Predicting Background Count Rate of a Mobile Detector using an Optimal Linear Ensemble of Learning Kernel Machines

2020 ◽  
Author(s):  
M. Alamaniotis
Keyword(s):  
Count Rate ◽  
Kernel Machines ◽  
Background Count ◽  
Background Count Rate ◽  
Optimal Linear

scholarly journals Newly Designed 0.8-ML Teflon® Vial for Microvolume Radiocarbon Dating

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 743-747 ◽  
Author(s):  
Michael Buzinny ◽  
Vadim Skripkin
Keyword(s):  
Significant Influence ◽  
Count Rate ◽  
Radiocarbon Dating ◽  
Figure Of Merit ◽  
Liquid Scintillation ◽  
Detection Efficiency ◽  
Operational Parameters ◽  
Counting Period ◽  
Background Count ◽  
Background Count Rate

We have tested two versions of an 0.8-ml volume Teflon® vial, designed specifically for radiocarbon dating in the microvolume range, using a modern Quantulus 1220™ liquid scintillation (LS) spectrometer. We determined the counting performance of each vial type in conjunction with different designs of copper holder, viz., with and without the incorporation of a “Teflon® light coupler”. We also compared the losses of sample benzene during a typical 28-day counting period. Results show that neither vial design nor the type of vial holder used in the intercomparison had a significant influence on counting performance. We recorded an absolute 14C detection efficiency of 82% against a background count rate of 0.1 cpm, i.e., a “figure of merit (FM) value” = 67,240. This compares favorably with the operational parameters anticipated for microvolume 14C dating by modern LS spectrometry. However, variations in the design of the sealing method used between the vial types was reflected in an apparent approximate tenfold difference in the amount of benzene lost during routine counting. In the better case, the evaporation loss was equivalent to 0.032 mg of benzene per day.

scholarly journals Precision Measurements of the Minimum Detectable Activity of Radionuclides by Plastic Scintillators for Radiation Monitoring

2019 ◽  
pp. 3-9
Author(s):  
B. Grynyov ◽  
N. Gurdzhian ◽  
O. Zelenskaya ◽  
V. Lyubynskiy ◽  
N. Molchanova ◽  
...  
Keyword(s):  
Count Rate ◽  
Statistical Processing ◽  
Sensitivity Coefficient ◽  
Minimum Detectable Activity ◽  
National Academy Of Sciences ◽  
Background Count ◽  
Background Count Rate ◽  
Energy Radiation ◽  
Detectable Activity ◽  
Plastic Scintillators

This work is devoted to the precision evaluation of the minimum detectable activity (MDA) measurement of gamma radiation radionuc­lides 137Cs and 60Co using plastic scintillators (PS). Scintillators are part of the detectors, which are sensitive elements of radiation portal moni­tors (PM). PS were produced at the Institute for scintillation materials of the National Academy of Sciences of Ukraine (ISMA NAS of Ukraine). The evaluation was generate in accordance with State standard of Ukraine ISO 5725-2:2005 [1] through statistical processing of experi­mental material. This made it possible to take into account the factors that determine the scattering of results without a model equation. Influence of PS sizes, energy radiation detected and distance from PS to the source of ionizing radiation (SIR) on the value of MDA precision measurement was studied. Precision coefficients of radionuclides MDA measurement evalua­ted when changing PS sizes from 500×300×50 mm (7500 cm3) up to 500×500×50 mm (12500 cm3), changing the energy radiation detected from 662 keV (137Cs) until 1332 keV (60Co), changing the distance from the PS to SIR from 10 to 50 cm. The results are presen­ted in Fig. 6—9 and Table. Found, that the greatest contribution to the increase in MDA precision coefficient measurements makes a change in the irradia­tion geometry. It is shown that when distance from PS to SIR increases from 10 to 50 cm, precision values increase: when registering 137Cs, from 3,9 to 7,0 % (V = 7500 cm3) and from 3,6 to 6,3 % (V = 12500 cm3); when registering 60Co, from 3,1 to 4,3 % (V = 7500 cm3) and from 3,2 to 3,8 % (V = 12500 cm3). It is established, that the obtained results are due to the change in the contribution of background count rate to PS count rate under different measurements conditions. This contribution affects on the value of sensitivity coefficient and consequently on the value of MDA and precision coefficient.

