Sensitivity improvement of a two-mode gravitational-radiation detector through the use of a transducer not perfectly tuned to the antenna

Summary The detailed analysis of the behaviour of a gravitational-wave antenna coupled to a passive resonant transducer has been performed for short bursts of gravitational radiation. An expression for the noise temperature of the system is given for the general case of a transducer with resonant frequency and mechanical quality factor different from those of the antenna. The analysis of the optimum noise temperature obtainable for a given system shows that the optimum performance is obtained when the frequency of the transducer is slightly different from that of the antenna. The main point of this paper has been presented byC. Cosmelli at theSecond Workshop on Precision Measurements on Relativistic Effects in Astrophysical Systems, held in Rome, 11–13 July 1983.     

Observable signatures of a black hole ejected by gravitational-radiation recoil in a galaxy merger

According to recent simulations, the coalescence of two spinning black holes (BHs) could lead to a BH remnant with recoil speeds of up to thousands of km s(-1). Here we examine the circumstances resulting from a gas-rich galaxy merger under which the ejected BH would carry an accretion disk and be observable. As the initial BH binary emits gravitational radiation and its orbit tightens, a hole is opened in the disk which delays the consumption of gas prior to the eventual BH ejection. The punctured disk remains bound to the ejected BH within the region where the gas orbital velocity is larger than the ejection speed. For a approximately 10(7) M[middle dot in circle] BH the ejected disk has a characteristic size of tens of thousands of Schwarzschild radii and an accretion lifetime of approximately 10(7) yr. During that time, the ejected BH could traverse a considerable distance and appear as an off-center quasar with a feedback trail along the path it left behind.     

Radiation effects on a GE:GA photoconductive detector

We have investigated radiation effects on a Ge:Ga photoconductive infrared detector at low photon background level of 4×10⁸ ph cm^–2s^–1, using Cobalt 60 as a gamma ray source. The irradiation immediately induced spike noises which degrded NEP (short term effect), while it gradually increased responsivity (long term effect). After the removal of the gamma ray source, the spikes disappeared while the responsivity still stayed in a higher level and gradually decreased with a time scale of several hours. The responsivity-change-rate before and after the irradiation is smaller for a higher bias voltage. Finally we have made the first trial to cure the long term effect, using a flashing procedure and have found out its effectiveness.     

Asymmetries in semi-leptonic hyperon decay

Based on the thermodynamic model for particle production, inclusive two-particle correlations are studied. The model is used to study integrated correlations R⁽²⁾(s) and rapidity correlations at accelerator and ISR energies.Particle production is described via the formation of clusters called fireballs. The average mass of these clusters changes as $\text{s}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext><mtext>w</mtext>}}\text{exp}\text{(? |η|ν), (0 ? ν, w ? 1)}$ with the primary energy s and fireball rapidity η. The model produces in the limiting cases the same correlations as the multiperipheral model (with w = 0) and the diffractive excitation model (with w = 1) but contains also all intermediate cases (0 < w < 1) in which fireballs increasing in mass and number are formed. The average number of fireballs produced is also calculated. At ISR energies integrated correlations R⁽²⁾ and rapidity correlations are very different in the cases $\text{w = 0,}\text{1}\text{2}\text{and}\text{1}$. Therefore, experimental data at high energy on R⁽²⁾(s) or on rapidity correlations will allow one to determine the parameter w. Measurements of these different quantities should result in a consistent picture for the production of fireballs.     

基于四象限光位置检测器的同步光位置测量系统

为了克服现有双丝型检测器无法进行水平、垂直两个方向同时测量同步光位置的缺点,合肥光源新研制了基于四象限光位置检测器的同步光位置测量系统,并使用对数比处理技术进行后续的数据处理。通过分别对光学成像系统和四象限光位置检测器的标定,最终得到基于四象限光位置检测器的光位置测量系统的性能参数为:水平方向灵敏度0.471 2 mm-1,线性范围为±1.83 mm,垂直方向灵敏度0.635 0 mm-1,线性范围±1.32 mm。与合肥光源现有的光位置测量系统相比,具有较高的性价比。     

多元探测器在玫瑰扫描红外亚成像系统中的应用

玫瑰扫描红外亚成像系统是利用玫瑰扫描机构和红外单元探测器构成的一种亚成像系统。提出了一种利用多元小面阵来替代单元探测器的红外亚成像系统 ,可以提高成像系统的空间分辨率和帧频。分析了系统的原理 ,并给出了系统的构成框图。此外 ,就玫瑰扫描成像系统中应用多元探测器可能出现的问题进行了讨论 ,并提出了解决方案。结果表明 ,这种多元小面阵玫瑰扫描成像系统的成本远低于焦平面阵列探测器红外成像系统 ,在性能改善后是诸如末制导炮弹等低成本应用场合的理想红外成像系统     

On the optimum thickness of a photoconductive detector: A 0.1 eV HgCdTe detector

The effect of the variation of detector thickness on the voltage responsivity, g-r noise and the specific detectivity of a 0.1 eV HgCdTe photoconductive detector has been calculated. The results of these calculations show that the optimum thickness of the detector should be determined by the diffusion length of the minority carriers rather than the optical absorption coefficient.     

A fast detector system with cooled NaI-scintillators

Detector systems with cooled non-thallium-activated NaI-crystals allow to improve the time resolution in -coincidence experiments. Such a system has been developed and yielded typical time resolutions a factor of 2.5 better than conventional NaI(Tl)-systems. Two examples for possible applications are given.     

