An improved Pulse Shape Discrimination (PSD) method to detect directly for a non-baryonic dark matter

A hybrid pulse shape discrimination (PSD) method is presented that combines a charge-integration PSD method with a reference-pulses PSD method. The reference-pulses PSD method uses detailed knowledge of the average detector response to radiation. To obtain the reference pulses, many thousands of neutron and gamma-ray pulses were averaged in several pulse height regions. The average neutron and gamma-ray pulses were then used in the new PSD algorithm for classification of a large number of measured pulses. The reference-pulses PSD method is applied below 70 keVee (keV electron equivalent) while the standard charge-integration PSD method is used above 70 keVee. This new hybrid PSD method proves to be more accurate than the standard charge-integration PSD method alone for classification of neutrons and gamma rays. Specifically, the improvement is approximately 40% for neutrons in the smallest pulse height bin considered, which was between 23 and 30 keVee (corresponding to approximately 175 keV and 225 keV neutron energy deposited, respectively). For this pulse height bin, approximately 66% of the neutrons were correctly classified. The average number of correctly classified neutrons is approximately 82% for the hybrid PSD method between 23 and 100 keVee (corresponding to approximately 175 keV and 670 keV neutron energy deposited, respectively).

A hybrid pulse shape discrimination (PSD) method is presented that combines a charge-integration PSD method with a reference-pulses PSD method. The reference-pulses PSD method uses detailed knowledge of the average, energy-dependent detector response to radiation. To obtain the reference pulses, a large number of neutron and gamma-ray pulses were averaged in several pulse height regions. The reference neutron and gamma-ray pulses were then used in the new PSD method for the classification of `known' measured pulses. The reference-pulses PSD method was applied below 70 keVee (keV electron equivalent), whereas the standard charge-integration PSD method was used above 70 keVee. This new hybrid PSD method proves to be more accurate than the standard charge-integration PSD method for classification of neutrons and gamma rays. Specifically, the improvement is approximately 30% for neutrons between 20 and 30 keVee (corresponding to approximately 50 and 225 keV neutron energy deposited). For this pulse height bin, approximately 72% of the neutrons were correctly classified by the hybrid PSD method. The average number of correctly classified neutrons is approximately 88% for the hybrid PSD method between 20 and 100 keVee (150 and 670 keV neutron energy deposited) as opposed to 83% for the charge-integration PSD method.

This paper introduces a new method for neutron-gamma pulse shape discrimination (PSD) and pile-up signal rejection (PUR) based on multi-resolution analysis (MRA). The method uses a fast wavelet transform to decompose the original signal, extracting approximate components through low-pass filtering and detail components through high-pass filtering. Following reconstruction, the approximate and detail components are analyzed to achieve efficient PSD and PUR, respectively. The experiments used an EJ276 plastic scintillator detector to collect neutron and gamma signals from an Am-Be source for PSD analysis and mixed signals with pile-up pulses (with an additional Na-22 source) for PUR analysis. The MRA method with different wavelet bases was compared to the charge comparison (CC) method in terms of PSD performance across time gate widths and energy ranges. The results show that the CC method works well only with wide time gates and high energy ranges. Except for the Haar wavelet, the MRA method's PSD performance is more stable across different time gates, performing better with smaller time gates. The db3 wavelet provides the best discrimination at small time gates. The PUR results of the MRA method with the db3 wavelet were compared at time gates of 50 ns, 100 ns, 150 ns, and 200 ns. The 200 ns gate offers the best pulse discrimination but loses the most piled-up and neutron signals, increasing the computational load. The 50 ns gate retains the most neutron signals with the lowest load but has the least PSD. Based on users' needs, the ideal time gate for high count rate neutron-gamma PUR and PSD measurements is between 50 ns and 100 ns.

Adipose Tissue Gene Expression Associations Reveal Hundreds of Candidate Genes for Cardiometabolic Traits

A BC523A liquid scintillator loaded with boron-10 was tested as a detector for both fast and thermal neutrons. Pulse shape discrimination (PSD) method based on a zero-crossing principle was applied to distinguish between neutron and gamma radiation. High quantum efficiency Photonis XP5500B photomultiplier was used to enhance light detection from the scintillator. This allowed a good registration of the energy spectrum of neutron capture events on boron-10, corresponding to about 60 keVee. The applied PSD method proved to be useful for n/y discrimination. A good resolving power of the method was achieved even without gating on neutron capture events. A comparison with a standard BC501A liquid scintillator was done to evaluate thermal neutrons detection efficiency in BC523A.

The application of pulse shape discrimination in NE 213 to neutron spectrometry

Quantitative analysis and efficiency study of PSD methods for a LaBr3:Ce detector

The use of Time-over-Threshold (TOT) for the discrimination between fast neutrons and gamma-rays is advantageous when large number of detection channels are required due to the simplicity of its implementation. However, the results obtained using the standard, Constant Threshold TOT (CT-TOT) are usually inferior to those obtained using other pulse shape discrimination (PSD) methods, such as Charge Comparison or Zero-Crossing approaches, especially for low amplitude neutron/gamma-ray pulses. We evaluate another TOT approach for fast neutron/gamma-ray PSD using Constant-Fraction Time-over-Threshold (CF-TOT) pulse shape analysis. The CT-TOT and CF-TOT methods were compared quantitatively using digitized waveforms from a liquid scintillator coupled to a photomultiplier tube as well as from a stilbene scintillator coupled to a photomultiplier tube and a silicon photomultiplier. The quality of CF-TOT neutron/gamma-ray discrimination was evaluated using Receiver Operator Characteristics curves and the results obtained with this approach were compared to that of the standard CT-TOT method. The CF-TOT PSD method results in > 99.9% rejection of gamma-rays with > 80% neutron acceptance, much better than CT-TOT.

