (ADS)

    Gehrels, N.; Chipman, E.; Kniffen, D. A.

    1993-01-01

    The Arthur Holly Compton Gamma Ray Observatory (Compton) was launched by the Space Shuttle Atlantis on 5 April 1991. The spacecraft and instruments are in good health and returning exciting results. The mission provides nearly six orders of magnitude in spectral coverage, from 30 keV to 30 GeV, with sensitivity over the entire range an order of magnitude better than that of previous observations. The 16,000 kilogram observatory contains four instruments on a stabilized platform. The mission began normal operations on 16 May 1991 and is now over half-way through a full-sky survey. The mission duration is expected to be from six to ten years. A Science Support Center has been established at Goddard Space Flight Center for the purpose of supporting a vigorous Guest Investigator Program. New scientific results to date include: (1) the establishment of the isotropy, combined with spatial inhomogeneity, of the distribution of gamma-ray bursts in the sky; (2) the discovery of intense high energy (100 MeV) gamma-ray emission from 3C 279 and other quasars and BL Lac objects, making these the most distant and luminous gamma-ray sources ever detected; (3) one of the first images of a gamma-ray burst; (4) the observation of intense nuclear and position-annihilation gamma-ray lines and neutrons from several large solar flares; and (5) the detection of a third gamma-ray pulsar, plus several other transient and pulsing hard X-ray sources.

  13. Compton scattering profile for in vivo XRF techniques.

    PubMed

    Tartari, A; Baraldi, C; Felsteiner, J; Casnati, E

    1991-05-01

    The contribution from single Compton scattered photons to the background in in vivo x-ray fluorescence analysis is evaluated by taking into account the energy broadening of the scattered photons which reflects the momentum distribution of the target electrons. A general-purpose Monte Carlo evaluation of multiple scattering components, as well as accurate experimental verifications with 59.54 keV photons impinging on various targets of interest for real-life irradiation, confirm that the single Compton scattering profiles of the elements composing the biological matrix dominate the trend and amplitude of the background in the region of interest with near-backscatter configurations. Step features are likewise explained in terms of single Compton phenomenology. Other probable sources of background, such as photoelectron Bremsstrahlung and pile-up distribution, are studied both theoretically and experimentally in order to compare their amplitude and features with those of single Compton scattered photon profiles. PMID:2068224

  14. Analysis of a village chicken production system and performance of improved dual purpose chickens under a subtropical hill agro-ecosystem in India.

    PubMed

    Kumaresan, A; Bujarbaruah, K M; Pathak, K A; Chhetri, Bijoy; Ahmed, S K; Haunshi, Santosh

    2008-08-01

    This study was designed to analyze the low input backyard poultry production system practiced by the tribal farmers, and evaluate the performance of an improved dual-purpose breed, the Vanaraja. Results revealed that a significantly (p < 0.05) higher number of farmers used temporary, non-conventional poultry houses made of locally available materials, such as bamboo and wood. Most of the farmers (65.9 %) did not provide balanced feed to their poultry and did not vaccinate their birds against any disease. Under standard management conditions, the average body weight of Vanaraja birds at 6 weeks was 625 +/- 10.9 g. Under backyard conditions, the body weight at 18 months was 3.6 +/- 0.8 kg. The age at first egg was 154 +/- 9 days in the backyard system, whereas under the intensive system it was 196 +/- 4 days. Annual production under the backyard and intensive systems of rearing was 176 +/- 9 and 152 +/- 7 eggs, respectively. Mortality of adult birds was 12 % and predation by foxes and wild cats accounted for 1.67 %. This study revealed that village chickens are an important income source for household expenses, and that traditional free-range poultry production in the smallholder sector of developing countries can possibly be improved through the use of improved dual-purpose birds. PMID:18575965

  15. Development and Application of a Dual-Purpose Nanoparticle Platform for Delivery and Imaging of siRNA in Tumors

    PubMed Central

    Medarova, Zdravka; Kumar, Mohanraja; Ng, Shu-wing; Moore, Anna

    2013-01-01

    The vision of using a single therapeutic agent with sufficient generality to allow application to a wide variety of diseases, yet specific enough to permit intervention at single molecular stages of the pathology, is rapidly becoming a reality through the emergence of RNA interference. RNA interference can be used to inhibit the expression of virtually any gene and, at the same time, has single-nucleotide specificity. Major challenges in applying RNA interference in vivo are adequate delivery of the siRNA molecule to the tissue of interest and methods of monitoring this delivery in a noninvasive manner. With this in mind, we have developed an approach not only to deliver siRNA to tumors, but also to track the success of the delivery by noninvasive imaging. To accomplish this, we designed a dual-function probe, MN-NIRF-siRNA, which consists of magnetic nanoparticles (MN) for magnetic resonance imaging (MRI), labeled with Cy5.5 dye for near-infrared in vivo optical imaging (NIRF), conjugated to myristoylated polyarginine peptides (MPAPs) for translocation of the complex into the cytosol, and carrying siRNA targeting tumor-specific genes. Administration of MN-NIRF-siRNA to tumor-bearing mice allowed us to monitor the delivery of the agent to tumors by MRI and NIRF imaging and resulted in efficient silencing of the target genes. This approach can significantly advance the therapeutic potential of RNA interference by providing a way not only to effectively shuttle siRNA to target sites but also to noninvasively assess the bioavailability of the siRNA molecule. PMID:19495684

  16. Compton polarimetry revisited

    NASA Astrophysics Data System (ADS)

    Bernard, D.

    2015-11-01

    We compute the average polarisation asymmetry from the Klein-Nishina differential cross-section on free electrons at rest. As expected from the expression for the asymmetry, the average asymmetry is found to decrease like the inverse of the incident photon energy asymptotically at high energy. We then compute a simple estimator of the polarisation fraction that makes optimal use of all the kinematic information present in an event final state, by the use of "moments" method, and we compare its statistical power to that of a simple fit of the azimuthal distribution. In contrast to polarimetry with pair creation, for which we obtained an improvement by a factor of larger than two in a previous work, here for Compton scattering the improvement is only of 10-20%.

  17. The "Temporary Recommendations for Use": A dual-purpose regulatory framework for off-label drug use in France.

    PubMed

    Degrassat-Théas, Albane; Bocquet, François; Sinègre, Martine; Peigné, Jérôme; Paubel, Pascal

    2015-11-01

    In 2012, following the Mediator(®) (benfluorex) scandal, France displayed the ambitious goal to implement a regulatory framework for controlling off-label drug use: the "Temporary Recommendations for Use" (RTUs). It aims to regulate the use of pharmaceuticals outside the scope of a marketing authorization (MA) by establishing a framework for patient monitoring and data collection. This is intended to ensure that the benefit/risk ratio is favorable for the indication approved by the RTU. The granting of an RTU enables the reimbursement of off-label drug use and encourages pharmaceutical companies to expand their MA. Between 2012 and 2014, the regulator framework for RTUs was amended twice in order to allow the bypassing of an MA for economic reasons, when a licensed alternative drug exists (so far, this is only illustrated by the bevacizumab (Avastin(®))/ranibizumab (Lucentis(®)) case). The primary purpose of the RTU framework is interesting by implementing an original national control for off-label uses that respond to a public health need. The secondary purpose is more controversial as it promotes off-label use. This has raised legal issues and has created a ground for litigation between pharmaceutical firms and health authorities. RTUs provide an interesting example for other countries that are exploring the possibility of regulating off-label drug use. At the same time, the processes surrounding the implementation of RTUs illustrate the difficulties of public policies to balance public health needs, safety and economic goals. PMID:26455642

  18. Weak Deeply Virtual Compton Scattering

    SciTech Connect

    Ales Psaker; Wolodymyr Melnitchouk; Anatoly Radyushkin

    2007-03-01

    We extend the analysis of the deeply virtual Compton scattering process to the weak interaction sector in the generalized Bjorken limit. The virtual Compton scattering amplitudes for the weak neutral and charged currents are calculated at the leading twist within the framework of the nonlocal light-cone expansion via coordinate space QCD string operators. Using a simple model, we estimate cross sections for neutrino scattering off the nucleon, relevant for future high intensity neutrino beam facilities.

  19. Compton scattering by a pion and off-shell effects

    SciTech Connect

    Scherer, S.; Fearing, H.W. )

    1995-01-01

    We consider Compton scattering by a pion in the framework of chiral perturbation theory. We investigate off-shell effects in the [ital s]- and [ital u]-channel pole diagrams. For that purpose we perform a field transformation which, in comparison with the standard Gasser and Leutwyler Lagrangian, generates additional terms at order [ital p][sup 4] proportional to the lowest-order equation of motion. As a result of the equivalence theorem the two Lagrangians predict the same Compton scattering [ital S]-matrix even though they generate different off-shell form factors. We conclude that off-shell effects are not only model dependent but also representation dependent.

  20. The Compton Effect Red Shift

    NASA Astrophysics Data System (ADS)

    Kierein, John

    2004-05-01

    In 1923 (Phil Mag. 46, 897.) A. H. Compton noted that the Compton effect produces a red shift for all wavelengths when the scattered electron is free and not bound to an atom or molecule. He suggested that the red shift in the visible spectrum at the limb of the sun is larger than that at the center due to the Compton effect from the greater number of free electrons in the sun's atmosphere along the line of sight. Kierein and Sharp (1968, Solar Physics 3, 450) quantified this and showed a good correlation of red shift observations with the variation in the number of these electrons along the line of sight from center to limb and suggested that the quasar red shift and cosmological red shift could be similarly explained. Grote Reber mapped and measured the background hectometric radiation and found it to be unexpectedly bright. In 1968 (J. Franklin Inst. 285,1), while describing these measurements and maps he explained this brightness as being due to the Compton effect causing the cosmological red shift and accelerating intergalactic electrons. The resulting universe is static. The predicted red shift from the Compton effect deviates from Hubble's law only at large red shifts.

  1. Compton scattering and generalized polarizabilities

    SciTech Connect

    Scherer, S.

    2005-05-06

    In recent years, real and virtual Compton scattering off the nucleon have attracted considerable interest from both the experimental and theoretical sides. Real Compton scattering gives access to the so-called electromagnetic polarizabilities containing the structure information beyond the global properties of the nucleon such as its charge, mass, and magnetic moment. These polarizabilities have an intuitive interpretation in terms of induced dipole moments and thus characterize the response of the constituents of the nucleon to a soft external stimulus. The virtual Compton scattering reaction e- p {yields} e- p{gamma} allows one to map out the local response to external fields and can be described in terms of generalized electromagnetic polarizabilities. A simple classical interpretation in terms of the induced electric and magnetic polarization densities is proposed. We will discuss experimental results for the polarizabilities of the proton and compare them with theoretical predictions.

  2. A dual purpose optical truss laser metrology system for a space-based far-IR segmented telescope: Figure maintenance and pointing control

    NASA Technical Reports Server (NTRS)

    Lau, Kenneth

    1992-01-01

    To obtain imaging performance as for monolithic mirrors, large segmented reflectors used for astronomy must be actively aligned and pointed to extreme levels of precision. A system concept for a dual purpose optical truss laser metrology system is described which is used for both figure and alignment maintenance and telescope pointing. A two-stage figure active control approach was developed for several proposed spaceborne far infrared segmented telescopes, one of which is the 10-20 meters Large Deployable Reflector (LDR). The first active control stage, the figure initialization control system, aligns the optical elements (i.e., the primary segments, secondary and focal plane assembly) based on images obtained. The second stage, the figure maintenance control system, maintains the alignment between re-initializations using measurements provided by laser interferometers arranged in an optical truss configuration. It measures the relative positions and alignments of the telescope segments so that a controller can reposition them appropriately. The application of this optical truss for figure maintenance control is the subject of the first part of this paper. The second portion of this paper discusses the application of the optical truss to telescope pointing. Here, the laser metrology system is used to transfer pointing information from an external fine guidance sensor (FGS) to the telescope optical boresight as defined by the primary mirror, secondary mirror, and focal plane assembly. Thus, any alignment variations between the two boresights can be observed and accounted for.

  3. First-Generation Hybrid Compact Compton Imager

    SciTech Connect

    Cunningham, M; Burks, M; Chivers, D; Cork, C; Fabris, L; Gunter, D; Krings, T; Lange, D; Hull, E; Mihailescu, L; Nelson, K; Niedermayr, T; Protic, D; Valentine, J; Vetter, K; Wright, D

    2005-11-07

    At Lawrence Livermore National Laboratory, we are pursuing the development of a gamma-ray imaging system using the Compton effect. We have built our first generation hybrid Compton imaging system, and we have conducted initial calibration and image measurements using this system. In this paper, we present the details of the hybrid Compton imaging system and initial calibration and image measurements.

  4. Polarization Measurements with Compton Telescopes

    NASA Astrophysics Data System (ADS)

    Akyuz, A.; O'Neill, T. J.; Bhattacharya, D.; Dixon, D. D.; Tumer, T. O.; White, R. S.; Zych, A. D.

    1994-12-01

    The response of the Tracking and Imaging Gamma-Ray Experiment (TIGRE) instrument to polarized celestial gamma rays above 300 keV is presented. TIGRE uses multilayers of silicon strip detectors both as a gamma-ray converter and to track Compton recoil electrons and positron-electron pairs up to 100 MeV. For Compton events, the direction and energy of the Compton scattered gamma ray are measured with arrays of small CsI(Tl)-photodiode detectors. A small balloon prototype instrument is being constructed that has a high absolute detection efficiency of 10% and a sensitivity of 100 milliCrabs for an exposure of 12 hours. The prototype's sensitivity to polarized gamma radiation has been calculated with the MCNP detector simulation code which was modified to include the polarization dependence of the Klein-Nishina formula. Polarized events and unpolarized source events with background are combined to simulate an observation of the Crab Nebula and pulsar. TIGRE's polarization modulation factor varies from 0.17 to 0.42 depending on the energy and Compton scatter angle cuts that are used. With 12 hours of observation on the Crab, polarized gamma radiation can be detected down to the level of about 10%. Potential celestial sources of polarized gamma-ray emission will be discussed.

  5. The Compton Gamma Ray Observatory

    NASA Astrophysics Data System (ADS)

    Gehrels, N.; Chipman, E.; Kniffen, D.

    1994-06-01

    The Arthur Holly Compton Gamma Ray Observatory Compton) is the second in NASA's series of great Observatories. Launched on 1991 April 5, Compton represents a dramatic increase in capability over previous gamma-ray missions. The spacecraft and scientific instruments are all in good health, and many significant discoveries have already been made. We describe the capabilities of the four scientific instruments, and the observing program of the first 2 years of the mission. Examples of early discoveries by Compton are enumerated, including the discovery that gamma-ray bursts are isotropic but spatially inhomogeneous in their distribution; the discovery of a new class of high-energy extragalacatic gamma-ray sources, the gamma-ray AGNs; the discovery of emission from SN 1987A in the nuclear line of Co-57; and the mapping of emission from Al-26 in the interstellar medium (ISM) near the Galactic center. Future observations will include deep surveys of selected regions of the sky, long-tem studies of individual objects, correlative studies of objects at gamma-ray and other energies, a Galactic plane survey at intermediate gamma-ray energies, and improved statistics on gamma-ray bursts to search for small anisotropies. After completion of the all-sky survey, a Guest Investigator program is in progress with guest observers' time share increasing from 30% upward for the late mission phases.

  6. Diamond Detectors for Compton Polarimetry

    NASA Astrophysics Data System (ADS)

    Martin, J. W.; Dutta, D.; Narayan, A.; Wang, P.

    2009-12-01

    Parity-violating electron scattering experiments aim to test the standard model of particle physics through precise low-energy determinations of the weak mixing angle. These experiments require determination of the polarization of the incident electron beam to the 1% level or better. An example of this type of experiment is the Q-weak experiment, which will be conducted in Hall C at Jefferson Lab in 2010 and beyond. We are constructing a Compton polarimeter in Hall C to provide continuous monitoring of the polarization with the goal of 1% absolute polarization determination. In our Compton polarimeter, circularly polarized laser light will impinge upon the electron beam. Electrons scattered by the Compton process will be momentum-analyzed in a dipole magnet downstream of the interaction point. A diamond strip tracker will be placed further downstream of the dipole to sense the Compton-scattered electrons and determine their momenta. The design of the polarimeter, focusing on electron detection, and our progress in prototyping and constructing the diamond strip tracker, are discussed.

  7. The Compton Gamma Ray Observatory

    NASA Technical Reports Server (NTRS)

    Gehrels, N.; Chipman, E.; Kniffen, D.

    1994-01-01

    The Arthur Holly Compton Gamma Ray Observatory Compton) is the second in NASA's series of great Observatories. Launched on 1991 April 5, Compton represents a dramatic increase in capability over previous gamma-ray missions. The spacecraft and scientific instruments are all in good health, and many significant discoveries have already been made. We describe the capabilities of the four scientific instruments, and the observing program of the first 2 years of the mission. Examples of early discoveries by Compton are enumerated, including the discovery that gamma-ray bursts are isotropic but spatially inhomogeneous in their distribution; the discovery of a new class of high-energy extragalacatic gamma-ray sources, the gamma-ray AGNs; the discovery of emission from SN 1987A in the nuclear line of Co-57; and the mapping of emission from Al-26 in the interstellar medium (ISM) near the Galactic center. Future observations will include deep surveys of selected regions of the sky, long-tem studies of individual objects, correlative studies of objects at gamma-ray and other energies, a Galactic plane survey at intermediate gamma-ray energies, and improved statistics on gamma-ray bursts to search for small anisotropies. After completion of the all-sky survey, a Guest Investigator program is in progress with guest observers' time share increasing from 30% upward for the late mission phases.

  8. Milk yield, gross composition and fatty acid profile of dual-purpose Aosta Red Pied cows fed separate concentrate-forage versus total mixed ration.

    PubMed

    Renna, Manuela; Cornale, Paolo; Lussiana, Carola; Battaglini, Luca Maria; Turille, Germano; Mimosi, Antonio

    2014-01-01

    This study was designed to evaluate the effects of two feeding methods on milk yield, composition and fatty acid (FA) profile obtained from dual-purpose cattle. Twenty-four Aosta Red Pied cows beyond peak of lactation were assigned to two groups and fed hay and concentrates in the proportions 0.69 and 0.31 on a dry matter basis for 10 weeks. Concentrates were offered separately from forages 6 times a day (separate ration, SR) or as a total mixed ration (TMR). The feeding method did not significantly influence dry matter intake (16.8 vs. 16.9 kg/head/day for SR- and TMR-fed cows, respectively), milk yield (17.4 vs. 17.5 kg/head/day), milk fat, protein and lactose contents (36.4 vs. 35.2, 33.5 vs. 32.8, and 47.3 vs. 47.4 g/kg) and yields (607.9 vs. 613.4, 567.4 vs. 572.7 and 805.5 vs. 829.7 g/head/day). The overall milk FA profile was very similar between groups. Milk concentrations of FA used as indirect markers of rumen function (C18:2 t10c12, odd- and branched-chain FA) and the extent of ruminal biohydrogenation were comparable (P > 0.05) between SR- and TMR-fed cows, suggesting that ruminal pH did not vary considerably as a consequence of the feeding strategy applied. PMID:23841857

  9. The use of Compton suppression spectrometers for trace element studies in biological materials.

    PubMed

    Rossbach, M; Zeisler, R; Woittiez, J R

    1990-01-01

    A straightforward method for demonstrating the powerful background reduction of Compton suppression spectrometers for neutron activation purposes is presented. The shorter acquisition time needed in Anti-Compton mode (A/C on) for peaks of appropriate counting statistics, compared to normal gamma counting (A/C off), allows a much higher sample throughput, thus compensating for the higher cost of the instrument. Two examples of artificial mixtures of radionuclides demonstrate the drastic time saving for measurement of monoenergetic decaying isotopes. The comparison of results from three different instruments proves the general usefulness of Compton suppression spectrometers for Neutron Activation Analysis of biological samples. PMID:1704771

  10. SPEIR: A Ge Compton Camera

    SciTech Connect

    Mihailescu, L; Vetter, K M; Burks, M T; Hull, E L; Craig, W W

    2004-02-11

    The SPEctroscopic Imager for {gamma}-Rays (SPEIR) is a new concept of a compact {gamma}-ray imaging system of high efficiency and spectroscopic resolution with a 4-{pi} field-of-view. The system behind this concept employs double-sided segmented planar Ge detectors accompanied by the use of list-mode photon reconstruction methods to create a sensitive, compact Compton scatter camera.

  11. The Compton polarimeter for SLC

    SciTech Connect

    Fero, M.J.; The SLD Collaboration

    1992-12-01

    We report on the use of a Compton scattering based polarimeter to measure beam polarization near the e{sup +}e{sub -} interaction point at the SLAC Linear Collider (SLC). Measurement of the beam polarization to a statistical precision of {delta}P/P={plus_minus}3% requires approximately three minutes under normal conditions. An average beam polarization of 22.4{plus_minus}0.7%(syst.) was measured over the course of the 1992 polarized beam run.

  12. The Compton polarimeter for SLC

    SciTech Connect

    Fero, M.J. )

    1992-12-01

    We report on the use of a Compton scattering based polarimeter to measure beam polarization near the e[sup +]e[sub -] interaction point at the SLAC Linear Collider (SLC). Measurement of the beam polarization to a statistical precision of [delta]P/P=[plus minus]3% requires approximately three minutes under normal conditions. An average beam polarization of 22.4[plus minus]0.7%(syst.) was measured over the course of the 1992 polarized beam run.

  13. Gibberellic acid mediated co-ordination of calcium and magnesium ameliorate physiological activities, seed yield and fibre yield of Linum usitatissimum L.-a dual-purpose crop.

    PubMed

    Khan, Mohammad Nasir; Mohammad, Firoz; Siddiqui, Manzer H; Naeem, M

    2010-12-01

    Commercial cultivation of linseed for both seed and fibre is not keeping pace with increasing demand for linseed products. Although, different strategies are being adopted to produce a dual-purpose linseed crop with good yield of seed and fibre, little progress has been achieved. The present study was carried out to investigate whether application of gibberellic acid (GA3) along with CaCl2 and/or MgSO4 could ameliorate the seed yield in three linseed genotypes 'Parvati', 'Shekhar' and 'Shubhra' without compromising the fibre production. Before sowing the seeds of linseed genotypes were soaked for 8 h in 10(-6) M GA3. Forty days after sowing (DAS), the plants were sprayed with 10(-6) M GA3 along with 2 kg Ca/ha (Ca2) and/or 0.5 kg Mg/ha (Mg0.5). Treatments comprised of (1) 10(-6) M GA3 + Ca0Mg0 (control, T0); (2) 10(-6) M GA3 + Ca2Mg0 (T1); (3) 10(-6) M GA3 + Ca0Mg0.5 (T2) and (4) 10(-6) M GA3 + Ca2Mg0.5 (T3). Performance of the crop was assessed in terms of growth characteristics, physiological and biochemical parameters at 60 and 75 DAS and yield and quality attributes at harvest. Treatment T3 proved best, it enhanced dry weight per plant by 38.2 and 20.6%, P N by 20.7 and 19.1% and gs by 18.2 and 8.8% at 60 and 75 DAS, respectively and seed yield by 39.6%, oil yield by 46.9% and fibre yield by 36.9% at harvest. Further, a decrease in lodging by 13.9% was recorded. Of the three genotypes tested, all exhibited significant difference for all the parameters studied, except for leaf-N content, biological yield and iodine value which showed no difference. However, 'Shubhra' performed better than 'Parvati'. PMID:23572983

  14. Development of a conditioning system for the dual-purpose transport and storage cask for spent nuclear fuel from decommissioned Russian submarines

    SciTech Connect

    Dyer, R.S.; Barnes, E.; Snipes, R.L.; Guskov, V.; Makarchuk, T.

