19F(α,n) thick target yield from 3.5 to 10.0 MeV
Abstract
Using a target of PbF2, the thick-target yield from the (19)F(α,n) reaction was measured from Eα=3.5-10MeV. From these results, we infer the thick-target neutron yields from targets of F2 and UF6 over this same alpha-particle energy range.
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... [29,30] without and with the DR contribution, respectively. The data for fluorine are taken from Wrean et al. [32], Vukolov et al. [33], Balakrishnan et al. [34], Norman et al. [35], Peters et al. [36] and Gladun et al. [37]. (Note that Ref. [35] has reported previous measurements of thick target neutron yield used to evaluate the cross-section of the (α, n) reaction on fluorine [38] shown here.) ...
... The data for fluorine are taken from Wrean et al. [32], Vukolov et al. [33], Balakrishnan et al. [34], Norman et al. [35], Peters et al. [36] and Gladun et al. [37]. (Note that Ref. [35] has reported previous measurements of thick target neutron yield used to evaluate the cross-section of the (α, n) reaction on fluorine [38] shown here.) Figure 2: Cross-sections of (α, n) reactions in 13 C as calculated in different models in EMPIRE3.2.3. ...
... EM-PIRE3.2.3 and TALYS1.9 in comparison with experimental data. The data for fluorine are taken from Wrean et al.[32], Vukolov et al.[33], Balakrishnan et al.[34], Norman et al.[35], Peters et al.[36] and Gladun et al.[37].. ...
... Neutron-induced nuclear recoil background in the PandaX-4T experiment * Zhou Huang(黄周) 1 Guofang Shen(申国防) 2 Qiuhong Wang(王秋红) 3 Abdusalam Abdukerim(阿布都沙拉木·阿布都克力木) 1 Zihao Bo(薄子豪) 1 Wei Chen(陈葳) 1 Xun Chen(谌勋) 1,4 Yunhua Chen(陈云华) 5 Chen Cheng(程晨) 6 Yunshan Cheng(成云珊) 7,8 Xiangyi Cui(崔祥仪) 9 Yingjie Fan(樊英杰) 10 Deqing Fang(方德清) 3 Changbo Fu(符长波) 3 Mengting Fu(付孟婷) 11 Lisheng Geng(耿立升) 2,12,13 Karl Giboni 1 Linhui Gu(顾琳慧) 1 Xuyuan Guo(郭绪元) 5 Chencheng Han(韩晨成) 1 Ke Han(韩柯) 1 Changda He(何昶达) 1 Jinrong He(何金荣) 5 Di Huang(黄迪) 1 Yanlin Huang(黄彦霖) 14 Ruquan Hou(侯汝全) 4 Xiangdong Ji(季向东) 15 Yonglin Ju(巨永林) 16 Chenxiang Li(李晨翔) 1 Mingchuan Li(李名川) 5 Shu Li(李舒) 16 Shuaijie Li(李帅杰) 9 Qing Lin(林箐) 17,18 Jianglai Liu(刘江来) 1,9,4 † Xiaoying Lu(芦晓盈) 7,8 Lingyin Luo(罗棱尹) 11 Wenbo Ma(马文博) 1 Yugang Ma(马余刚) 3 Yajun Mao(冒亚军) 11 Yue Meng(孟月) 1,4 Xuyang Ning(宁旭阳) 1 Ningchun Qi(祁宁春) 5 Zhicheng Qian(钱志成) 1 Xiangxiang Ren(任祥祥) 7,8 Nasir Shaheed 7,8 Changsong Shang(商长松) 5 Lin Si(司琳) 1 Wenliang Sun(孙文良) 5 Andi Tan(谈安迪) 15 Yi Tao(陶奕) 1,4 Anqing Wang(王安庆) 7,8 Meng Wang(王萌) 7,8 Shaobo Wang(王少博) 1,19 Siguang Wang(王思广) 11 Wei Wang(王为) 6 Xiuli Wang(王秀丽) 16 Zhou Wang(王舟) 1,4,9 Mengmeng Wu(武蒙蒙) 6 Weihao Wu(邬维浩) 1 Jingkai Xia(夏经铠) 1 Mengjiao Xiao(肖梦姣) 15 Xiang Xiao(肖翔) 6 Pengwei Xie(谢鹏伟) 9 Binbin Yan(燕斌斌) 1 Xiyu Yan(颜玺雨) 14 Jijun Yang(杨继军) 1 Yong Yang(杨勇) 1 Chunxu Yu(喻纯旭) 10 Jumin Yuan(袁鞠敏) 7,8 Ying Yuan(袁影) 1 Dan Zhang(张丹) 15 Minzhen Zhang(张敏祯) 1 Peng Zhang(张鹏) 5 Tao Zhang(张涛) 1 Li Zhao(赵力) 1 Qibin Zheng(郑其斌) 14 Jifang Zhou(周济芳) 5 Ning Zhou(周宁) Dark matter is one of the top mysteries in modern physics [1]. Weakly interacting massive particle (WIMP) is a promising candidate and predicted by many new physics models beyond the standard model, such as super-symmetric theories. ...
