The paper is devoted to computational analysis of shielding properties of spectrometer GAMMACELL irradiated by neutrons from 14.1 MeV Neutron Generator (NG). The shielding is required to protect the BaF2 crystals of the gamma spectrometer GAMMACELL from background thermal neutrons, scattered from the walls and equipment in experimental room. GAMMACELL is a scintillation spectrometer of full gamma particles absorption. It consists of 9 BaF2 crystals; each of them has 40×40×100 mm3 dimensions and is viewed by photomultiplier tube. Neutrons also cause flashes in BaF2 crystals and give spurious pulses. The ultimate aim of the work is to simulate the severe radiation load on spectrometer GAMMACELL and to find proper radiation shield to fulfill the most favorable operating conditions for the GAMMACELL. The neutrons were generated with energy 14.1 MeV form the source on titanium–tritium target on a copper substrate. Accelerator tube makes deuteron current with spot 4 mm diameter on the target. Between the neutron source and GAMMACELL crystals collimator is placed in order to separate neutron current with particular energy and angle. The collimator is pointed to the central BaF2 crystal, counter is turned on only in case when gammas hit it. The other 8 periphery BaF2 crystals are intended for registration of Compton and annihilation gamma radiation which scattered from central crystal. The periphery crystals must be covered by lateral shielding case for protection form background radiation. It is supposed that on the basis of shielding analyses provided and data obtained in this work the real experiment on the Neutron Generator (NG) will be performed. But the experiment on NG will be not at the final destination for the results application obtained in this work, diagnostics of plasma in fusion tokamak-type reactor by means of GAMMACELL gamma spectrometry is planned. Plasma diagnostics by gamma emission from nuclear reactions on particles accelerated upon high energy during Deuterium-Tritium nuclear fusion. Resonances and thresholds in nuclear reactions reveal the value of particle energy based on registered gamma energy in GAMMACELL. High-penetrating capability of gamma quantum gives an opportunity to examine the plasma on all full depth.

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