Design of a high-dynamic-range prototype readout system for VLAST calorimeter

In the future, the Very Large Area gamma-ray Space Telescope is expected to observe high-energy electrons and gamma rays in the MeV to TeV range with unprecedented acceptance. As part of the detector suite, a high-energy imaging calorimeter(HEIC) is currently being developed as a homogeneous calorimeter that utilizes long bismuth germanate(BGO) scintillation crystals as both absorbers and detectors. To accurately measure the energy deposition in the BGO bar of HEIC, a highdynamic-range readout method using a silicon photomultiplier(SiPM) and multiphotodiode(PD) with different active areas has been proposed. A prototype readout system that adopts multichannel charge measurement ASICs was also developed to read out the combined system of SiPMs and PDs. Preliminary tests confirmed the feasibility of the readout scheme, which is expected to have a dynamic range close to 10~6.

Event plane determination from the zero degree calorimeter at the cooling storage ring external-target experiment

The Cooling Storage Ring external-target experiment(CEE)spectrometer is used to study the nuclear matter created in heavy-ion collisions at√sNN=2.1-2.4 GeV with the aim to reveal the quantum chromodynamics phase structure in the high-baryon-density region.Collective flow is considered an effective probe for evaluating the properties of media during high-energy nuclear collisions.One of the main functions of the zero-degree calorimeter(ZDC),a subdetector system in the CEE,is to determine the reaction plane in heavy-ion collisions.This step is crucial for measuring the collective flow and other reaction-plane-related analyses.In this paper,we illustrate the procedures for event plane determination using the ZDC.Finally,isospin-dependent quantum molecular dynamics model-based predictions of the rapidity dependence of the directed and elliptical flows for p,d,t,3He,and 4He,produced in 2.1 GeV U+U collisions,are presented.

Study of Complexes of Lanthanum with Amino Acids by Titration Calorimeter

The stability constants and thermodynamic functions for complexes of lanthanum with eight kind of amino acids according to 1∶1 and 1∶2 in proportion have been determined by titration calorimeter at 298.15 K. The enthalpy change makes a predominant contribution to the stability of these complexes. The ring in amino acid associated with lanthanum ion helps to enhance the stability of complexes. Steric effects between rings in complexes leads to that the equilibrium constants of reaction of the complexes (1∶2) is much less than that of the complexes (1∶1).

Energy calibration of laterally segmented electromagnetic calorimeters based on neutral pion detection

This paper describes a method for energy calibration of laterally segmented electromagnetic calorimeters based on the detection of two-photon decays of π~0 mesons.The calibration procedure performs a X^2 function minimization between the measured π~0 energy in the calorimeter and its expected energy deduced from the π~0 momentum direction. The performance of this technique is demonstrated with a Monte Carlo simulation of an experimental case where biased calibration coefficients are employed. The real calibration coefficients are restored with less than 1% relative accuracy when a sufficient number of π~0 is detected. This technique is applied to monitor daily the calibration coefficients of the calorimeter used in the Jefferson Lab Hall A DVCS experiments.

Adiabatic Decomposition of Two Kinds of Organic Peroxides by Accelerating Rate Calorimeter

The accelerating rate calorimeter was applied to study the thermal hazard of two kinds of organic peroxides, i.e. methyl ethyl ketone peroxide (MEKPO) and benzoyl peroxide (BPO). And their thermal decomposition characteristics were discussed. Meanwhile, thermal decomposition characteristics of MEKPO and BPO vvere compared. The result indicated that MEKPO is more sensitive to thermal effect than BPO. While once the thermal decomposition takes place. BPO will be more hazardous than MEKPO due to its serious pressure effect. Thermal kinetic analysis of these two kinds of organic peroxides was also taken, and the kinetic parameters for them were calculated. The study of thermal decomposition of MEKPO solution with different initial concentrations indicated that, the lower concentration MEKPO solution is, the higher onset temperature will be. And with the addition of organic solvent, it becomes more difficult for MEKPO to reach a thermal decomposition. Therefore, its thermal hazard is reduced.

Readout system for ground-based tests of BGO calorimeter of DAMPE satellite

A readout system for ground-based tests of the bismuth germanium oxide(BGO) calorimeter of the Dark Matter Particle Explorer satellite is described in this paper.The system mainly consists of a data acquisition board with a field-programmable gate array to implement the control logic, and a graphical user interface software based on LabWindows/CVI. The system has been successfully applied in a series of ground-based environmental experiments and almost all the performance tests throughout the entire manufacturing processes. These contribute significantly to the development of the BGO calorimeter before being submitted for satellite-level integration.

