EUROCON 2007 - The International Conference on Computer as a Tool, 2007
AbstractThe bremsstrahlung spectrum generated by the accelerated field emission electrons at the... more AbstractThe bremsstrahlung spectrum generated by the accelerated field emission electrons at the 1st of five super-conducting TESLA accelerator modules driving the FLASH (Free Electron Laser in Hamburg) was analyzed using a batch of radiochromic (Gaf-EBT) films ...
— Energy distributions of neutrons emitted from the interaction of 20 MeV protons incident on a t... more — Energy distributions of neutrons emitted from the interaction of 20 MeV protons incident on a thick Be target were estimated at two angles (0 • and 90 •) with respect to the incident beam using activation foils as threshold detectors. A recently developed unfolding code GAMCD based on Genetic Algorithm and Monte Carlo methods was used to estimate the neutron spectra by unfolding the counts obtained from the activation foils. These results were compared with the unfolding codes, MAXED and GRAVEL. In the GAMCD code, a guess spectrum as a-priori information need not be provided as input unlike in MAXED and GRAVEL. Results obtained from all these codes matched each other reasonably well. Out of 30 reactions studied experimentally only the selected 15 were found sufficient to generate acceptable spectra in the case of neutrons emitted from the p + Be reaction at 20 MeV. A peak in the energy distributions around 3 MeV at both the measured angles is contributed by the three body breakup process while a broad hump between 6 MeV and 10 MeV only in the forward direction suggests contribution from the pre-equilibrium emissions from the 9 Be(p, n) 9 B channel, which also contributes to the small peak observed around 15 MeV. The code GAMCD was found to perform satisfactorily for the present data set.
EUROCON 2007 - The International Conference on Computer as a Tool, 2007
AbstractThe bremsstrahlung spectrum generated by the accelerated field emission electrons at the... more AbstractThe bremsstrahlung spectrum generated by the accelerated field emission electrons at the 1st of five super-conducting TESLA accelerator modules driving the FLASH (Free Electron Laser in Hamburg) was analyzed using a batch of radiochromic (Gaf-EBT) films ...
Extensive data have been gathered in the past on the response of different detectors, based on th... more Extensive data have been gathered in the past on the response of different detectors, based on the registration of neutron-induced fissions in bismuth, gold, tantalum and thorium by the spark-replica counter and the thin film breakdown counter. These detectors make it possible to exploit the excellent characteristics of the fission reactions for the measurements of high-energy neutrons. Most of the investigations have been carried out at the quasi-monoenergetic neutron beam facility at The Svedberg Laboratory-TSL of the Uppsala University in cooperation with the Khlopin Radium Institute (KRI). The responses of different fission detectors in the neutron energy range 35-180 MeV have been evaluated: a region where the predictive power of available nuclear reaction models and codes is not reliable yet. For neutron energy >200 MeV, the fission-detector responses have been derived from the data of the proton fission cross sections. By using the ratio of the responses of these detectors, a simple and accurate way to evaluate the spectrum hardness can be obtained, thus providing a tool to obtain spectral information needed for neutron dosimetry without the need to know the entire spectrum. Extensive data have been already obtained for the high-energy neutron spectrum from the CERN concrete facility. In the present paper, the measured values of the response ratios for different fissile detectors exposed at the CERN facility are compared with those calculated for the spectra from the same facility and from different altitudes in the atmosphere, respectively.
ABSTRACT In this work, neutron measurements were carried out for the interaction of 60 and 67.5 M... more ABSTRACT In this work, neutron measurements were carried out for the interaction of 60 and 67.5 MeV 12C, 57.3 and 65 MeV 13C ions with thick aluminium target by using CR-39 detectors and neutron rem meter. Both the detector systems were irradiated at different angles viz. 0°, 30°, 60°, 90° with respect to the beam direction. The normalized track density (tracks cm -2 projectile -1 at 1 m) in CR-39 detectors was correlated with the normalized dose equivalent values (μSv projectile -1 at 1 m) obtained using the neutron rem meter. The track density was found to be more in case of 13C than 12C. However in all the cases, the track density per incident projectile was found to decrease as the angle with respect to beam direction increases, indicating non-isotropic nature of neutron emission. The ratio between measured dose equivalent in rem meter to the measured track densities in CR-39 detectors was found to be (2.8±0.2) μSv cm 2, which remains constant irrespective of the change in angle with respect to the beam direction as well as in neutron energy distribution, indicating a flat dose response of CR-39 detectors.
