VALIDATION OF THE GEIGER-MULLER COUNTER MODEL OF BDMG-04-02 USING THE MONTE-CARLO TECHNIQUE

The model of the Geiger-Muller counter as the internal part of BDMG-04-02 detection unit in the calibration fa-cility UPGD-2 was developedin MCNP6.2. The different methods are used for the determination of the Geiger-Muller counter response. The F1 and F8 tally applicability is briefly described. BDMG-04-02 model was validated by comparative analysis of the calculated results and experimental values of the counter responses that obtained on the UPGD-2 calibration facility. Additionally, the absolute, geometric and intrinsic registration efficiency of BDMG-04-02 was determined. The paper has been emphasized the disadvantages of using the method of direct counting of the electrons on the surface of the Geiger-Muller counter (F1).

Deuteron disintegration by reactor antineutrinos

The existence of a new interaction involving the electron neutrino and the nucleons, which has received a convincing confirmation through a good agreement between the theoretical and experimental results concerning all observable processes with solar neutrinos, should also inevitably manifest itself in the deuteron disintegration by the neutral currents of reactor antineutrinos. The special attention is drawn to the problem of finding the neutron registration efficiency, discussed in the preparation of the experiment at the Sudbury Neutrino Observatory and in a number of special studies. Lessons are noted that can be learned from three long-standing experiments on the deuteron disintegration by reactor neutrinos.

Alpha track registration and revelation in CR-39 using new etching method for ultratrace alpha radioactivity quantification in solution media

A CR-39 based method was developed for measuring the ultra-trace alpha radio activities in aqueous samples having curie levels of γ/β-radio activities. The chemical etching method was optimized to reveal the alpha tracks in CR-39. This new chemical etching method involved the use of a phase transfer catalyst tetraethylammonium bromide which reduced the track revelation induction time without deteriorating the track-etch parameters. The alpha track-etch parameters such as bulk-etch rate, track-etch rate, induction time, and the critical angle of alpha track registration were measured at 60 and 70 °C, with and without using a phase transfer catalyst in the chemical etching for the comparison and optimization. The track registration efficiency of CR-39 in the solution medium was measured using the samples having known alpha activity of mixPu, and value obtained was found to be (4.42 ± 0.12) × 10−4 cm. The registration efficiency value thus obtained was corroborated with the expected efficiency expected from the calculated range of alpha particles in the solution. This CR-39 based method was employed to quantify the alpha activity, as low as 0.2 Bq mL−1, in the aqueous radiopharmaceutical samples having the curie levels of γ/β radio activities.

Voxel Grid-Based Fast Registration of Terrestrial Point Cloud

Terrestrial laser scanning (TLS) is an important part of urban reconstruction and terrain surveying. In TLS applications, 4-point congruent set (4PCS) technology is widely used for the global registration of point clouds. However, TLS point clouds usually enjoy enormous data and uneven density. Obtaining the congruent set of tuples in a large point cloud scene can be challenging. To address this concern, we propose a registration method based on the voxel grid of the point cloud in this paper. First, we establish a voxel grid structure and index structure for the point cloud and eliminate uneven point cloud density. Then, based on the point cloud distribution in the voxel grid, keypoints are calculated to represent the entire point cloud. Fast query of voxel grids is used to restrict the selection of calculation points and filter out 4-point tuples on the same surface to reduce ambiguity in building registration. Finally, the voxel grid is used in our proposed approach to perform random queries of the array. Using different indoor and outdoor data to compare our proposed approach with other 4-point congruent set methods, according to the experimental results, in terms of registration efficiency, the proposed method is more than 50% higher than K4PCS and 78% higher than Super4PCS.

The Investigation of Mechanisms of Fast Neutron Registration in Oxide Scintillators

The contributions of gamma rays from the inelastic scattering reaction and the resonant reaction in the process of slowing down fast neutrons inside the oxide detector volume are investigated. For this the countable efficiency of the ZnWO4, CdWO4, Bi4Ge3O12 oxide scintillators in terms of pulses/neutron during the registration of the fast neutrons from a 239Pu-Be source was measured. It is assumed that the response of detectors during neutron moderation in oxide scintillators with an effective thickness of about 40—50 mm is formed by instantaneous gamma rays from inelastic, resonant inelastic scattering reactions, as well as delayed gamma rays from the capture reaction of resonance neutrons. The parameters of the nuclei, which determine the detector response — the density of the nuclear levels of the compound nuclei being formed, the widths of the resonance regions, the lifetimes of the excited nucleus state were considered. It was found that the registration of a cascade of gamma rays from the discharge of excited levels leads to a significant increase in the countable efficiency of the detector and, as a consequence, an increase in the sensitivity of the detector to fast neutrons. The measured response in terms of pulses/neutron for the ZWO detector — 64, for CWO — 36, for BGO — 2.5. The response of the detectors was recorded by the broadband tract with a time feedback of τ~```0.7 ns. The measured values of the efficiency are explained by the fact that, in our case, the reaction of inelastic scattering is the starting process, which starts the process of discharging nuclear long-lived (~``` 1–1000 ns) states excited in both inelastic scattering and in resonance capture reaction. The registration of the gamma-quanta from discharge leads to an increase the countable efficiency of the detector. The observed increase of the countable efficiency of the secondary gamma quanta is realized when neutrons are moderated inside the oxide detectors with a thickness of 40—50 mm or more. The measurement error of the registration efficiency was about 7%.

Development of Unified Spectrometric Module Based on HPGE Detectors with Electric Machine Cooling

The development results of unified spectrometric module based on HPGe detectors with electric machine cooling for application in nuclear physical equipment of various application are presented. Unified module has cryostat with HPGe detector of the required size, electric machine cooler and electronic unit. The analysis of the cooling processes dynamics and HPGe detectors heating in cryostats, cooled by liquid nitrogen and EMC is made on the sample of the typical cooling circuits. Much attention is paid to design technological aspects of the cryostat development, cooled with electric coolers. With Solidworks software package the modal analysis of the cryostat cover and HPGe detector with various registration efficiency and weight was carried out. Based on the modal analysis of HPGe detector assembly the design of the holders where axial vibration mode was removed to the area of higher harmonics with smaller amplitudes was selected. The design of the developed unified module is reviewed. To increase EMC efficiency the additional radiators with heat tubes are installed and active method of blow off was applied. It secured the temperature decrease of EMC extender and accordingly provided the heat mode comfort for EMC operation what increases the safety of the developed module. The spectra of radioisotopes Co-57 and Co-60 are presented, registered by unified spectrometric module with HPGe detector with gamma radiation registration efficiency of 40%. The energy resolution by energies 122 and 1332 keV is 0,98 and 1,85 accordingly. The overall sizes of the unified module is 280×315×265 mm, its weight with the detector is about 20 kg. The module provides the radiation registration in any spatial position. It allows easy installation of the developed module on various equipment. The samples of the manufactured devices with unified spectrometric module are presented.