scholarly journals Stability of a New, Multichannel, Low-Level Liquid Scintillation Counter System, Kvartett

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 727-736 ◽  
Author(s):  
Sigurđur Einarsson ◽  
Páll Theodórsson
Keyword(s):  
Count Rate ◽  
Liquid Scintillation ◽  
Scintillation Counter ◽  
Counting System ◽  
Background Count ◽  
Background Count Rate ◽  
Low Level ◽  
Quality Control Standard ◽  
Conventional Systems ◽  
Sample Vial

Kvartett is a new liquid scintillation counting (LSC) system for radiocarbon dating that takes a radical departure from conventional systems to obtain a compact, low-level counting system measuring four samples simultaneously. Each sample vial, inside the well of a large NaI(Tl) guard-counter crystal (facing down), sits on top of a vertical PMT. The fourfold counting capacity can be used to increase the number of samples being dated or to get higher precision. The increased throughput helps to keep a rigid quality-control standard. We monitored the background count rate almost continuously for 7 months, and measured the count rate of a standard repeatedly for 2 months. The results show the background and system reproducibility to be stable.

Comparison of a Solid-State Si Detector to a Conventional Scintillation Detector-Monochromator System in X-Ray Powder Diffraction Analysis

1989 ◽  
Vol 4 (3) ◽  
pp. 137-143 ◽  
Author(s):  
David L. Bish ◽  
Steve J. Chipera
Keyword(s):  
Solid State ◽  
Powder Diffraction ◽  
Scintillation Detector ◽  
Count Rate ◽  
Detection Limits ◽  
Background Count ◽  
Background Count Rate ◽  
X Ray ◽  
Graphite Monochromator ◽  
Lower Background

AbstractA new Peltier-cooled solid-state Si(Li) detector has been compared to a traditional scintillation detector/diffracted-beam graphite monochromator system in conventional X-ray powder diffraction applications. Parameters studied included absolute count rates, detector linearity, peak-to-background ratios, detection limits, fluorescent radiation elimination, and peak profile shapes. Comparisons were performed on a Siemens D-500 θ-2θ diffractometer using constant sample and nondetector instrumental parameters. Advantages of the Si(Li) detector include a significantly increased count rate (3.4 - 3.8 times), primarily due to the elimination of the graphite monochromator, slightly lower background count rates, and the ability to change the analysis energy quickly. The higher count rate and slightly lower background count rate of the Si(Li) detector allow collection of data more rapidly than possible with a scintillation detector/diffracted-beam monochromator system and yield improved peak-to-background ratios and detection limits. Significant disadvantages of the Si(Li) detector include pronounced deviation from linearity at low count rates, making accurate measurement of even moderate countrate peaks difficult, and detector shutdown due to 100% deadtime between 4 and 5 × 10 4 counts/s (cps). The Si(Li) detector and the scintillation detector/diffracted-beam monochromator system are comparable in terms of fluorescence radiation elimination, resolution, and peak shape, although it appears tfiat die diffracted-beam monochromator measurably reduces the low-angle portion of the half width of all reflections.

scholarly journals Natural Gamma-Ray Background Characterization in Pyhasalmi Mine

2021 ◽  
Author(s):  
Vladimir Gostilo ◽  
Serhii Pohuliai ◽  
Alexander Sokolov ◽  
Jari Joutsenvaara ◽  
Julia Puputti
Keyword(s):  
Energy Range ◽  
Count Rate ◽  
Gamma Ray ◽  
Background Level ◽  
Nitrogen Gas ◽  
Background Count ◽  
Background Count Rate ◽  
Natural Gamma ◽  
Hpge Spectrometer ◽  
Background Gamma Radiation

