Neutron spectroscopy with a high-pressure nitrogen-filled spherical proportional counter

用于 CERN NA62 实验 Kaon 标记的新型充氢 Cherenkov 探测器

A new hydrogen-filled Cherenkov detector for Kaon tagging at the NA62 experiment at CERN

针对 NA62 对 kaon 鉴别的高性能要求，本文介绍采用氢气辐射体的新型 CEDAR-H 探测器，其经 2022 年束流测试验证并自 2023 年投入取数。

A novel modular neutron long counter for (α,n) reactions

In this work, we present the design of a new modular and transportable neutron detector for (α,n) reactions. The detector is based on the use of several 3He-filled proportional counters embedded in high density polyethylene. In order to provide the detector with a response independent of the neutron energy, a flat response, an innovative design methodology has been applied. The method is based on the optimization of the counters contribution to the total efficiency by using thermal neutron absorbers. This allows to obtain flat responses up to 10 MeV. The characterization of a proof-of-concept …

An efficient fluorescent single-particle position tracking system for long-term pulsed measurements of nitrogen-vacancy centers in diamond

A simple and convenient design enables real-time three-dimensional position tracking of nitrogen-vacancy (NV) centers in diamond. The system consists entirely of commercially available components (a single photon counter, a high-speed digital-to-analog converter, a phase-sensitive detector-based feedback device, and a piezo stage), eliminating the need for custom programming or rigorous optimization processes. With a large input range of counters and trackers combined with the high sensitivity of single-photon counting, high-speed position tracking (upper bound recovery time of 0.9 s upon 250 …

AVOLAR. A high voltage generator for liquid argon time projection chambers

Some of the main neutrino oscillation and dark matter experiments have chosen time projection chambers (TPC) filled with liquid argon (LAr) as their technology for the next generation of detectors. Because of its typical drift length of several meters, relatively large cathode voltages are desirable to provide a sizeable drift field. Current designs are based on feedthroughs with high voltages (HV) limited to several hundred kV. The present work proposes a novel method to produce higher voltages inside the detector. It is based on a Van de Graaff HV generator where the charge transporting belt…

Proof of principle of a high-spatial-resolution, resonant-response gamma-ray detector for Gamma Resonance Absorption in 14N

The development of a mm-spatial-resolution, resonant-response detector based on a micrometric glass capillary array filled with liquid scintillator is described. This detector was developed for Gamma Resonance Absorption (GRA) in 14N. GRA is an automatic-decision radiographic screening technique that combines high radiation penetration (the probe is a 9.17 MeV gamma ray) with very good sensitivity and specificity to nitrogenous explosives. Detailed simulation of the detector response to electrons and protons generated by the 9.17 MeV gamma-rays was followed by a proof-of-principle experiment, …

Thermally-driven scintillator flow in the SNO+ neutrino detector

The SNO+ neutrino detector is an acrylic sphere of radius 6 m filled with liquid scintillator, immersed in a water-filled underground cavern, with a thin vertical neck (radius 0.75 m) extending upwards about 7 m from the sphere to a purified nitrogen cover gas. To explain a period of unexpected motion of the scintillator, time-dependent flow simulations have been performed using OpenFoam. It appears that the motion, inferred from subsequent 24 h-averaged patterns of transient $^{222}\mathrm{Rn}$ contamination introduced during earlier recirculation of scintillator, can be explained as owing to…

Development of a Parallel-Plate Avalanche Counter with Optical Readout (O-PPAC)

We describe a novel gaseous detector concept for heavy-ion tracking and imaging: the Optical Parallel-Plate Avalanche Counter (O-PPAC). The detector consists of two thin parallel-plate electrodes separated by a small (typically 3 mm) gap filled with low-pressure scintillating gas (i.e. CF4). The localization of the impinging particles is achieved by recording the secondary scintillation, created during the avalanche processes within the gas gap, with dedicated position-sensitive optical readouts. The latter may comprise arrays of collimated photo-sensors (e.g. SiPMs) that surround the PPAC eff…

Results of measurements of an environment neutron background at BNO INR RAS objects with the helium proportional counter

A method of measurements of the environmental neutron background at the Baksan Neutrino Observatory of the INR RAS are described. Measurements were done by using of a proportional counter filled with mixture of Ar(2 at)+$^3$He(4 at). The results obtained at the surface and the underground laboratory of the BNO INR RAS are presented. It is shown that a neutron background in the underground laboratory at the 4900 m w.e. depth is decreased by $\sim 260$ times without any special shield in a comparison with the Earth surface. A neutron flux density in the 5-1323.5~cm air height region is constant …

Neutron spectroscopy: The case of the spherical proportional counter

Neutron spectroscopy is an invaluable tool for many scientific and industrial applications, including underground Dark Matter searches. Neutron-induced backgrounds produced by cosmic ray muons and the cavern radioactivity can mimic the expected Dark Matter signal. However, existing neutron detection methods have several drawbacks and limitations, thus measurements remain elusive. A promising new approach to neutron spectroscopy is the use of a nitrogen-filled spherical proportional counter that exploits the $^{14}$N(n,$α$)$^{11}$B and $^{14}$N(n, p)$^{14}$C reactions. This is a safe, inexpensi…

Low-Background Experiments with High Pressure Gas Scintillation Proportional Detector

A scintillation proportional counter with wavelength shifting fiber readout filled with Xe or Kr under a pressure of up to 20 atm is proposed for the low-background experiments on search for dark matter of the Universe and 2K-decay of 78 Kr.

Characteristics of a matrix proportional counter with circular anodes

The construction of a butt-end multicell matrix proportional counter (MMPC) is presented in the work. Each cell is a butt-end proportional counter with a 5 mm cathode diameter and 0.8 mm circular anode diameter. In the example of the $3\times3$ matrix, it is shown that the gas multiplication of the central cell depends on the potentials at the anodes of the peripheral cells, the drift electrode, the forming rings, and the surrounding metal parts of the structure. The amplitude characteristics were measured when the MMPC was filled with mixtures of 96.3\% Ar + 3.7\% Xe and 90\% Ar + 10\% CH$_4$…

First result of the experimental search for the 9.4 keV solar axion reactions with Kr-83 in the copper proportional counter

The experimental search for solar hadronic axions is started at the Baksan Neutrino Observatory of the Institute for Nuclear Researches Russian Academy of Science. It is assumed that axions are created in the Sun during M1-transition between the first thermally excited level at 9.4 keV and the ground state in Kr-83. The experiment is based on axion detection via resonant absorption process by the same nucleus in the detector. The big copper proportional counter filled with krypton is used to detect signals from axions. The experimental setup is situated in the deep underground low background l…

Observation of hard radiations in a laboratory atmospheric high-voltage discharge

The new results concerning neutron emission detection from a laboratory high-voltage discharge in the air are presented. Data were obtained with a combination of plastic scintillation detectors and $^3$He filled counters of thermal neutrons. Strong dependence of the hard x-ray and neutron radiation appearance on the field strength near electrodes, which is determined by their form, was found. We have revealed a more sophisticated temporal structure of the neutron bursts observed during of electric discharge. This may indicate different mechanisms for generating penetrating radiation at the tim…