Studies of Photonuclear Reactions and Photon Activation Analysis in the Giant Dipole Resonance Region Using Microtrons

Abstract

Mictrorons are accelerators of electrons and are simultaneous sources of bremsstrahlung
 photon flux and fission neutrons. In 1982, a microtron of seventeen trajectories
 Microtron MT - 17 was put into operation at the National Institute of Physics of Vietnam.
 Though very modest, microtons are very useful for developing countries such as Vietnam
 in both fundamental and applied physics research. During the recent years by using the
 above mentioned MT - 17 and microtrons from other institutes we have carried out different
 investigations. In this report we present some results obtained in the studies of photonuclear
 reactions and photon activation analysis in the giant dipole resonance region.

Mass distribution in the bremsstrahlung-induced fission of 232Th, 238U and 240Pu

“…Similarly yields of fission fragments in the excitation energy range of the GDR region due to electromagnetic fission in inverse kinematics [52][53][54] are available for neutron-deficient lighter actinides such as 214-223 Ac, 220-229 Th, 224-232 Pa and 231-234 U. On the other hand, yields of fission products in the bremsstrahlung-induced fission of actinides are available in a broad energy range for a limited number of actinides including 232 Th [55][56][57][58][59][60], 235,238 U [61][62][63][64][65][66][67][68][69][70][71][72][73][74] and 240,242,244 Pu [75][76][77][78]. Most of the yield data on fission products available in the 9 MeV to several GeV bremsstrahlung-induced fission of 232 Th [55][56][57][58][59] and 235,238 U [61][62][63][64][65][66][67] are based on radiochemical separation and beta counting or γ -ray spectrometric techniques.…”

“…This is because only a limited amount of even-even Pu-isotopes are available due to their high alpha activity. Some of the yield data of fission products in the 18.1 and 20.7 MeV bremsstrahlung-induced fission of 242 Pu became available in the recent past [78] based on off-line γ -ray spectrometric techniques. The yields of fission products are not available in the bremsstrahlung-induced fission of Pu-isotopes at lower or higher energies based on either physical or off-line γ -ray spectrometric techniques.…”

Mass distribution in the 50-, 60-, and 70-MeV bremsstrahlung-induced fission of232Th

“…On the other hand, yields of fission products in the bremsstrahlung-induced fission of actinides are available in a broad energy range for a limited number of actinides, such as 232 Th [47][48][49][50][51][52][53] and 235,238 U [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68]. For other actinides, such as 237 Np [68,69] and 239,240,242,244 Pu [53,68,[70][71][72][73], the yields of fission products are available within the bremsstrahlung energy range of 10-70 MeV.…”