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元件破损实时监测与分析中裂变产物光子能量的选择 总被引:1,自引:0,他引:1
计算了不同裂变产物的主要γ光子对φ76.2mm×76.2mm NaI探测器光电峰的相对探测效率。结果表明,在燃料元件破损监测中,光电效应计数率最高的几种光子能量与核素是81keV(^133Xe)、196.3keV(^88Kr)、220.9keV(^89Kr)、249.8keV(^135Xe)、402.6keV(^87Kr)和529.8keV(^133I)。由于活化产物γ辐射的干扰,监测用γ光子的能 相似文献
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用γ能谱分析法作元件破损实时监测中的影响因素 总被引:2,自引:0,他引:2
本文对用γ能谱分析法反应堆燃料元件破损实时监测中的影响因素进行了分析,干扰监测的主要因素为由^19O和^16N产生的γ光子,活化腐蚀产物的γ辐射,湮灭辐射以及NaI探测器周围铅屏蔽上由高能γ产生的PbX射线,在一座压水反应堆的两次故障排除工作中,作者利用上述分析结果,对实时监测中产生的异常情况作了正确分析,并正确报判断了反应堆内元件的安全性。 相似文献
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14MeV中子在φ600mm贫化铀球中造钚率测量 总被引:1,自引:1,他引:0
使用中子活化技术对238U(n,γ)239U反应产物239U衰变后的239Np子体的278keVγ射线的绝对测量,获得了14MeV中子在600mm贫化铀球中的造钚率。其实验测量值为2.46±0.09。278keVγ射线用高纯锗探测器测量,探测器的有效计数效率用243Am源刻度。600mm贫化铀球由7层贫化铀球壳组成,球心有一80mm源腔,总重约2.1t。 相似文献
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使用片状法生长HgI2单晶片制砀20mm2×0.4mm探测器在常温下对59.5keVγ射线和5.9keVX射线的能量分辨率分别为1.9keV和900eV。已用于Cu、Pb、Zn等矿样分析,取得了新结果。 相似文献
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自制一套^37Co源激发与K系X射线荧光(K-XRF)分析系统,用^37Co的keVγ射线激发工艺溶液中U,Pu的K系X射线荧光,用HPGe探测器-多道微机分析系统进行测量,并以122keVγ射线康昔顿散射线为内标,建立强度比-浓度校正曲线,快速同地测定了PWR乏燃料后处理工艺溶液中U,Pu浓度,测定范围为0.5-200g/L,精密度为5.0%-1.5%。方法适于PWR乏燃料后处理工艺中,U,Pu 相似文献
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碘化汞半导体探测器的能量分辨率 总被引:5,自引:0,他引:5
介绍了HgI2晶体的生长方法及探测器制备技术,讨论了HgI2半导体探测器的能量分辨率,测得HgI2探测器在室温玻地^55Fe5.9keV和^241Am59.5keVA射线的能量分辨率分别为1.3keV和3.4keV。 相似文献
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用^54Mn、^57Co、^65Zn、^85Sr、^109Cd、^137Cs等核素发射的KX射线和I(KX)/I(γ)比值法在5 ̄40keV范围内对Si(Li)探测器的效率进行了刻度(不确定度小于2%)。在此基础上,用Si(Li)X射线谱仪系统和HPGeγ射线谱仪系统对核素^75Se和^113Sn的主γ射线和KX射线进行了测量,获得了^75Se和^113Sn的KX射线发射几率,并与文献报道值进行了 相似文献
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自制一套57Co源激发K系X射线荧光(K-XRF)分析系统。用57Co的122keVγ射线激发工艺溶液中U、Pu的K系X射线荧光,用HPGe探测器-多道微机分析系统进行测量,并以122keVγ射线康普顿散射线为内标,建立强度比-浓度校正曲线,快速无损地测定PWR乏燃料后处理工艺溶液中U、Pu浓度。测定范围为0.5—200g/L,精密度为5.0%—1.5%。方法适于PWR乏燃料后处理工艺中U、Pu浓度的快速控制分析或在线分析。在同时应用57Co透射源的情况下,精密度达0.5%,方法适于核燃料衡算分析。 相似文献
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HPGe低本底反康普顿γ谱仪 总被引:6,自引:2,他引:4
本文报道了以HPGe为主探测器的低本底反康普顿γ谱仪,该谱仪以环形和圆柱形NaI(TI)组成阱型反符合屏蔽探测器,以钢,铅及不锈钢等材料组成复合结构屏蔽室。对^40Co1332.5keVγ射线,HPGe主探测器能量分辨率为1.86keV,相对效率为38%,在阱型反符合屏蔽条件下,谱仪对^137Cs点状薄膜源测得康普顿抑制系数为4.4;峰康比为870:1;50 ̄2000keV能区内每min积分本底为 相似文献
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The feasibility and usefulness of a coaxial Ge(Li) spectrometer as a well-type detector for sum spectra of coincident gamma rays is demonstrated. The value of the welltype geometry has previously been established in nuclear gamma spectroscopy with the use of (NaI(Tl) detectors. In this work a 16 cm3 hollow cylindrical germaniun detector has been made and mounted in such a way that access to the center of the detector is achieved from outside the cryostat. The detector is a fully depleted structure in which a hole of 1 cm diameter was ultrasonically cut, and a non-injecting contact applied to the inside surface. The measured resolution of the detector for a 1173 keV gamma ray sum peak from 144Pm was 2.6 keV f.w.h.m, which was mainly limited by statistics and preamplifier noise. The detection of sum lines arising from 2 or more coincident gamma rays is demonstrated by using the radioactive source of 144pm. With the source inside the well, for which the counting solid angle is nearly 4?, the sum peak of three lines at 1791 keV (696 + 618 + 477) was observed with an energy resolution of 3.5 keV f.w.h.m, and a peak to background ratio greater than 15:1. For the source outside the detector at a distance of 10 cm, this sum line was not observed above background for comparable counting statistics. Comparison is also made to results obtained from a 3" well-type NaI(Tl) crystal. 相似文献