    2007-07-01

    Russia, stores large quantities of spent nuclear fuel (SNF) from submarine and ice-breaker nuclear powered naval vessels. This high-level radioactive material presents a significant threat to the Arctic and marine environments. Much of the SNF from decommissioned Russian nuclear submarines is stored either onboard the submarines or in floating storage vessels in Northwest and Far East Russia. Some of the SNF is damaged, stored in an unstable condition, or of a type that cannot currently be reprocessed. In many cases, the existing Russian transport infrastructure and reprocessing facilities cannot meet the requirements for moving and reprocessing all of this fuel from remote locations. Additional transport and storage options are required. Some of the existing storage facilities being used in Russia do not meet health and safety and physical security requirements. The U.S. has assisted Russia in the development of a new dual-purpose metal-concrete transport and storage cask (TUK-108/1) for their military SNF and assisted them in building several new facilities for off-loading submarine SNF and storing these TUK-108/1 casks. These efforts have reduced the technical, ecological, and security challenges for removal, handling, interim storage, and shipment of this submarine fuel. Currently, Russian licensing limits the storage period of the TUK-108/1 casks to no more than two years before the fuel must be shipped for reprocessing. In order to extend this licensed storage period, a system is required to condition the casks by removing residual water and creating an inert storage environment by backfilling the internal canisters with a noble gas such as argon. The U.S. has assisted Russia in the development of a mobile cask conditioning system for the TUK-108/1 cask. This new conditioning system allows the TUK 108/1 casks to be stored for up to five years after which the license may be considered for renewal for an additional five years or the fuel will be shipped to

  15. Design of a Compton scatter based radiation tracking system

    NASA Astrophysics Data System (ADS)

    Healy, Heather

    Gamma spectroscopy is one of the most common techniques used for the detection of radiologic materials. This technology is deployed in a variety of scenarios such as emergency response, monitoring, and the recovery of lost, stolen, or otherwise unaccounted radiologic material. In most practical scenarios, it is useful to know the location of a source in relation to a detector, in addition to the classic output from gamma spectrometers such as decay rate and energy peak information. In collaboration with the Remote Sensing Laboratory (RSL) at Andrews Air Force Base, a novel detector design by RSL, which utilizes a 360° detectable range in order to increase the probability of remote detection, was investigated for the possibility to recreate source location information from Compton scattering events within the detector. A recreation of this novel detector is simulated using Geant4 to determine the optimal dimensions of sodium iodide detectors that produce the most single Compton scattering events in order to facilitate source location through the back-projection of Compton scattering angles. The optimal detector dimensions are determined by maximizing the number of single Compton scatter events and minimizing the percentage of Compton events that undergo multiple successive scatters in detectors of varying thicknesses and lengths. The optimal detector thickness was chosen to be 1.88 in, and the optimal detector length was chosen to be 4 to 4.5 in. In future projects, these optimized detectors can be used to apply suggested back-projection algorithms in order to determine the feasibility and functionality of this detector design for the purpose of radiologic source location.

  16. Abdominal Dual Energy Imaging

    NASA Astrophysics Data System (ADS)

    Sommer, F. Graham; Brody, William R.; Cassel, Douglas M.; Macovski, Albert

    1981-11-01

    Dual energy scanned projection radiography of the abdomen has been performed using an experimental line-scanned radiographic system. Digital images simultaneously obtained at 85 and 135 kVp are combined, using photoelectric/Compton decomposition algorithms to create images from which selected materials are cancelled. Soft tissue cancellation images have proved most useful in various abdominal imaging applications, largely due to the elimination of obscuring high-contrast bowel gas shadows. These techniques have been successfully applied to intravenous pyelography, oral cholecystography, intravenous abdominal arteriog-raphy and the imaging of renal calculi.

  17. Spectral properties of Compton inverse radiation: Application of Compton beams

    NASA Astrophysics Data System (ADS)

    Bulyak, Eugene; Urakawa, Junji

    2014-05-01

    Compton inverse radiation emitted due to backscattering of laser pulses off the relativistic electrons possesses high spectral density and high energy of photons - in hard x-ray up to gamma-ray energies - because of short wavelength of laser radiation as compared with the classical electromagnetic devices such as undulators. In this report, the possibility of such radiation to monochromatization by means of collimation is studied. Two approaches have been considered for the description of the spectral-angular density of Compton radiation based on the classical field theory and on the quantum electrodynamics. As is shown, both descriptions produce similar total spectra. On the contrary, angular distribution of the radiation is different: the classical approach predicted a more narrow radiation cone. Also proposed and estimated is a method of the 'electronic' monochromatization based on the electronic subtraction of the two images produced by the electron beams with slightly different energies. A 'proof-of-principle' experiment of this method is proposed for the LUXC facility of KEK (Japan).

  18. Compton Dry-Cask Imaging System

    ScienceCinema

    None

    2013-05-28

    The Compton-Dry Cask Imaging Scanner is a system that verifies and documents the presence of spent nuclear fuel rods in dry-cask storage and determines their isotopic composition without moving or opening the cask. For more information about this project, visit http://www.inl.gov/rd100/2011/compton-dry-cask-imaging-system/

  19. Spin Degrees of Freedom in Compton Scattering

    NASA Astrophysics Data System (ADS)

    Miskimen, R.

    2016-02-01

    The next generation of Compton scattering experiments is underway at Mainz and other laboratories, where the goal is precision measurements of the scalar and vector polarizabilities of the nucleon using polarized photons and polarized targets. Results are presented for the first double polarized Compton scattering experiment utilizing a polarized proton target. Preliminary results are presented for the four spin polarizabilities of the proton.

  20. Compton Dry-Cask Imaging System

    SciTech Connect

    2011-01-01

    The Compton-Dry Cask Imaging Scanner is a system that verifies and documents the presence of spent nuclear fuel rods in dry-cask storage and determines their isotopic composition without moving or opening the cask. For more information about this project, visit http://www.inl.gov/rd100/2011/compton-dry-cask-imaging-system/

  1. GRAPE: A Compton Polarimetry Experiment

    NASA Astrophysics Data System (ADS)

    Connor, Taylor; Bloser, Peter; Legere, Jason; McConnell, Mark; Ryan, James

    2009-10-01

    We review the design, calibration and data analysis of the Gamma Ray Polarimetry Experiment (GRAPE), a Compton polarimeter device for measuring the polarization of photons in the 50-500 keV energy range. In Compton scattering, X-ray and gamma-ray photons tend to scatter at right angles with respect to their polarization vector. We exploit this fact to measure the polarization of the incident radiation by looking at the azimuthal distribution of the scattered photons. This distribution gives us a measure of both the level of polarization and the orientation of the polarization vector. These measurements will allow us to probe the particle acceleration regions of astronomical sources. GRAPE will be flown in the fall of 2011 on as a high altitude balloon payload. The primary target of that flight will be the Crab Nebula, with the Sun (solar flares) and Cygnus X-1 as secondary targets. Our observations of the Crab will be compared to the findings of the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), which provided constraints on the location of the particle acceleration region within the Crab Nenbula. Following the initial flight in 2011, we hope to fly GRAPE on a long duration balloon flight from Antarctica to study gamma-ray bursts.

  2. Bulk Comptonization by turbulence in accretion discs

    NASA Astrophysics Data System (ADS)

    Kaufman, J.; Blaes, O. M.

    2016-06-01

    Radiation pressure dominated accretion discs around compact objects may have turbulent velocities that greatly exceed the electron thermal velocities within the disc. Bulk Comptonization by the turbulence may therefore dominate over thermal Comptonization in determining the emergent spectrum. Bulk Comptonization by divergenceless turbulence is due to radiation viscous dissipation only. It can be treated as thermal Comptonization by solving the Kompaneets equation with an equivalent `wave' temperature, which is a weighted sum over the power present at each scale in the turbulent cascade. Bulk Comptonization by turbulence with non-zero divergence is due to both pressure work and radiation viscous dissipation. Pressure work has negligible effect on photon spectra in the limit of optically thin turbulence, and in this limit radiation viscous dissipation alone can be treated as thermal Comptonization with a temperature equivalent to the full turbulent power. In the limit of extremely optically thick turbulence, radiation viscous dissipation is suppressed, and the evolution of local photon spectra can be understood in terms of compression and expansion of the strongly coupled photon and gas fluids. We discuss the consequences of these effects for self-consistently resolving and interpreting turbulent Comptonization in spectral calculations in radiation magnetohydrodynamic simulations of high luminosity accretion flows.

  3. Bayesian Event Reconstruction for Advanced Compton Telescopes

    NASA Astrophysics Data System (ADS)

    Zoglauer, A.; ACT

    2004-12-01

    Measuring gamma rays via Compton scattering in a space environment is a challenging task: weak source signals have to be extracted from dominating background, which mainly originates from cosmic rays (prompt interactions as well as delayed decays) and earth albedo photons. The approach of Advanced Compton Telescopes (ACT) to overcome this problem is to measure more parameters of the events (several Compton interactions, the recoil electron direction, etc.) with a higher accuracy than previous Compton telescopes like COMPTEL. Still, this leaves the event reconstruction with three main tasks: Find the correct sequence of interactions, identify background and suppress incompletely absorbed events. The most promising approach to accomplish those tasks is based on Bayesian statistics: The Compton interactions are parameterized in an eight-dimensional data space, which contains the interaction information of the Compton sequence. For each data space cell the probability that the corresponding interaction sequence is those of a correctly ordered, completely absorbed source photon can be determined by detailed simulations. The result is an absolute quality factor for each event, based on which source events can be distinguished from background and incompletely absorbed photons. We will report on the performance of the algorithm for a typical advanced Compton telescope design.

  4. Real Compton scattering via color dipoles

    SciTech Connect

    Kopeliovich, B. Z.; Schmidt, Ivan; Siddikov, M.

    2009-09-01

    We study the photoabsorption reaction and real Compton scattering within the color dipole model. We rely on a photon wave function derived in the instanton-vacuum model and on the energy-dependent phenomenological elastic dipole amplitude. Data for the photoabsorption cross section at high energies agree with our parameter-free calculations. We also provide predictions for the differential real Compton scattering cross section. Although no data for small angle Compton scattering are available so far, this process can be measured in ultraperipheral hadronic and nuclear collisions at the LHC.

  5. Hidden baryons: The physics of Compton composites

    NASA Astrophysics Data System (ADS)

    Mayer, Frederick J.

    2016-06-01

    A large fraction of the mass-energy of the Universe appears to be composed of Compton composites. How is it then that these composites are not frequently observed in experiments? This paper addresses this question, and others, by reviewing recent publications that: 1) introduced Compton composites, 2) showed how and where they are formed and 3) explained how they interact with other systems. Though ubiquitous in many physical situations, Compton composites are almost completely hidden in experiments due to their unique interaction characteristics. Still, their presence has been indirectly observed, though not interpreted as such until recently. Looking to the future, direct-detection experiments are proposed that could verify the composites' components. It is with deep sadness that I dedicate this paper to my mentor, collaborator, and friend, Dr. John R. Reitz, who passed away within days of the publication of our paper “Compton Composites Late in the Early Universe”.

  6. RELATIVISTIC ACCRETION MEDIATED BY TURBULENT COMPTONIZATION

    SciTech Connect

    Socrates, Aristotle E-mail: socrates@astro.princeton.ed

    2010-08-10

    Black hole and neutron star accretion flows display unusually high levels of hard coronal emission in comparison to all other optically thick, gravitationally bound, turbulent astrophysical systems. Since these flows sit in deep relativistic gravitational potentials, their random bulk motions approach the speed of light, therefore allowing turbulent Comptonization to be an important effect. We show that the inevitable production of hard X-ray photons results from turbulent Comptonization in the limit where the turbulence is trans-sonic and the accretion power approaches the Eddington limit. In this regime, the turbulent Compton y-parameter approaches unity and the turbulent Compton temperature is a significant fraction of the electron rest mass energy, in agreement with the observed phenomena.

  7. Neutron Compton scattering from selectively deuterated acetanilide

    NASA Astrophysics Data System (ADS)

    Wanderlingh, U. N.; Fielding, A. L.; Middendorf, H. D.

    With the aim of developing the application of neutron Compton scattering (NCS) to molecular systems of biophysical interest, we are using the Compton spectrometer EVS at ISIS to characterize the momentum distribution of protons in peptide groups. In this contribution we present NCS measurements of the recoil peak (Compton profile) due to the amide proton in otherwise fully deuterated acetanilide (ACN), a widely studied model system for H-bonding and energy transfer in biomolecules. We obtain values for the average width of the potential well of the amide proton and its mean kinetic energy. Deviations from the Gaussian form of the Compton profile, analyzed on the basis of an expansion due to Sears, provide data relating to the Laplacian of the proton potential.

  8. Compton scattering with low intensity radioactive sources

    NASA Astrophysics Data System (ADS)

    Quarles, Carroll

    2012-03-01

    Compton scattering experiments with gamma rays typically require a ``hot'' source (˜5mCi of Cs137) to observe the scattering as a function of angle. (See Ortec AN34 Experiment #10 Compton Scattering) Here a way is described to investigate Compton scattering with micro Curie level radioactive sources that are more commonly available in the undergraduate laboratory. A vertical-looking 2 inch coaxial hpGe detector, collimated with a 2 inch thick lead shield, was used. Cylindrical Al targets of various thicknesses were placed over the collimator and several available sources were placed around the target so that the average Compton scattering angle into the collimator was 90 deg. A peak could be observed at the expected energy for 90 deg. Compton scattering by doing 24 hour target-in minus target-out runs. The peak was broadened by the spread in the scattering angle due to the variation in the angle of the incoming gamma ray and the angular acceptance of the collimator. A rough analysis can be done by modeling the angular spread due to the geometry and correcting for the gamma ray absorption from the target center. Various target materials and sources can be used and some variation in average Compton scattering angle can be obtained by adjusting the geometry of the source and target.

  9. Dual purpose recovered coagulant from drinking water treatment residuals for adjustment of initial pH and coagulation aid in electrocoagulation process.

    PubMed

    Jung, Kyung-Won; Ahn, Kyu-Hong

    2016-07-01

    The present study is focused on the application of recovered coagulant (RC) by acidification from drinking water treatment residuals for both adjusting the initial pH and aiding coagulant in electrocoagulation. To do this, real cotton textile wastewater was used as a target pollutant, and decolorization and chemical oxygen demand (COD) removal efficiency were monitored. A preliminary test indicated that a stainless steel electrode combined with RC significantly accelerated decolorization and COD removal efficiencies, by about 52% and 56%, respectively, even at an operating time of 5 min. A single electrocoagulation system meanwhile requires at least 40 min to attain the similar removal performances. Subsequently, the interactive effect of three independent variables (applied voltage, initial pH, and reaction time) on the response variables (decolorization and COD removal) was evaluated, and these parameters were statistically optimized using the response surface methodology. Analysis of variance showed a high coefficient of determination values (decolorization, R(2) = 0.9925 and COD removal, R(2) = 0.9973) and satisfactory prediction second-order polynomial quadratic regression models. Average decolorization and COD removal of 89.52% and 94.14%, respectively, were achieved, corresponding to 97.8% and 98.1% of the predicted values under statistically optimized conditions. The results suggest that the RC effectively played a dual role of both adjusting the initial pH and aiding coagulant in the electrocoagulation process. PMID:26593378

  10. Cost effective, dual-purpose machine vision-based detectors for (1) smoke and flame detection, and (2) engine overhead/burn-through and flame detection

    NASA Astrophysics Data System (ADS)

    Goedeke, A. D.; Drda, B.; Fitzpatrick, C.; Healey, G.

    1995-03-01

    Three major accomplishments resulted from this effort: (1) It was determined that the Machine Vision Fire Detection System (MVFDS) could be augmented with a near-infrared imaging FPA/CCD, 4-8 IR transmitting optic waveguides, and modified algorithms to measure small changes in temperature of small areas on the engine casing and therefore determine overheat condition and/or possible burn-through condition. The IR-MVFDS would also detect small burn-through torch-like fires as well as nacelle fires associated with munitions and leaking/broken fuel and hydraulic lines. (2) Tests verified the ability of the visible MVFDS flame detector to simultaneously detect smoke and measure its transmissivity. This dual function, in addition to possibly as many as 16 or more separate fields-of-view using small fiber optic cables, makes the Smoke/Flame-MVFDS cost effective in aircraft and in commercial applications. (3) The potential benefits and cost savings of both the IR-MVFDS and Smoke/Flame-MVFDS were demonstrated. The technical basis was proven feasible with minimum risk for development of both the IR-MVFDS and the Flame/Smoke-MVFDS in Phase II.

  11. 30 CFR 1206.181 - How do I establish processing costs for dual accounting purposes when I do not process the gas?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., the proposal will be deemed to be denied and subject to appeal to the ONRR Director under 30 CFR part... accounting purposes when I do not process the gas? 1206.181 Section 1206.181 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR Natural Resources Revenue...

  12. A Compton camera for spectroscopic imaging from 100 keV to 1 MeV

    SciTech Connect

    Earnhart, J.R.D.

    1998-12-31

    A review of spectroscopic imaging issues, applications, and technology is presented. Compton cameras based on solid state semiconductor detectors stands out as the best system for the nondestructive assay of special nuclear materials. A camera for this application has been designed based on an efficient specific purpose Monte Carlo code developed for this project. Preliminary experiments have been performed which demonstrate the validity of the Compton camera concept and the accuracy of the code. Based on these results, a portable prototype system is in development. Proposed future work is addressed.

  13. Technical Note: Influence of Compton currents on profile measurements in small-volume ion chambers

    SciTech Connect

    Tanny, Sean; Sperling, Nicholas; Parsai, E. Ishmael; Holmes, Shannon

    2015-10-15

    Purpose: This work is to evaluate the effects of Compton current generation in three small-volume ionization chambers on measured beam characteristics for electron fields. Methods: Beam scans were performed using Exradin A16, A26, and PTW 31014 microchambers. Scans with varying chamber components shielded were performed. Static point measurements, output factors, and cable only irradiations were performed to determine the contribution of Compton currents to various components of the chamber. Monte Carlo simulations were performed to evaluate why one microchamber showed a significant reduction in Compton current generation. Results: Beam profiles demonstrated significant distortion for two of the three chambers when scanned parallel to the chamber axis, produced by electron deposition within the wire. Measurements of ionization produced within the cable identified Compton current generation as the cause of these distortions. The size of the central collecting wire was found to have the greatest influence on the magnitude of Compton current generation. Conclusions: Microchambers can demonstrate significant (>5%) deviations from properties as measured with larger volume chambers (0.125 cm{sup 3} and above). These deviations can be substantially reduced by averaging measurements conducted at opposite polarities.

  14. FRONT-END ASIC FOR A SILICON COMPTON TELESCOPE.

    SciTech Connect

    DE GERONIMO,G.; FRIED, J.; FROST, E.; PHLIPS, B.; VERNON, E.; WULF, E.A.

    2007-10-27

    We describe a front-end application specific integrated circuit (ASIC) developed for a silicon Compton telescope. Composed of 32 channels, it reads out signals in both polarities from each side of a Silicon strip sensor, 2 mm thick 27 cm long, characterized by a strip capacitance of 30 pF. Each front-end channel provides low-noise charge amplification, shaping with a stabilized baseline, discrimination, and peak detection with an analog memory. The channels can process events simultaneously, and the read out is sparsified. The charge amplifier makes uses a dual-cascode configuration and dual-polarity adaptive reset, The low-hysteresis discriminator and the multi-phase peak detector process signals with a dynamic range in excess of four hundred. An equivalent noise charge (ENC) below 200 electrons was measured at 30 pF, with a slope of about 4.5 electrons/pF at a peaking time of 4 {micro}s. With a total dissipated power of 5 mW the channel covers an energy range up to 3.2 MeV.

  15. Compton suppression through rise-time analysis.

    PubMed

    Selvi, S; Celiktas, C

    2007-11-01

    We studied Compton suppression for 60Co and 137Cs radioisotopes using a signal selection criterion based on contrasting the fall time of the signals composing the photo peak with those composing the Compton continuum. The fall time criterion is employed by using the pulse shape analysis observing the change in the fall times of the gamma-ray pulses. This change is determined by measuring the changes in the rise times related to the fall time of the scintillator and the timing signals related to the fall time of the input signals. We showed that Compton continuum suppression is achieved best via the precise timing adjustment of an analog rise-time analyzer connected to a NaI(Tl) scintillation spectrometer. PMID:17703943

  16. The Compton Gamma Ray Observatory: mission status.

    NASA Astrophysics Data System (ADS)

    Gehrels, N.; Chipman, E.; Kniffen, D. A.

    The Arthur Holly Compton Gamma Ray Observatory (Compton) is the second in NASA's series of Great Observatories. Compton has now been operating for over two and a half years, and has given a dramatic increase in capability over previous gamma-ray missions. The spacecraft and scientific instruments are all in good health, and many significant discoveries have already been made and continue to be made. The authors describe the capabilities of the four scientific instruments and the observing programs for the first three years of the mission. During Phases 2 and 3 of the mission a Guest Investigator program has been in progress with the Guest Observers' time share increasing from 30% to over 50% for the later mission phases.

  17. A Compton scatter attenuation gamma ray spectrometer

    NASA Technical Reports Server (NTRS)

    Austin, W. E.

    1972-01-01

    A Compton scatter attenuation gamma ray spectrometer conceptual design is discussed for performing gamma spectral measurements in monodirectional gamma fields from 100 R per hour to 1,000,000 R per hour. Selectable Compton targets are used to scatter gamma photons onto an otherwise heavily shielded detector with changeable scattering efficiencies such that the count rate is maintained between 500 and 10,000 per second. Use of two sum-Compton coincident detectors, one for energies up to 1.5 MeV and the other for 600 keV to 10 MeV, will allow good peak to tail pulse height ratios to be obtained over the entire spectrum and reduces the neutron recoil background rate.

  18. Compton Gamma Ray Observatory Guest Investigator Program

    NASA Technical Reports Server (NTRS)

    Lingenfelter, Richard E.