<p>We present the results of measuring the gamma-ray background performance of Pyhasalmi mine, the deepest one in Europe. Two underground facilities in Lab 2 (1440 m) and Lab 5 (1410 m) were investigated. Based on measurements made in Lab 2 with a low-background HPGe spectrometer, we determined the integral gamma-ray background count rate in the energy range of 40 keV to 2.7 MeV to be 0.095 s<sup>–1</sup> kg<sup>–1</sup>. The minimum detectable activities of some natural and artificial nuclides were less than 0.071 Bq/kg (<sup>226</sup>Ra), 0.77 Bq/kg (<sup>40</sup>K) and 0.012 Bq/kg (<sup>137</sup>Cs). The specific activities of natural nuclides in the shotcrete covering the walls of the Lab 2 were higher than those in the rock: 100.3 Bq/kg (<sup>232</sup>Th), 161.7 Bq/kg (<sup>226</sup>Ra) and 1171 Bq/kg (<sup>40</sup>K) in the shotcrete covering and 47.6 Bq/kg (<sup>232</sup>Th), 83.1 Bq/kg (<sup>226</sup>Ra) and 1513 Bq/kg (<sup>40</sup>K) in the rock. The measurements showed that the gamma-ray background level in Lab 5 is significantly lower than that in Lab 2. The integrated gamma-ray background count rate for the energy range of 40 keV to 2.7 MeV was 0.028 s<sup>–1</sup> kg<sup>–1</sup> for Lab 5. Purging the measuring chamber of the gamma spectrometer with nitrogen gas at a rate of 0.15 L/h allowed to further improve this parameter to 0.021 s<sup>–1</sup> kg<sup>–1</sup>. In general, the results of this study confirm that the level and energy spectrum of background gamma radiation in the underground facility within the studied energy range is defined mainly by the composition of the walls of the Labs.</p><p> </p>

scholarly journals Performance of the Packard 2000 CA/LL and 2250 CA/XL Liquid Scintillation Counters for 14C Dating

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 352-358 ◽  
Author(s):  
G T Cook ◽  
D D Harkness ◽  
Robert Anderson
Keyword(s):  
Count Rate ◽  
Liquid Scintillation ◽  
Scintillation Counter ◽  
14C Dating ◽  
Background Count ◽  
Background Count Rate ◽  
Low Level ◽  
On Line ◽  
Guide System ◽  
Careful Manipulation

Results are presented on the comparative characteristics of the Packard 2000 CA/LL liquid scintillation counter with and without the low-level option on line. An initial performance assessment using 14C labeled benzene with butyl-PBD as the scintillant revealed that although the background count rate decreased by approximately a factor of 3 using the low-level option, a substantial decrease in efficiency was also observed. However, subsequent investigations have indicated that, by careful manipulation of both scintillant composition and concentration, this loss in efficiency can largely be overcome with little or no concurrent increase in background count rate. The introduction of an active vial sample holder and a new light-guide system proved to be significant advances on the standard 2000 CA/LL.

scholarly journals The Potential of the London Underground for Liquid Scintillation Counting

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 592-596
Author(s):  
Sheridan Bowman
Keyword(s):  
Count Rate ◽  
Liquid Scintillation ◽  
Cosmic Ray ◽  
Gamma Spectrometer ◽  
Background Count ◽  
Background Count Rate ◽  
Low Potassium ◽  
London Underground ◽  
Order Of Magnitude ◽  
Cosmic Ray Flux

A portable gamma spectrometer has been used to survey three locations that are part of the London Underground Transport System (the “tube”). Up to an order of magnitude reduction in the cosmic ray flux was observed relative to the laboratory level. The likely reduction in background count rate achievable by underground siting of currently used Packard and LKB liquid scintillation counters is considered. It is noted that in the present, surface usage for radiocarbon dating, the background count rate of low-potassium glass vials in the LKB is not substanially higher than that of PTFE vials.

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