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利用同轴P型高纯锗探测器,对X荧光分析的~(238)Pu低能光子源进行γ能谱分析,并对~(233)Pa、~(224)Ra、~(212)Pb、~(212)Bi及~(208)Tl的特征γ射线进行分析,确定上述核素的来源。其中,~(233)Pa是生产~(238)Pu的原料237 Np的衰变产物,~(224)Ra、~(212)Pb、~(212)Bi及~(208)Tl均为生产~(238)Pu的副产物~(236)Pu的衰变子核。能量为350、440、844、1 014、1 130、1 266、1 368、1 454keV的γ射线是α粒子轰击源封装材料引起原子核库伦激发或γ射线照射周边环境引起核激发产生。进行效率刻度后,使用γ能谱法计算各放射性核素的活度,并根据放射性平衡计算各放射性核素的质量。通过对~(238)Pu源γ能谱的分析,建立计算放射性同位素活度与质量的方法。 相似文献
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Watabe H. Nakamura T. Takahashi H. Itoh M. Matsumoto M. Yamadera A. 《IEEE transactions on nuclear science》1993,40(2):88-94
Two types of miniature gamma-ray endoscopic probes developed for insertion into a body cavity to detect invisibly small or deeply located tumors are described. One is a single detector system using a small BGO (Bi4Ge3O12) crystal connected with a fiber optic light guide, and the other is a dual detector system using a pair of single detector probes of the same size combined with a random coincidence technique. The performance of these detectors was tested by using a point source and a hollow cylindrical water phantom that simulated a body cavity. Measured and calculated results indicated that a dual detector system can be used for realistic tumor localization in a body cavity, and a single detector system may be applied only for the detection of tumors in which radiopharmaceuticals that emit gamma rays of energy below about 200 keV are accumulated 相似文献
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Koichi Okada Atsushi Fushimi Shun Sekimoto Tsutomu Ohtsuki 《Journal of Nuclear Science and Technology》2020,57(5):514-522
ABSTRACTMonitoring only neutron flux in a nuclear reactor core has an advantage of offering reactor power monitoring accuracy. We started the development of a new nuclear instrumentation based on the measurement of prompt gamma rays emitted from metals placed at the neutron flux monitoring positions. The thermal neutron flux at the position of each placed metal piece can be monitored by measuring the prompt gamma rays as the count rate of each energy. The gamma-ray energy range was limited from 6 to 10 MeV to mitigate the interference of environmental gamma rays. Four metals, Ti, V, Ni, and Cu, were chosen as candidates in consideration of their neutron emission rates and self-absorption. In an experiment with a high-purity germanium semiconductor detector, we considered the identification of individual peak energies in an assumed situation where prompt gamma rays were emitted from the four different metals at the same time. Energy resolutions of the peak with the largest energy gap from the nearest energy peak of the other candidate metals were smaller than the gap. Thus, we confirmed that at least one peak for each candidate metal was able to be separated from the peaks derived from other candidate metals. 相似文献
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The use of modeling programs such as MCNP to predict the response of HPGe detectors is increasing in importance. Accurate simulation of germanium detectors to incident gamma rays relies on knowledge of the performance of the detector in different detector–source geometries. Two important performance parameters are the resolution and sensitivity. The resolution is the FWHM and FW.1M/FWHM ratio. The IEEE 325-1996 standard only specifies the FWHM measurement at one geometry and two energies. Nearly all measurements are made in a different geometry and at other energies. Other investigators [Specifications for Today’s Coaxial HPGe Detectors, 2001 ANS Annual Meeting, Milwaukee, WI; Metzger, private communication, see also: Radionuclide