A comprehensive evaluation of the thermal neutron detection efficiency by a single crystal CVD diamond detector with a LiF thermal neutron converter

To enhance safeguards technologies, neutron resonance transmission analysis, neutron resonance capture analysis, and neutron-induced fission neutron analysis are combined to improve the detection of fissile materials. These techniques are implemented using an integrated instrument that employs plastic scintillators to detect prompt gamma rays and fission neutrons, and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${ }^{6} \text{Li}$</tex>-doped glass scintillators such as GS20, along with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${ }^{6} \text{Li}$</tex>-loaded plastic scintillators like EJ-270, to measure transmitted neutrons. Effective neutron/gamma pulse shape discrimination (PSD) is critical for accurate sample analysis. To address this and to minimize human bias, a novel data-driven PSD approach was developed. Experiments using natural and enriched uranium were conducted at the Institute for Integrated Radiation and Nuclear Science, Kyoto University, and the data were analyzed with the new PSD method. The results demonstrate strong discrimination capabilities and clear identification of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${ }^{235} \mathrm{U}$</tex> signatures.

Identification of different reaction channels of high energy neutrons in liquid scintillators by the pulse shape discrimination method

Boron neutron capture therapy (BNCT) is an advanced and emerging cancer treatment that selectively targets tumor cells by delivering boron-10 via a drug prior to neutron beam irradiation. Through the nuclear reaction between boron-10s and thermal neutrons, high-LET α-particles and lithium nuclei are yielded to damage cancer cells with minimal damage to surrounding healthy tissue. Accurate characterization of neutron beam properties during treatment is essential for accomplishing dosimetry control, treatment planning, and quality assurance (QA). A small scintillator-on-fiber (SOF) detector, featuring sub-millimeter scale and relatively low sensitivity to neutrons and gamma rays, shows strong potential for realizing a QA system compatible with highflux neutron and gamma-ray fields in BNCT. We examine the responses of SOF detectors composed of 140 μg, 230 μg, and 1 mg Li-glass scintillators when irradiated by epithermal neutron beams from the Tsing Hua Open-Pool Reactor at power levels ranging from 0.3 to 1.7 MW. The pulse shape discrimination (PSD) method, employing a fiducial cut, is proposed to effectively distinguish neutron events from significant overlap with gamma-ray and pile-up signals. Consequently, excellent linearity between neutron counts and reactor power is achieved for measurements obtained with the 140 μg and 230 μg Li-glass scintillators, making SOF detectors applicable for real-time neutron monitoring in clinical BNCT applications.

Characterization of the neutron/[formula omitted]-ray discrimination performance in an EJ-301 liquid scintillator for application to prompt fission neutron spectrum measurements at CSNS

In this paper, we propose a cooperative multi-relay scheme for a secondary system to achieve spectrum access along with a primary system.In the primary network, a primary transmitter (PT) transmits the primary signal to a primary receiver (PR).In the secondary network, N secondary transmitter-receiver pairs (ST-SR) selected by a centralized control unit (CCU) are ready to assist the primary network.In particular, in the first time slot, PT broadcasts the primary signal to PR, which is also received by STs and SRs.At STs, the primary signal is regenerated and linearly combined with the secondary signal by assigning fractions of the available power to the primary and secondary signals respectively.The combined signal is then broadcasted by STs in a predetermined order.In order to achieve diversity gain, STs, SRs and PT will combine received replicas of the primary signal, using selection combining technique (SC).We derive the exact outage probability for the primary network as well as the secondary network.The simulation results are presented to verify the theoretical analyses.

NE213 liquid scintillation detectors have been used in mixed radiation fields with great success due to their pulse shape discrimination (PSD) ability. Numerous PSD techniques using various analog equipments had been proposed and developed by various individuals in past years. A common method for PSD is to evaluate the fall-time of the voltage across a resistor terminating the output of the photomultiplier tube (PMT) attached to the NE213 cell. The product of the terminating resistor and the terminating capacitance is known as the time- constant. Additionally, the combination of the terminating resistance and capacitance create a high-pass filter whose characteristics depend upon the value of the time constant. The greater the time-constant the less attenuation of the longer frequencies in a given signal occur. This paper will present a quantitative comparison of the fall time PSD technique using various terminating resistors. Specifically, 50 ohm, 500 ohm and a 1 kohm termination schemes are tested. Furthermore, due to nonlinearities in the system, a linear PSD spectrum may not be possible to obtain. In such cases, a traditional figure of merit (FOM) may not be usable to quantify the PSD capability of the system. A modified version of FOM is explored and used to describe the PSD capability of the current system.