    1997-01-01

    This paper presents a final report for the Compton Gamma Ray Observatory Guest Investigator Program from 06/01/91-07/31/97. The topics include: 1) Solar Flare Neutron Spectra and Accelerated Ions; 2) Gamma Ray Lines From The Orion Complex; 3) Implications of Nuclear Line Emission From The Orion Complex; 4) Possible Sites of Nuclear Line Emission From Massive OB Associations; 5) Gamma-Ray Burst Repitition and BATSE Position Uncertainties; 6) Effects of Compton Scattering on BATSE Gamma-Ray Burst Spectra; and 7) Selection Biases on the Spectral and Temporal Distribution of Gamma Ray Bursts.

  19. Timelike Compton Scattering - A First Look (CLAS)

    SciTech Connect

    Pawel Nadel-Turonski

    2009-12-01

    A major goal of the 12 GeV upgrade at Jefferson Lab is to map out the Generalized Parton Distributions (GPDs) in the valence region. This is primarily done through Deeply Virtual Compton Scattering (DVCS), which provides the simplest and cleanest way of accessing the GPDs. However, the “inverse” process, Timelike Compton Scattering (TCS), can provide an important complement, in particular formeasuring the real part of the amplitude and understanding corrections at finite Q2. The first measurements of TCS have recently been carried out in Hall B at Jefferson Lab, using both tagged and untagged photon beams.

  20. Timelike Compton Scattering—A First Look

    NASA Astrophysics Data System (ADS)

    Nadel-Turonski, P.; Horn, T.; Ilieva, Y.; Klein, F. J.; Paremuzyan, R.; Stepanyan, S.

    2009-12-01

    A major goal of the 12 GeV upgrade at Jefferson Lab is to map out the Generalized Parton Distributions (GPDs) in the valence region. This is primarily done through Deeply Virtual Compton Scattering (DVCS), which provides the simplest and cleanest way of accessing the GPDs. However, the "inverse" process, Timelike Compton Scattering (TCS), can provide an important complement, in particular for measuring the real part of the amplitude and understanding corrections at finite Q2. The first measurements of TCS have recently been carried out in Hall B at Jefferson Lab, using both tagged and untagged photon beams.

  1. A novel pressed porous silicon-polycaprolactone composite as a dual-purpose implant for the delivery of cells and drugs to the eye.

    PubMed

    Irani, Yazad D; Tian, Yuan; Wang, Mengjia; Klebe, Sonja; McInnes, Steven J; Voelcker, Nicolas H; Coffer, Jeffery L; Williams, Keryn A

    2015-10-01

    Dysfunction of corneal epithelial stem cells can result in painful and blinding disease of the ocular surface. In such cases, treatment may involve transfer of growth factor and normal adult stem cells to the ocular surface. Our purpose was to develop an implantable scaffold for the delivery of drugs and cells to the ocular surface. We examined the potential of novel composite biomaterials fabricated from electrospun polycaprolactone (PCL) fibres into which nanostructured porous silicon (pSi) microparticles of varying sizes (150-250 μm or <40 μm) had been pressed. The PCL fabric provided a flexible support for mammalian cells, whereas the embedded pSi provided a substantial surface area for efficient delivery of adsorbed drugs and growth factors. Measurements of tensile strength of these composites revealed that the pSi did not strongly influence the mechanical properties of the polymer microfiber component for the Si loadings evaluated. Human lens epithelial cells (SRA01/04) attached to the composite materials, and exhibited enhanced attachment and growth when the materials were coated with foetal bovine serum. To examine the ability of the materials to deliver a small-drug payload, pSi microparticles were loaded with fluorescein diacetate prior to cell attachment. After 6 hours (h), cells exhibited intracellular fluorescence, indicative of transfer of the fluorescein diacetate into viable cells and its subsequent enzymatic conversion to fluorescein. To investigate loading of large-molecule biologics, murine BALB/c 3T3 cells, responsive to epidermal growth factor, insulin and transferrin, were seeded on composite materials. The cells showed significantly more proliferation at 48 h when seeded on composites loaded with these biologics, than on unloaded composites. No cell proliferation was observed on PCL alone, indicating the biologics had loaded into the pSi microparticles. Drug release, measured by ELISA for insulin, indicated a burst followed by a slower

  2. Investigating the Compton Effect with a Spreadsheet.

    ERIC Educational Resources Information Center

    Kinderman, Jesusa Valdez

    1992-01-01

    Describes a computer simulation of the Compton effect designed to lead students to discover (1) the relationship of the electron's final kinetic energy to its angle of scattering and (2) the relationship between the scattering angles of the outgoing electron and photon. (MDH)

  3. Compton Community College Information Notebook, Fall 1994.

    ERIC Educational Resources Information Center

    Camacho, Julian S.

    Each year, Compton Community College (CCC), in California, collects statistical information on current trends related to the gender, race/ethnicity, and age of the college's student body, faculty, and classified employees. Findings from an analysis of the period from fall 1991 to fall 1994 included the following: (1) the vast majority of CCC…

  4. The Compton effect: Transition to quantum mechanics

    NASA Astrophysics Data System (ADS)

    Stuewer, R. H.

    2000-11-01

    The discovery of the Compton effect at the end of 1922 was a decisive event in the transition to the new quantum mechanics of 1925-1926 because it stimulated physicists to examine anew the fundamental problem of the interaction between radiation and matter. I first discuss Albert Einstein's light-quantum hypothesis of 1905 and why physicists greeted it with extreme skepticism, despite Robert A. Millikan's confirmation of Einstein's equation of the photoelectric effect in 1915. I then follow in some detail the experimental and theoretical research program that Arthur Holly Compton pursued between 1916 and 1922 at the University of Minnesota, the Westinghouse Lamp Company, the Cavendish Laboratory, and Washington University that culminated in his discovery of the Compton effect. Surprisingly, Compton was not influenced directly by Einstein's light-quantum hypothesis, in contrast to Peter Debye and H.A. Kramers, who discovered the quantum theory of scattering independently. I close by discussing the most significant response to that discovery, the Bohr-Kramers-Slater theory of 1924, its experimental refutation, and its influence on the emerging new quantum mechanics.

  5. Shadowing in Compton scattering on nuclei

    SciTech Connect

    Kopeliovich, B. Z.; Schmidt, Ivan; Siddikov, M.

    2010-05-01

    We evaluate the shadowing effect in deeply virtual and real Compton scattering on nuclei in the framework of the color dipole model. We rely on the soft photon wave function derived in the instanton vacuum model and employ the impact parameter dependent phenomenological elastic dipole amplitude. Both the effects of quark and the gluon shadowing are taken into account.

  6. Design and experimental testing of air slab caps which convert commercial electron diodes into dual purpose, correction-free diodes for small field dosimetry

    SciTech Connect

    Charles, P. H.; Cranmer-Sargison, G.; Thwaites, D. I.; Kairn, T.; Crowe, S. B.; Langton, C. M.; Trapp, J. V.; Pedrazzini, G.; Aland, T.; Kenny, J.

    2014-10-15

    Purpose: Two diodes which do not require correction factors for small field relative output measurements are designed and validated using experimental methodology. This was achieved by adding an air layer above the active volume of the diode detectors, which canceled out the increase in response of the diodes in small fields relative to standard field sizes. Methods: Due to the increased density of silicon and other components within a diode, additional electrons are created. In very small fields, a very small air gap acts as an effective filter of electrons with a high angle of incidence. The aim was to design a diode that balanced these perturbations to give a response similar to a water-only geometry. Three thicknesses of air were placed at the proximal end of a PTW 60017 electron diode (PTWe) using an adjustable “air cap”. A set of output ratios (OR{sub Det}{sup f{sub c}{sub l}{sub i}{sub n}}) for square field sizes of side length down to 5 mm was measured using each air thickness and compared to OR{sub Det}{sup f{sub c}{sub l}{sub i}{sub n}} measured using an IBA stereotactic field diode (SFD). k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}} was transferred from the SFD to the PTWe diode and plotted as a function of air gap thickness for each field size. This enabled the optimal air gap thickness to be obtained by observing which thickness of air was required such that k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}} was equal to 1.00 at all field sizes. A similar procedure was used to find the optimal air thickness required to make a modified Sun Nuclear EDGE detector (EDGEe) which is “correction-free” in small field relative dosimetry. In addition, the feasibility of experimentally transferring k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r

  7. Compton coincidence volumetric imaging: a new x-ray volumetric imaging modality based on Compton scattering

    NASA Astrophysics Data System (ADS)

    Xu, Xiaochao

    2014-03-01

    Compton scattering is a dominant interaction during radiography and computed tomography x-ray imaging. However, the scattered photons are not used for extracting imaging information, but seriously degrade image quality. Here we introduce a new scheme that overcomes most of the problems associated with existing Compton scattering imaging schemes and allows Compton scattered photons to be effectively used for imaging. In our scheme, referred as Compton coincidence volumetric imaging (CCVI), a collimated monoenergetic x-ray beam is directed onto a thin semiconductor detector. A small portion of the photons is Compton scattered by the detector and their energy loss is detected. Some of the scattered photons intersect the imaging object, where they are Compton scattered a second time. The finally scattered photons are recorded by an areal energy resolving detector panel around the object. The two detectors work in coincidence mode. CCVI images the spatial electron density distribution in the imaging object. Similar to PET imaging, the event location can be located within a curve; therefore the imaging reconstruction algorithms are also similar to those of PET. Two statistical iterative imaging reconstruction algorithms are tested. Our study verifies the feasibility of CCVI in imaging acquisition and reconstruction. Various aspects of CCVI are discussed. If successfully implemented, it will offer a great potential for imaging dose reduction compared with x-ray CT. Furthermore, a CCVI modality will have no moving parts, which potentially offers cost reduction and faster imaging speed.

  8. One-step dual purpose joining technique

    NASA Technical Reports Server (NTRS)

    Buckley, J. D.; Swaim, R. J.; Fox, R. L. (Inventor)

    1982-01-01

    This fastener used in induction heating is a wire screen basically of an eddy current carrying material such as carbon steel. Selected wires in the screen are copper, sheathed in an insulating material. The screen is placed between two sheets of thermoplastics. When inductively heated, the composite softens and flows around the apertures of the screen. After this heating and joining, the copper wires may be used to conduct electricity.

  9. Dual-purpose chamber-cooling system

    NASA Technical Reports Server (NTRS)

    Fraze, R. E.

    1968-01-01

    Inexpensive, portable system was designed for cooling small environmental test chambers with a temperature-controlled gas stream evaporated from a cryogenic liquid. The system reduces the temperature of a chamber to any desired point in a fraction of the time required by previous systems.

  10. Dual-purpose laboratory cage/antenna

    NASA Technical Reports Server (NTRS)

    Lalande, B. H.

    1977-01-01

    Part of steel cage enclosing laboratory animals is used as an antenna to transmit biotelemetry over short distances. Receiving and signal processing equipment are located above ground potential to avoid transmission-path difficulties.

  11. Compton scattering in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Daugherty, Joseph K.; Harding, Alice K.

    1986-01-01

    The relativistic cross section for Compton scattering by electrons in strong magnetic fields is derived. The results confirm and extend earlier work which has treated only transitions to the lowest or first excited Landau levels. For the teragauss field strengths expected in neutron star magnetospheres, the relative rates for excited state transitions are found to be significant, especially for incident photon energies several times the cyclotron frequency. Since these transitions must result in the rapid emission of one or more cyclotron photons as well as the Compton-scattered photon, the scattering process actually becomes a photon 'splitting' mechanism which acts to soften hard photon spectra, and also provides a specific mechanism for populating higher Landau levels in the electron distribution function. The results should be significant for models of gamma-ray bursters and pulsating X-ray sources.

  12. Unitarity constraints on deeply virtual Compton scattering

    NASA Astrophysics Data System (ADS)

    Laget, J. M.

    2007-11-01

    At moderately low momentum transfer (-t up to 1 GeV2) the coupling to the vector meson production channels gives the dominant contribution to real Compton and deeply virtual Compton scattering (DVCS). Starting from a Regge pole approach that successfully describes vector meson production, the singular part of the corresponding box diagrams (where the intermediate vector meson-baryon pair propagates on-shell) is evaluated without any further assumptions (unitarity). Such a treatment explains not only the unexpectedly large DVCS unpolarized cross section that has been recently measured at Jefferson Laboratory (JLab), but also all the beam spin and charge asymmetries that have been measured at JLab and Hermes, without explicit need of Generalized Parton Distributions (GPD). The issue of the relationship between the two approaches is addressed.

  13. Unitary constraints on Deeply Virtual Compton Scattering

    SciTech Connect

    J.M. Laget

    2007-11-01

    At moderately low momentum transfer ($-t$ up to 1 GeV$^2$) the coupling to the vector meson production channels gives the dominant contribution to real Compton and deeply virtual Compton scattering (DVCS). Starting from a Regge Pole approach that successfully describes vector meson production, the singular part of the corresponding box diagrams (where the intermediate vector meson-baryon pair propagates on-shell) is evaluated without any further assumptions (unitarity). Such a treatment explains not only the unexpectedly large DVCS unpolarized cross section that has been recently measured at Jefferson Laboratory (JLab), but also all the beam spin and charge asymmetries that has been measured at JLab and Hermes, without explicit need of Generalized Parton Distributions (GPD). The issue of the relationship between the two approaches is addressed.

  14. Selective dual-purpose photocatalysis for simultaneous H2 evolution and mineralization of organic compounds enabled by a Cr2O3 barrier layer coated on Rh/SrTiO3.

    PubMed

    Cho, Young-Jin; Moon, Gun-Hee; Kanazawa, Tomoki; Maeda, Kazuhiko; Choi, Wonyong

    2016-08-11

    Dual-functional photocatalysis for H2 evolution with the simultaneous mineralization of 4-chlorophenol was achieved under de-aerated conditions using a Cr2O3/Rh/SrTiO3 photocatalyst which has Rh nanoparticles covered with a thin Cr2O3 barrier layer to selectively control and maximize the dual-functional photocatalytic activity. PMID:27384472

  15. Portable compton gamma-ray detection system

    DOEpatents

    Rowland, Mark S.; Oldaker, Mark E.

    2008-03-04

    A Compton scattered gamma-ray detector system. The system comprises a gamma-ray spectrometer and an annular array of individual scintillators. The scintillators are positioned so that they are arrayed around the gamma-ray spectrometer. The annular array of individual scintillators includes a first scintillator. A radiation shield is positioned around the first scintillator. A multi-channel analyzer is operatively connected to the gamma-ray spectrometer and the annular array of individual scintillators.

  16. Virtual Compton Scattering: Results from Jefferson Lab

    SciTech Connect

    L. Van Hoorebeke

    2003-05-01

    Virtual Compton Scattering o013 the proton has been studied at Q 2 -values of 1:0 and 1:9 (GeV=c) 2 in Hall A at the Thomas Je013erson National Accelerator Facility (JLab). Data were taken below and above the pion production threshold as well as in the resonance region. Results obtained below pion threshold at Q 2 = 1:0 (GeV=c) 2 are presented in this paper.

  17. Deeply Virtual Compton Scattering with CLAS

    SciTech Connect

    F.X. Girod

    2007-12-17

    The beam spin asymmetries of the reaction ep -> epg in the Bjorken regime were measured over a wide kinematical domain using the CLAS detector and a new lead-tungstate calorimeter. Through the interference of the Bethe-Heitler process with Deeply Virtual Compton Scattering, those asymmetries provide constraints for the nucleon Generalized Parton Distributions models. The observed shapes are in agreement with twist-2 dominance predictions.

  18. Nonlinear Brightness Optimization in Compton Scattering

    DOE PAGESBeta

    Hartemann, Fred V.; Wu, Sheldon S. Q.

    2013-07-26

    In Compton scattering light sources, a laser pulse is scattered by a relativistic electron beam to generate tunable x and gamma rays. Because of the inhomogeneous nature of the incident radiation, the relativistic Lorentz boost of the electrons is modulated by the ponderomotive force during the interaction, leading to intrinsic spectral broadening and brightness limitations. We discuss these effects, along with an optimization strategy to properly balance the laser bandwidth, diffraction, and nonlinear ponderomotive force.

  19. Resonant Compton Physics for Magnetar Astrophysics

    NASA Astrophysics Data System (ADS)

    Ickes, Jesse; Gonthier, Peter L.; Eiles, Matthew; Baring, Matthew G.

    2016-01-01

    Various telescopes including RXTE, INTEGRAL, Suzaku, and Fermi have detected steady non-thermal X-ray emission in the 10 - 200 keV band from strongly magnetic neutron stars known as magnetars. Magnetic inverse Compton scattering is believed to be the leading candidate for the production of this intense X-ray radiation. Scattering at ultra-relativistic energies leads to attractive simplifications in the analytics of the magnetic Compton cross section. We have recently addressed such a case by developing compact analytic expressions using correct spin-dependent widths acquired through the implementation of Sokolov & Ternov basis states, focusing specifically on ground-state-ground-state scattering. Compton scattering in magnetar magnetospheres can cool electrons down to mildly relativistic energies. Moreover, soft gamma-ray flaring in magnetars may involve strong Comptonization in expanding clouds of mildly relativistic pairs. Such environs necessitate the development of more general magnetic scattering cross sections, in which the incoming photons acquire substantial incident angles relative to the field in the rest frame of the electron leading to arbitrary Landau excitations of the intermediate and final states. Due to the rapid transitions of the excited-state to the ground-state, the initial electron is still assumed to be in the ground state. The cross sections treat the plethora of harmonic resonances associated with various cyclotron transitions between Landau states. Polarization and spin dependence of the cross section for the four scattering modes is compared to the cross section obtained with spin-averaged widths. We present numerical results to show the comparisons to highlight the role of the spin-dependent widths of the resonances. The findings presented here will have applications to various neutron star problems, including computation of Eddington luminosities and polarization mode-switching rates in transient magnetar fireballs.

  20. Nonlinear brightness optimization in compton scattering.

    PubMed

    Hartemann, Fred V; Wu, Sheldon S Q

    2013-07-26

    In Compton scattering light sources, a laser pulse is scattered by a relativistic electron beam to generate tunable x and gamma rays. Because of the inhomogeneous nature of the incident radiation, the relativistic Lorentz boost of the electrons is modulated by the ponderomotive force during the interaction, leading to intrinsic spectral broadening and brightness limitations. These effects are discussed, along with an optimization strategy to properly balance the laser bandwidth, diffraction, and nonlinear ponderomotive force. PMID:23931374

  1. Helium Compton Form Factor Measurements at CLAS

    SciTech Connect

    Voutier, Eric J.-M.

    2013-07-01

    The distribution of the parton content of nuclei, as encoded via the generalized parton distributions (GPDs), can be accessed via the deeply virtual Compton scattering (DVCS) process contributing to the cross section for leptoproduction of real photons. Similarly to the scattering of light by a material, DVCS provides information about the dynamics and the spatial structure of hadrons. The sensitivity of this process to the lepton beam polarization allows to single-out the DVCS amplitude in terms of Compton form factors that contain GPDs information. The beam spin asymmetry of the $^4$He($\\vec {\\mathrm e}$,e$' \\gamma ^4$He) process was measured in the experimental Hall B of the Jefferson Laboratory to extract the real and imaginary parts of the twist-2 Compton form factor of the $^4$He nucleus. The experimental results reported here demonstrate the relevance of this method for such a goal, and suggest the dominance of the Bethe-Heitler amplitude to the unpolarized process in the kinematic range explored by the experiment.

  2. Compton Scattering Experiments with Polychromatic Radiation

    NASA Astrophysics Data System (ADS)

    Schütz, Wolfgang; Waldeck, Beate; Flösch, Dietmar; Weyrich, Wolf

    1993-02-01

    We show an iterative algorithm that allows to obtain accurate Compton profiles J(q) from Compton scattering spectra I2 (ω2), if the excitation radiation is not strictly monochromatic. It requires knowledge of the spectral distribution of the primary radiation I1(ω1), validity of the impulse approximation and dominance of a monochromatic part in I1(ω1) over the polychromatic rest. Conversely, the primary spectrum is often experimentally not directly accessible. In such a situation it is possible to evaluate the primary spectrum I1(ω1) from the spectrum of scattered photons, I2(ω2), with a similar iterative algorithm. We use a scattering target of high atomic number in order to ensure that the elastically scattered photons dominate the inelastically scattered ones. From the scattered spectrum we get a model for the Compton profile that allows us to separate the inelastic part of the scattered spectrum from the elastic part, which, in turn, is proportional to the spectral distribution of the primary radiation.

  3. Spin momentum density of Nd using Compton spectroscopy

    SciTech Connect

    Sahariya, Jagrati; Dashora, Alpa; Mund, H. S.; Ahuja, B. L.; Tiwari, Shailja; Itou, M.; Sakurai, Y.

    2013-02-05

    Spin momentum density of Nd has been measured at 6K temperature using magnetic Compton scattering. The individual contribution of different electronic states, in the formation of total spin moment, is deduced from the analysis of magnetic Compton profile. The electron-specific spin moments deduced from the experimental Compton data are compared with the theoretical results obtained from full potential linearized augmented plane wave method and are found to be in good agreement.

  4. HERMES impact for the access of Compton form factors

    NASA Astrophysics Data System (ADS)

    Kumerički, K.; Müller, D.; Murray, M.

    2014-07-01

    We utilize the DVCS asymmetry measurements of the HERMES collaboration for access to Compton form factors in the deeply virtual regime and to generalized parton distributions. In particular, the (almost) complete measurement of DVCS observables allows us to map various asymmetries into the space of Compton form factors, where we still rely in this analysis on dominance of twist-two associated Compton form factors. We compare this one-to-one map with local Compton form factor fits and a model dependent global fit.

  5. Dual Coding in Children.

    ERIC Educational Resources Information Center

    Burton, John K.; Wildman, Terry M.

    The purpose of this study was to test the applicability of the dual coding hypothesis to children's recall performance. The hypothesis predicts that visual interference will have a small effect on the recall of visually presented words or pictures, but that acoustic interference will cause a decline in recall of visually presented words and…

  6. Proton spin polarizabilities from polarized Compton scattering

    SciTech Connect

    B. Pasquini; D. Drechsel; M. Vanderhaeghen

    2007-07-01

    Polarized Compton scattering off the proton is studied within the framework of subtracted dispersion relations for photon energies up to 300 MeV. As a guideline for forthcoming experiments, we focus the attention on the role of the proton's spin polarizabilities and investigate the most favorable conditions to extract them with a minimum of model dependence. We conclude that a complete separation of the four spin polarizabilities is possible, at photon energies between threshold and the $\\Delta(1232)$ region, provided one can achieve polarization measurements with an accuracy of a few percent.

  7. Study of Compton vs. Photoelectric Interactions

    SciTech Connect

    Gronberg, J B; Johnson, S C; Lange, D J; Wright, D M; Beiersdorfer, P

    2004-07-09

    We have studied how often incoming photons interact via a Compton interaction and/or a photoelectric interaction as a function of energy and detector material Results are using a 1m{sup 3} detector, and discrete energy photons from 0.1 MeV up to 10 MeV. Essentially all of the lower energy photons interact at least once in a detector of this size. This is not the case at higher energies. Each detector, photon energy combination was simulated with 2000 photons.