Physics performance of the STAR zero degree calorimeter at relativistic heavy ion collider

The zero degree calorimeter(ZDC) at RHICSTAR was installed in the year 2000.After running for more than 10 years,the performance of the STAR-ZDC cannot maintain a proper status because of the radiation damage.The ZDC on RHIC-BRAHMS had been moved to STAR in 2011 after some tests.We present here the result of the tests as well as the physical performance of those ZDC modules between the 2011 and 2015 RHIC runs.The excellent energy resolution of the ZDC in heavy ion collision provides a good candidate for future detector development,such as the CSR experiment at CAS-Lanzhou facility.

Heat of Boron Trifluoride–Methanol System Determined by Bunsen Ice Calorimeter

The complex heat of BF_3 with methanol was measured by utilizing the principle of the Bunsen ice calorimeter. The complex heat of BF_3 –methanol was found to be 49.2 and 58.1 kJ/mol when the molar ratio of BF_3 to methanol was 1:2 and 1:1,respectively. In addition,the complex heat of BF_3 –anisole was also measured to test the apparatus error. The BF_3 –anisole result showed a calorimeter value of 53.1 kJ/mol with a system error of 2.3% as compared with the value reported in the literature. The mechanism of the reaction of BF_3 and methanol was interpreted based on our obtained results. This apparatus is useful and suitable for measuring the heat of other liquid–gas and liquid–liquid reactions.

Proposed Cone Calorimeter for Woven Carpet

It is necessary to achieve the best specifications in carpets that provide safety to human health in establishments and buildings. This can be achieved by reducing the emissions of toxic gases from combustion via controlling the carpets composition. This research presents a study on carpets behavior when burning samples with different mixing specifications to determine the combustion products by conducting a test using cone Calorimeter to determine the effect of different structures of the carpet on combustion products. The study includes the effect of both the quality of the material used and their different densities and thicknesses. The research provides an analysis of carpet combustion products from different emissions, such as the amount of carbon monoxide CO, the amount of carbon dioxide CO2, smoke density, heat of combustion, and the heat released rate. It is clear that the rate of heat released is uneven in samples with different percentages of mixing. The samples with higher mixing percentage of synthetic fibers give lower temperature while the samples with higher wool percentage give higher temperature. The temperature of combustion increases gradually with the increase of the percentage of wool while the density of the smoke decreases which achieves the required safety of carpets. In addition to this, the research proves the increase of both CO and CO2 as the percentage of synthetic fibers in products which confirms the necessity to avoid the adverse effects of these emissions on human health.

Comparison of Proton Shower Developments in the BGO Calorimeter of the Dark Matter Particle Explorer between GEANT4 and FLUKA Simulations

The DArk Matter Particle Explorer(DAMPE)is a satellite-borne detector for high-energy cosmic rays and y-rays.To fully understand the detector performance and obtain reliable physical results,extensive simulations of the detector are necessary.The simulations are particularly important for the data analysis of cosmic ray nuclei,which relies closely on the hadronic and nuclear interactions of particles in the detector material.Widely adopted simulation softwares include the GEANT4 and FLUKA,both of which have been implemented for the DAMPE simulation tool.Here we describe the simulation tool of DAMPE and compare the results of proton shower properties in the calorimeter from the two simulation softwares.Such a comparison gives an estimate of the most significant uncertainties of our proton spectral analysis.

Study of Burning Behaviors and Fire Risk of Flame Retardant Plywood by Cone Calorimeter and TG Test

