CHARACTERIZATION AND COMPARSION OF NEUTRON GENERATORS OF IEC AND LINEAR D-T BY THE SPECTROMETRIC SYSTEM NGA-01

This article focuses on description of two different neutron fields from linear and cylindrical Inertial Electrostatic Confinement (IEC) neutron generators. Both of these generators are well defined and commonly used. They use a deuterium-tritium reaction that produces neutrons with energies in the range 13 – 16 MeV, depending on the direction and the energy of the incoming deuterium nucleus. Two-parametric spectrometric system for neutron/gamma mixed fields NGA-01 was used to characterize neutron spectra in the proximity of generators. The cylindrical 45x45 mm stilbene scintillator was connected to this device using an active voltage divider. This way, we were able to measure neutron energies in the range 1 - 15 MeV while filtering out gamma radiation, even when counts per second is high. For the neutron spectrum calculation recoil spectra using deconvolution through maximum likelihood estimation was used. Measured neutron spectra have been compared with simulations realized via MCNP6. According to the theoretical prediction, these two types of generators produce different neutron fields. In case of the linear generator the target is very close to point located tritium bombarded by deuterons. Thus the neutron spectrum varies depending on the angle between the detector axis and the axis of the generator. Both experimental results and simulation show a shift of the neutron energy peak in pulse height histogram. For IEC type generators the neutron spectrum is more complicated. The shape and the position of the neutron energy peak depend heavily on the position of the detector. The most prominent effect is in the position in the plane perpendicular to the generator axis. In this case, the peak splits into two peaks that can be measured and distinguished. These results were verified by the diamond detector which was also used for characterization of the IEC type generator.

Comparison of Neutron-Gamma Separation Qualities of Various Organic Scintillation Materials and Liquid Scintillator LSB-200

In this work, we compare the pulse-shape discrimination (PSD) properties of newly developed liquid scintillator LSB-200, EJ-299-33A, BC-501A, stilbene, p-terphenyl, and Hidex Aqualight in neutron field generated by the LVR-15 reactor with silicon filter utilization. Pulses from the scintillators are processed by the Neutron-Gamma spectrometer. This spectrometric system with fast digitizer card contains two analog–digital converters with a resolution of 12 bits and sampling frequency 500 × 106 Hz. For photomultiplier linearity improvement, the active divider has been used. Measured data from scintillators have been processed using the integration method and compared. The results are presented.

A Portable Spectrometric System for Quantitative Prediction of the Soluble Solids Content of Apples with a Pre-calibrated Multispectral Sensor Chipset

A portable spectrometric system for nondestructive assessment of the soluble solids content (SSC) of fruits for practical applications has been proposed and its performance has been examined by an experiment on quantitative prediction of the SSC of apples. Although the spectroscopic technique is a powerful tool for predicting the internal qualities of fruits, its practical applications are limited due to its high cost and complexity. In the proposed system, the spectra of apples were collected by a simple optical setup with a cheap pre-calibrated multispectral chipset. An optimal multiple linear regression model with five wavebands at 900, 760, 730, 680, and 535 nm revealed the best performance with the coefficient of determination of prediction and the root mean square error of prediction of 0.861 and 0.403 °Brix, respectively, which was comparable to that of the previous studies using dispersive spectrometers. Compared with previously reported systems using discrete filters or light emitting diodes, the proposed system was superior in terms of manufacturability and reproducibility. The experimental results confirmed that the proposed system had a considerable potential for practical, cost-effective applications of the SSC prediction, not only for apples but also for other fruits.

Comparison of neutron/gamma separation qualities of various organic scintillation materials

In this work we compare the pulse-shape discrimination (PSD) properties of EJ-299-33A, BC-501A, stilbene, p-terphenyl and Hidex Aqualight in neutron field generated by the LVR-15 reactor with silicon filter utilization. Pulses from the scintillators are processed by Neutron-Gamma spectrometer. This spectrometric system with fast digitizer card contains two analog-digital (A/D) converters with a resolution of 12 bits and sampling frequency 500 MHz. For photomultiplier (PMT) linearity improvement active divider has been used. Measured data from scintillators have been processed using the integration method and compared. Results are presented.

Comparison of neutron/gamma separation qualities of various organic scintillation materials

In this work we compare the pulse-shape discrimination (PSD) properties of EJ-299-33A, BC-501A, stilbene, p-terphenyl and Hidex Aqualight in neutron field generated by the LVR-15 reactor with silicon filter utilization. Pulses from the scintillators are processed by Neutron-Gamma spectrometer. This spectrometric system with fast digitizer card contains two analog-digital (A/D) converters with a resolution of 12 bits and sampling frequency 500 MHz. For photomultiplier (PMT) linearity improvement active divider has been used. Measured data from scintillators have been processed using the integration method and compared. Results are presented.

The remote-controlled spectrometric system for searching and characterization of high-level radioactive waste

In 2003, the work on environmental rehabilitation of the former coastal technical base of the Russian Navy in Gremikha town, with technical and financial support of the State Atomic Energy Corporation “Rosatom” and the French Alternative Energies and Atomic Energy Commission had begun. In 2017, the task of searching, characterization and packaging in transport containers for export to the long-term storage of high-level waste containing 152Eu was set as part of this program. These wastes were presented as fragments of reactor control and safety system rods of first generation nuclear submarine reactors and were placed in temporary storage containers mixed with other radioactive waste and construction garbage on the territory of the Gremikha branch of the North-West Center “SevRAO”. To accomplish the task, the spectrometric system “Gamma-Pioneer” was developed and made at National Research Center “Kurchatov Institute”. The system consist of a collimated spectrometric gamma-ray CdZnTe detector 500 mm3 volume, a dosimeter for continuous measurement of ambient equivalent dose rate at the instrument location and a color video camera with zoom lens. The device is placed in a protective frame and installed as an attachment implements on robot Brokk-90. Communication between the measuring system and the control computer is carried out using USB extender and 100 meters cable. The video camera is connected to the control computer via Ethernet. To search for the most active sources of gamma radiation, an equivalent dose rate calculation program using the results of measured instrumental spectra was developed. The characterization of the extracted fragments was carried out by activity evaluation of the main radionuclides polluting the samples under investigation. The paper describes design and operating principles of the system, as well as methods for the equivalent dose rate calculation and the activity evaluation of the fragments of reactor control and safety system rods based on spectral measurements obtained using the developed radiometric system