  8. Deeply Virtual Compton Scattering off the Neutron

    SciTech Connect

    Mazouz, M.; Guillon, B.; Real, J.-S.; Voutier, E.

    2007-12-14

    The present experiment exploits the interference between the deeply virtual Compton scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D(e-vector,e{sup '}{gamma})X cross section measured at Q{sup 2}=1.9 GeV{sup 2} and x{sub B}=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to E{sub q}, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced.

  9. Biophysical applications of neutron Compton scattering

    NASA Astrophysics Data System (ADS)

    Wanderlingh, U. N.; Albergamo, F.; Hayward, R. L.; Middendorf, H. D.

    Neutron Compton scattering (NCS) can be applied to measuring nuclear momentum distributions and potential parameters in molecules of biophysical interest. We discuss the analysis of NCS spectra from peptide models, focusing on the characterisation of the amide proton dynamics in terms of the width of the H-bond potential well, its Laplacian, and the mean kinetic energy of the proton. The Sears expansion is used to quantify deviations from the high-Q limit (impulse approximation), and line-shape asymmetry parameters are evaluated in terms of Hermite polynomials. Results on NCS from selectively deuterated acetanilide are used to illustrate this approach.

  10. Deeply virtual Compton scattering and nucleon structure

    SciTech Connect

    M. Garcon

    2006-11-01

    Deeply Virtual Compton Scattering (DVCS) is the tool of choice to study Generalized Parton Distributions (GPD) in the nucleon. After a general introduction to the subject, a review of experimental results from various facilities is given. Following the first encouraging results, new generation dedicated experiments now allow unprecedented precision and kinematical coverage. Several new results were presented during the conference, showing significant progress in this relatively new field. Prospects for future experiments are presented. The path for the experimental determination of GPDs appears now open.

  11. The development of a Compton lung densitometer

    SciTech Connect

    Loo, B.W.; Goulding, F.S.; Madden, N.W.; Simon, D.S.

    1988-11-01

    A field instrument is being developed for the non-invasive determination of absolute lung density using unique Compton backscattering techniques. A system consisting of a monoenergetic gamma-ray beam and a shielded high resolution high-purity-germanium (HPGe) detector in a close-coupled geometry is designed to minimize errors due to multiple scattering and uncontrollable attenuation in the chestwall. Results of studies on system performance with phantoms, the optimization of detectors, and the fabrication of a practical gamma-ray source are presented. 3 refs., 6 figs., 2 tabs.

  12. Experimental confirmation of neoclassical Compton scattering theory

    SciTech Connect

    Aristov, V. V.; Yakunin, S. N.; Despotuli, A. A.

    2013-12-15

    Incoherent X-ray scattering spectra of diamond and silicon crystals recorded on the BESSY-2 electron storage ring have been analyzed. All spectral features are described well in terms of the neoclassical scattering theory without consideration for the hypotheses accepted in quantum electrodynamics. It is noted that the accepted tabular data on the intensity ratio between the Compton and Rayleigh spectral components may significantly differ from the experimental values. It is concluded that the development of the general theory (considering coherent scattering, incoherent scattering, and Bragg diffraction) must be continued.

  13. Deeply virtual compton scattering off the neutron.

    PubMed

    Mazouz, M; Camsonne, A; Camacho, C Muñoz; Ferdi, C; Gavalian, G; Kuchina, E; Amarian, M; Aniol, K A; Beaumel, M; Benaoum, H; Bertin, P; Brossard, M; Chen, J-P; Chudakov, E; Craver, B; Cusanno, F; de Jager, C W; Deur, A; Feuerbach, R; Fieschi, J-M; Frullani, S; Garçon, M; Garibaldi, F; Gayou, O; Gilman, R; Gomez, J; Gueye, P; Guichon, P A M; Guillon, B; Hansen, O; Hayes, D; Higinbotham, D; Holmstrom, T; Hyde, C E; Ibrahim, H; Igarashi, R; Jiang, X; Jo, H S; Kaufman, L J; Kelleher, A; Kolarkar, A; Kumbartzki, G; Laveissiere, G; Lerose, J J; Lindgren, R; Liyanage, N; Lu, H-J; Margaziotis, D J; Meziani, Z-E; McCormick, K; Michaels, R; Michel, B; Moffit, B; Monaghan, P; Nanda, S; Nelyubin, V; Potokar, M; Qiang, Y; Ransome, R D; Réal, J-S; Reitz, B; Roblin, Y; Roche, J; Sabatié, F; Saha, A; Sirca, S; Slifer, K; Solvignon, P; Subedi, R; Sulkosky, V; Ulmer, P E; Voutier, E; Wang, K; Weinstein, L B; Wojtsekhowski, B; Zheng, X; Zhu, L

    2007-12-14

    The present experiment exploits the interference between the deeply virtual Compton scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D(e,e'gamma)X cross section measured at Q2=1.9 GeV2 and xB=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to E_{q}, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced. PMID:18233443

  14. Deeply Virtual Compton Scattering off the neutron

    SciTech Connect

    M. Mazouz; A. Camsonne; C. Munoz Camacho; C. Ferdi; G. Gavalian; E. Kuchina; M. Amarian; K. A. Aniol; M. Beaumel; H. Benaoum; P. Bertin; M. Brossard; J.-P. Chen; E. Chudakov; B. Craver; F. Cusanno; C.W. de Jager; A. Deur; R. Feuerbach; J.-M. Fieschi; S. Frullani; M. Garcon; F. Garibaldi; O. Gayou; R. Gilman; J. Gomez; P. Gueye; P.A.M. Guichon; B. Guillon; O. Hansen; D. Hayes; D. Higinbotham; T. Holmstrom; C.E. Hyde; H. Ibrahim; R. Igarashi; X. Jiang; H.S. Jo; L.J. Kaufman; A. Kelleher; A. Kolarkar; G. Kumbartzki; G. Laveissiere; J.J. LeRose; R. Lindgren; N. Liyanage; H.-J. Lu; D.J. Margaziotis; Z.-E. Meziani; K. McCormick; R. Michaels; B. Michel; B. Moffit; P. Monaghan; S. Nanda; V. Nelyubin; M. Potokar; Y. Qiang; R.D. Ransome; J.-S. Real; B. Reitz; Y. Roblin; J. Roche; F. Sabatie; A. Saha; S. Sirca; K. Slifer; P. Solvignon; R. Subedi; V. Sulkosky; P.E. Ulmer; E. Voutier; K. Wang; L.B. Weinstein; B. Wojtsekhowski; X. Zheng; L. Zhu

    2007-12-01

    The present experiment exploits the interference between the Deeply Virtual Compton Scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D$({\\vec e},e'\\gamma)X$ cross section measured at $Q^2$=1.9 GeV$^2$ and $x_B$=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to $E_q$, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced.

  15. The Latino Experience: New Implications for Compton Community College.

    ERIC Educational Resources Information Center

    Camacho, Julian S.

    Census data from 1990 reveal that Latinos (n=133,009) comprised 47% of California's Compton Community College District, a higher percentage than Blacks (n=91,574) who made up 32% and Whites, Asians, and others (n=60,417) who comprised 21%. This is reflected in Compton Community College's (CCC's) student population. Between fall 1994 and spring…

  16. FITS data conversion efforts at the Compton Observatory Science Support Center

    NASA Technical Reports Server (NTRS)

    Jennings, D. G.; Jordan, J. M.; Mcglynn, T. A.; Ruggiero, N. G.; Serlemitsos, T. A.

    1992-01-01

    The Compton Gamma Ray Observatory (CGRO) is an active, earth orbiting satellite consisting of four gamma-ray telescopes. Each telescope is maintained by an independent principal investigator (PI) team, and each PI team has devised separate data formats to handle the needs of their particular instrument. As mandated by NASA, the Compton Observatory Science Support Center (COSSC) intends to archive and distribute PI data to the public in FITS (Flexible Image Transport System) format. To accomplish this task, we at COSSC have been developing a set of general purpose software tools that facilitate the transformation of non-FITS formatted data into FITS format. These tools, known as ToFU (To FITS Utilities), serve as the kernel of our CGRO data conversion software. This presentation describes the problems encountered in transcribing large amounts of data into a standard FITS form and the capabilities of the COSSC-built conversion software designed to perform the transformations.

  17. Compton scattering from a pion: Off-shell effects and the equivalence theorem

    SciTech Connect

    Scherer, S.; Fearing, H.W.

    1995-05-10

    We consider Compton scattering from a pion in the framework of chiral perturbation theory ({chi}{ital PT}). We investigate off-shell effects in the s- and u-channel pole diagrams. For that purpose we perform a field transformation which, in comparison with the standard Gasser and Leutwyler lagrangian, generates additional terms at order {ital p}{sup 4} proportional to the lowest-order equation of motion. We demonstrate that the two lagrangians which generate different off-shell form factors predict the same Compton scattering S-matrix. This result is interpreted as an application of a generalized equivalence theorem. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  18. Deeply Virtual Compton Scattering off 4He

    NASA Astrophysics Data System (ADS)

    Joosten, Sylvester; CLAS Collaboration

    2015-10-01

    The European Muon Collaboration (EMC) observed the first signs of a modification of the partonic structure of the nucleon when present in a nuclear medium. The precise nature of these effects, as well as their underlying cause, is yet to be determined. The generalized parton distribution (GPD) framework provides a powerful tool to study the partonic structure of nucleons inside a nucleus. Hard exclusive leptoproduction of a real photon off a nucleon, deeply virtual Compton scattering (DVCS), is presently considered the cleanest experimental access to the GPDs, through the Compton form factors (CFFs). This is especially the case for scattering off the spin-zero helium nucleus, where only a single CFF contributes to the process. The real and imaginary parts of this CFF can be constrained through the beam-spin asymmetry (BSA). We will present the first measurements of the DVCS process off 4He using the CEBAF 6 GeV polarized electron beam and the CLAS detector at JLab. The CLAS detector was supplemented with an inner electromagnetic calorimeter for photons produced at small angles, as well as a radial time projection chamber (RTPC) to detect low-energy recoil nuclei. This setup allowed for a clean measurement of the BSA in both the coherent and incoherent channels.

  19. Compton backscattered collmated X-ray source

    DOEpatents

    Ruth, Ronald D.; Huang, Zhirong

    2000-01-01

    A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

  20. Compton backscattered collimated x-ray source

    DOEpatents

    Ruth, R.D.; Huang, Z.

    1998-10-20

    A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

  1. Compton backscattered collimated x-ray source

    DOEpatents

    Ruth, Ronald D.; Huang, Zhirong

    1998-01-01

    A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

  2. Compton effect thermally activated depolarization dosimeter

    DOEpatents

    Moran, Paul R.

    1978-01-01

    A dosimetry technique for high-energy gamma radiation or X-radiation employs the Compton effect in conjunction with radiation-induced thermally activated depolarization phenomena. A dielectric material is disposed between two electrodes which are electrically short circuited to produce a dosimeter which is then exposed to the gamma or X radiation. The gamma or X-radiation impinging on the dosimeter interacts with the dielectric material directly or with the metal composing the electrode to produce Compton electrons which are emitted preferentially in the direction in which the radiation was traveling. A portion of these electrons becomes trapped in the dielectric material, consequently inducing a stable electrical polarization in the dielectric material. Subsequent heating of the exposed dosimeter to the point of onset of ionic conductivity with the electrodes still shorted through an ammeter causes the dielectric material to depolarize, and the depolarization signal so emitted can be measured and is proportional to the dose of radiation received by the dosimeter.

  3. Compton-edge-based energy calibration of double-sided silicon strip detectors in Compton camera

    NASA Astrophysics Data System (ADS)

    Seo, Hee; Park, Jin Hyung; Kim, Chan Hyeong; Lee, Ju Hahn; Lee, Chun Sik; Sung Lee, Jae

    2011-05-01

    Accurate energy calibration of double-sided silicon strip detectors (DSSDs) is very important, but challenging for high-energy photons. In the present study, the calibration was improved by considering the Compton edge additionally to the existing low-energy calibration points. The result, indeed, was very encouraging. The energy-calibration errors were dramatically reduced, from, on average, 15.5% and 16.9% to 0.47% and 0.31% for the 356 (133Ba) and 662 keV (137Cs) peaks, respectively. The imaging resolution of a double-scattering-type Compton camera using DSSDs as the scatterer detectors, for a 22Na point-like source, also was improved, by ˜9%.

  4. Compton Radiation for Nuclear Waste Management and Transmutation

    NASA Astrophysics Data System (ADS)

    Bulyak, E.; Urakawa, J.

    2015-10-01

    Compton inverse radiation is emitted in the process of backscattering of the laser pulses off the relativistic electrons. This radiation possesses high spectral density and high energy of photons--in hard x-ray up to gammaray energy range--with moderate electron energies (hundreds of MeV up to 1 GeV) due to short wavelength of the laser radiation. The Compton radiation is well collimated: emitting within a narrow cone along the electron beam. A distinct property of the Compton inverse radiation is a steep high-energy cutoff of the spectrum and the maximal intensity just below the cutoff. The Compton sources can attain: spectral density up to 1014 gammas/(s 0.1%bandwidth) in MeV range of energies, and spectral brightness up to 1020 gammas/(smm2mr2 0.1% bw). Applicability of Compton sources for nuclear waste management and detection of radioisotopes and fissionable nuclides are discussed in the report. Also application limits of Compton gamma sources for transmutation of radioactive isotopes are estimated. A recently proposed subtracting method, in which two sets of data obtained by irradiating the object by the Compton beams with slightly different maximal energies are compared, will enhance resolution of detection radioactive elements at the 'atomic' (hundreds of keV) and the 'nuclear' (a few MeV) photon energies.

  5. Nucleon Compton scattering in the Dyson-Schwinger approach

    NASA Astrophysics Data System (ADS)

    Eichmann, Gernot; Fischer, Christian S.

    2013-02-01

    We analyze the nucleon’s Compton scattering amplitude in the Dyson-Schwinger/Faddeev approach. We calculate a subset of diagrams that implements the nonperturbative handbag contribution as well as all t-channel resonances. At the quark level, these ingredients are represented by the quark Compton vertex whose analytic properties we study in detail. We derive a general form for a fermion two-photon vertex that is consistent with its Ward-Takahashi identities and free of kinematic singularities, and we relate its transverse part to the on-shell nucleon Compton amplitude. We solve an inhomogeneous Bethe-Salpeter equation for the quark Compton vertex in rainbow-ladder truncation and implement it in the nucleon Compton scattering amplitude. The remaining ingredients are the dressed quark propagator and the nucleon’s bound-state amplitude which are consistently solved from Dyson-Schwinger and covariant Faddeev equations. We verify numerically that the resulting quark Compton vertex and nucleon Compton amplitude both reproduce the πγγ transition form factor when the pion pole in the t channel is approached.

  6. The Compton Mirror in NGC 4151

    NASA Technical Reports Server (NTRS)

    Poutanen, Juri; Sikora, Marek; Begelman, Mitchell C.; Magdziarz, Pawel

    1996-01-01

    We show that the sharp cutoff in the hard X-ray spectrum of NGC 4151, unusual for Seyfert 1 galaxies, can be reconciled with the average Seyfert 1 spectrum if we assume that the central source is completely hidden from our line of sight by the thick part of the accretion disk or by the broad emission-line clouds. The observed X-ray radiation is produced by scattering of the Seyfert 1 type spectrum in the higher, cooler parts of the accretion disk corona, or in a wind. A sharp cutoff appears as a result of the Compton recoil effect. This model naturally explains a discrepancy regarding the inclination of the central source, inferred to be low (face-on) from observations of the iron K-alpha emission line, but inferred to be high on the basis of optical and UV observations.

  7. Deeply Virtual Compton Scattering on the Proton

    NASA Astrophysics Data System (ADS)

    Hirlinger Saylor, Nicholas; JLab, CLAS Collaboration

    2013-10-01

    DVCS on the proton was measured at Jefferson Lab with CLAS at Hall B with a polarized 5.88 GeV electron beam on an unpolarized hydrogen target. A preliminary measurement of unpolarized and polarized cross sections was made over wide kinematics, from 1GeV2 Compton form factor HIm , which is proportional to H, was extracted. In addition, we have made a comparison of measured cross sections with predictions from several different handbag based models. This measurement allows for further constraints to be placed on the various models, especially on H. Preliminary results for the extraction of the GPD H will be presented and discussed.

  8. Compton scattering vertex for massive scalar QED

    SciTech Connect

    Bashir, A.; Concha-Sanchez, Y.; Delbourgo, R.; Tejeda-Yeomans, M. E.

    2009-08-15

    We investigate the Compton scattering vertex of charged scalars and photons in scalar quantum electrodynamics (SQED). We carry out its nonperturbative construction consistent with Ward-Fradkin-Green-Takahashi identity which relates 3-point vertices to the 4-point ones. There is an undetermined part which is transverse to one or both the external photons, and needs to be evaluated through perturbation theory. We present in detail how the transverse part at the 1-loop order can be evaluated for completely general kinematics of momenta involved in covariant gauges and dimensions. This involves the calculation of genuine 4-point functions with three massive propagators, the most nontrivial integrals reported in this paper. We also discuss possible applications of our results.

  9. The GSFC Advanced Compton Telescope (ACT)

    NASA Astrophysics Data System (ADS)

    Hartman, R.; Fichtel, C.; Kniffen, D.; Trombka, J.; Stacy, G.

    1983-08-01

    A new telescope is being developed at GSFC for the study of point sources of gamma rays in the energy range 1-30 MeV. Using the detection principle of a Compton scatter in a 2.5 cm thick NaI(Tl) detector followed by absorption in a 15 cm thick NaI(Tl) detector, the telescope uses a rocking collimator for field-of-view reduction and background subtraction. Background reduction techniques include lead-plastic scintillator shielding, pulse shape discrimination and Anger camera operation to both NaI detectors, as well as a time-of-flight measurement between them. The instrument configuration and status is described.

  10. The dose from Compton backscatter screening.

    PubMed

    Rez, Peter; Metzger, Robert L; Mossman, Kenneth L

    2011-04-01

    Systems based on the detection of Compton backscattered X rays have been deployed for screening personnel for weapons and explosives. Similar principles are used for screening vehicles at border-crossing points. Based on well-established scattering cross sections and absorption coefficients in conjunction with reasonable estimates of the image contrast and resolution, the entrance skin dose and the dose at a depth of 1 cm can be calculated. The effective dose can be estimated using the same conversion coefficients as used to convert exposure measurements to the effective dose. It is shown that the effective dose is highly dependent on image resolution (i.e. pixel size).The effective doses for personnel screening systems are unlikely to be in compliance with the American National Standards Institute standard NS 43.17 unless the pixel sizes are >4 mm. Nevertheless, calculated effective doses are well below doses associated with health effects. PMID:21068018

  11. Compton scattering off polarized electrons with a high-finesse Fabry-Perot Cavity at Jlab

    SciTech Connect

    Nicolas Falletto; Martial Authier; Maud Baylac; M. Boyer; Francois Bugeon; Etienne Burtin; Christian Cavata; Nathalie Colombel; G. Congretel; R. Coquillard; G. Coulloux; Bertrand Couzy; P Deck; Alain Delbart; D. Desforges; A. Donati; B. Duboue; Stephanie Escoffier; F. Farci; Bernard Frois; P Girardot; J Guillotau; C Henriot; Claude Jeanney; M Juillard; J. P. Jorda; P. Legou; David Lhuillier; Y Lussignol; Phillippe Mangeot; X. Martin; Frederic Marie; Jacques Martino; M. Maurier; Bernard Mazeau; J.F. Millot; F. Molinie; J.-P. Mols; Jean-pierre Mouly; M. Mur; Damien Neyret; T. Pedrol; Stephane Platchkov; G. Pontet; Thierry Pussieux; Yannick Queinec; Philippe Rebourgeard; J. C. Sellier; Gerard Tarte; Christian Veyssiere; Andre Zakarian; Pierre Bertin; Alain Cosquer; Jian-ping Chen; Joseph Mitchell; J.-M. Mackowski; L. Pinard

    2001-03-01

    We built and commissioned a new type of Compton polarimeter to measure the electron beam polarization at the Thomas Jefferson National Accelerator Facility (Virginia, USA). The heart of this polarimeter is a high-finesse monolithic Fabry-Perot cavity. Its purpose is to amplify a primary 300 mW laser beam in order to improve the signal to noise ratio of the polarimeter. It is the first time that a high-finesse Fabry-Perot cavity is enclosed in the vacuum of a particle accelerator to monitor the beam polarization by Compton polarimetry. The measured finesse and amplification gain of the cavity are F=26000 and G=7300. The electron beam crosses this high-power photon source at an angle of 23 mrad in the middle of the cavity where the photon beam power density is estimated to be 0.85MW/cm2. We have used this facility during the HAPPEX experiment (April-July 1999) and we give a preliminary measurement of Compton scattering asymmetry.

  12. AXIS: an instrument for imaging Compton radiographs using the Advanced Radiography Capability on the NIF.

    PubMed

    Hall, G N; Izumi, N; Tommasini, R; Carpenter, A C; Palmer, N E; Zacharias, R; Felker, B; Holder, J P; Allen, F V; Bell, P M; Bradley, D; Montesanti, R; Landen, O L

    2014-11-01

    Compton radiography is an important diagnostic for Inertial Confinement Fusion (ICF), as it provides a means to measure the density and asymmetries of the DT fuel in an ICF capsule near the time of peak compression. The AXIS instrument (ARC (Advanced Radiography Capability) X-ray Imaging System) is a gated detector in development for the National Ignition Facility (NIF), and will initially be capable of recording two Compton radiographs during a single NIF shot. The principal reason for the development of AXIS is the requirement for significantly improved detection quantum efficiency (DQE) at high x-ray energies. AXIS will be the detector for Compton radiography driven by the ARC laser, which will be used to produce Bremsstrahlung X-ray backlighter sources over the range of 50 keV-200 keV for this purpose. It is expected that AXIS will be capable of recording these high-energy x-rays with a DQE several times greater than other X-ray cameras at NIF, as well as providing a much larger field of view of the imploded capsule. AXIS will therefore provide an image with larger signal-to-noise that will allow the density and distribution of the compressed DT fuel to be measured with significantly greater accuracy as ICF experiments are tuned for ignition. PMID:25430200

  13. AXIS: An instrument for imaging Compton radiographs using the Advanced Radiography Capability on the NIF

    SciTech Connect

    Hall, G. N. Izumi, N.; Tommasini, R.; Carpenter, A. C.; Palmer, N. E.; Zacharias, R.; Felker, B.; Holder, J. P.; Allen, F. V.; Bell, P. M.; Bradley, D.; Montesanti, R.; Landen, O. L.

