Thermodynamic performance of the 3-stage ADR for the Astro-H Soft-X-ray Spectrometer instrument

The Soft X-ray Spectrometer (SXS) instrument (Mitsuda et al., 2010) [1] on Astro-H (Takahashi et al., 2010) [2] will use a 3-stage ADR (Shirron et al., 2012) to cool the microcalorimeter array to 50 mK. In the primary operating mode, two stages of the ADR cool the detectors using superfluid helium at ⩽1.20 K as the heat sink (Fujimoto et al., 2010). In the secondary mode, which is activated when the liquid helium is depleted, the ADR uses a 4.5 K Joule–Thomson cooler as its heat sink. In this mode, all three stages operate together to continuously cool the (empty) helium tank and single-shot cool the detectors. The flight instrument – dewar, ADR, detectors and electronics – were integrated in 2014 and have since undergone extensive performance testing. This paper presents a thermodynamic analysis of the ADR’s operation, including cooling capacity, heat rejection to the heat sinks, and various measures of efficiency.     

Operating modes and cooling capabilities of the 3-stage ADR developed for the Soft-X-ray Spectrometer instrument on Astro-H

A 3-stage adiabatic demagnetization refrigerator (ADR) (Shirron et al., 2012) is used on the Soft X-ray Spectrometer instrument (Mitsuda et al., 2010) on Astro-H (Takahashi et al., 2010) [3] to cool a 6 × 6 array of X-ray microcalorimeters to 50 mK. The ADR is supported by a cryogenic system (Fujimoto et al., 2010) consisting of a superfluid helium tank, a 4.5 K Joule–Thomson (JT) cryocooler, and additional 2-stage Stirling cryocoolers that pre-cool the JT cooler and cool radiation shields within the cryostat. The ADR is configured so that it can use either the liquid helium or the JT cryocooler as its heat sink, giving the instrument an unusual degree of tolerance for component failures or degradation in the cryogenic system. The flight detector assembly, ADR and dewar were integrated into the flight dewar in early 2014, and have since been extensively characterized and calibrated. This paper summarizes the operation and performance of the ADR in all of its operating modes.     

ADR design for the Soft X-ray Spectrometer instrument on the Astro-H mission

In its instrument suite, the Japanese Astro-H mission will include the Soft X-ray Spectrometer (SXS), whose 36-pixel detector array of ultra-sensitive X-ray microcalorimeters will be cooled to 50 mK. This will be accomplished using a two-stage adiabatic demagnetization refrigerator (ADR). A complicating factor for its design is that the ADR will be integrated into a superfluid helium dewar at 1.3 K that will be coupled to a 1.8 K Joule-Thomson (JT) stage through a heat switch. When liquid helium is present, the coupling will be weak, and the JT stage will act primarily as a shield to reduce parasitic heat loads. When the liquid is depleted, the heat switch will couple more strongly so that the ADR can continue to operate using the JT stage as its heat sink. A two-stage ADR is the most mass efficient option and it has the operational flexibility to work well with a stored cryogen and a cryocooler. The ADR’s design and operating modes are discussed, with emphasis on how they reflect the capabilities and limitations of the hybrid cryogenic system.     

Mechanical design of a 3-stage ADR for the Astro-H mission

The X-ray micro-calorimeter array in the Soft X-ray Spectrometer (SXS) instrument on Astro-H will be cooled by a 3-stage adiabatic demagnetization refrigerator (ADR). The ADR consists of two mechanically independent assemblies. When integrated with a mounting structure and the detector assembly, they form a self-contained unit that will be inserted into the top end of a liquid helium tank. The unique configuration requires many components and sub-assemblies to be thermally isolated from their structural mount. Normally in an ADR this is limited to suspending cold salt pills within their (much warmer) magnets, but in the case of SXS, it also involves one ADR stage being supported by, but thermally isolated from, the helium tank. This paper will describe the complex thermal and mechanical design of the SXS ADR, and summarize vibration and mechanical properties tests that have been performed to validate the design.     