A flame retardant composition was prepared by using phosphoguanidine,guanidine sulfamate,disodium octaborate tetrahydrate and dodecyl dimethyl benzyl ammonium chloride.Veneers were immersed in such flame retardant mixture to prepare plywood.The combustion characteristics and thermal stability of plywood were assessed using a cone calorimeter and TG.Results showed that:(1)High concentration and loading of flame retardant were beneficial for the fire resistance of the plywood.(2)The limiting oxygen index(LOI)and residual mass of plywood processed using the flame retardant was increased by 87.52%and 58.66%compared to those of the untreated plywood,while the average heat release rate(av-HRR),total heat release(THR),effective heat of combustion(EHC),total smoke release(TSR),CO yield(COY),CO_(2) yield(CO_(2)Y)and oxygen consumption were decreased by 44.3%,82.9%,47.0%,86.0%,89.9%,50.1%and 83.1%,respectively.(3)Treated plywood which had a low fire growth index(FGI)displayed a later combustion heat release rate peak and slower flame spread than observed for the untreated material.Combustion of treated plywood displayed a higher fire performance index(FPI),indicating a longer time to ignition.This suggests that burning structures from this material would be subject to a longer time for escape from the structure and would present lower fire risk than similar structures containing treated plywood.(4)TG results demonstrated that the presence of the flame retardant can decrease the pyrolysis temperature for hemicellulose and cellulose,change the decomposition and reaction progress for plywood degradation and promote dehydration carbonization and accelerated charformation.Moreover,the formed char was more stable than that combustion of untreated plywood.(5)The flame retardant contains nitrogen(N),phosphorus(P),boron(B),chlorine(Cl)and guanidine(Gu)compounds.The adhesive also contains N and P compounds.These substances display flame resistance and supplement each other to generate flame retardance than any one used alone.By changing the thermolysis and thermal decomposition processes,the heat release and smoke release from plywood,undergoing combustion was reduced.This controlled generation of combustible substances and promoted dehydration and carbonization to form char.As a result,the flame resistance of plywood was improved significantly.The probability of smoke asphyxia or poisoning death of those trapped in structures containing treated plywood during fire accidents can be decreased dramatically.

Theoretical and experimental assessment of a novel method to establish the complete measurement range of the calorimeter and its limit of detection and quantification

For determining the accuracy of a calorimeter over the instrument’s entire measuring range,a novel method has been established.For this new approach,(a)benzoic acid(C_(6)H_(5)CO_(2)H) as a certified reference material(CRM),(b)SiO_(2) and(c)a mixture of CRM benzoic acid and SiO_(2) have been used.To illustrate the essential difference between 1)the novel analytical method for control of the entire measurement range and 2)the calorimeter calibration,both applications of benzoic acid(BA)have been demonstrated.An experimental result showed that BA was successfully used to check the whole calorimeter measurement range.The results also showed that the same new method was successfully applied to determine the limit of detection and quantification.A new instrument testing process and a new measurement technique have thus been established.In this way,the cost of using CRM to control the accuracy of measuring the entire measuring range of the calorimeter,as shown in this paper,is minimized.The requirements of the ISO/IEC 17025:2017 standard are satisfied.ISO/IEC 17025:2017,together with ISO 9001:2015(quality management systems),ISO 14001:2015(relate to environmental protection)and ISO45001:2018(occupational safety),constitute an integrated quality system by which a testing laboratory may also accredit.

Refractory Materials-Determination of Thermal Conductivity(Calorimeter)YB/T 4130-2005

1 Scope This standard specifies the definition, theory, equipment, samples, test procedures, test error, etc. of test method （calorimeter） for thermal conductivity of refractories.

New method for analyzing recrystallization kinetics of deformed metal by differential scanning calorimeter

The drawn copper wires have been analyzed by differential scanning calorimeter(DSC) and a new method, which uses DSC measurements to determine the Johnson-Mehl-Avrami-Kolmogorov(JMAK) exponent via introducing Arrhenius behavior and modifying the baseline of DSC curves, has been proposed. The results show that JMAK exponent and recrystallization activation energy of the drawn copper wires with a strain of 2.77 are about 2.39 and 125 k J/mol, respectively. The line linking the tangency points of DSC curve hypotenuse can be used as the baseline when calculating recrystallization fraction. The JMAK exponent obtained by the DSC method is in a good agreement with that obtained by microhardness measurements. Compared to traditional methods to measure the exponent, the proposed method is faster and less labor intensive.

饲用油脂总能测定条件优化研究

试验选用氧弹量热法进行饲用油脂总能测定条件优化研究。选用豆油、调和油作为试验材料,研究是否添加基质对总能测定结果的影响,进行检测方法优化;选用11种油脂作为试验材料,验证不同试样质量(0.4、0.6、0.8、1.0、1.2 g)对测定结果的影响;选用5种油脂作为试验材料,比对不同仪器对测定结果的影响。结果表明:测定豆油总能,添加基质后测定结果变异系数大,重复性差(P<0.05),不添加基质重复性好(P>0.05);不添加基质方法进行日内、日间试验,测定结果差异不显著(P>0.05),测定结果稳定性好(P<0.05)。不同试样质量对豆油、调和油、椰子油、月桂酸、鱼油、鸡油1#、鸡油2#、猪油1#、猪油2#等9种油脂总能测定结果差异不显著(P>0.05),对棕榈油总能测定结果表现为差异显著(P<0.05),对磷脂总能测定结果表现为差异极显著(P<0.001),试样质量适宜范围为0.6~0.8 g。两种氧弹量热仪测定椰子油、棕榈油、豆油、月桂酸、磷脂5种油脂相同试样质量,测定总能结果差异不显著(P>0.05)。本试验条件下,油脂测定试验无需添加基质,该方法测定总能结果稳定、重复性好。不同试样质量对豆油、调和油、椰子油、月桂酸、鱼油、鸡油1#、鸡油2#、猪油1#、猪油2#等9种油脂表现为差异不显著,适宜试样质量为0.4~1.0 g;对棕榈油表现为差异显著,适宜试样质量为0.6~1.0 g;对磷脂表现为差异极显著,适宜试样质量为0.8~1.0 g。用两种氧弹量热仪测定油脂总能结果无明显差异。