    2014-11-15

    Compton radiography is an important diagnostic for Inertial Confinement Fusion (ICF), as it provides a means to measure the density and asymmetries of the DT fuel in an ICF capsule near the time of peak compression. The AXIS instrument (ARC (Advanced Radiography Capability) X-ray Imaging System) is a gated detector in development for the National Ignition Facility (NIF), and will initially be capable of recording two Compton radiographs during a single NIF shot. The principal reason for the development of AXIS is the requirement for significantly improved detection quantum efficiency (DQE) at high x-ray energies. AXIS will be the detector for Compton radiography driven by the ARC laser, which will be used to produce Bremsstrahlung X-ray backlighter sources over the range of 50 keV–200 keV for this purpose. It is expected that AXIS will be capable of recording these high-energy x-rays with a DQE several times greater than other X-ray cameras at NIF, as well as providing a much larger field of view of the imploded capsule. AXIS will therefore provide an image with larger signal-to-noise that will allow the density and distribution of the compressed DT fuel to be measured with significantly greater accuracy as ICF experiments are tuned for ignition.

  14. Some Issues in Deeply-Virtual Compton Scattering

    NASA Astrophysics Data System (ADS)

    Bakker, B. L. G.; Ji, C.-R.

    2010-04-01

    Compton scattering provides a unique tool for studying hadron structure. In contrast to elastic electron scattering, which provides information about the hadron's structure in terms of form factors, Compton scattering is more versatile, as the basic process is the coupling of two electro-magnetic currents. Therefore, the hadronic structure can be described at high momentum transfer in the language of generalized parton distributions (GPDs), which code information about the light-front wave functions of the probed hadrons. In this paper we discuss some issues involved in the application of the GPD idea, in particular the effectivity of Compton scattering as a filter of the hadron structure.

  15. The results of the in-flight attitude sensor calibration for the Arthur Holly Compton Gamma Ray Observatory

    NASA Astrophysics Data System (ADS)

    Davis, W. S.; Eudell, A. H.; Kulp, L. S.; Lindrose, L. A.; Harman, R. R.

    1993-02-01

    The Arthur Holly Compton Gamma Ray Observatory (GRO) was launched by the shuttle Atlantis in April 1991. This paper presents the results of the attitude sensor calibration that was performed during the early mission. The GSFC Flight Dynamics Facility (FDF) performed an alignment calibration of the two fixed-head star trackers (FHST's) and two fine Sun sensors (FSS's) on board Compton GRO. The results show a 27-arcsecond shift between the bore sights of the FHST's with respect to prelaunch measurements. The alignments of the two FSS's shifted by 0.20 and 0.05 degree. During the same time period, the Compton GRO science teams performed an alignment calibration of the science instruments with respect to the attitude reported by the on board computer (OBC). In order to preserve these science alignments, FDF adjusted the overall alignments of the FHST's and FSS's, obtained by the FDF calibration, such that when up linked to the OBC, the shift in the OBC-determined attitude is minimized. FDF also calibrated the inertial reference unit (IRU), which consists of three dual-axis gyroscopes. The observed gyro bias matched the bias that was solved for by the OBC. This bias drifted during the first 6 days after release. The results of the FDF calibration of scale factor and alignment shifts showed changes that were of the same order as their uncertainties.

  16. The results of the in-flight attitude sensor calibration for the Arthur Holly Compton Gamma Ray Observatory

    NASA Technical Reports Server (NTRS)

    Davis, W. S.; Eudell, A. H.; Kulp, L. S.; Lindrose, L. A.; Harman, R. R.

    1993-01-01

    The Arthur Holly Compton Gamma Ray Observatory (GRO) was launched by the shuttle Atlantis in April 1991. This paper presents the results of the attitude sensor calibration that was performed during the early mission. The GSFC Flight Dynamics Facility (FDF) performed an alignment calibration of the two fixed-head star trackers (FHST's) and two fine Sun sensors (FSS's) on board Compton GRO. The results show a 27-arcsecond shift between the bore sights of the FHST's with respect to prelaunch measurements. The alignments of the two FSS's shifted by 0.20 and 0.05 degree. During the same time period, the Compton GRO science teams performed an alignment calibration of the science instruments with respect to the attitude reported by the on board computer (OBC). In order to preserve these science alignments, FDF adjusted the overall alignments of the FHST's and FSS's, obtained by the FDF calibration, such that when up linked to the OBC, the shift in the OBC-determined attitude is minimized. FDF also calibrated the inertial reference unit (IRU), which consists of three dual-axis gyroscopes. The observed gyro bias matched the bias that was solved for by the OBC. This bias drifted during the first 6 days after release. The results of the FDF calibration of scale factor and alignment shifts showed changes that were of the same order as their uncertainties.

  17. Double deeply virtual Compton scattering on nucleons and nuclei

    SciTech Connect

    Kopeliovich, B. Z.; Schmidt, Ivan; Siddikov, M.

    2010-07-01

    In this paper we evaluate the double deeply virtual Compton scattering on nucleons and nuclei in the framework of the color dipole model. Both the effects of quark and the gluon shadowing are taken into account.

  18. Compton Profile Study of Intermetallic Ti{sub 3}Al

    SciTech Connect

    Vyas, V.; Sharma, G.; Mishra, M. C.; Sharma, B. K.; Joshi, K. B.

    2011-10-20

    The Compton scattering measurement on intermetallic alloy Ti{sub 3}Al is reported in this work. The measurement is made using 59.54 keV gamma-rays from Am{sup 241} source. Theoretical calculation of Compton profile is also performed employing CRYSTAL code within the framework of density functional theory to compare with the measurement. The theoretical profile of the alloy is also synthesized following the superposition model taking the published Compton profiles of elemental solids from the APW method. The experimental study of charge transfer in the alloys has also been done by performing the experimental Compton profile measurements on Ti and Al following the superposition model and charge transfer from Al to Ti is clearly seen on the alloy formation.

  19. Adjoint calculations for multiple scattering of Compton and Rayleigh effects

    NASA Astrophysics Data System (ADS)

    Fernández, J. E.; Sumini, M.

    1992-08-01

    As is well known, the experimental determination of the Compton profile requires a particular geometry with a scattering angle close to π. That situation involves a narrow multiple-scattering spectrum that overlaps the Compton peak, making it difficult to analyze the different contributions to the profile. We show how the solution of the adjoint problem can help in devising more useful experimental configurations, giving, through its classical "importance" meaning, a formally clear picture of the whole problem.

  20. Why compton-suppressed germanium detector arrays?

    SciTech Connect

    Diamond, R.M.

    1993-10-01

    Nuclear spectroscopic studies have provided a strong incentive to obtain {gamma}-ray detectors with increasingly better energy resolution, higher full-energy peak efficiencies, and greater sensitivity or resolving power. A major step was the introduction of Ge detectors in the early 60`s. But because of the low atomic number of Ge they have a poor response function; a majority of interacting gamma rays of moderate energy Compton scatter out of the detector leaving a large low-energy background. The remedy was to add a Compton-suppression shield made of NaI around the Ge crystal, and if interactions occurred simultaneously in the NaI scintillator and in the Ge detector to veto that event. Efficiencies also increased greatly when an English-Danish collaboration assembled five Ge detectors, each with a NaI suppressor, into the first array at the end of 1980. Obviously, a system of five such detectors gave much better statistics than the usual two bare detectors used for obtaining coincidence data (by a factor of 10). A few years later, another major improvement came with replacement of the NaI suppressors with shields made of the much denser bismuth germanate (BGO) as scintillator, as these could be thinner leading to arrays with of order 20 detectors. Use of such a large number of detectors led to the realization that for cascades of coincident gamma rays, as in going down a band, the improvement in the peak/background ratio observed and already appreciated in going from singles spectra to gated (double-) coincidence spectra continued when doubly-gated triple-coincidence data were compared for the first time to singly-gated double-coincidence ones. The higher-gated spectra were much cleaner and more selective, though with poorer statistics, and the advantages of higher folds and efficiencies led to the proposals for the larger 4{pi} arrays of today, Eurogam and GASP in Europe and Gammasphere in the U.S.

  1. Laser-Compton photon radiography for nondestructive test of bulk materials

    NASA Astrophysics Data System (ADS)

    Toyokawa, Hiroyuki; Ohgaki, Hideaki; Kudo, Katshuhisa; Takeda, Naoto; Mikado, Tomohisa; Yamada, Kawakatsu

    2001-12-01

    Experimental results of transmission photon radiography of bulk materials using the laser-Compton photon beam in the energy range of 2-20 MeV are given. The purpose of this work is to demonstrate the effectiveness and to survey a potential need and a technical limit of the present method for industrial application, such as nondestructive test of bulk materials. Several radiographs of metals, ceramics, and concrete were measured with the present method. Position resolution of the system was measured with using 10 MeV photon beam and slit. It was less than 1 mm.

  2. New Compton densitometer for measuring pulmonary edema

    SciTech Connect

    Loo, B.W.; Goulding, F.S.; Simon, D.S.

    1985-10-01

    Pulmonary edema is the pathological increase of extravascular lung water found most often in patients with congestive heart failure and other critically ill patients who suffer from intravenous fluid overload. A non-invasive lung density monitor that is accurate, easily portable, safe and inexpensive is needed for clinical evaluation of pulmonary edema. Other researchers who have employed Compton scattering techniques generally used systems of extended size and detectors with poor energy resolution. This has resulted in significant systematic biases from multiply-scattered photons and larger errors in counting statistics at a given radiation dose to the patient. We are proposing a patented approach in which only backscattered photons are measured with a high-resolution HPGe detector in a compact system geometry. By proper design and a unique data extraction scheme, effects of the variable chest wall on lung density measurements are minimized. Preliminary test results indicate that with a radioactive source of under 30 GBq, it should be possible to make an accurate lung density measurement in one minute, with a risk of radiation exposure to the patient a thousand times smaller than that from a typical chest x-ray. The ability to make safe, frequent lung density measurements could be very helpful for monitoring the course of P.E. at the hospital bedside or outpatient clinics, and for evaluating the efficacy of therapy in clinical research. 6 refs., 5 figs.

  3. Statistical simulation of multiple Compton backscattering process

    NASA Astrophysics Data System (ADS)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.

    2014-09-01

    A number of laboratories are currently developing monochromatic sources of X-rays and gamma quanta based on the Compton backscattering (CBS) of laser photons by relativistic electrons. Modern technologies are capable of providing a concentration of electrons and photons in the interaction point such that each primary electron can emit several hard photons. In contrast to the well-known nonlinear CBS process, in which an initial electron "absorbs" a few laser photons and emits a single hard one, the above-mentioned process can be called a multiple CBS process and is characterized by a mean number of emitted photons. The present paper is devoted to simulating the parameters of a beam of back scattered quanta based on the Monte Carlo technique. It is shown that, even in the case of strong collimation of a resulting photon beam, the radiation monochromaticity may deteriorate because of the contribution coming from the multiple photon emission, which is something that must be considered while designing new CBS sources.

  4. Radiation therapy at compact Compton sources.

    PubMed

    Jacquet, Marie; Suortti, Pekka

    2015-09-01

    The principle of the compact Compton source is presented briefly. In collision with an ultrarelativistic electron bunch a laser pulse is back-scattered as hard X-rays. The radiation cone has an opening of a few mrad, and the energy bandwidth is a few percent. The electrons that have an energy of the order of a few tens of MeV either circulate in storage ring, or are injected to a linac at a frequency of 10-100 MHz. At the interaction point the electron bunch collides with the laser pulse that has been amplified in a Fabry-Perot resonator. There are several machines in design or construction phase, and projected fluxes are 10(12) to 10(14) photons/s. The flux available at 80 keV from the ThomX machine is compared with that used in the Stereotactic Synchrotron Radiation Therapy clinical trials. It is concluded that ThomX has the potential of serving as the radiation source in future radiation therapy programs, and that ThomX can be integrated in hospital environment. PMID:25752735

  5. Anomalous nonlinear X-ray Compton scattering

    NASA Astrophysics Data System (ADS)

    Fuchs, Matthias; Trigo, Mariano; Chen, Jian; Ghimire, Shambhu; Shwartz, Sharon; Kozina, Michael; Jiang, Mason; Henighan, Thomas; Bray, Crystal; Ndabashimiye, Georges; Bucksbaum, Philip H.; Feng, Yiping; Herrmann, Sven; Carini, Gabriella A.; Pines, Jack; Hart, Philip; Kenney, Christopher; Guillet, Serge; Boutet, Sébastien; Williams, Garth J.; Messerschmidt, Marc; Seibert, M. Marvin; Moeller, Stefan; Hastings, Jerome B.; Reis, David A.

    2015-11-01

    X-ray scattering is typically used as a weak linear atomic-scale probe of matter. At high intensities, such as produced at free-electron lasers, nonlinearities can become important, and the probe may no longer be considered weak. Here we report the observation of one of the most fundamental nonlinear X-ray-matter interactions: the concerted nonlinear Compton scattering of two identical hard X-ray photons producing a single higher-energy photon. The X-ray intensity reached 4 × 1020 W cm-2, corresponding to an electric field well above the atomic unit of strength and within almost four orders of magnitude of the quantum-electrodynamic critical field. We measure a signal from solid beryllium that scales quadratically in intensity, consistent with simultaneous non-resonant two-photon scattering from nearly-free electrons. The high-energy photons show an anomalously large redshift that is incompatible with a free-electron approximation for the ground-state electron distribution, suggesting an enhanced nonlinearity for scattering at large momentum transfer.

  6. Learning from the Past: Dual Credit

    ERIC Educational Resources Information Center

    Mansell, Nicole; Justice, Madeline

    2014-01-01

    This study involved identifying, categorizing, and comparing critical incidents related to qualifying dual credit high school students' decisions to enroll or not to enroll in dual credit coursework in either a traditional or early college high school. The purpose of the study was (a) to identify the reasons qualifying students decide to enroll in…

  7. Apprenticeships in Germany: Modernising the Dual System

    ERIC Educational Resources Information Center

    Deissinger, Thomas; Hellwig, Silke

    2005-01-01

    Purpose ? This paper proposes to investigate the modernisation of the German Dual System for apprenticeships. Design/methodology/approach ? The paper looks at the history of the development of the Dual System and looks at the challenges it faces today. Findings ? The paper finds that Germany, with its long-standing tradition of dual…

  8. Inverse Compton Scattering in Mildly Relativistic Plasma

    NASA Technical Reports Server (NTRS)

    Molnar, S. M.; Birkinshaw, M.

    1998-01-01

    We investigated the effect of inverse Compton scattering in mildly relativistic static and moving plasmas with low optical depth using Monte Carlo simulations, and calculated the Sunyaev-Zel'dovich effect in the cosmic background radiation. Our semi-analytic method is based on a separation of photon diffusion in frequency and real space. We use Monte Carlo simulation to derive the intensity and frequency of the scattered photons for a monochromatic incoming radiation. The outgoing spectrum is determined by integrating over the spectrum of the incoming radiation using the intensity to determine the correct weight. This method makes it possible to study the emerging radiation as a function of frequency and direction. As a first application we have studied the effects of finite optical depth and gas infall on the Sunyaev-Zel'dovich effect (not possible with the extended Kompaneets equation) and discuss the parameter range in which the Boltzmann equation and its expansions can be used. For high temperature clusters (k(sub B)T(sub e) greater than or approximately equal to 15 keV) relativistic corrections based on a fifth order expansion of the extended Kompaneets equation seriously underestimate the Sunyaev-Zel'dovich effect at high frequencies. The contribution from plasma infall is less important for reasonable velocities. We give a convenient analytical expression for the dependence of the cross-over frequency on temperature, optical depth, and gas infall speed. Optical depth effects are often more important than relativistic corrections, and should be taken into account for high-precision work, but are smaller than the typical kinematic effect from cluster radial velocities.

  9. Compton Thick AGN in the COSMOS field

    NASA Astrophysics Data System (ADS)

    Lanzuisi, Giorgio; Cosmos Collaboration

    2015-09-01

    I will present the results we published in a couple of recent papers (Lanzuisi et al. 2015, A&A 573A 137, Lanzuisi et al. 2015, arXiv 1505.01153) on the properties of X-ray selected Compton Thick (CT, NH>10^24 cm^-2) AGN, in the COSMOS survey. We exploited the rich multi-wavelength dataset available in this field, to show that CT AGN tend to harbor smaller, rapidly growing SMBH with respect to unobscured AGN, and have a higher chance of being hosted by star-forming, merging and post-merger systems.We also demonstrated the detectability of even more heavily obscured AGN (NH>10^25 cm^-2), thanks to a truly multi-wavelength approach in the same field. The extreme source detected in this way shows strong evidences of ongoing powerful AGN feedback, detected as blue-shifted wings of high ionization optical emission lines such as [NeV] and [FeVII], as well as of the [OIII] emission line.The results obtained from these works point toward a scenario in which highly obscured AGN occupy a peculiar place in the galaxy-AGN co-evolution process, in which both the host and the SMBH rapidly evolve toward the local relations.We will also present estimates on the detectability of such extreme sources up to redshift ~6-7 with Athena. Combining the most up to date models for the Luminosity Function of CT AGN at high z, aggressive data analysis techniques on faint sources, and the current Athena survey design, we demonstrate that we will detect, and recognize as such, a small (few to ten) but incredibly valuable sample of CT AGN at such high redshift.

  10. Compton scattering: From deeply virtual to quasi-real

    NASA Astrophysics Data System (ADS)

    Belitsky, A. V.; Müller, D.; Ji, Y.

    2014-01-01

    We address the question of interpolation of the virtual Compton scattering process off a polarized nucleon target between the deeply virtual regime for the initial-state photon and its near on-shell kinematics making use of the photon helicity-dependent Compton Form Factors (CFFs) as a main ingredient of the formalism. The five-fold differential cross section for the reaction with all possible polarization options for the lepton and nucleon spins is evaluated in terms of CFFs in the rest reference frame of the initial-state nucleon. We suggest a rather simple parametrization of the Compton hadronic tensor in terms of CFFs which are free from kinematical singularities and are directly related, at large photon virtualities, to generalized parton distributions. We also provide a relation of our basis spanned by a minimal number of Dirac bilinears to the one introduced by Tarrach for the parametrization of the virtual Compton tensor and utilize the former to establish a set of equalities among our CFFs and generalized polarizabilities. As a complementary result, we express Compton scattering in the Born approximation in terms of CFFs as well.

  11. A Compton profile representation for some second period elements

    NASA Astrophysics Data System (ADS)

    Harding, Geoffrey; Olesinski, Stephan

    2011-09-01

    Compton profiles for the elements C, N and O, which are important both in medical science and security screening, are represented here as weighted sums of three Gaussians. Simple scaling relationships describe the dependence on atomic number ( Z) of the amplitudes and standard deviations of the component Gaussians, which are identified with the Compton profiles of the 1s, 2s and 2p orbitals. This representation of the Compton profile agrees with tabulated values for C, N and O to a rms deviation of the order of 1% of the mean profile amplitude over the momentum range 0≤ q≤4, where q is expressed in units of the hydrogen ground state momentum. This representation allows a "mean atomic number" for mixtures and compounds dominated by second period elements to be assigned on the basis of experimental measurements of the Doppler broadening of back-scattered X-ray K characteristic lines. Processed spectra of water and ethanol from a Compton spectrometer equipped with a room-temperature semiconductor detector are compared with the Compton profiles synthesized as suggested here, and a satisfactory agreement between the measured and theoretical mean atomic numbers and the profile shapes is found.

  12. Results of a Si/Cdte Compton Telescope

    SciTech Connect

    Oonuki, Kousuke; Tanaka, Takaaki; Watanabe, Shin; Takeda, Shin'ichiro; Nakazawa, Kazuhiro; Mitani, Takefumi; Takahashi, Tadayuki; Tajima, Hiroyasu; Fukazawa, Yasushi; Nomachi, Masaharu; /Sagamihara, Inst. Space Astron. Sci. /Tokyo U. /SLAC /Hiroshima U. /Osaka U.

    2005-09-23

    We have been developing a semiconductor Compton telescope to explore the universe in the energy band from several tens of keV to a few MeV. We use a Si strip and CdTe pixel detector for the Compton telescope to cover an energy range from 60 keV. For energies above several hundred keV, the higher efficiency of CdTe semiconductor in comparison with Si is expected to play an important role as an absorber and a scatterer. In order to demonstrate the spectral and imaging capability of a CdTe-based Compton Telescope, we have developed a Compton telescope consisting of a stack of CdTe pixel detectors as a small scale prototype. With this prototype, we succeeded in reconstructing images and spectra by solving the Compton equation from 122 keV to 662 keV. The energy resolution (FWHM) of reconstructed spectra is 7.3 keV at 511 keV and 3.1 keV at 122 keV, respectively. The angular resolution obtained at 511 keV is measured to be 12.2{sup o}(FWHM).

  13. Coded-aperture Compton camera for gamma-ray imaging

    NASA Astrophysics Data System (ADS)

    Farber, Aaron M.

    This dissertation describes the development of a novel gamma-ray imaging system concept and presents results from Monte Carlo simulations of the new design. Current designs for large field-of-view gamma cameras suitable for homeland security applications implement either a coded aperture or a Compton scattering geometry to image a gamma-ray source. Both of these systems require large, expensive position-sensitive detectors in order to work effectively. By combining characteristics of both of these systems, a new design can be implemented that does not require such expensive detectors and that can be scaled down to a portable size. This new system has significant promise in homeland security, astronomy, botany and other fields, while future iterations may prove useful in medical imaging, other biological sciences and other areas, such as non-destructive testing. A proof-of-principle study of the new gamma-ray imaging system has been performed by Monte Carlo simulation. Various reconstruction methods have been explored and compared. General-Purpose Graphics-Processor-Unit (GPGPU) computation has also been incorporated. The resulting code is a primary design tool for exploring variables such as detector spacing, material selection and thickness and pixel geometry. The advancement of the system from a simple 1-dimensional simulation to a full 3-dimensional model is described. Methods of image reconstruction are discussed and results of simulations consisting of both a 4 x 4 and a 16 x 16 object space mesh have been presented. A discussion of the limitations and potential areas of further study is also presented.

  14. Broadband Observations of the Compton-thick Nucleus of NGC 3393

    NASA Astrophysics Data System (ADS)

    Koss, Michael J.; Romero-Cañizales, C.; Baronchelli, L.; Teng, S. H.; Baloković, M.; Puccetti, S.; Bauer, F. E.; Arévalo, P.; Assef, R.; Ballantyne, D. R.; Brandt, W. N.; Brightman, M.; Comastri, A.; Gandhi, P.; Harrison, F. A.; Luo, B.; Schawinski, K.; Stern, D.; Treister, E.