Depth Distribution by Collimated Spectroscopy, 2002 ANS Topical Meeting, Santa Fe, NM], have shown that the sensitivity and resolution change with position of the incident gamma ray on the front of the detector. Such variability has possible implications for the accuracy of peak shape and area determination, since the calibration is potentially a function of angle of incidence. To quantify the sensitivity and resolution variation as a function of energy and point of incidence, measurements have been made on several coaxial detectors of various crystal types and sizes in different source–detector geometries. The full-energy peaks from 59 keV to 2.6 MeV were used. The detectors were placed in a low-background shield to reduce any contribution from external sources. None of the detectors tested was a low-background type. The sources used were an 241Am source, 60Co source and a natural thorium oxide sample. The 241Am 59 keV gamma rays were collimated by a 2 cm thick, 1 mm diameter lead collimator. Several gamma rays from the thorium source were used and collimated by a 10 cm thick and 2 mm diameter tungsten collimator. These collimated sources were used to collect spectra for the incident beam on the front and sides of the detectors. The peak widths were calculated using the methods outlined in IEEE 325-1996. Data are presented to show that the peak shape and sensitivity change with incident beam position and full peak energy. 相似文献
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The Monte Carlo method was used to calculate the photon detection efficiency and energy resolution curves for a 1.5″ × 1″ NaI(Tl) scintillator detector (crystal + housing + photomultiplier tube material equivalent) exposed to gamma rays in the energy range from 20 keV to 662 keV. This work aims to design a precise computational model, based in Monte Carlo simulation, which can be used in practical application. The energy resolution curve was used to improve the response of the mathematical simulation of the detector. The detector was modeled with the MCNP-X code and the results were compared to experimental photopeak efficiency measurements of radiation sources. The results showed good agreement with the experimental data. 相似文献
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燃料组件是反应堆的核心部分,在高温、高压及强中子辐射场等复杂环境条件下,燃料棒中芯块会出现肿胀、变形甚至包壳破裂,严重威胁反应堆的安全运行。为了更好地了解燃料组件在反应堆内的变化,研究高燃耗的燃料组件中燃料棒的中心空洞形成和燃料棒的变形情况,高能X射线无损检测是一种有效的技术手段。由于辐照后核燃料组件自身具有强放射性,探测系统设计中必须考虑减弱燃料组件自身辐射对探测采集的影响,因此组件探测系统中探测器阵列及准直器的优化设计十分必要。经过建模及相关模拟计算,得到了探测器单元最佳尺寸,优化了后准直器的结构设计,为提高燃料组件无损检测系统重建图像的质量提供帮助。 相似文献
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Fuel assemblies are the central components of a reactor. The core fuel pellets in the fuel pins will swell and deform and the fuel cladding may even break under the complex environment of high temperature, high pressure and intense neutron radiation field, which threats the safety of the reactor. To better understand the changes in the behavior of the fuel assembly in the reactor and study the central void formations and deformations of fuel pins in fuel assemblies to high burn-up, high-energy X-ray non-destructive testing is an effective technical means. Irradiated nuclear fuel assembly has a strong radioactivity, it is necessary to optimize the design of the detector system and the collimator to reduce the effect from gamma rays emitted from the irradiated fuel assembly during detection system designing phase. Through modeling, estimating and optimization, the optimal size of the detector unit is obtained and the collimator design is optimized which can lay the foundation to improve the quality of the reconstructed images of the fuel assembly nondestructive system. 相似文献