Design and test results of a low-noise readout integrated circuit for high-energy particle detectors

A low-noise readout integrated circuit for high-energy particle detector is presented.The noise of charge sensitive amplifier was suppressed by using single-side amplifier and resistors as source degeneration.Continuous-time semi-Gaussian filter is chosen to avoid switch noise.The peaking time of pulse shaper and the gain can be programmed to satisfy multi-application.The readout integrated circuit has been designed and fabricated using a 0.35 μm double-poly triple-metal CMOS technology.Test results show the functions of the readout integrated circuit are correct.The equivalent noise charge with no detector connected is 500–700 e in the typical mode,the gain is tunable within 13–130 mV/fC and the peaking time varies from 0.7 to 1.6 μs,in which the average gain is about 20.5 mV/fC,and the linearity reaches 99.2%.     

Development of hybrid photon detectors with integrated siliconpixel readout for the RICH counters of LHCb

We report on the ongoing work towards a hybrid photon detector with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment at the Large Hadron Collider at CERN. The photon detector is based on a cross-focussed image intensifier tube geometry where the image is demagnified by a factor of 4. The anode consists of a silicon pixel array, bump-bonded to a fast, binary readout chip with matching pixel electronics. The developments and tests of full-scale prototypes with 80% active area are presented. Specific requirements for pixel front-end and readout electronics in LHCb are outlined, and recent results obtained from pixel chips applicable to hybrid photon detector design are summarized     

带增益的气体探测器读出ASIC的研制

设计了用于带增益的气体探测器比如GEM、RPC等读出的ASIC,实现对探测器信号的放大、成形和对后续实时采样ADC的驱动电路.电荷增益和成形时间可调,有利于探测器不同增益下性能的研究,也扩展了芯片的应用范围.由于成形电路引入的噪声变得显著,在低电荷增益下,ENC会随增益下降而增加.芯片采用Chartered 0.35μm2P4M CMOS工艺,论文介绍了芯片的详细设计和仿真结果.     

Monte Carlo simulations of response functions for gas filled and scintillator detectors with MCNPX code

Monte Carlo simulation of a detector response function presents a very challenging problem. The detector response functions have been calculated for different neutron and gamma detectors: ³He gas filled proportional counter, NE213 organic scintillator, BrillanCe 350 or LaCl₃(Tl), and an ionization chamber with mixed gas composition. MCNPX code was used for simulations. The simulations were done with different neutron and gamma energies. The effects of neutron scattering, wall effects, recoil continua and contribution from charged particles have been included. The detector response function for the NE213 organic scintillator was obtained with consideration of light output curves of different products of neutron reactions with materials of the scintillator. The simulated data has been compared with experiments.     

一种前端ASIC芯片测试系统的设计与实现

介绍了一种专用集成电路芯片性能测试系统的设计与实现,该芯片适用于构建硅探测器前端读出电子学.描述了测试系统主要硬件电路设计,基于CPLD的快读出控制时序发生模块的实现,利用并口线来模拟I2C总线的方法,系统的调试和主要性能的分析.     

Resolution and sensitivity as a function of energy and incident geometry for germanium detectors

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.     

Depletion voltage and charge collection for highly irradiatedsilicon microstrip detectors with various initial resistivities

We have irradiated p-on-n silicon microstrip detectors of initial bulk resistivity between 0.2 and 2.7 kΩ-cm with 55 MeV protons to fluences of 0.7, 2 and 11×10¹³ p/cm² (equivalent to twice the fluence in high energy protons), and have measured the depletion voltage before and after irradiation using C-V methods. In addition, we have measured the charge collection of minimum ionization on a single strip with a fast amplifier as a function of bias voltage. We compare the depletion voltage deduced from both methods for samples with different initial resistivities     

Method for calculating the transmission of gamma spectrometers with semiconductor detectors and volume radiation sources

Translated from Atomnaya Énergiya, Vol. 65, No. 4, pp. 288–290, October, 1988.     

加压贮存和活性炭吸附在核电站放射性废气处理中的应用

加压贮存和活性炭吸附是目前国内处理压水堆核电站放射陛废气最常用的两种方法。以大亚湾核电站和田湾核电站的放射性废气处理系统为例,并结合国内其他核电机组同类系统,分别介绍这两种方法在国内核电站的应用情况,并分析它们各自的优缺点：加压贮存系统结构简单但设备体积庞大,适合处理流量变化较大的放射性废气;活性炭吸附具有安全性高,操作简单的特点,适合于处理流量较小的放射性废气。     

Resonance ionization in a gas cell: a feasibility study for a laser ion source

A laser ion source based on resonance photo-ionization in a gas cell is proposed. The gas cell, filled with helium, consists of a target chamber in which the recoil products are stopped and neutralized, and an ionization chamber where the atoms of interest are selectively ionized by the laser light. The extraction of the ions from the ionization chamber through the exit hole-skimmer setup is similar to the ion-guide system. The conditions to obtain an optimal system are given. The results of a two-step one-laser resonance photo-ionization of nickel and the first results of laser ionization in a helium buffer gas cell are presented.     

Development of a passive fast-neutron spectrometer based on electrochemically etched CR-39 detectors with radiators and degraders

In the present paper we describe, first, our theoretical and experimental work to determine the registration properties of electrochemically etched (ECE) CR-39 detectors to protons. Here, we have irradiated CR-39 detectors with monoenergetic protons over the energy range of 0.6 to 6 MeV, at normal incidence, and found that the lower and upper limits of protons energies that can yield ECE spots in CR-39 are ~ 50 keV and ~ 2.2 MeV, respectively. The ECE registration limits at other angles have been determined by attuning the calculated response of bare CR-39 to the experimental response values. The paper then proceeds to describe a technique developed by us for the energy-selective fast-neutron detection. This technique is based on the ECE spot-density measurements in CR-39 detectors placed in conjunction with judiciously chosen thicknesses of a polyethylene radiator and a lead degrader (or absorber). The optimum thicknesses of the radiator and degrader. for a given neutron energy, are determined from computer calculations.     

