Measurement of the ionization yields for nuclear recoils is related to the energy calibration of dark matter and low-energy neutrino detectors. In this study, some results of the previous measurements of the ionization yields for nuclear recoils in liquid argon using the neutron scattering technique in the two-phase detector are discussed. The methods to increase light collection of scintillation (S (1)) and ionization (S (2)) signals in the two-phase detector using SiPM matrices and THGEM electrodes with increased optical transparency are proposed. These steps are necessary to implement the neutron double-scattering technique, which will provide measurement of the ionization yield of recoiling nuclei in the unexplored energy range.

A slim-shaped portable DD-neutron generator is developed at Budker institute of Nuclear Physics. The generator is a combination of Cockcroft–Walton voltage multiplier and a sealed gas-filled neutron tube driven by dispenser cathode. Neutron burst shape in pulsed mode of neutron tube operation is measured with stroboscopic time spectrometry, implemented on scintillation detector, and modeled with Comsol Script 1.3 and Comsol Multiphysics 3.5. Modeling appears to be in good agreement with experimental results. Measured pulse rise and fall times are 110 ns and 100 ns respectively.

A new simple predictor-corrector method for stationary self-consistent electrostatic field modeling is developed on the basis of Comsol Multiphysics 3.5 capabilities. The method is implemented in the script written in Comsol Script 1.3. The basic idea of the method is iterative computation of space charge density from a set of virtually traced trajectories of charged particles. The script is tailored for modeling of charged particle movement in a cylindrically symmetric self-consistent stationary electric field of a gas-filled DD-neutron tube with an ion source driven by a heated cathode. The proposed approach is useful for determining the mode of operation of a tube (whether plasma is formed in ion source or the mode of operation is plasmaless) and for verification of design modifications for plasmaless neutron tubes. The computed charge fields are shown to be self-consistent with a space charge adjustment error of 2.5% at worst.

A numerical method of calculating the neutron yield of accelerator neutron generators using the nuclear reactions D(d, n)3He and T(d, n)4He and results are presented. For a generator with a titanium target, the neutron yield is presented for different accelerating voltages and ratios of the ion-flux components and approximate relations suitable for real-time evaluation of the neutron yield are obtained.

Erosion of copper target irradiated by deuterium ion beam with ultimate fluence is studied. The target originally destined for neutron generation represents bulk copper substrate covered by 3-\mum titanium layer. The target was irradiated by deuterium ion beam generated in Bayard-Alpert type ion source with energy of ions 17.5 keV/nuclear. Maximal fluence in the center of the target achieves 2.5x10^23atoms/cm^2. Measurements of the profile of irradiated target and estimation of fluence shows that physical sputtering is a dominating process that determines the target erosion Most interesting feature is growth of \mum-size tadpole-shaped structures, localized in the cracks of the surface. RFA analysis of these structures showed extremely large (up to 60%at.) carbon content.

For studying entries of impurities into thermonuclear plasma, when injecting heated neutral beams, the spectroscopic diagnostics intended for promptly monitoring the plasma composition of the radiofrequency (RF) emitter of the powerful fast neutral beam injector is designed. The analysis of plasma radiation spectra allowed us to determine the rotational temperature of the neutral hydrogen and estimate the oxygen-to-carbon impurity ratio in the RF emitter. In this work, the long-term dynamics of the neutral oxygen line brightness is studied, and the influence of the discharge chamber ageing and warming-up on the impurity content is determined.