Dose Measurements around Spallation Neutron Sources

Neutron dose measurements and calculations around spallation sources are of importance for an appropriate shielding study. Two spallation sources, consisted of Pb target, have been irradiated by high-energy proton beams, delivered by the Nuclotron accelerator (JINR), Dubna. Dose measurements of the neutrons produced by the two spallation sources were performed using Solid State Nuclear Track Detectors (SSNTDs). In addition, the neutron dose after polyethylene and concrete was calculated using phenomenological model based on empirical relations applied in high energy Physics. Analytical and experimental neutron benchmark analysis has been performed using the transmission factor. A comparison of experimental results with calculations is given.

Spallation Neutron Production in the Dubna Transmutation Assembly

A large lead target with a U blanket was irradiated by 1.5 GeV protons at the Dubna Nuclotron accelerator. Spatial distributions of neutron fluxes were determined by Solid State Nuclear Track Detectors in the new experimental transmutation assembly. Slow and fast neutron components were studied inside sections of the setup and on the U blanket surface. Neutron distributions after Cd and polyethylene shielding were also investigated. The results show that the new arrangement is efficient mainly to transmutation experiments by fission and (η,χη) reactions as well as by (η,γ) reactions.

Shielding around spallation neutron sources

Spallation neutron sources provide more intense and harder neutron spectrum than nuclear reactors for which a substantial amount of shielding measurements have been performed. Although the main part of the cost for a spallation station is the cost of the shielding, measurements regarding shielding for the high energy neutron region are still very scarce. In this work calculation of the neutron interaction length in polyethylene moderator for different neutron energies is presented. Measurements which were carried out in Nuclotron accelerator at the Laboratory of High Energies (Joint Institute for Nuclear Research, Dubna) and comparison with calculation are also presented. The measurements were performed with Solid State Nuclear Track Detectors (SSNTDs).

High energy fission cross sections induced by deuteron on 232Th and proton on natPb targets

Total fission cross sections induced by deuterons with energies 1.6, 2.5 and 4.0 GeV on 232Th targets and by protons on natPb targets at energy 2.0 GeV were measured during irradiations at the Nuclotron accelerator, JINR, Dubna. Using Solid State Nuclear Track detectors, the fission cross sections induced by deuterons on 232Th were determined as 1277±216, 1232±207 and 1153±198 mb, corresponding to the energies mentioned above. The total fission cross section of protons on natPb was estimated by the same method as 131±30 mb. These results were compared to the previous systematic parameterization of proton induced fission and new values for the parameters of deuteron-induce fission on actinides, 232Th and 238U and proton induced fission on natPb were deduced. Fitting results obtained for deuterons on actinides are discussed and compared to results for protons.

Performance of the BM@N GEM/CSC tracking system at the Nuclotron beam

BM@N (Baryonic Matter at the Nuclotron) is a fixed target experiment aimed to study nuclear matter in the relativistic heavy-ion collisions at the Nuclotron accelerator in JINR. The BM@N tracking system is based on Gas Electron Multipliers (GEM) detectors mounted inside the BM@N analyzing magnet. The Cathode Strip Chamber (CSC) is installed outside the magnet. The CSC is used for improvement of particles momentum identification. The structure of the GEM detectors and the CSC prototype and the results of study of their characteristics are presented. The GEM detectors and CSC are integrated into the BM@N experimental setup and data acquisition system. The results of first tests of the GEM tracking system and CSC in last runs are shortly reviewed.

Status of the SPI for the JINR Accelerator Complex

The Source of Polarized Ions (SPI) of deuterons and protons with nearly resonant charge-exchange plasma ionizer is under construction at the LHEP, JINR. The [Formula: see text]D[Formula: see text] ([Formula: see text]H[Formula: see text]) current output of the source is expected to be at a level of 10[Formula: see text]mA. The polarization will be up to 90% of the maximal vector (±1) for [Formula: see text]D[Formula: see text] ([Formula: see text]H[Formula: see text]) and tensor ([Formula: see text]1, [Formula: see text]) polarization for [Formula: see text]D[Formula: see text]. Realization of the project is carried out in close cooperation with INR of the RAS (Moscow). The equipment available from the CIPIOS ion source (IUCF, Bloomington, USA) is partially used for the Dubna setup. The new source at the JINR NUCLOTRON accelerator facility will make it possible to increase the polarized deuteron beam intensity up to the level of 10[Formula: see text] [Formula: see text]/pulse.