Study of localised radiation damage to PIPS detectors by a scanning ion microprobe: Measured effects and the consequences for STIM analysis

Radiation damage effects in a PIPS particle detector have been studied by direct irradiation with a 4 MeV He⁺ focused ion beam, using the Eindhoven scanning ion microprobe set-up. This set-up enables extreme sensitivity and accuracy in pulse-height measurement. Pulse-height dependence on ion dose and the lateral variations of pulse-height response after damaging were studied, for different bias voltages. Pulse height was found to decrease linearly with ion dose and this could be observed after only a few ions per scan position, corresponding to a dose of 10⁸/cm². Pulse-height loss was found to be restricted to damaged detector areas. Consequences of this pulse-height dependence on ion dose and scan position for the accuracy of STIM analyses are discussed.     

Evaporation and condensation heat transfer with a noncondensable gas present

To evaluate the system pressure of an external water wall type containment vessel, which is one of the passive systems for containment cooling, the evaporation and condensation behavior under a noncondensable gas presence has been experimentally examined. In the system, steam evaporated from the suppression pool surface into the wetwell, filled with noncondensable gas, and condensed on the containment vessel wall. The system pressure was the sum of the noncondensable gas pressure and saturated steam pressure in the wetwell. The wetwell temperature was, however, lower than the supression pool temperature and depended on the thermal resistance on the suppression pool surface. The evaporation and condensation heat transfer coefficients in the presence of air as noncondensable gas were measured and expressed by functions of steam/air mass ratio. The evaporation heat transfer coefficients were one order higher than the condensation heat transfer coefficients because the local noncondensable gas pressure was much lower on the evaporating pool surface than on the condensing liquid surface. Using logal properties of the heat transfer surfaces, there was a similar trend between evaporation and condensation even with a noncondensable gas present.     

基于3D Si PIN阵列热中子探测器的变增益宽动态前端读出电子学设计

基于Si CMOS技术的前端读出ASIC主要是根据3D Si PIN阵列热中子探测器的输出信号特性设计的。所设计的读出ASIC的主要电路模块包括电荷灵敏放大器（CSA）、模拟开关设计、具有三级电荷灵敏自动转换的自动增益控制模块（AGC）、相关双采样（CDS）和基准电流源电路。仿真结果表明,前端电路的输入动态范围为10 fC~80 pC。根据热中子探测器输出信号特性设计的ASIC的3个增益系数分别为19 V/pC、039 V/pC和94 mV/pC。所设计的ASIC的积分非线性小于 1%。单通道静态功耗约为 536 mW。零输入探测器电容时的等效噪声电荷为2416e-。计数率可达1 MHz 。     

Fracture and general yield for carbon steel pipes with local wall thinning

Monotonic bending tests without internal pressure are conducted on 4 and 3.5 in. diameter full-scale carbon steel pipe specimens with local wall thinning in order to evaluate the structural integrity of power plant piping. The local wall thinning is simulated as erosion/corrosion metal loss. The eroded area of the wall thinning is subjected to tensile or compressive stress by applied bending moment. The maximum moments obtained from the tests are compared with the plastic collapse moments based on the net-section stress approach. The net-section stress approach based on flow stress σ_f gives a conservative estimation, sometimes overly conservative. Although the net-section approach based on ultimate tensile strength σ_u gives a slightly non-conservative estimation for some cases, the calculated values are close to the experimental data. Using the net-section stress approach based on σ_u, the eroded depth and the angle at which a pipe undergoes general yielding were obtained.     

Energy conversion in a gas shock tube: Theory and experiments

The gas shock tube used in these experiments consists of a low pressure chamber and a high pressure chamber, divided by a metal-diaphragm-to-rupture. In contrast to the shock mode of operation, where incident and reflected shocks in the low pressure chamber are studied which occur within 3.5 ms, in this work the compression mode of operation was studied, whose maxima occur (in the low pressure chamber) about 9 ms after rupture. Theoretical analysis was done with the finite element computer code EURDYN-1M, where the computation was carried out to 30 ms.The compression mode was enforced by inserting on the low pressure side, just behind the diaphragm, a small piston. In the corresponding analysis the computation time was up to 112 ms.Results showed that the work done on the low pressure gas could be approached with adiabatic compression. It was extrapolated that at high pressure loads, the work done corresponded to 1.5% of the potential energy in the high pressure chamber when no piston was used, and to 4% when a piston was used.     

Penetration depth and concentrationdistribution for implanted heavy ions with low energies in plant seeds bySEM and EDS

The penetration depth and concentration distribution of implanted ions have been studied for low energy heavy ions implanted in the dry seeds of plant,such as peanut,mung bean,sunflower,wheat and radish seeds,etc.by SEM EDS.The results show that the maximum penetration depth is about 12μm for V^ with an energy 200keV implanted in cotyledon of the peanut,18μm,15μm,20μm for V^2 with 90keV implanted in sunflower,wheat,radish seeds,respectively.The penetration depth of implanted Cu^2 with 80keV is about 90μm in the remainder funicle derivative of the mung bean seeds.The experimental result of the maximum penetration depth of implanted V^ in the peanut seeds was compared with the calculated value of the TRIM95.