... The TPC is surrounded by polytetrafluoroethylene (PTFE) panels for higher collection efficiencies, which divide the detector into several regions along with the four electrodes. Outside of the PTFE panels is the veto region for multi-scattering background rejection, where one-inch PMTs are installed [12]. The sensitive volume is confined within the PTFE panels and the gate and cathode electrodes, containing 3.7 tonnes of liquid xenon. ...
... This is known as the (α, n) reaction [14,15]. The final product 12 C primarily lies in the ground state or first excited state. The latter case can emit a 4.4 MeV gamma ray. ...
Neutron-induced nuclear recoil background is critical to the dark matter searches in the PandaX-4T liquid xenon experiment. This paper studies the feature of neutron background in liquid xenon and evaluates their contribution in the single scattering nuclear recoil events through three methods. The first method is fully Monte Carlo simulation based. The last two are data-driven methods that also use the multiple scattering signals and high energy signals in the data, respevtively. In the PandaX-4T commissioning data with an exposure of 0.63 tonne-year, all these methods give a consistent result that there are 1.15 0.57 neutron-induced background in dark matter signal region within an approximated nuclear recoil energy window between 5 and 100 keV. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
... [29,30] without and with the DR contribution, respectively. The data for fluorine are taken from Wrean et al. [32], Vukolov et al. [33], Balakrishnan et al. [34], Norman et al. [35], Peters et al. [36] and Gladun et al. [37]. (Note that Ref. [35] has reported previous measurements of thick target neutron yield used to evaluate the cross-section of the (α, n) reaction on fluorine [38] shown here.) ...
... The data for fluorine are taken from Wrean et al. [32], Vukolov et al. [33], Balakrishnan et al. [34], Norman et al. [35], Peters et al. [36] and Gladun et al. [37]. (Note that Ref. [35] has reported previous measurements of thick target neutron yield used to evaluate the cross-section of the (α, n) reaction on fluorine [38] shown here.) Figure 2: Cross-sections of (α, n) reactions in 13 C as calculated in different models in EMPIRE3.2.3. ...
... EM-PIRE3.2.3 and TALYS1.9 in comparison with experimental data. The data for fluorine are taken from Wrean et al.[32], Vukolov et al.[33], Balakrishnan et al.[34], Norman et al.[35], Peters et al.[36] and Gladun et al.[37].. ...
Neutrons can induce background events in underground experiments looking for rare processes. Neutrons in a MeV range are produced in radioactive decays via spontaneous fission and (alpha, n) reactions, and by cosmic rays. Neutron fluxes from radioactivity dominate at large depths (>1 km w. e.). A number of computer codes are available to calculate cross-sections of (alpha, n) reactions, excitation functions and neutron yields. We have used EMPIRE2.19/3.2.3 and TALYS1.9 to calculate neutron production cross-sections and branching ratios for transitions to the ground and excited states, and modified SOURCES4A to evaluate neutron yields and spectra in different materials relevant to high-sensitivity underground experiments. We report here a comparison of different models and codes with experimental data, to estimate the accuracy of these calculations.
... The measurements for natural fluorine have been reported in Refs. [23][24][25]. We have chosen fluorine here as it is a quite common material in underground experiments (used as a light reflector) and has a very high neutron yield due to (α, n) reactions. ...
