Particle discrimination and fast neutron response for a NaIL:Tl and a NaI:Tl scintillator detector

Lai, Caifeng; Qin, Jianguo; Xiao, Jun; Zhu, T; Lü, Xinxin; Liu, An; Yunfeng, Mou; Peng, Zheng; Sun, Jianning; Li, Jiang; Wang, Mei; Han, Zijie

doi:10.1016/j.nima.2020.164372

Cited by 15 publications

(7 citation statements)

References 22 publications

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“…After experimental tests, the measured energy spectra under three different shielding conditions are obtained, as shown in figure 3, in which the relationship between relative electronic energy and pulse integration has been obtained through energy calibration in advance. As can be seen from figure 3(a), a significant 6 Li(n,𝛼)T neutron capture peak appears due to a certain moderation of neutrons after the addition of HDPE shielding relative to the absence of shielding, within 2800-3900 keV energy window, similar to those reported in the literature [23]. After adding the lead brick shield, although the gamma event was largely reduced and the total event counts decreased significantly, the neutron capture peak was still visible.…”

Section: Spectrum and Pulse Waveformssupporting

confidence: 84%

“…where 𝜏 𝑓 is the fast component decay time constant, 𝜏 𝑠 is the slow component decay time constant, and 𝐴 and 𝐵 are the intensity coefficients of the two components, respectively. Studies have shown that the fast component usually dominates the pulses of NaIL scintillators [22,23], and the decay time constant of event pulses can be used to optimize frequency domain discrimination. According to Saleh's report [14], the optimal discriminating frequency can be obtained from eq.…”

Section: Length Of Pulse Transformationmentioning

confidence: 99%

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Optimization of pulse shape discrimination based on frequency domain for SiPM-based NaIL scintillator detector

Li,

Fan,

Zhu

et al. 2024

J. Inst.

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Frequency gradient analysis (FGA) neutron-gamma pulse shape discrimination (PSD) based on Fourier transform has proved to be an effective method for discrimination between two types of pulses by simply constructing a discrimination parameter by subtracting the amplitude of the 1st frequency component from the 0th frequency component. However, the discrimination parameter constructed by the above method could not meet the requirements at some lower sample rates, and the dark noise caused using optoelectronic devices such as miniaturized SiPMs array further erodes the difference between the two frequency components. This paper proposes a new discrimination parameter construction method based on FGA for neutron-gamma discrimination, which is referred as mFGA (modified FGA). This discrimination parameter uses the 0th frequency component and other frequency components to enhance the discrimination performance. A neutron detector module consisting of a 25.4 mm× 25.4 mm× 50.8 mm NaI:Tl,6Li (NaIL) scintillator and an array of 8 × 8 SiPMs was established to verify the method of mFGA. The module measured a 252Cf neutron source under three shielding conditions: no shield, 5 cm high-density polyethylene (HDPE), and 10 cm lead brick. The proposed mFGA method was used to calculate the figure of merit (FoM) under each shielding condition and compared to the traditional frequency gradient method (FGA) and the traditional charge comparison method (CCM). The results show that the discrimination performance with the mFGA method is significantly improved. Taking the HDPE shielding group as an example, the performances of the three methods are FoM-FGA =1.14, FoM-mFGA =2.75, FoM-CCM =0.92. At the same time, with the increase of energy, due to the neutron gamma pulse becoming similar, and the discrimination performance of FGA and CCM decrease significantly. The discrimination performance of the mFGA method is relatively stable in all energy regions. Therefore, the proposed method is superior to the traditional FGA of the 0th frequency minus the 1st frequency and has a good application prospect for neutron-gamma discrimination with detectors of poor signal quality.

