Abstract
The international collaboration Energy and Transmutation of Radioactive Waste (E&T RAW) performed intensive studies of several simple accelerator-driven system (ADS) setups consisting of lead, uranium and graphite which were irradiated by relativistic proton and deuteron beams in the past years at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The most recent setup called Quinta, consisting of natural uranium target-blanket and lead shielding, was irradiated by deuteron beams in the energy range between 1 and 8 GeV in three accelerator runs at JINR Nuclotron in 2011 and 2012 with yttrium samples among others inserted inside the setup to measure the neutron flux in various places. Suitable activation detectors serve as one of possible tools for monitoring of proton and deuteron beams and for measurements of neutron field distribution in ADS studies. Yttrium is one of such suitable materials for monitoring of high energy neutrons. Various threshold reactions can be observed in yttrium samples. The yields of isotopes produced in the samples were determined using the activation method. Monte Carlo simulations of the reaction rates leading to production of different isotopes were performed in the MCNPX transport code and compared with the experimental results obtained from the yttrium samples.
Highlights
accelerator-driven system (ADS) studies [1,2,3,4]
The only apparent discrepancy appears at the maximum of isotopes production which is located at about 26 cm from the target beginning where the simulation underestimates the experimental data by a factor of two for the position at 4 cm in the 2, 4 and 6 GeV experiments performed without lead shielding but not in the rest of experiments where the Quinta setup was shielded with lead
Measurements of fast neutron field in the Quinta assembly were performed by means of yttrium activation detectors irradiated with 1, 2, 4, 6 and 8 GeV deuteron beams from the Nuclotron accelerator at Joint Institute for Nuclear Research (JINR), Dubna
Summary
ADS studies [1,2,3,4]. Yttrium in natural occurrence is monoisotopic with one stable isotope 89Y. Products of (n,xn) threshold reactions on yttrium are identifiable. Half-lives of the products have suitable duration for gamma spectroscopy. Gamma transitions are intensive enough for detection and they are well separated from each other. The yttrium activation detectors were irradiated during experiments with the Quinta uranium target [5, 6] at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The deuteron beams with energies ranging from 1 GeV up to 8 GeV were produced by JINR Nuclotron synchrotron. Residual radionuclides in the samples were measured by the gamma spectrometry
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