    2015-07-01

    We present new Nuclear Spectroscopic Telescope Array (NuSTAR ) and Chandra observations of NGC 3393, a galaxy reported to host the smallest separation dual active galactic nuclei (AGN) resolved in the X-rays. While past results suggested a 150 pc separation dual AGN, three times deeper Chandra imaging, combined with adaptive optics and radio imaging suggest a single, heavily obscured, radio-bright AGN. Using Very Large Array and Very Long Baseline Array data, we find an AGN with a two-sided jet rather than a dual AGN and that the hard X-ray, UV, optical, near-infrared, and radio emission are all from a single point source with a radius <0 .″ 2. We find that the previously reported dual AGN is most likely a spurious detection resulting from the low number of X-ray counts (<160) at 6-7 keV and Gaussian smoothing of the data on scales much smaller than the point-spread function (PSF) (0 .″ 25 versus 0 .″ 80 FWHM). We show that statistical noise in a single Chandra PSF generates spurious dual peaks of the same separation (0 .″ 55±0 .″ 07 versus 0 .″ 6) and flux ratio (39% ± 9% versus 32% counts) as the purported dual AGN. With NuSTAR, we measure a Compton-thick source ({N}{{H}}=2.2+/- 0.4× {10}24 {{cm}}-2) with a large torus half-opening angle, {θ }{tor}={79}-19+1^\\circ which we postulate results from feedback from strong radio jets. This AGN shows a 2-10 keV intrinsic-to-observed flux ratio of ≈ 150 ({L}2-10\\{keV\\{int}}=2.6+/- 0.3× {10}43 {erg} {{{s}}}-1 versus {L}2-10\\{keV\\{observed}}=1.7+/- 0.2× {10}41 {erg} {{{s}}}-1). Using simulations, we find that even the deepest Chandra observations would severely underestimate the intrinsic luminosity of NGC 3393 above z\\gt 0.2, but would detect an unobscured AGN of this luminosity out to high redshift (z≈ 5).

  15. Thermal Comptonization and Disk Thermal Reprocessing in NGC3516

    NASA Technical Reports Server (NTRS)

    Chiang, James; Blaes, Omer; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We present an application of the thermal Comptonization/disk reprocessing model recently proposed by Zdziarski, Lubiniski, and Smith. We show that the absence of strong optical variations in the presence of strong concurrent X-ray variations, similar to those found by Hubble Space Telescope (HST)/Rossi X-Ray Timing Explorer (RXTE) monitoring observations of NGC 3516, can be explained by changing the geometry of the Comptonizing plasma rather than the accretion disk itself. The total X-ray luminosity of the Comptonizing plasma must decrease as its spatial extent increases. In contrast, the disk inner radius must be roughly fixed in order not to produce optical/ultraviolet color variations stronger than observed. By including emission due to internal viscous dissipation in the disk, we can roughly match the optical and X-ray flux levels and variability amplitudes seen from NGC 3516 during the HST/RXTE campaign.

  16. Compton Scattering from Bulk and Surface of Water

    NASA Astrophysics Data System (ADS)

    Wang, Wenjie; Kuzmenko, Ivan; Vaknin, David

    2014-03-01

    Elastic and Compton scattering at grazing angle X-ray incidence from water show distinct behaviors below and above the critical angle for total reflections suggesting surface restructuring of the water surface. Using X-ray synchrotron radiation in reflectivity mode, we collect the Thomson and Compton scattering signals with energy dispersive detector at various angles near the normal to surface as a function of the angle of incidence. Analysis of the ratio between the Thomson and Compton intensity above the critical angle (which mainly probes bulk water) is a constant as expected from incoherent scattering from single water molecule, whereas the signal from the surface shows strong angular dependence on the incident angle. Although we do not fully understand the phenomena, we attribute the observation to more organized water at the interface. Ames Laboratory, DOE under contract No. DE-AC02-07CH11358 and Advanced Photon Source, DOE under contract No. DE-AC02-06CH11357.

  17. G. E. M. Jauncey and the Compton Effect

    NASA Astrophysics Data System (ADS)

    Jenkin, John

    In late 1922 Arthur Holly Compton (1892-1962) discovered that an X-ray quantum of radiation undergoes a discrete change in wavelength when it experiences a billiard-ball collision with a single atomic electron, a phenomenon that became known as the Compton effect and for which he shared the Nobel Prize in Physics for 1927. But for more than five years before he made his discovery, Compton had analyzed X-ray scattering in terms of classical electrodynamics. I suggest that his colleague at Washington University in St. Louis, G. E. M. Jauncey (1888-1947), helped materially to persuade him to embrace the quantum interpretation of his X-ray scattering experiments.

  18. Inclusive and Exclusive Compton Processes in Quantum Chromodynamics

    SciTech Connect

    Ales Psaker

    2005-12-31

    In our work, we describe two types of Compton processes. As an example of an inclusive process, we consider the high-energy photoproduction of massive muon pairs off the nucleon. We analyze the process in the framework of the QCD parton model, in which the usual parton distributions emerge as a tool to describe the nucleon in terms of quark and gluonic degrees of freedom. To study its exclusive version, a new class of phenomenological functions is required, namely, generalized parton distributions. They can be considered as a generalization of the usual parton distributions measured in deeply inelastic lepton-nucleon scattering. Generalized parton distributions (GPDs) may be observed in hard exclusive reactions such as deeply virtual Compton scattering. We develop an extension of this particular process into the weak interaction sector. We also investigate a possible application of the GPD formalism to wide-angle real Compton scattering.

  19. Electronic structure of lanthanum sesquioxide: A Compton scattering study

    NASA Astrophysics Data System (ADS)

    Sharma, Sonu; Sahariya, Jagrati; Arora, Gunjan; Ahuja, B. L.

    2014-10-01

    We present the first-ever experimental and theoretical momentum densities of La2O3. The Compton line shape is measured using a 20 Ci 137Cs Compton spectrometer at an intermediate resolution with full width at half maximum of 0.34 a.u. The experimental Compton profile is compared with the theoretical electron momentum densities computed using linear combination of atomic orbitals (LCAO) method with density functional theory (DFT). It is seen that the generalized gradient approximation (GGA) within DFT reconciles better with the experiment than other DFT based approximations, validating the GGA approximation for rare-earth sesquioxides. The energy bands and density of states computed using LCAO calculations show its wide band gap nature which is in tune with the available reflectivity and photo-absorption data. In addition, Mulliken's population and charge density are also computed and discussed.

  20. Non-thermal shielding effects on the Compton scattering power in astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Shin, Dong-Soo; Jung, Young-Dae

    2015-10-01

    The non-thermal shielding effects on the inverse Compton scattering are investigated in astrophysical non-thermal Lorentzian plasmas. The inverse Compton power is obtained by the modified Compton scattering cross section in Lorentzian plasmas with the blackbody photon distribution. The total Compton power is also obtained by the Lorentzan distribution of plasmas. It is found that the influence of non-thermal character of the plasma suppresses the inverse Compton power in astrophysical Lorentzian plasmas. It is also found that the non-thermal effect on the inverse Compton power decreases with an increase of the temperature. In addition, the non-thermal effect on the total Compton power with Lorentzan plasmas increases in low-temperature photons and, however, decreases in intermediate-temperature photons with increasing Debye length. The variation of the total Compton power is also discussed.

  1. The scanning Compton polarimeter for the SLD experiment

    SciTech Connect

    Woods, M.; SLD Collaboration

    1996-10-01

    For the 1994/95 run of the SLD experiment at SLAC, a Compton polarimeter measured the luminosity-weighted electron beam polarization to be (77.2 {+-} 0.5)%. This excellent accuracy is achieved by measuring the rate asymmetry of Compton-scattered electrons near the kinematic endpoint. The polarimeter takes data continuously while the electron and positron beams are in collision and achieves a statistical precision of better than 1% in a three minute run. To calibrate the polarimeter and demonstrate its accuracy, many scans are frequently done. These include scans of the laser polarization, the detector position with respect to the kinematic edge, and the laser power.

  2. Compton profile study of ZrB2

    NASA Astrophysics Data System (ADS)

    Vyas, V.; Kumar, R.; Sharma, G.; Sharma, B. K.

    2013-06-01

    In this paper, we investigate the Compton profile of ZrB2. The theoretical Compton profile of ZrB2 is computed within the framework of density functional theory (DFT) based on linear combination of atomic orbitals (LCAO). To compare the spherically averaged theoretical values, the measurement on polycrystalline ZrB2 is performed using 59.54 keV gamma-rays emanating from an 241Am radioisotope. To estimate the charge transfer in ZrB2, ionic model based calculations have also been performed which suggest transfer of electron from Zr to B atoms.

  3. Imaging Performance of the Si/Ge Hybrid Compton Imager

    SciTech Connect

    Burks, M; Chivers, D; Cork, C; Cunningham, M; Fabris, L; Gunter, D; Hull, E; Lange, D; Manini, H; Mihailescu, L; Nelson, K; Niedermayr, T; Valentine, J; Vetter, K; Wright, D

    2005-11-10

    The point spread function (PSF) of a fully-instrumented silicon/germanium Compton telescope has been measured as a function of energy and angle. Overall, the resolution ranged from 3{sup o} to 4{sup o} FWHM over most of the energy range and field of view. The various contributions to the resolution have been quantified. These contributions include the energy uncertainty and position uncertainty of the detector; source energy; Doppler broadening; and the 1/r broadening characteristic of Compton back-projection. Furthermore, a distortion of the PSF is observed for sources imaged off-axis from the detector. These contributions are discussed and compared to theory and simulations.

  4. Relativistic dynamics of the Compton diffusion on a bound electron

    NASA Astrophysics Data System (ADS)

    Al Saleh, Salwa

    2016-05-01

    A covariant relativistic formalism for the electron-photon and nuclear dynamics is summarised making more accurate predictions in agreement with experiments for Compton scattering in shells with large electron binding energy. An exact solution for the Dirac equation for an electron in the nuclear Coulomb field is obtained, in order to write the relativistic dynamics for this QED process. This is a preparation for the calculation of the relativistic cross-section for Compton scattering on bound electrons, as a precision test for QED.

  5. A nonlinear plasma retroreflector for single pulse Compton backscattering

    NASA Astrophysics Data System (ADS)

    Palastro, J. P.; Kaganovich, D.; Gordon, D.; Hafizi, B.; Penano, J.; Helle, M.; Ting, A.

    2014-10-01

    A long laser pulse focused onto the edge of a gas jet nozzle launches a shock wave. The shock wave and gas jet flow collide forming a density spike. The leading edge of an incident ultrashort laser pulse ionizes the gas, while the bulk undergoes a nonlinear Poynting flux reversal from the ionized spike. The resulting counterpropagating field can Compton backscatter from electrons accelerated in the ultrashort pulse's wakefield, upshifting the frequency. We examine the reversal mechanism and properties of the counterpropagating field to optimize the Compton scattered radiation.

  6. Generalized parton distributions from deep virtual compton scattering at CLAS

    SciTech Connect

    Guidal, M.

    2010-04-24

    Here, we have analyzed the beam spin asymmetry and the longitudinally polarized target spin asymmetry of the Deep Virtual Compton Scattering process, recently measured by the Jefferson Lab CLAS collaboration. Our aim is to extract information about the Generalized Parton Distributions of the proton. By fitting these data, in a largely model-independent procedure, we are able to extract numerical values for the two Compton Form Factors $H_{Im}$ and $\\tilde{H}_{Im}$ with uncertainties, in average, of the order of 30%.

  7. Generalized parton distributions from deep virtual compton scattering at CLAS

    DOE PAGESBeta

    Guidal, M.

    2010-04-24

    Here, we have analyzed the beam spin asymmetry and the longitudinally polarized target spin asymmetry of the Deep Virtual Compton Scattering process, recently measured by the Jefferson Lab CLAS collaboration. Our aim is to extract information about the Generalized Parton Distributions of the proton. By fitting these data, in a largely model-independent procedure, we are able to extract numerical values for the two Compton Form Factorsmore » $$H_{Im}$$ and $$\\tilde{H}_{Im}$$ with uncertainties, in average, of the order of 30%.« less

  8. Spin and orbital magnetization loops obtained using magnetic Compton scattering

    SciTech Connect

    Itou, M.; Sakurai, Y.; Koizumi, A.

    2013-02-25

    We present an application of magnetic Compton scattering (MCS) to decompose a total magnetization loop into spin and orbital magnetization contributions. A spin magnetization loop of SmAl{sub 2} was measured by recording the intensity of magnetic Compton scattering as a function of applied magnetic field. Comparing the spin magnetization loop with the total magnetization one measured by a vibrating sample magnetometer, the orbital magnetization loop was obtained. The data display an anti-coupled behavior between the spin and orbital magnetizations and confirm that the orbital part dominates the magnetization.

  9. 15 CFR 730.6 - Control purposes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Control purposes. 730.6 Section 730.6... Control purposes. The export control provisions of the EAR are intended to serve the national security... carry out its international obligations. Some controls are designed to restrict access to dual use...

  10. 49 CFR 538.2 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL VEHICLES § 538.2 Purpose. The purpose of this part is to specify one of the criteria in 49 U.S.C. chapter 329 “Automobile Fuel Economy” for identifying dual-fueled passenger automobiles that are manufactured in model years 1993 through 2019. The...

  11. 49 CFR 538.2 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL VEHICLES § 538.2 Purpose. The purpose of this part is to specify one of the criteria in 49 U.S.C. chapter 329 “Automobile Fuel Economy” for identifying dual-fueled passenger automobiles that are manufactured in model years 1993 through 2019. The...

  12. 49 CFR 538.2 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL VEHICLES § 538.2 Purpose. The purpose of this part is to specify one of the criteria in 49 U.S.C. chapter 329 “Automobile Fuel Economy” for identifying dual-fueled passenger automobiles that are manufactured in model years 1993 through 2019. The...

  13. 49 CFR 538.2 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL VEHICLES § 538.2 Purpose. The purpose of this part is to specify one of the criteria in 49 U.S.C. chapter 329 “Automobile Fuel Economy” for identifying dual-fueled passenger automobiles that are manufactured in model years 1993 through 2019. The...

  14. 49 CFR 538.2 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL VEHICLES § 538.2 Purpose. The purpose of this part is to specify one of the criteria in 49 U.S.C. chapter 329 “Automobile Fuel Economy” for identifying dual-fueled passenger automobiles that are manufactured in model years 1993 through 2019. The...

  15. Analytical reconstruction formula for one-dimensional Compton camera

    SciTech Connect

    Basko, R.; Zeng, G.L.; Gullberg, G.T.

    1996-12-31

    The Compton camera has been proposed as an alternative to the Anger camera in SPECT. The advantage of the Compton camera is its high geometric efficiency due to electronic collimation. The Compton camera collects projections that are integrals over cone surfaces. Although some progress has been made toward image reconstruction from cone projections, at present no filtered backprojection algorithm exists. This paper investigates a simpler 2D version of the imaging problem. An analytical formula is developed for 2D reconstruction from data acquired by a 1D Compton camera that consists of two linear detectors, one behind the other. Coincidence photon detection allows the localization of the 2D source distribution to two lines in the shape of a {open_quotes}V{close_quotes} with the vertex on the front detector. A set of {open_quotes}V{close_quotes} projection data can be divided into subsets whose elements can be viewed as line-integrals of the original image added with its mirrored shear transformation. If the detector has infinite extent, reconstruction of the original image is possible using data from only one such subset. Computer simulations were performed to verify the newly developed algorithm.

  16. Measurement of Deeply Virtual Compton Scattering at HERMES

    SciTech Connect

    Kopytin, M.

    2005-10-06

    The measurement of azimuthal cross section asymmetries from deeply virtual Compton scattering on the proton and deuteron at HERMES is discussed. In particular results on the longitudinal target spin asymmetry as a function of the azimuthal angle and the Mandelstam t are given. The t-dependence of the asymmetry is compared with calculations based on generalized parton distribution models.

  17. New JLab/Hall A Deeply Virtual Compton Scattering results

    SciTech Connect

    Defurne, Maxime

    2015-08-01

    New data points for unpolarized Deeply Virtual Compton Scattering cross sections have been extracted from the E00-110 experiment at Q2=1.9 GeV2 effectively doubling the statistics available in the valence region. A careful study of systematic uncertainties has been performed.

  18. Compton-thick AGN in the 3XMM spectral survey

    NASA Astrophysics Data System (ADS)

    Georgantopoulos, I.; Corral, A.; Watson, M.; Rosen, S.

    2014-07-01

    In the framework of an ESA Prodex project, we have derived X-ray spectral fits for a large number (120,000) of 3XMM sources. We focus our study on the 120 square degrees that overlap with the SDSS survey. For about 1,100 AGN there are spectroscopic redsifts available. We automatically select candidate Compton-thick sources using simple spectral models. Various selection criteria are applied including a) a high equivalent width FeK line b) a flat spectrum with a photon index of 1.4 or lower at the 90% confidence level or at higher redshift an absorption turnover consistent with a column density of logNh=24. We find 30 candidate Compton-thick sources. More detailed spectral models are applied trying to secure the Compton-thick nature of these sources. We compare our findings with X-ray background synthesis models as well as with Compton-thick surveys in the COSMOS and XMM/CDFS areas.

  19. Compton scatter imaging: A tool for historical exploration.

    PubMed

    Harding, G; Harding, E

    2010-06-01

    This review discusses the principles and technological realisation of a technique, termed Compton scatter imaging (CSI), which is based on spatially resolved detection of Compton scattered X-rays. The applicational focus of this review is to objects of historical interest. Following a historical survey of CSI, a description is given of the major characteristics of Compton X-ray scatter. In particular back-scattered X-rays allow massive objects to be imaged, which would otherwise be too absorbing for the conventional transmission X-ray technique. The ComScan (an acronym for Compton scatter scanner) is a commercially available backscatter imaging system, which is discussed here in some detail. ComScan images from some artefacts of historical interest, namely a fresco, an Egyptian mummy and a mediaeval clasp are presented and their use in historical analysis is indicated. The utility of scientific and technical advance for not only exploring history, but also restoring it, is briefly discussed. PMID:20138773

  20. Analysis of a proposed Compton backscatter imaging technique

    NASA Astrophysics Data System (ADS)

    Hall, James M.; Jacoby, Barry A.

    1994-03-01

    One-sided imaging techniques are currently being used in nondestructive evaluation of surfaces and shallow subsurface structures. In this work we present both analytical calculations and detailed Monte Carlo simulations aimed at assessing the capability of a proposed Compton backscattering imaging technique designed to detect and characterize voids located several centimeters below the surface of a solid.

  1. Enhancement of Compton scattering by an effective coupling constant

    SciTech Connect

    Barbiellini, Bernardo; Nicolini, Piero

    2011-08-15

    A robust thermodynamic argument shows that a small reduction of the effective coupling constant {alpha} of QED greatly enhances the low-energy Compton-scattering cross section and that the Thomson scattering length is connected to a fundamental scale {lambda}. A discussion provides a possible quantum interpretation of this enormous sensitivity to changes in the effective coupling constant {alpha}.

  2. A Non-Relativistic Look at the Compton Effect

    ERIC Educational Resources Information Center

    Feller, Steve; Giri, Sandeep; Zakrasek, Nicholas; Affatigato, Mario

    2014-01-01

    In a usual modern physics class the Compton effect is used as the pedagogical model for introducing relativity into quantum effects. The shift in photon wavelengths is usually introduced and derived using special relativity. Indeed, this works well for explaining the effect. However, in the senior author's class one of the student coauthors…

  3. Models of unsaturated Compton disks around supermassive black holes

    NASA Technical Reports Server (NTRS)

    Liang, E. P. T.; Thompson, K. A.

    1979-01-01

    Two inverse-Compton disk models for the hard X-ray spectra of quasi-stellar objects and active galactic nuclei are studied and compared. One is a slightly generalized version of the Shapiro, Lightman and Eardley optically thin disk model, and the other is a conduction-stabilized Corona model. Observational distinctions between the two models are discussed.

  4. Scheme of Laser-Compton Gamma-ray Beamline in SAGA-LS

    SciTech Connect

    Ohgaki, H.; Koda, S.; Iwasaki, Y.; Takabayashi, Y.; Yoshida, K.; Tomimasu, T.; Uozumi, Y.; Ishibashi, K.

    2007-01-19

    A Laser-Compton Gamma-ray beamline in SAGA-LS has been planned to investigate the nuclear science and technology. The electron beam energy of 1.4 GeV and a small emittance are attractive to generate an intense and narrow energy bandwidth of Laser-Compton gamma-ray beam in MeV-region. Thus a design work for a gamma-ray beamline has been performed. Since the electron energy will be fixed, 1.4 GeV, for SR users, the laser wavelength should be variable to tune the energy of the gamma-ray beam. An OPO-DFG laser is one of candidate for this purpose. However, the laser power is not high enough to obtain the gamma-ray yield of -106 photons/s/100mA. The other method to tune the energy of gamma-ray beam is selecting the scattering angle by using a collimator and an absorber. However, simulation shows that the collimator-absorber scheme produce a poor bandwidth of the gamma-ray beam. An acceptable performance beam can be obtained by controlling the energy of electron beam at present stage.

  5. High-Accuracy Analysis of Compton Scattering in Chiral EFT: Proton and Neutron Polarisabilities

    NASA Astrophysics Data System (ADS)

    Griesshammer, Harald W.; Phillips, Daniel R.; McGovern, Judith A.

    2013-10-01

    Compton scattering from protons and neutrons provides important insight into the structure of the nucleon. A new extraction of the static electric and magnetic dipole polarisabilities αE 1 and βM 1 of the proton and neutron from all published elastic data below 300 MeV in Chiral Effective Field Theory shows that within the statistics-dominated errors, the proton and neutron polarisabilities are identical, i.e. no iso-spin breaking effects of the pion cloud are seen. Particular attention is paid to the precision and accuracy of each data set, and to an estimate of residual theoretical uncertainties. ChiEFT is ideal for that purpose since it provides a model-independent estimate of higher-order corrections and encodes the correct low-energy dynamics of QCD, including, for few-nucleon systems used to extract neutron polarisabilities, consistent nuclear currents, rescattering effects and wave functions. It therefore automatically respects the low-energy theorems for photon-nucleus scattering. The Δ (1232) as active degree of freedom is essential to realise the full power of the world's Compton data.Its parameters are constrained in the resonance region. A brief outlook is provided on what kind of future experiments can improve the database. Supported in part by UK STFC, DOE, NSF, and the Sino-German CRC 110.

  6. Wide angle Compton scattering on the proton: study of power suppressed corrections

    NASA Astrophysics Data System (ADS)

    Kivel, N.; Vanderhaeghen, M.

    2015-10-01

    We study the wide angle Compton scattering process on a proton within the soft-collinear factorization (SCET) framework. The main purpose of this work is to estimate the effect due to certain power suppressed corrections. We consider all possible kinematical power corrections and also include the subleading amplitudes describing the scattering with nucleon helicity flip. Under certain assumptions we present a leading-order factorization formula for these amplitudes which includes the hard- and soft-spectator contributions. We apply the formalism and perform a phenomenological analysis of the cross section and asymmetries in the wide angle Compton scattering on a proton. We assume that in the relevant kinematical region where -t,-u>2.5 GeV2 the dominant contribution is provided by the soft-spectator mechanism. The hard coefficient functions of the corresponding SCET operators are taken in the leading-order approximation. The analysis of existing cross section data shows that the contribution of the helicity-flip amplitudes to this observable is quite small and comparable with other expected theoretical uncertainties. We also show predictions for double polarization observables for which experimental information exists.