... SOURCES4A calculations with crosssections from Ref.[26] up to 6.7 MeV and TALYS1.9 model above 6.7 MeV, are plotted together with the data from Refs.[23][24][25]. ...
Neutrons produced in spontaneous fission and ( \alpha,n α , n ) reactions can induce background events in underground experiments looking for rare processes. A number of computer codes are available to calculate cross-sections of ( \alpha,n α , n ) reactions, branching ratios to various states and neutron yields. SOURCES4 code has been used in this work to calculate neutron yields and energy spectra with input cross-sections and branching ratios taken from experimental data and models from EMPIRE2.19/3.2.3 and TALYS1.9 codes. A comparison of SOURCES4 calculations with experimental data from alpha beams and radioactive decay chains is presented.
... Above this energy, the choice of the cross-section is quite arbitrary and an option of using TALYS 1.96 was dictated by: a) the most recent update to the calculations and b) a reasonable agreement with experimental data at energies close to the upper end of data range. [44,45,46,47,48,49]. ...
The sensitivity of underground experiments searching for rare events such as dark matter, neutrino interactions or several beyond the standard model phenomena is often limited by the background caused by neutrons from spontaneous fission and () reactions. A number of codes exist to calculate neutron yields and energy spectra due to these processes. In this paper we present new calculations of neutron production using the modified SOURCES4A code with recently updated cross-sections for () reactions and the comparison of the results with available experimental data. The cross-sections for () reactions in SOURCES4 have been taken from reliable experimental data where possible, complemented by the calculations with EMPIRE 2.19/3.2.3, TALYS 1.96 or evaluated data library JENDL-5 where the data were scarce or unavailable.
... Note that the threshold energies of these reactions depend on the levels of the residual nucleus from which the emission of specific photons takes place and can be obtained from [Croft et al., 2013], here 19 F(α,n), 19 F(α,p), and 19 F(α,α ′ ) reactions have the thresholds of 2.36 MeV, 0.10 × 10 − 4 eV and 0.133 MeV energies, respectively. Fig. 1 shows the variation of the total cross-section of the 19 F(α, n) 22 Na reaction as a function of alpha particle energy, that is used in the Nedis-2m codes (corrections by Vlaskin et al. in this work), SOURCES-4С (LANL) and Japanese Evaluated Nuclear Data Library (JENDL) [Murata and Matsunobu, 2006] performed based on the data of [Norman et al., 1984;Norman et al., 2015] with the EGNASH-2 code. ...
Corrigendum to “Neutron and gamma-ray signatures for the control of alpha-emitting materials in uranium production: A Nedis2m-MCNP6 simulation” [Radiat. Phys. Chem. 208 (2023) 110919]
... Note that the threshold energies of these reactions depend on the levels of the residual nucleus from which the emission of specific photons takes place and can be obtained from [Croft et al., 2013], here 19 F(α,n), 19 F(α,p), and 19 F(α,α ′ ) reactions have the thresholds of 2.36 MeV, 0.10 × 10 − 4 eV and 0.133 MeV energies, respectively. Fig. 1 shows the variation of the total cross-section of the 19 F(α, n) 22 Na reaction as a function of alpha particle energy, that is used in the Nedis-2m codes (corrections by Vlaskin et al. in this work), SOURCES-4С (LANL) and Japanese Evaluated Nuclear Data Library (JENDL) [Murata and Matsunobu, 2006] performed based on the data of [Norman et al., 1984;Norman et al., 2015] with the EGNASH-2 code. ...
The radiations emitted via 19F(α,nγ), 19F(α,pγ), and 19F(α,α′γ) reactions in compounds containing alpha-emitting elements and fluorine are used for non-destructive neutron and gamma-ray analyses in monitoring the contents of nuclear fissile materials during the manufacture, processing, and storage of nuclear fuels. As far as the literature survey confirms, the data available on the yield of (α,n) reaction on fluorine, which depends on alpha particle energy, have significant dispersion. For the accompanying gamma-rays, on the other hand, no reliable absolute data exist for the production yield of gamma-rays per number of interacting alpha particles or emitted nucleonsas a function of alpha particle energy. Therefore, to improve the monitoring and control of nuclear materials and to ensure the safety of production processes, the present study was undertaken, where the neutron yields and energy spectra were calculated using the Nedis-2m program taking into account the updated values of the total cross-section for (α,n) reactions on 19F. The resulting Nedis-2m input datasets were used in the MCNP6 code to calculate the leakage multiplication factor and spectrum.