长脉冲高功率负离子源实验平台量热靶研制

[目的]高能、强流、长脉冲中性束负离子源技术是磁约束聚变堆等离子体达到燃烧条件的核心技术之一。为满足长脉冲高功率负离子源实验平台200 kV/20 A参数下的束诊断需求,研制了用于截获负离子束或中性束、诊断两种束功率密度分布和束发散角以及负离子的中性化效率等性能参数的量热靶。[方法]根据现有的实验平台真空室结构和引出电极尺寸,利用matlab程序获得了该参数下,束发散角为1°时的负离子束在量热靶前端处的功率密度分布和束斑尺寸,进而设计了V字形靶板的量热靶物理结构;在此基础上采用Workbench软件对无氧铜V字形靶板结构进行满功率运行状态下的热负荷模拟计算,获得了水流量为80 m~3/h条件下的量热靶长脉冲运行时的温度分布,最高温度为610℃。[结果]根据模拟计算结果,结合实验平台工程结构和诊断需求,完成了量热靶的工程设计。[结论]量热靶采用磁流体真空密封,实现V字形靶板开合,靶板背面布置了热电偶阵列实时监测靶板温度。量热靶工程结构紧凑,安装尺寸能够兼容离子束流诊断真空室和中性束流诊断真空室,满足诊断需求,能够长脉冲安全运行。

核心层厚度对聚乙烯基铝塑板燃烧特性影响研究

通过锥形量热仪研究了不同核心层厚度聚乙烯基铝塑板的燃烧特性。选用35、50、65、80 kW/m2共4种热流强度,得到不同核心层厚度铝塑板的点燃特性、火灾风险和烟气毒性等。结果发现:聚乙烯基铝塑板符合热薄型材料点燃规律,3、4、5 mm厚核心层铝塑板临界点燃热流强度的推导值分别为33.9、25.1、9.9 kW/m2。铝塑板燃烧的热释放速率随热流强度增加而明显增加,且有向双峰发展的趋势。随着热流强度和铝塑板核心层厚度增加,聚乙烯基铝塑板的火灾性能指数(FPI)由41迅速下降到0.14,火灾蔓延指数(FGI)则由0.02迅速增加到3.19,CO释放速率也迅速增大,导致火灾危险性大幅增加。

质子束水量热计中量热芯的超纯水制备与预辐照

针对质子束的水吸收剂量绝对测量中化学热缺陷的修正问题,本研究基于热敏电阻研制水量热计,并进行气体饱和超纯水系统的设计。通过向量热芯内的超纯水充入高纯气体形成饱和状态,最大程度减少辐射化学反应的产额。在量热芯封装后通过预辐照,使量热芯超纯水中O2充分发生辐解反应,使量热芯内水环境达到无热损的稳定状态,成功研制了稳定的零热损水量热计,减少了量热芯热损对水吸收剂量绝对测量结果的影响,可为后续水吸收剂量的绝对测量提供技术支持。

基于Krylov子空间降阶的温控算法研究

针对当前常用的散热前馈获取方法存在耗时长、能耗大、步骤繁杂等缺点,文中提出引入模型降阶方法获取散热前馈。通过3组实验获取控制对象响应特性;对在ANSYS Workbench仿真平台建立的控制对象模型进行校正,使仿真模型特性与实际控制对象特性尽可能相同;使用Krylov子空间法对仿真模型进行降阶,降阶后的模型可以通过Matlab计算得出散热前馈;以差示扫描量热仪炉体为控制对象验证散热前馈-PID控制策略的效果。实验结果表明,在环境温度至300℃范围内,扫描模式温控误差小于±5%,恒温模式温控误差小于±0.2℃。