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Section: Spectrum and Pulse Waveformssupporting

confidence: 84%

Section: Length Of Pulse Transformationmentioning

confidence: 99%

Optimization of pulse shape discrimination based on frequency domain for SiPM-based NaIL scintillator detector

Li,

Fan,

Zhu

et al. 2024

J. Inst.

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“…Corresponding observations have been made by other authors (e.g. in [25]), but have not been interpreted correctly.…”

Section: Discussionmentioning

confidence: 61%

Neutron Detection in Mixed Neutron-Gamma Fields with Common NaI(Tl) Detectors

Pausch¹,

Kreuels²,

Scherwinski³

et al. 2021

Preprint

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<p>Searching digitized detector signals for piled-up delayed components with distinct energy and delay time signatures is a smart method to provide common NaI(Tl) detectors with additional neutron detection capabilities at no extra cost. This technique nicely complements the idea of neutron detection by analyzing events with high energy depositions above the range of common gamma-ray energies. In combination, both approaches can provide half of the neutron sensitivity offered by a commercial <sup>6</sup>Li co-doped NaI(Tl) (NaIL™) scintillator of the same size, at the price of higher and load-dependent background contributions. Delayed-coincidence techniques are most suitable for neutron monitoring or long-term measurements, where the statistics of the acquired delay-time distributions allows separate fitting of the effect and background contributions. In this case, the thermal neutron flux can be quantified in parallel to gamma-ray spectroscopy at overall detector loads exceeding 10 kcps.</p>

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“…Therefore, it is important to discuss the contributions of other particles in the spectrum obtained from the NaI detector. There have been different studies on the efficiency of NaI (Tl) crystal to detect neutrons [20,27,28], and they concur that it is very low for lower energy neutrons (< 10 MeV). As pointed out by Arakelyan et al (2014) [20], the ratio of efficiencies of a NaI (Tl) detector to detect gamma and neutrons varies from 5:1 to 8:1 in the energy range 3 MeV-10 MeV.…”

Section: Jcap09(2021)045 4 Discussionmentioning

confidence: 97%

Barometric pressure correction to gamma-ray observations and its energy dependence

Datar

Vichare

Selvaraj³

2021

J. Cosmol. Astropart. Phys.

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Cosmic rays (CRs) have been studied extensively in the last century to understand the processes in the universe as well as in the solar system. In today's satellite era, although many observations are made from space, CR observations from the ground are still viewed as a significant tool. These observations, however, mainly detect the secondary cosmic rays (SCRs) produced via nuclear spallation processes during the interactions of the primary CR with the atmospheric nuclei. Neutron, muon, and gamma are the major components of SCRs detected on the ground. It is well known that atmospheric pressure plays a vital role in the SCR flux observed on the ground. Barometric pressure correction is standard practice for neutron monitor (NM) data. For gamma-rays, however, being massless, their pressure dependence is not intuitive. Nevertheless, the pressure affects the particles such as e±, μ±, which produce gamma rays in the cascade. Subsequently, the indirect pressure dependence of the gamma-ray flux can be anticipated. We examine this aspect in detail by studying the gamma-ray counts detected by the NaI (Tl) detector. The present study confirms that there is no correlation between the atmospheric pressure and the total counts covering the entire energy range (150 keV–10 MeV) recorded by the NaI detector. However, the scenario differs when the fluxes of different energies are investigated separately. The gamma rays of energy below ∼3 MeV are primarily due to the radioactivity originating from the ground, whereas gamma rays above 3 MeV are mainly produced in the CR cascade. It is observed that the counts of energy above 3 MeV are well anti-correlated with the atmospheric pressure. The barometric coefficient obtained here matches well with that reported by the previous studies which used anti-coincidence methods. This may indicate that the role of directly detected muons and electrons by the NaI (Tl) in the observed pressure dependence is non-significant. It is demonstrated that applying the barometric correction formula to NaI (Tl) data successfully removes the pressure dependence in the flux above 3 MeV. Therefore, we suggest that the particle flux data above 3 MeV measured by NaI (Tl) detector needs to be corrected for the local atmospheric pressure variations.

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Particle discrimination and fast neutron response for a NaIL:Tl and a NaI:Tl scintillator detector

Cited by 15 publications

References 22 publications

Optimization of pulse shape discrimination based on frequency domain for SiPM-based NaIL scintillator detector

Optimization of pulse shape discrimination based on frequency domain for SiPM-based NaIL scintillator detector

Neutron Detection in Mixed Neutron-Gamma Fields with Common NaI(Tl) Detectors

Barometric pressure correction to gamma-ray observations and its energy dependence

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