Neutron-induced nuclear recoil background is critical to the dark matter searches in the PandaX-4T liquid xenon experiment. This paper studies the feature of neutron background in liquid xenon and evaluates their contribution in the single scattering nuclear recoil events through three methods. The first method is fully Monte Carlo simulation based. The last two are data-driven methods that also use the multiple scattering signals and high energy signals in the data, respectively. In the PandaX-4T commissioning data with an exposure of 0.63 tonne-year, all these methods give a consistent result that there are neutron-induced background in dark matter signal region within an approximated nuclear recoil energy window between 5 and 100 keV.
Interest in safeguards verification measurements using passive thermal neutron counting to assay ²³⁵U content in large 30B UF6 canisters has grown in recent years. The prohibitively high cost and impracticality of using reference 30B calibration cylinders extensively will likely make accurate simulations of increasing interest. Accuracy of the simulated response will define the confidence in the predicted response and the extent to which simulations can reasonably be relied upon. With ²³⁴U driven ¹⁹F(α, n) reactions being the main neutron source in low enriched uranium the uncertainties of the ¹⁹F(α, n) energy spectrum and the thick target yield of ²³⁴U in UF6 propagate into the uncertainty in the predicted response and represent a major influence of basic nuclear data. Here sensitivity of the simulated total (Singles) and coincidence (Doubles) count rates are assessed for the Passive Neutron Enrichment Meter using six potential ¹⁹F(α, n) neutron energy spectra over a range of enrichments and material distributions. The results indicate that variations in the Singles and Doubles due to simulated (α, n) neutron spectrum are less than 1.5% for this set of simulated neutron spectra, with dependence varying inversely with enrichment. Singles uncertainty is only slightly less than that of the thick target ¹⁹F(α, n) yield corresponding to the primary neutron source, whereas the ¹⁹F(α, n) yield dependence of the Doubles is reduced by the non-negligible ²³⁸U(SF) coincident neutron emissions. Based on available thick target ¹⁹F(α, n) yield estimates the uncertainty is on the order of 5%, establishing this as the main nuclear data limitation when simulating thermal neutron detectors response for 30B UF6 storage cylinders. Based on these findings, it appears that the measurement and evaluation of the thick target ¹⁹F(α, n) yield for uranium hexafluoride is due.
Neutrons can induce background events in underground experiments looking for rare processes. Neutrons in a MeV range are produced in radioactive decays via spontaneous fission and (α,n) reactions, and by cosmic rays. Neutron fluxes from radioactivity dominate at large depths (>1 km w. e.). A number of computer codes are available to calculate cross-sections of (α,n) reactions, excitation functions and neutron yields. We have used EMPIRE2.19/3.2.3 and TALYS1.9 to calculate neutron production cross-sections and branching ratios for transitions to the ground and excited states, and modified SOURCES4A to evaluate neutron yields and spectra in different materials relevant to high-sensitivity underground experiments. We report here a comparison of different models and codes with experimental data, to estimate the accuracy of these calculations.
The thick-target neutron yield from the 19F(α,n) reaction has been measured in 0.25-MeV steps over the energy range 3.5<~Eα<~10.0 MeV. From these measurements, 22Na production cross sections have been deduced. These cross sections are compared with the results of a Hauser-Feshbach calculation and with the results of previous experimental investigations.
This paper describes an unattended mode neutron measurement that can provide the enrichment of the uranium in UF cylinders. The new passive neutron measurement provides better penetration into the uranium mass than prior gamma-ray enrichment measurement methods. The Passive Neutron Enrichment Monitor (PNEM) provides a new measurement technique that uses passive neutron totals and coincidence counting together with neutron self-interrogation to measure the enrichment in the cylinders. The measurement uses the neutron rates from two detector pods. One of the pods has a bare polyethylene surface next to the cylinder and the other polyethylene surface is covered with Cd to prevent thermal neutrons from returning to the cylinder. The primary neutron source from the enriched UF is the alpha-particle decay from the U that interacts with the fluorine to produce random neutrons. The singles neutron counting rate is dominated by the U neutrons with a minor contribution from the induced fissions in the U. However, the doubles counting rate comes primarily from the induced fissions (i.e., multiplication) in the U in enriched uranium. The PNEM concept makes use of the passive neutrons that are initially produced from the U reactions that track the U enrichment during the enrichment process. The induced fission reactions from the thermal-neutron albedo are all from the U and provide a measurement of the U. The Cd ratio has the desirable feature that all of the thermal-neutron-induced fissions in U are independent of the original neutron source. Thus, the ratio is independent of the uranium age, purity, and prior reactor history.