EUROCON 2007 - The International Conference on Computer as a Tool, 2007
AbstractThe bremsstrahlung spectrum generated by the accelerated field emission electrons at the... more AbstractThe bremsstrahlung spectrum generated by the accelerated field emission electrons at the 1st of five super-conducting TESLA accelerator modules driving the FLASH (Free Electron Laser in Hamburg) was analyzed using a batch of radiochromic (Gaf-EBT) films ...
— Energy distributions of neutrons emitted from the interaction of 20 MeV protons incident on a t... more — Energy distributions of neutrons emitted from the interaction of 20 MeV protons incident on a thick Be target were estimated at two angles (0 • and 90 •) with respect to the incident beam using activation foils as threshold detectors. A recently developed unfolding code GAMCD based on Genetic Algorithm and Monte Carlo methods was used to estimate the neutron spectra by unfolding the counts obtained from the activation foils. These results were compared with the unfolding codes, MAXED and GRAVEL. In the GAMCD code, a guess spectrum as a-priori information need not be provided as input unlike in MAXED and GRAVEL. Results obtained from all these codes matched each other reasonably well. Out of 30 reactions studied experimentally only the selected 15 were found sufficient to generate acceptable spectra in the case of neutrons emitted from the p + Be reaction at 20 MeV. A peak in the energy distributions around 3 MeV at both the measured angles is contributed by the three body breakup process while a broad hump between 6 MeV and 10 MeV only in the forward direction suggests contribution from the pre-equilibrium emissions from the 9 Be(p, n) 9 B channel, which also contributes to the small peak observed around 15 MeV. The code GAMCD was found to perform satisfactorily for the present data set.
EUROCON 2007 - The International Conference on Computer as a Tool, 2007
AbstractThe bremsstrahlung spectrum generated by the accelerated field emission electrons at the... more AbstractThe bremsstrahlung spectrum generated by the accelerated field emission electrons at the 1st of five super-conducting TESLA accelerator modules driving the FLASH (Free Electron Laser in Hamburg) was analyzed using a batch of radiochromic (Gaf-EBT) films ...
Extensive data have been gathered in the past on the response of different detectors, based on th... more Extensive data have been gathered in the past on the response of different detectors, based on the registration of neutron-induced fissions in bismuth, gold, tantalum and thorium by the spark-replica counter and the thin film breakdown counter. These detectors make it possible to exploit the excellent characteristics of the fission reactions for the measurements of high-energy neutrons. Most of the investigations have been carried out at the quasi-monoenergetic neutron beam facility at The Svedberg Laboratory-TSL of the Uppsala University in cooperation with the Khlopin Radium Institute (KRI). The responses of different fission detectors in the neutron energy range 35-180 MeV have been evaluated: a region where the predictive power of available nuclear reaction models and codes is not reliable yet. For neutron energy >200 MeV, the fission-detector responses have been derived from the data of the proton fission cross sections. By using the ratio of the responses of these detectors, a simple and accurate way to evaluate the spectrum hardness can be obtained, thus providing a tool to obtain spectral information needed for neutron dosimetry without the need to know the entire spectrum. Extensive data have been already obtained for the high-energy neutron spectrum from the CERN concrete facility. In the present paper, the measured values of the response ratios for different fissile detectors exposed at the CERN facility are compared with those calculated for the spectra from the same facility and from different altitudes in the atmosphere, respectively.
ABSTRACT In this work, neutron measurements were carried out for the interaction of 60 and 67.5 M... more ABSTRACT In this work, neutron measurements were carried out for the interaction of 60 and 67.5 MeV 12C, 57.3 and 65 MeV 13C ions with thick aluminium target by using CR-39 detectors and neutron rem meter. Both the detector systems were irradiated at different angles viz. 0°, 30°, 60°, 90° with respect to the beam direction. The normalized track density (tracks cm -2 projectile -1 at 1 m) in CR-39 detectors was correlated with the normalized dose equivalent values (μSv projectile -1 at 1 m) obtained using the neutron rem meter. The track density was found to be more in case of 13C than 12C. However in all the cases, the track density per incident projectile was found to decrease as the angle with respect to beam direction increases, indicating non-isotropic nature of neutron emission. The ratio between measured dose equivalent in rem meter to the measured track densities in CR-39 detectors was found to be (2.8±0.2) μSv cm 2, which remains constant irrespective of the change in angle with respect to the beam direction as well as in neutron energy distribution, indicating a flat dose response of CR-39 detectors.
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Papers by Sam Tripathy