  7. A Practical Review of the Kompaneets Equation and its Application to Compton Scattering

    SciTech Connect

    D.G. Shirk

    2006-05-15

    In this study, we explore both inverse Compton and Compton scattering processes using the Chang and Cooper scheme to form a deterministic solution of the Kompaneets equation. We examine the individual terms of the Kompaneets equation and illustrate their effect on the equilibrium solution. We use two examples (a Gaussian line profile and a Planck profile) to illustrate the advective and diffusive properties of the Kompaneets operator. We also explore both inverse Compton scattering and Compton scattering, and discuss and illustrate the Bose-Einstein condensation feature of the Compton scattering spectrum.

  8. Measuring multimegavolt pulsed voltages using Compton-generated electrons

    NASA Astrophysics Data System (ADS)

    Swanekamp, S. B.; Weber, B. V.; Pereira, N. R.; Hinshelwood, D. D.; Stephanakis, S. J.; Young, F. C.

    2004-01-01

    The "Compton-Hall" voltmeter is a radiation-based voltage diagnostic that has been developed to measure voltages on high-power (TW) pulsed generators. The instrument collimates photons generated from bremsstrahlung produced in the diode onto an aluminum target to generate Compton-generated electrons. Permanent magnets bend the Compton electron orbits that escape the target toward a silicon pin diode detector. A GaAs photoconductive detector (PCD) detects photons that pass through the Compton target. The diode voltage is determined from the ratio of the electron dose in the pin detector to the x-ray dose in the PCD. The Integrated Tiger Series of electron-photon transport codes is used to determine the relationship between the measured dose ratio and the diode voltage. Variations in the electron beam's angle of incidence on the bremsstrahlung target produce changes in the shape of the photon spectrum that lead to large variations in the voltage inferred from the voltmeter. The voltage uncertainty is minimized when the voltmeter is fielded at an angle of 45° with respect to the bremsstrahlung target. In this position, the photon spectra for different angles of incidence all converge onto a single spectrum reducing the uncertainty in the voltage to less than 10% for voltages below 4 MV. Higher and lower voltages than the range considered in this article can be measured by adjusting the strength of the applied magnetic field or the position of the electron detector relative to the Compton target. The instrument was fielded on the Gamble II pulsed-power generator configured with a plasma opening switch. Measurements produced a time-dependent voltage with a peak (3.7 MV) that agrees with nuclear activation measurements and a pulse shape that is consistent with the measured radiation pulse shape.

  9. RXTE, Chandra, and XMM Spectroscopy of the Fe-K Lines and Compton Reflection in Type 1 AGN

    NASA Technical Reports Server (NTRS)

    Yaqoob, Tahir

    2004-01-01

    This award pertains to an RXTE observation of the Seyfert 1 galaxy Akn 120. The purpose of the observation was to measure the Fe-K emission line and the Compton reflection continuum with RXTE, simultaneously with Chandra and XMM. Such measurements can severely constrain accretion disk models of the central engine since the Fe-K line emission and Compton reflection are intimately related in terms of the physics of X-ray reprocessing in optically-thick matter. Akn 120 was selected for this study because it is amongst the brightest AGN in its class and has a particularly strong and apparently broad Fe-K emission line. The results could then also be used to lay the ground work for even higher resolution studies with Astro-E2. Unfortunately, the Chandra observation was not performed but a contemporaneous XMM observation was performed by another group of researchers. Those data recently became public and can be compared with the RXTE data. In addition, non-contemporaneous observations with other missions do still provide additional important constraints (for example any non-varying line or continuum emission components can be established and used to reject or preserve various model scenarios). We analyzed the RXTE data and found a strong Fe-K emission line (resolved even with the poor resolution of RXTE), and a strong Compton-reflection continuum (see Fig. l(a)). We found that the results of archival ASCA data on Akn 120 had not been published in the literature so we analyzed the ASCA data too, in order to compare with the new RXTE data. Fig. l(b) shows that the ASCA data also reveal a strong, broad FeK emission line (but the data are not sensitive to the Compton-reflection continuum). We compared our spectral fitting results for the RXTE and ASCA data with the results from XMM and from previous RXTE observations.

  10. Noise evaluation of Compton camera imaging for proton therapy.

    PubMed

    Ortega, P G; Torres-Espallardo, I; Cerutti, F; Ferrari, A; Gillam, J E; Lacasta, C; Llosá, G; Oliver, J F; Sala, P R; Solevi, P; Rafecas, M

    2015-03-01

    Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming γ energy is considered as a variable in the reconstruction inverse problem. Jointly with prompt gamma, secondary neutrons and scattered photons, not strongly correlated with the dose map, can also reach the imaging detector and produce false events. These events deteriorate the image quality. Also, high intensity beams can produce particle accumulation in the camera, which lead to an increase of random coincidences, meaning events which gather measurements from different incoming particles. The noise scenario is expected to be different if double or triple events are used, and consequently, the reconstructed images can be affected differently by spurious data. The aim of the present work is to study the effect of false events in the reconstructed image, evaluating their impact in the determination of the beam particle ranges. A simulation study that includes misidentified events (neutrons and random coincidences) in the final image of a Compton Telescope for PT monitoring is presented. The complete chain of

  11. Noise evaluation of Compton camera imaging for proton therapy

    NASA Astrophysics Data System (ADS)

    Ortega, P. G.; Torres-Espallardo, I.; Cerutti, F.; Ferrari, A.; Gillam, J. E.; Lacasta, C.; Llosá, G.; Oliver, J. F.; Sala, P. R.; Solevi, P.; Rafecas, M.

    2015-02-01

    Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming γ energy is considered as a variable in the reconstruction inverse problem. Jointly with prompt gamma, secondary neutrons and scattered photons, not strongly correlated with the dose map, can also reach the imaging detector and produce false events. These events deteriorate the image quality. Also, high intensity beams can produce particle accumulation in the camera, which lead to an increase of random coincidences, meaning events which gather measurements from different incoming particles. The noise scenario is expected to be different if double or triple events are used, and consequently, the reconstructed images can be affected differently by spurious data. The aim of the present work is to study the effect of false events in the reconstructed image, evaluating their impact in the determination of the beam particle ranges. A simulation study that includes misidentified events (neutrons and random coincidences) in the final image of a Compton Telescope for PT monitoring is presented. The complete chain of

  12. A prototype compton camera for in-vivo dosimetry of ion beam cancer irradiation

    SciTech Connect

    Kormoll, T.; Fiedler, F.; Golnik, C.; Heidel, K.; Kempe, M.; Schoene, S.; Sobiella, M.; Zuber, K.; Enghardt, W.

    2011-07-01

    Three-dimensional in-vivo dose monitoring of ion beam cancer irradiation can improve the quality of treatment. For this purpose we investigate the feasibility of imaging the single photon emissions due to nuclear reactions of projectiles with target nuclei (in-beam SPECT). A suitable imaging technique in the energy range of the emitted gamma rays is the Compton camera. A prototype based on prior simulations is currently under construction. Te system comprises two CdZnTe cross-strip detectors with steering grid and depth-of-interaction capability and one segmented LSO scintillator crystal with modified Anger light readout. We present the concept of the system including the front-end and DAQ electronics as well as first measurements. (authors)

  13. Development of Compton radiography of inertial confinement fusion implosionsa)

    NASA Astrophysics Data System (ADS)

    Tommasini, R.; Hatchett, S. P.; Hey, D. S.; Iglesias, C.; Izumi, N.; Koch, J. A.; Landen, O. L.; MacKinnon, A. J.; Sorce, C.; Delettrez, J. A.; Glebov, V. Yu.; Sangster, T. C.; Stoeckl, C.

    2011-05-01

    An important diagnostic tool for inertial confinement fusion will be time-resolved radiographic imaging of the dense cold fuel surrounding the hot spot. The measurement technique is based on point-projection radiography at photon energies from 60 to 200 keV where the Compton effect is the dominant contributor to the opacity of the fuel or pusher. We have successfully applied this novel Compton radiography technique to the study of the final compression of directly driven plastic capsules at the OMEGA facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The radiographs have a spatial and temporal resolution of ˜10 μm and ˜10 ps, respectively. A statistical accuracy of ˜0.5% in transmission per resolution element is achieved, allowing localized measurements of areal mass densities to 7% accuracy. The experimental results show 3D nonuniformities and lower than 1D expected areal densities attributed to drive asymmetries and hydroinstabilities.

  14. Inverse Compton Scattering from Laser Accelerated Quasi-Monoenergetic Electrons

    NASA Astrophysics Data System (ADS)

    Mori, Yoshitaka; Kuwabara, Hajime; Ishii, Katsuhiro; Hanayama, Ryohei; Kawashima, Toshiyuki; Kitagawa, Yoneyoshi

    2010-11-01

    The progress of the laser accelerator shows us the possible applications to the industries, such as an inspection source for soft materials like as human bodies, plants foods and medicines. The inverse Compton scattering will realize such a novel inspection system. We demonstrate for the fist time that the laser-accelerated mono-energetic electrons inversely scatter the same counter laser beam to the Compton X-ray emissions. A Ti:sapphire laser (500mJ width 150fs) is divided into two beams. Main beam is focused to an edge of a helium gasjet to accelerate electrons to 13 and 22 MeV monoenergies, which inversely scattered the counter laser beam into 6 and 11 keV X-ray emissions in agreement with that calculated from the obtained electron spectra. The scattering is within 30 deg. around the main beam direction.

  15. Simplified slow anti-coincidence circuit for Compton suppression systems.

    PubMed

    Al-Azmi, Darwish

    2008-08-01

    Slow coincidence circuits for the anti-coincidence measurements have been considered for use in Compton suppression technique. The simplified version of the slow circuit has been found to be fast enough, satisfactory and allows an easy system setup, particularly with the advantage of the automatic threshold setting of the low-level discrimination. A well-type NaI detector as the main detector surrounded by plastic guard detector has been arranged to investigate the performance of the Compton suppression spectrometer using the simplified slow circuit. The system has been tested to observe the improvement in the energy spectra for medium to high-energy gamma-ray photons from terrestrial and environmental samples. PMID:18222698

  16. Prototype TIGRE Compton γ-ray balloon-borne telescope

    NASA Astrophysics Data System (ADS)

    Bhattacharya, D.; O'Neill, T. J.; Akyüz, A.; Samimi, J.; Zych, A. D.

    2004-02-01

    A prototype balloon-borne telescope is being constructed for γ-ray observations in the MeV energy range. The Tracking and Imaging Gamma-Ray Experiment (TIGRE) uses multi-layers of thin silicon detectors to track and measure the energy losses of Compton recoil electrons. When combined with the direction and energy of the Compton scattered γ-ray a unique incident direction for each photon event is determined. This facilitates background rejection, improved sensitivity and image reconstruction. The converter/tracker also serves as an electron-positron pair detector for γ-rays up to 100 MeV. The initial continental US flight will be used to determine the sub-orbital atmospheric backgrounds and search for polarized γ-emission for the Crab pulsar. Longer southern hemisphere flights with an enhanced instrument will map out the 26Al emissions from the galactic center region.

  17. Comparison between electron and neutron Compton scattering studies

    NASA Astrophysics Data System (ADS)

    Moreh, Raymond; Finkelstein, Yacov; Vos, Maarten

    2015-05-01

    We compare two techniques: Electron Compton Scattering (ECS) and neutron Compton scattering (NCS) and show that using certain incident energies, both can measure the atomic kinetic energy of atoms in molecules and solids. The information obtained is related to the Doppler broadening of nuclear levels and is very useful for deducing the widths of excited levels in many nuclei in self absorption measurements. A comparison between the atomic kinetic energies measured by the two methods on the same samples is made. Some results are also compared with calculated atomic kinetic energies obtained using the harmonic approximation where the vibrational frequencies were taken from IR/Raman optical measurements. The advantages of the ECS method are emphasized.

  18. Development of Compton Radiography Diagnostics for Inertial Confinement Fusion Implosions

    SciTech Connect

    Tommasini, R; Hatchett, S P; Hey, D S; Izumi, N; Koch, J A; Landen, O L; Mackinnon, A J; Delettrez, J; Glebov, V; Stoeckl, C

    2010-11-16

    An important diagnostic tool for inertial confinement fusion will be time-resolved radiographic imaging of the dense cold fuel surrounding the hot spot. The measurement technique is based on point-projection radiography at photon energies from 60-200 keV where the Compton effect is the dominant contributor to the opacity of the fuel or pusher. We have successfully applied this novel Compton Radiography technique to the study of the final compression of directly driven plastic capsules at the OMEGA facility. The radiographs have a spatial and temporal resolution of {approx}10 {micro}m and {approx}10ps, respectively. A statistical accuracy of {approx}0.5% in transmission per resolution element is achieved, allowing localized measurements of areal mass densities to 7% accuracy. The experimental results show 3D non-uniformities and lower than 1D expected areal densities attributed to drive asymmetries and hydroinstabilities.

  19. Compton profile study of polycrystalline ZnBr{sub 2}

    SciTech Connect

    Dhaka, M. S.; Sharma, G.; Mishra, M. C.; Kothari, R. K.; Sharma, B. K.

    2010-12-01

    The first ever Compton profile study of polycrystalline ZnBr{sub 2} is presented in this paper. The measurement of polycrystalline sample of ZnBr{sub 2} is performed using 59.54 keV gamma-rays emanating from an {sup 241}Am radioisotope. Theoretical calculations are performed following the Ionic model calculations for a number of configurations Zn{sup +x}Br{sub 2}{sup -x/2}(0.0{<=}x{<=}2.0 in step of 0.5) utilizing free atom profiles. The ionic model suggest transfer of 2.0 electrons from 4 s state of Zn to 4 p state of two Br atoms. The autocorrelation function B(z) is also derived from experiment and the most favoured ionic valence Compton profiles.

  20. Electronic properties and Compton scattering studies of monoclinic tungsten dioxide

    NASA Astrophysics Data System (ADS)

    Heda, N. L.; Ahuja, Ushma

    2015-01-01

    We present the first ever Compton profile measurement of WO2 using a 20 Ci 137Cs γ-ray source. The experimental data have been used to test different approximations of density functional theory in linear combination of atomic orbitals (LCAO) scheme. It is found that theoretical Compton profile deduced using generalized gradient approximation (GGA) gives a better agreement than local density approximation and second order GGA. The computed energy bands, density of states and Mulliken's populations (MP) data confirm a metal-like behavior of WO2. The electronic properties calculated using LCAO approach are also compared with those obtained using full potential linearized augmented plane wave method. The nature of bonding in WO2 is also compared with isoelectronic WX2 (X=S, Se) compounds in terms of equal-valence-electron-density profiles and MP data, which suggest an increase in ionic character in the order WSe2→WS2→WO2.

  1. External inverse-Compton Emission from Blazar Jets

    SciTech Connect

    Carson, Jennifer E.; Chiang, James; /SLAC

    2007-09-25

    According to leptonic models for the high-energy emission from blazars, relativistic electrons in the inner jets inverse-Compton scatter photons from a variety of sources. Seed photons are certainly introduced via the synchrotron process from the electrons themselves, but external sources of seed photons may also be present. In this paper, we present detailed derivations of the equations describing external inverse-Compton scattering from two sources of seed photons: direct emission from the accretion disk, and accretion disk photons that have scattered off the broad line region. For each source, we derive the seed photon spectrum incident on the jet, the single electron energy loss rate, and the emitted photon spectrum.

  2. Design and fabrication of endoscope-type Compton camera

    NASA Astrophysics Data System (ADS)

    Nakamura, Y.; Shimazoe, K.; Takahashi, H.

    2013-12-01

    We are constructing an endoscope coupled with a Compton camera to intra-operatively inspect early stage cancer and metastatic lymph node (5 mm-10 mm). The radiation imaging system is composed of pixelated semiconductor detectors, which are Si array and CdTe array, whose sizes are less than 10 mm×10 mm, and a digital signal-processing unit with ASIC and FPGA and reconstruction algorithm using spherical harmonics that can compute in real time. In this paper, we show some simulation results on the performance of the proposed prototype detector using EGS5, Monte Carlo simulation code. The FWHM of 1 mm spatial resolution for an object located 10 mm away from the detector surface and the intrinsic efficiency of 0.05% were observed. Imaging and data acquisition time to take fine images are just 1 min. It therefore can be considered that the endoscopic Compton camera is useful for intra-operative inspection.

  3. COMPACT, TUNABLE COMPTON SCATTERING GAMMA-RAY SOURCES

    SciTech Connect

    Hartemann, F V; Albert, F; Anderson, G G; Anderson, S G; Bayramian, A J; Betts, S M; Chu, T S; Cross, R R; Ebbers, C A; Fisher, S E; Gibson, D J; Ladran, A S; Marsh, R A; Messerly, M J; O'Neill, K L; Semenov, V A; Shverdin, M Y; Siders, C W; McNabb, D P; Barty, C J; Vlieks, A E; Jongewaard, E N; Tantawi, S G; Raubenheimer, T O

    2009-08-20

    Recent progress in accelerator physics and laser technology have enabled the development of a new class of gamma-ray light sources based on Compton scattering between a high-brightness, relativistic electron beam and a high intensity laser pulse produced via chirped-pulse amplification (CPA). A precision, tunable gamma-ray source driven by a compact, high-gradient X-band linac is currently under development at LLNL. High-brightness, relativistic electron bunches produced by the linac interact with a Joule-class, 10 ps laser pulse to generate tunable {gamma}-rays in the 0.5-2.5 MeV photon energy range via Compton scattering. The source will be used to excite nuclear resonance fluorescence lines in various isotopes; applications include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status are presented.

  4. Precise polarization measurements via detection of compton scattered electrons

    SciTech Connect

    Tvaskis, Vladas; Dutta, Dipangkar; Gaskell, David J.; Narayan, Amrendra

    2014-01-01

    The Qweak experiment at Jefferson Lab aims to make a 4% measurement of the parity-violating asymmetry in elastic scattering at very low Q{sup 2} of a longitudinally polarized electron beam off a proton target. One of the dominant experimental systematic uncertainties in Qweak will result from determining the beam polarization. A new Compton polarimeter was installed in the fall of 2010 to provide a non-invasive and continuous monitoring of the electron beam polarization in Hall C at Jefferson Lab. The Compton-scattered electrons are detected in four planes of diamond micro-strip detectors. We have achieved the design goals of <1% statistical uncertainty per hour and expect to achieve <1% systematic uncertainty.

  5. Development of Compton radiography of inertial confinement fusion implosions

    SciTech Connect

    Tommasini, R.; Hatchett, S. P.; Hey, D. S.; Iglesias, C.; Izumi, N.; Koch, J. A.; Landen, O. L.; MacKinnon, A. J.; Sorce, C.; Delettrez, J. A.; Glebov, V. Yu.; Sangster, T. C.; Stoeckl, C.

    2011-05-15

    An important diagnostic tool for inertial confinement fusion will be time-resolved radiographic imaging of the dense cold fuel surrounding the hot spot. The measurement technique is based on point-projection radiography at photon energies from 60 to 200 keV where the Compton effect is the dominant contributor to the opacity of the fuel or pusher. We have successfully applied this novel Compton radiography technique to the study of the final compression of directly driven plastic capsules at the OMEGA facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The radiographs have a spatial and temporal resolution of {approx}10 {mu}m and {approx}10 ps, respectively. A statistical accuracy of {approx}0.5% in transmission per resolution element is achieved, allowing localized measurements of areal mass densities to 7% accuracy. The experimental results show 3D nonuniformities and lower than 1D expected areal densities attributed to drive asymmetries and hydroinstabilities.

  6. Compact Laser-Compton X-ray Source Development

    NASA Astrophysics Data System (ADS)

    Yeh, Po-Chun

    The state-of-the-art X-ray source based on inverse-Compton scattering between a high-brightness, relativistic electron beam produced by an X-band RF accelerator and a high-intensity laser pulse generated by chirped-pulse amplification (CPA) has been carried out by our research team at Lawrence Livermore National Laboratory. This system is called "Compact Laser-Compton X-ray Source". The applications include nuclear resonance fluorescence, medical imaging and therapy, and nuclear waste imaging and assay. One of the key factors in this system is how we know the interaction happened in the vacuum chamber, which is the spectrometer of electron beams. The other key factor is the interaction after the spectrometer, which is the outgoing X-ray. In this thesis, the work in the simulation for the result of the interaction between electrons and the laser, the calibration of spectrometer, and laser focus characterization are discussed.

  7. A nonlinear plasma retroreflector for single pulse Compton backscattering

    NASA Astrophysics Data System (ADS)

    Palastro, J. P.; Kaganovich, D.; Gordon, D.; Hafizi, B.; Helle, M.; Penano, J.; Ting, A.

    2015-02-01

    Compton scattered x-rays can be generated using a configuration consisting of a single ultrashort laser pulse and a shaped gas target. Upon ionization the gas target serves as a plasma mirror that reflects the incident pulse providing a counter-propagating electromagnetic wiggler. While plasma mirrors are often conceived as linear Fresnel reflectors, we demonstrate that for high-intensity, ultrashort laser pulses the reflection results from two distinct nonlinear mechanisms. At lower densities, the reflection arises from the emission of an electromagnetic pulse during the saturation of the absolute Raman instability at the quarter critical surface. At higher densities the reflection of the pulse from the critical surface sets up a density fluctuation that acts as a Bragg-like reflector. These mechanisms, occurring in a non-perturbative regime of laser-plasma interactions, are examined numerically in order to characterize the Compton scattered radiation.

  8. Characteristics of final particles in multiple Compton backscattering process

    NASA Astrophysics Data System (ADS)

    Potylitsyn, A.; Kol‘chuzhkin, A.

    2013-08-01

    An electron passing through a counter propagating intense laser beam can interact with a few laser photons with emission of a hard photon in each collision event. In contrast with the well-known nonlinear Compton backscattering process the above mentioned process may be named as multiple Compton backscattering process (MCBS). In this paper we have investigated the evolution of the electron energy distribution during MCBS process using Monte-Carlo (M-C) simulation. The main characteristics of such a distribution as mean energy and variance obtained by M-C technique were compared with analytical solutions of kinetic equations. We found the kinematic region where the analytical solutions are applicable with a good accuracy. A photon spectrum, even for the case when each electron emits one photon (in average) differs significantly from that described by the Klein-Nishina formula.

  9. Low-Intensity Nonlinear Spectral Effects in Compton Scattering

    SciTech Connect

    Hartemann, F V; Albert, F; Siders, C W; Barty, C P

    2010-02-23

    Nonlinear effects are known to occur in Compton scattering light sources, when the laser normalized 4-potential, A = e{radical}-A{sub {mu}}A{sup {mu}}/m{sub 0}c approaches unity. In this letter, it is shown that nonlinear spectral features can appear at arbitrarily low values of A, if the fractional bandwidth of the laser pulse, {Delta}{phi}{sup -1}, is sufficiently small to satisfy A{sup 2} {Delta}{phi} {approx_equal} 1. A three dimensional analysis, based on a local plane-wave, slow-varying envelope approximation, enables the study of these effects for realistic interactions between an electron beam and a laser pulse, and their influence on high-precision Compton scattering light sources.