Hybrid Enrichment Assay Methods for a UF6 Cylinder Verification Station
The average yields of neutrons from proton-induced reactions in thick targets have been measured for about 33 elements in the mass region 90\lesssim at incident proton energies between 5.5 and 9.5 MeV. In this region of energies and masses, the () reaction overwhelms competing reactions so that, except in a few cases, the average () cross sections deduced from the measured yields are equal to the total reaction cross sections for protons. Reduced cross sections, which are directly related to the proton strength function, were obtained from the measurements. These results, as well as the results of previous measurements for , were compared with optical-model calculations. Proton reaction cross sections calculated from the optical potential of Perey are in remarkably good quantitative agreement with the measurements. The data are consistent with a resonance in the P-wave proton strength function at A\approx, and with dominant contributions from S- and D-wave protons at A\approx and for . The measured angular distributions for some of the nuclei showed symmetry about 90\ifmmode^\circ\else\textdegree\fi{} to about 2%, indicating no measurable direct-interaction component. The maximum anisotropy observed was about 7%.
The relative neutron yield of several targets of light elements exposed to monoenergetic ionized helium beams from the Argonne tandem accelerator was determined for alpha energies ranging from 4.8 to 8.8 Mev. Our ratio of the ne.utron yields for 5.3 Mev ate in agreement with published data on thick target yields obtained with Po TM a particles. The average (a, n) yield per a particle of the natural radioactive series for some elements and for different soil compositions was calculated from our results assuming an (a, n) yield of 75 neutrons per 108
Thick-target (..cap alpha..,n) neutron yields have been measured for /sup 6,7,NAT/Li, /sup 9/Be, /sup 10,11,NAT/B, Pb/sup 19/F/sub 2/, Zn /sup 19/F/sub 2/, /sup NAT/Mg, /sup 27/Al, /sup NAT/Si, and /sup 28/Si/sup NAT/O/sub 2/. From the Pb/sup 19/F/sub 2/ and Zn/sup 19/F/sub 2/ data, we have extracted the neutron yield that would result from the (..cap alpha..,n) reaction on a thick target of pure fluorine. Using the /sup 28/Si/sup NAT/O/sub 2/ data, the yield that would result from the (..cap alpha..,n) reaction on a thick target of pure /sup NAT/O/sub 2/ and the /sup NAT/O(..cap alpha..,n) cross section at alpha-particle energies above those for which measurements previously existed have been extracted. In addition, the thin-target oxygen cross section to obtain a correction to the previously measured values. Thick-target yields are calculated from the cross-section values for carbon and oxygen and are compared to the experimental thick-target data. Thick-target yields for /sup 238/U/sup NAT/O/sub 2/ and for /sup 238/U/sup NAT/C are calculated from the thin-target cross sections. Results are compared to existing experiment and calculations.
The decay scheme of 7Be has been reinvestigated. Known numbers of 7Be nuclei were produced in targets via the 7Li(p, n) reaction. Following activation, the yields of 478-keV γ rays from the targets were measured. From three such measurements, performed at different bombarding energies, the 7Be decay branching ratio to the first excited state of 7Li has been determined to be 10.8±0.4%. The implications of this result for the solar neutrino problem are discussed.RADIOACTIVITY 7Be: measured Iγ; deduced branching ratio to first excited state in 7Li. Neutron detector. Ge(Li) detector.
A set of thick-target neutron yields from the (α, n) reaction has been constructed using available data. Values for the elements with natural isotopic abundances from Z = 3 to 14 and Z = 26 excluding Z = 10 for α-particle energies from 1.0 to 9.8 MeV are presented.
The Stopping Powers and Ranges of Ions in Matter
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