Time-Dependent Spectra of Neutrons Emitted in Interaction of 1 and 4 GeV Deuterons with Massive Natural Uranium and Lead Targets

Abstract

Prompt and delayed neutrons (DN) from pulsed irradiation of geometrically identical natural uranium and lead targets by 1 and 4 GeV deuterons were measured at NUCLOTRON facility of Joint Institute for Nuclear Research. The massive (~300 kg) cubic shaped targets were surrounded by 10 cm lead blanket. Neutrons were measured by the assembly of 3 He counters embedded in moderator and by threshold activation detectors. The DN decay curves were analysed for both targets and information on fragment yields for lead target and fission properties for uranium one was extracted. The obtained experimental information could be useful for verification of INC and transport codes. The results of this experiment are important for development of advanced ADS systems and other applications.

Recent results of the study of ads with 500kg natural uranium target assembly QUINTA irradiated by deuterons with energies from 1 TO 8 GeV at JINR NUCLOTRON

“…Fission in the lead blanket is negligible as shown in Ref. [22]. The time spectra of neutron yield (normalized to one incident particle) measured in course of irradiation of TA QUINTA in March 2011 at deuteron energy of E d = 6 GeV is shown in Fig.…”

“…The time dependence of leakage neutron yields measured between NUCLOTRON bursts with aid of detector system ISOMER-M provides valuable information on fission processes within the target assembly [22]. The incident deuteron beam had duration of pulse ~ 500 ms with repletion rate ~ 8 s -1 .…”

“…The time structure and intensity of deuteron burst were monitoring one-line for each accelerator pulse. Some details of the DN measurements were given above in the beginning of Section 3 (see also [11] and [22]). Special measurements showed that the contribution of the background to these spectra was negligible…”

“…26 the systematic of weight ratios [23][24][25][26][27] of the abovementioned groups in dependence on neutron energy for 238 U(n,f)-reaction is presented together with the results of analysis of present data (red circles with crosses inside). The blue circles indicate results obtained in June 2009 [22] with smaller (~300 kg natural uranium) target assembly which had a lead blanket of 10 cm thick.…”

“…Beside that the lead-uranium assembly was placed into thick (~300 mm) and dense (ρ=0.7 g/cm 3 ) polyethelene box serving as a reflector and a moderator. In Fig.27 it is shown as the green curve the time dependence of neutron yield from the (E+T) target assembly measured by detector ISOMER-M in the same as in June 2009 geometry together with the respective spectra obtained for uranium and lead target assemblies [22] (red and blue curves respectively). As it follows from Fig.…”