  10. Hybrid Compton camera/coded aperture imaging system

    DOEpatents

    Mihailescu, Lucian; Vetter, Kai M.

    2012-04-10

    A system in one embodiment includes an array of radiation detectors; and an array of imagers positioned behind the array of detectors relative to an expected trajectory of incoming radiation. A method in another embodiment includes detecting incoming radiation with an array of radiation detectors; detecting the incoming radiation with an array of imagers positioned behind the array of detectors relative to a trajectory of the incoming radiation; and performing at least one of Compton imaging using at least the imagers and coded aperture imaging using at least the imagers. A method in yet another embodiment includes detecting incoming radiation with an array of imagers positioned behind an array of detectors relative to a trajectory of the incoming radiation; and performing Compton imaging using at least the imagers.

  11. A dual-energy transmission detector for vehicle scanning using wavelength-shifting fibers

    NASA Astrophysics Data System (ADS)

    Van Liew, Seth; Zhang, Ming

    2014-09-01

    A new dual energy detector for vehicle scanning is presented. The system is composed of a three-sided Compton backscatter imaging system utilizing flying-spot x-rays concurrent with a transmission detector using the same x-ray beam. This detector is under the vehicle and is thin enough to be driven over with a modest bump which does not impede vehicle trac. It uses sheet scintillator with wavelength-shifting fibers as light pipes. Results are presented on steel penetration, calibration procedures and issues, and dual energy performance. The system's dose is low enough for scanning people, including passenger vehicles.

  12. Detection of detachments and inhomogeneities in frescos by Compton scattering

    NASA Astrophysics Data System (ADS)

    Castellano, A.; Cesareo, R.; Buccolieri, G.; Donativi, M.; Palamà, F.; Quarta, S.; De Nunzio, G.; Brunetti, A.; Marabelli, M.; Santamaria, U.

    2005-07-01

    A mobile instrument has been developed for the detection and mapping of detachments in frescos by using Compton back scattered photons. The instrument is mainly composed of a high energy X-ray tube, an X-ray detection system and a translation table. The instrument was first applied to samples simulating various detachment situations, and then transferred to the Vatican Museum to detect detachments and inhomogeneities in the stanza di Eliodoro, one of the "Raphael's stanze".

  13. The Compton-Schwarzschild correspondence from extended de Broglie relations

    NASA Astrophysics Data System (ADS)

    Lake, Matthew J.; Carr, Bernard

    2015-11-01

    The Compton wavelength gives the minimum radius within which the mass of a particle may be localized due to quantum effects, while the Schwarzschild radius gives the maximum radius within which the mass of a black hole may be localized due to classial gravity. In a mass-radius diagram, the two lines intersect near the Planck point ( l P , m P ), where quantum gravity effects become significant. Since canonical (non-gravitational) quantum mechanics is based on the concept of wave-particle duality, encapsulated in the de Broglie relations, these relations should break down near ( l P , m P ). It is unclear what physical interpretation can be given to quantum particles with energy E ≫ m P c 2, since they correspond to wavelengths λ ≪ l P or time periods τ ≪ t P in the standard theory. We therefore propose a correction to the standard de Broglie relations, which gives rise to a modified Schrödinger equation and a modified expression for the Compton wavelength, which may be extended into the region E ≫ m P c 2. For the proposed modification, we recover the expression for the Schwarzschild radius for E ≫ m P c 2 and the usual Compton formula for E ≪ m P c 2. The sign of the inequality obtained from the uncertainty principle reverses at m ≈ m P , so that the Compton wavelength and event horizon size may be interpreted as minimum and maximum radii, respectively. We interpret the additional terms in the modified de Broglie relations as representing the self-gravitation of the wave packet.

  14. Method and apparatus for measuring lung density by Compton backscattering

    DOEpatents

    Loo, Billy W.; Goulding, Frederick S.

    1991-01-01

    The density of the lung of a patient suffering from pulmonary edema is monitored by irradiating the lung by a single collimated beam of monochromatic photons and measuring the energies of photons Compton backscattered from the lung by a single high-resolution, high-purity germanium detector. A compact system geometry and a unique data extraction scheme are utilized to monimize systematic errors due to the presence of the chestwall and multiple scattering.

  15. Method and apparatus for measuring lung density by Compton backscattering

    DOEpatents

    Loo, B.W.; Goulding, F.S.

    1988-03-11

    The density of the lung of a patient suffering from pulmonary edema is monitored by irradiating the lung by a single collimated beam of monochromatic photons and measuring the energies of photons compton back-scattered from the lung by a single high-resolution, high-purity germanium detector. A compact system geometry and a unique data extraction scheme are utilized to minimize systematic errors due to the presence of the chestwall and multiple scattering. 11 figs., 1 tab.

  16. The electromagnetic calorimeter in JLab Real Compton Scattering Experiment

    SciTech Connect

    Albert Shahinyan; Eugene Chudakov; A. Danagoulian; P. Degtyarenko; K. Egiyan; V. Gorbenko; J. Hines; E. Hovhannisyan; Ch. Hyde; C.W. de Jager; A. Ketikyan; V. Mamyan; R. Michaels; A.M. Nathan; V. Nelyubin; I. Rachek; M. Roedelbrom; A. Petrosyan; R. Pomatsalyuk; V. Popov; J. Segal; Yu. Shestakov; J. Templon; H. Voskanyan; B. Wojtsekhowski

    2007-04-16

    A hodoscope calorimeter comprising of 704 lead-glass blocks is described. The calorimeter was constructed for use in the JLab Real Compton Scattering experiment. The detector provides a measurement of the coordinates and the energy of scattered photons in the GeV energy range with resolutions of 5 mm and 6\\%/$\\sqrt{E_\\gamma \\, [GeV]}$, respectively. Design features and performance parameters during the experiment are presented.

  17. Compton-like polariton scattering in hyperbolic metamaterials.

    PubMed

    Iorsh, Ivan V; Poddubny, Alexander N; Ginzburg, Pavel; Belov, Pavel A; Kivshar, Yuri S

    2015-05-01

    We study the scattering of polaritons by free electrons in hyperbolic photonic media and demonstrate that the unconventional dispersion and high local density of states of electromagnetic modes in composite media with hyperbolic dispersion can lead to a giant Compton-like shift and dramatic enhancement of the scattering cross section. We develop a universal approach to study multiphoton processes in nanostructured media and derive the intensity spectrum of the scattered radiation for realistic metamaterial structures. PMID:26001008

  18. Resonant Compton scattering and gamma-ray burst continuum spectra

    NASA Technical Reports Server (NTRS)

    Baring, M. G.

    1995-01-01

    The Thomson limit of resonant inverse Compton scattering in the strong magnetic fields of neutron stars is considered as a mechanism for producing gamma-ray burst continuum spectra. Photon production spectra and electron cooling rates are presented using the full magnetic Thomson cross-section. Model emission spectra are obtained as self-consistent solutions of a set of photon and electron kinetic equations, displaying spectral breaks and other structure at gamma-ray energies.

  19. Measuring Flash X-Ray Spectra with a Compton Spectrometer

    NASA Astrophysics Data System (ADS)

    Gehring, Amanda; Espy, Michelle; Haines, Todd; Hunter, James; King, Nick; Merrill, Frank; Sedillo, Robert; Urbaitis, Algis; Volegov, Petr

    2014-09-01

    The determination of the x-ray energy spectra of flash radiographic sources is difficult due to the short nature of the pulses (~50 ns). Recently, a Compton spectrometer has been refurbished and investigated as a potential device for conducting these measurements. The spectrometer was originally designed and characterized by Morgan et al.. The spectrometer consists of a 300 kg neodymium-iron magnet and measures spectra in the <1 MeV to 20 MeV energy range. In this apparatus, the incoming x-rays are collimated into a narrow beam before encountering a converter foil. Compton electrons are ejected and collimated so that the forward-directed electrons enter the magnetic field region of the device. The position of the electrons on the magnet focal plane is a function of their energy, allowing the x-ray spectrum to be reconstructed. Recent energy calibration measurements and the spectrum reconstruction of a Bremsstrahlung source will be presented. The determination of the x-ray energy spectra of flash radiographic sources is difficult due to the short nature of the pulses (~50 ns). Recently, a Compton spectrometer has been refurbished and investigated as a potential device for conducting these measurements. The spectrometer was originally designed and characterized by Morgan et al.. The spectrometer consists of a 300 kg neodymium-iron magnet and measures spectra in the <1 MeV to 20 MeV energy range. In this apparatus, the incoming x-rays are collimated into a narrow beam before encountering a converter foil. Compton electrons are ejected and collimated so that the forward-directed electrons enter the magnetic field region of the device. The position of the electrons on the magnet focal plane is a function of their energy, allowing the x-ray spectrum to be reconstructed. Recent energy calibration measurements and the spectrum reconstruction of a Bremsstrahlung source will be presented. LA-UR-14-23602.

  20. Development of Compton radiography using high-Z backlighters produced by ultra-intense lasers

    SciTech Connect

    Tommasini, Riccardo; Park, Hye-Sook; Patel, Prav; Maddox, Brian; Le Pape, Sebastien; Hatchett, Stephen P.; Remington, Bruce A.; Key, Michael H.; Izumi, Nobuhiko; Tabak, Max; Koch, Jeffrey A.; Landen, Otto L.; Hey, Dan; MacKinnon, Andy; Seely, John; Holland, Glenn; Hudson, Larry; Szabo, Csilla

    2007-08-02

    High-energy x-ray backlighters will be valuable for radiography experiments at the National Ignition Facility (NIF), and for radiography of imploded inertial confinement fusion cores using Compton scattering to observe cold, dense plasma. Key considerations are the available backlight brightness, and the backlight size. To quantify these parameters we have characterized the emission from low- and high-Z planar foils irradiated by intense picosecond and femtosecond laser pulses from the TITAN laser facility at Lawrence Livermore National Laboratory. Spectra generated by a sequence of elements from Mo to Pb, spanning the x-ray energy range from 17 keV to 75 keV, have been recorded using a Charged Coupled Device (CCD) in single hit regime and a Dual Crystal Spectrometer (DCS). High-resolution point-projection 2D radiographs have also been recorded on Fuji BaFBr:Eu2 image plates using calibrated resolution grids. We discuss the results in light of the requirements for applications at NIF.

  1. SPECT Compton-scattering correction by analysis of energy spectra.

    PubMed

    Koral, K F; Wang, X Q; Rogers, W L; Clinthorne, N H; Wang, X H

    1988-02-01

    The hypothesis that energy spectra at individual spatial locations in single photon emission computed tomographic projection images can be analyzed to separate the Compton-scattered component from the unscattered component is tested indirectly. An axially symmetric phantom consisting of a cylinder with a sphere is imaged with either the cylinder or the sphere containing 99mTc. An iterative peak-erosion algorithm and a fitting algorithm are given and employed to analyze the acquired spectra. Adequate separation into an unscattered component and a Compton-scattered component is judged on the basis of filtered-backprojection reconstruction of corrected projections. In the reconstructions, attenuation correction is based on the known geometry and the total attenuation cross section for water. An independent test of the accuracy of separation is not made. For both algorithms, reconstructed slices for the cold-sphere, hot-surround phantom have the correct shape as confirmed by simulation results that take into account the measured dependence of system resolution on depth. For the inverse phantom, a hot sphere in a cold surround, quantitative results with the fitting algorithm are accurate but with a particular number of iterations of the erosion algorithm are less good. (A greater number of iterations would improve the 26% error with the algorithm, however.) These preliminary results encourage us to believe that a method for correcting for Compton-scattering in a wide variety of objects can be found, thus helping to achieve quantitative SPECT. PMID:3258023

  2. Non-linear Compton Scattering in Short Laser Pulses

    NASA Astrophysics Data System (ADS)

    Krajewska, Katarzyna; Kamiński, Jerzy

    2012-06-01

    The generation of short X-ray laser pulses attracts a great deal of attention. One of mechanisms to achieve this goal is the non-linear Compton scattering at very high laser powers. The majority of previous works on the non-linear Compton scattering have been devoted to the case when the incident laser field is treated as a monochromatic plane wave. There is, however, recent interest in analyzing the effect of a pulsed laser field on the non-linear Compton scattering [1-4]. We study the process for different durations of the incident laser pulse and compare it with the results for both a plane wave laser field and a laser pulse train. [4pt] [1] M. Boca and V. Florescu, Phys. Rev. A 80, 053403 (2009).[0pt] [2] M. Boca and V. Florescu, Eur. Phys. J. D 61, 446 (2011).[0pt] [3] D. Seipt and B. Kämpfer, Phys. Rev. A 83, 022101 (2011).[0pt] [4] F. Mackenroth and A. Di Piazza, Phys. Rev. A 83, 032106 (2011).

  3. The role of Compton scattering in scinti-mammography

    SciTech Connect

    Pani, R.; Scopinaro, F.; Pergola, A.

    1996-12-31

    Functional breast imaging using {sup 99m}Tc MIBI is showing that this technique is able to detect cancer with more than 90% specificity. Using a dedicated gamma camera, with the breast under compression, i.e. in similar conditions of mammography, the detection of sub-centimeter cancers can be improved. A number of factors affects the detection of small cancers as: thickness of the breast, distance between tumor and collimator, cardiac activity. Radioactivity emitted from the body can obscure the breast activity mainly due to the large difference on radioactivity concentration. In this work we analyze the intensity and the energy distribution of Compton scattering coming from the breast by a Germanium detector and by a dedicated imager with a small FOV placed in a geometrical condition similar to mammography. In vivo measurements were performed in patients with a breast cancer ranging between 8 mm and 15 mm. Intensity of Compton scattering from 4 to 10 times greater than full energy peak events resulted. Measurements were compared with ones obtained by a phantom simulating the breast without chest activity demonstrating how large is the Compton contribution from the chest.

  4. Unsaturated Comptonization of isotropic photon spectra by relativistic electrons

    NASA Technical Reports Server (NTRS)

    Loeb, Abraham; Mckee, Christopher F.; Lahav, Ofer

    1991-01-01

    The multiple scattering approach for evaluating the transformation of an arbitrary soft photon spectrum as a result of unsaturated Compton scatterings in a medium of relativistic electrons is explored. The medium is assumed to be infinite and spatially homogeneous but may be time-dependent, and the photons are isotropic. It is shown that the distortion of a radiation spectrum can be described analytically in a compact form using the Fourier transform of the single-scattering probability. In the nonrelativistic case, the validity of the known analytical results derived from the Kompaneets (1957) equation is extended to arbitrary electron distribution functions and photon spectra. For relativistic electrons, simple expressions are obtained for the total energy that is transferred from the electrons to the photons and for the distortion in the Rayleigh-Jeans regime of a blackbody spectrum. It is demonstrated that the treatment applies to Comptonization in a relativistic jet and that Comptonization of very soft trapped photons by semirelativistic electrons in an expanding medium leads naturally to a log Gaussian spectrum, of the form observed in blazars.

  5. "Stereo Compton cameras" for the 3-D localization of radioisotopes

    NASA Astrophysics Data System (ADS)

    Takeuchi, K.; Kataoka, J.; Nishiyama, T.; Fujita, T.; Kishimoto, A.; Ohsuka, S.; Nakamura, S.; Adachi, S.; Hirayanagi, M.; Uchiyama, T.; Ishikawa, Y.; Kato, T.

    2014-11-01

    The Compton camera is a viable and convenient tool used to visualize the distribution of radioactive isotopes that emit gamma rays. After the nuclear disaster in Fukushima in 2011, there is a particularly urgent need to develop "gamma cameras", which can visualize the distribution of such radioisotopes. In response, we propose a portable Compton camera, which comprises 3-D position-sensitive GAGG scintillators coupled with thin monolithic MPPC arrays. The pulse-height ratio of two MPPC-arrays allocated at both ends of the scintillator block determines the depth of interaction (DOI), which dramatically improves the position resolution of the scintillation detectors. We report on the detailed optimization of the detector design, based on Geant4 simulation. The results indicate that detection efficiency reaches up to 0.54%, or more than 10 times that of other cameras being tested in Fukushima, along with a moderate angular resolution of 8.1° (FWHM). By applying the triangular surveying method, we also propose a new concept for the stereo measurement of gamma rays by using two Compton cameras, thus enabling the 3-D positional measurement of radioactive isotopes for the first time. From one point source simulation data, we ensured that the source position and the distance to the same could be determined typically to within 2 meters' accuracy and we also confirmed that more than two sources are clearly separated by the event selection from two point sources of simulation data.

  6. LASER-ELECTRON COMPTON INTERACTION IN PLASMA CHANNELS

    SciTech Connect

    POGORELSKY,I.V.

    1998-10-01

    A concept of high intensity femtosecond laser synchrotron source (LSS) is based on Compton backscattering of focused electron and laser beams. The short Rayleigh length of the focused laser beam limits the length of interaction to a few picoseconds. However, the technology of the high repetition rate high-average power picosecond lasers required for high put through LSS applications is not developed yet. Another problem associated with the picosecond laser pulses is undesirable nonlinear effects occurring when the laser photons are concentrated in a short time interval. To avoid the nonlinear Compton scattering, the laser beam has to be split, and the required hard radiation flux is accumulated over a number of consecutive interactions that complicates the LSS design. In order to relieve the technological constraints and achieve a practically feasible high-power laser synchrotron source, we propose to confine the laser-electron interaction region in the extended plasma channel. This approach permits to use nanosecond laser pulses instead of the picosecond pulses. That helps to avoid the nonlinear Compton scattering regime and allows to utilize already existing technology of the high-repetition rate TEA CO{sub 2} lasers operating at the atmospheric pressure. We demonstrate the advantages of the channeled LSS approach by the example of the prospective polarized positron source for Japan Linear Collider.

  7. Compton scattering off elementary spin (3/2) particles

    SciTech Connect

    Delgado-Acosta, E. G.; Napsuciale, M.

    2009-09-01

    We calculate Compton scattering off an elementary spin (3/2) particle in a recently proposed framework for the description of high spin fields based on the projection onto eigensubspaces of the Casimir operators of the Poincare group. We also calculate this process in the conventional Rarita-Schwinger formalism. Both formalisms yield the correct Thomson limit but the predictions for the angular distribution and total cross section differ beyond this point. We point out that the average squared amplitudes in the forward direction for Compton scattering off targets with spin s=0, (1/2), 1 are energy independent and have the common value 4e{sup 4}. As a consequence, in the rest frame of the particle the differential cross section for Compton scattering in the forward direction is energy independent and coincides with the classical squared radius. We show that these properties are also satisfied by a spin (3/2) target in the Poincare projector formalism but not by the Rarita-Schwinger spin (3/2) particle.

  8. Compton DIV: Using a Compton-Based Gamma-Ray Imager for Design Information Verification of Uranium Enrichment Plants

    SciTech Connect

    Burks, M; Verbeke, J; Dougan, A; Wang, T; Decman, D

    2009-07-04

    A feasibility study has been performed to determine the potential usefulness of Compton imaging as a tool for design information verification (DIV) of uranium enrichment plants. Compton imaging is a method of gamma-ray imaging capable of imaging with a 360-degree field of view over a broad range of energies. These systems can image a room (with a time span on the order of one hour) and return a picture of the distribution and composition of radioactive material in that room. The effectiveness of Compton imaging depends on the sensitivity and resolution of the instrument as well the strength and energy of the radioactive material to be imaged. This study combined measurements and simulations to examine the specific issue of UF{sub 6} gas flow in pipes, at various enrichment levels, as well as hold-up resulting from the accumulation of enriched material in those pipes. It was found that current generation imagers could image pipes carrying UF{sub 6} in less than one hour at moderate to high enrichment. Pipes with low enriched gas would require more time. It was also found that hold-up was more amenable to this technique and could be imaged in gram quantities in a fraction of an hour. another questions arises regarding the ability to separately image two pipes spaced closely together. This depends on the capabilities of the instrument in question. These results are described in detail. In addition, suggestions are given as to how to develop Compton imaging as a tool for DIV.

  9. Stochastic image reconstruction for a dual-particle imaging system

    NASA Astrophysics Data System (ADS)

    Hamel, M. C.; Polack, J. K.; Poitrasson-Rivière, A.; Flaska, M.; Clarke, S. D.; Pozzi, S. A.; Tomanin, A.; Peerani, P.

    2016-02-01

    Stochastic image reconstruction has been applied to a dual-particle imaging system being designed for nuclear safeguards applications. The dual-particle imager (DPI) is a combined Compton-scatter and neutron-scatter camera capable of producing separate neutron and photon images. The stochastic origin ensembles (SOE) method was investigated as an imaging method for the DPI because only a minimal estimation of system response is required to produce images with quality that is comparable to common maximum-likelihood methods. This work contains neutron and photon SOE image reconstructions for a 252Cf point source, two mixed-oxide (MOX) fuel canisters representing point sources, and the MOX fuel canisters representing a distributed source. Simulation of the DPI using MCNPX-PoliMi is validated by comparison of simulated and measured results. Because image quality is dependent on the number of counts and iterations used, the relationship between these quantities is investigated.

  10. SU-E-I-99: Estimation of Effective Charge Distribution by Dual-Energy CT Reconstruction

    SciTech Connect

    Sakata, D; Kida, S; Nakano, M; Masutani, Y; Nakagawa, K; Haga, A

    2014-06-01

    Purpose: Computed Tomography (CT) is a method to produce slice image of specific volume from the scanned x-ray projection images. The contrast of CT image is correlated with the attenuation coefficients of the x-ray in the object. The attenuation coefficient is strongly dependent on the x-ray energy and the effective charge of the material. The purpose of this presentation is to show the effective charge distribution predicted by CT images reconstructed with kilovoltage(kV) and megavoltage(MV) x-ray energy. Methods: The attenuation coefficients of x-ray can be characterized by cross section of photoionization and Compton scattering for the specific xray energy. In particular, the photoionization cross section is strongly correlated with the effective charge of the object. Hence we can calculate effective charge by solving the coupled equation between the attenuation coefficient and the theoretical cross section. For this study, we use the megavoltage (MV) and kilovoltage (kV) x-rays of Elekta Synergy as the dual source x-ray, and CT image of the Phantom Laboratory CatPhan is reconstructed by the filtered back projection (FBP) and iterative algorithm for cone-beam CT (CBCT). Results: We report attenuation coefficients of each component of the CatPhan specified by each x-ray source. Also the effective charge distribution is evaluated by the MV and kV dual x-ray sources. The predicted effective charges are comparable with the nominal ones. Conclusion: We developed the MV and kV dual-source CBCT reconstruction to yield the effective charge distribution. For more accuracy, it is critical to remove an effect of the scattering photon in the CBCT reconstruction algorithm. The finding will be fine reference of the effective charge of tissue and lead to the more realistic absorbed-dose calculation. This work was partly supported by the JSPS Core-to-Core Program(No. 23003), and this work was partly supported by JSPS KAKENHI 24234567.