探测器前放组合件测试系统设计

介绍了一个利用虚拟仪器技术开发的探测器前放组合件测试系统。系统以工控机为主控平台,结合自研的图像采集与处理单元、切换控制单元,利用虚拟仪器开发软件Labview2011,实现对单个前放模块常温测试,对两发探测器前放组合件同时高低温、常温测试。对探测器盲元的检测做了详细的说明和分析。通过现场实际使用,证明了该系统测试精度高,完全满足了微弱小信号μV级测试,自动化程度高,测试速度快,实现了对测试数据、图表、图像的采集、保存和回放。     

Infrared scene displays and their use in detector and processor assessment

Broad bandwidth infrared display systems have been developed for use in evaluating infrared imagers and processors. The displays use electrically heated diode resistor arrays as the emitting devices which are line at a time addressed. The displays have a black body emission spectrum and accept data electronically. Maximum display temperature exceeding 25 K, temperature resolution of 0.1 K and a time constant of 10 ms have been demonstrated in a 100 line system.     

Autocorrelation measurement of femtosecond laser pulses by use of a ZnSe two-photon detector array

We demonstrate autocorrelation measurements of 85-fs Ti:sapphire laser pulses, using a 32-pixel ZnSe detector array in a single-shot geometry. The two-photon photoconductor is fabricated by deposition of an array of interdigitated gold fingers on a single-crystal ZnSe substrate.     

狭缝式高灵敏裂变中子探测系统

研制了狭缝-外延式高灵敏大面积PIN裂变中子探测系统. 其对14MeV，2.5MeV中子灵敏度可达10^-16C·cm²，比原有典型的脉冲裂变中子探测系统高4个量级. 采用外延式铅狭缝准直结构，研制灵敏区尺寸为60mm，厚度为200μm—300μm的大面积PIN半导体探测器、以Be膜为衬底，有效直径为60的²³⁵U裂变靶，解决了该探测器研制中的高灵敏度和n/γ分辨难题. 该系统已在实践中获得成功应用. 关键词： 裂变中子探测系统 大面积PIN探测器 大面积裂变靶 高灵敏探测系统     

Discussion on a possible neutrino detector located in India

We have identified some important and worthwhile physics opportunities with a possible neutrino detector located in India. Particular emphasis is placed on the geographical advantage with a stress on the complimentary aspects with respect to other neutrino detectors already in operation.     

热释电探测器积分响应测试系统研究

为了实现对红外探测器积分响应的自动测量,配合虚拟仪器技术搭建了一套热释电红外探测器积分响应自动测试系统。利用双绞线将测试仪器与计算机连接,以LabVIEW为开发平台编写软件测试系统,遥控测量仪器,实现计算机自动采集和处理数据实时绘制曲线,对LT-020-H型热释电红外探测器在不同调制频率下的积分响应度进行了测试并分析。在500K的黑体辐射下,探测器积分响应度达到3.5×106V/W。通过对实验结果进行分析,得到了探测器响应、黑体辐射温度以及信号调制频率之间的关系。     

基于高纯锗γ谱仪的环境放射性测量

随着我国核电事业发展,人们对环境中的放射性问题越来越关注.基于高纯锗γ谱仪的环境放射性测量实验,提供了有效的途径让学生将核物理知识与日常生活中大家关心的环境辐射问题联系起来.该实验充分利用高纯锗γ谱仪对环境中γ放射性具有很好的能量分辨的特性,通过对伽马能谱的测量结果分析得到地球环境中放射性来源.这套探测系统需要学生通过调试各项参数找到谱仪的最佳工作状态,该过程让学生掌握高纯锗γ谱仪的工作原理和特性,为以后核物理领域科研工作打下基础;另外,通过对~(152)Eu和环境γ谱的分析学生会初步了解复杂γ谱的谱学分析方法.     

射线平板探测器成像系统的数理模型

非晶硅X射线数字平板探测器是目前唯一可取代胶片照相的新型技术,对其成像特性的研究已成为高像质的DR和三维CT检测技术的基础。目前X射线成像系统均是以线性时不变理论作为分析基础的。基于X射线平板探测器成像系统、成像机理和几何参数建立了成像系统的点扩展函数(PSF)。用圆柱体等效二维PSF模型,使成像系统退化为比例系统,从而把复杂的反卷积运算转化成用代数方程来求解,能够快速实现通过探测器输出图像来估计透照工件的二维输入图像。此模型的建立为在实际检测中利用输出的图像通过线性变换得到输入估计。在DR系统中,基于上述数理模型建立了灵敏度模型,利用输出场强可以很好的再现输入场强。     

Silex-I飞秒激光装置X射线探测系统时间特性北大核心CSCD

在Silex-Ⅰ飞秒激光装置上,利用32fs、800nm的激光辐照平面金靶,产生小于1ps的X射线脉冲,作为δ脉冲X射线源,研究XRD探测器的时间响应特性,并且探索X射线条纹相机时间分辨和分幅相机曝光时间的X射线标定方法。实验给出了XRD探测器的时间响应特性。解决了条纹相机和分幅相机触发晃动问题,给出了条纹相机时间分辨和分幅相机曝光时间的X射线标定方法,初步给出条纹相机时间分辨和分幅相机曝光时间。     

Search for light penetrating bosons with the use of a rotatable detector arrangement at a nuclear reactor

The search for the two-photon decay of light penetrating bosons (axions or others), produced in a nuclear reactor, was supplemented by measurements with a rotatable set-up at the Jülich 10 MW research reactor FRJ-1. Measurements were performed in “effect” and “background” positions, the latter not allowing the simultaneous detection of both photons due to decay kinematics. Preliminary measurements, carried out at reactor ON condition only, show no positive effect.