Development of mechanical cryocoolers for the cooling system of the Soft X-ray Spectrometer onboard Astro-H

Astro-H is the Japanese X-ray astronomy satellite planned for launch in 2014. The Soft X-ray Spectrometer (SXS) onboard Astro-H, is a high energy resolution spectrometer utilizing an X-ray micro-calorimeter array, which is operated at 50 mK by the ADR with the 30-L superfluid liquid helium (LHe). The mechanical cryocoolers, 4 K-class Joule Thomson (JT) cooler and 20 K-class double-staged Stirling (2ST) cooler are key components to achieve a LHe lifetime for over 3 years in orbit (5 years as a goal). Based on the existing cryocoolers onboard Akari (2006) and JEM/SMILES (2009), modifications for higher cooling power and reliability had been investigated. In the present development phase, the Engineering Models (EMs) of these upgraded cryocoolers are fabricated to carry out verification tests for cooling performance, mechanical performance and lifetime. Nominal cooling power of 200 mW at 20 K for the 2ST cooler and 40 mW at 4.5 K for the JT cooler were demonstrated with temperature and power margin. Mechanical performance test for the 2ST cooler units proves tolerability for pyro shock and vibration environment of the Astro-H criteria. Continuous running of the 4 K-class JT cooler combined with the 2ST precooler for lifetime test has achieved over 5000 h without any degradation of cooling performance.     

Design and performance of cryogenic, scanning Fabry-Perot interferometers for the Long-Wavelength Spectrometer on the Infrared Space Observatory

The design of cryogenic, scanning Fabry-Perot interferometers for the Long-Wavelength Spectrometer on the ESA Infrared Space Observatory is presented. The interferometers were designed to provide a spectral resolving power of 10(4) over the wavelength range 45-180 μm, with the highest possible transmission efficiency consistent with this requirement. Metal meshes, custom designed with the aid of a theoretical model of metallic reflection, were used as the reflecting elements. The scanning mechanism featured a spring-suspended plate, which was servocontrolled by moving coil actuators and monitored by capacitance micrometers. The spectroscopic performance of the interferometers was measured in the laboratory and is compared with the model developed for the interferometer design. Although the measured resolving powers were somewhat lower than expected because of the laboratory measurement conditions, the transmission efficiencies were in approximate agreement with the design specification.     

Design and performance of an instrument for soft landing of biomolecular ions on surfaces

A new ion deposition apparatus was designed and constructed in our laboratory. Our research objectives were to investigate interactions of biomolecules with hydrophilic and hydrophobic surfaces and to carry out exploratory experiments aimed at highly selective deposition of spatially defined and uniquely selected biological molecules on surfaces. The apparatus includes a high-transmission electrospray ion source, a quadrupole mass filter, a bending quadrupole that deflects the ion beam and prevents neutral molecules originating in the ion source from impacting the surface, an ultrahigh vacuum (UHV) chamber for ion deposition by soft landing, and a vacuum lock system for introducing surfaces into the UHV chamber without breaking vacuum. Ex situ analysis of surfaces following soft landing of mass-selected peptide ions was performed using 15 keV Ga+ time-of-flight secondary ion mass spectrometry and grazing incidence infrared reflection-absorption spectroscopy. It is shown that these two techniques are highly complementary methods for characterization of surfaces prepared with a range of doses of mass-selected biomolecular ions. We also demonstrated that soft landing of peptide ions on surfaces can be utilized for controlled preparation of peptide films of known coverage for fundamental studies of matrix effects in SIMS.     

Design and performance analyses of the new time-of-flight smaller-angle neutron scattering instrument at J-PARC

The new time-of-flight smaller-angle neutron scattering (TOF-SANS) instrument HI-SANS is projected to be built in the Materials and Life Science Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC). The target of the HI-SANS is to study microstructures and hierarchical structures of nano-meter sized materials and their complexes. For the simultaneous collection of scattering data in the wide q range (～3×10^?3<q<～50 Å^?1) with good q-resolution and high efficiency, this instrument is designed to use large area detectors and broad wavelength bandwidth within the first frame. For the high-quality beam transport and the efficacious utilization of pulsed neutrons, the state of the art neutron optics is installed. Moreover, a focusing device based on sextupole magnets is adopted in the TOF-SANS for the first time to make accessible minimum q value (q_min) lower with high q resolution. The design optimization and performance analyses of the HI-SANS have been performed by Monte Carlo simulations.     

一种测量牙动度仪器的设计与制作

本文主要阐述一种测量牙齿松动度仪器的工作原理、构造和使用方法。本装置以 5 1单片机和NSWDC— 3L型位移传感器为主要部件 ,通过对采集量软件滤波处理 ,实现对牙动位移的直接测量     

HIS和LIS的ADR自动监测系统的设计与实现

通过对药品不良反应(ADR)的研究,以最为常见的药品肝肾损害为例,设计并实现了一个自动监测软件系统.该系统采集医院信息系统(HIS)和检验信息系统(LIS)的数据,通过数据融合分析,实现了药品肝肾损害自动监测的功能,能帮助医生发现、判断、收集和上报临床发现的ADR,建立医院ADR数据库,并且对新ADR因果关系的预测有一定的参考意义.     

Porous plug and superfluid helium film flow suppressor for the soft X-ray spectrometer onboard Astro-H

Suppression of superfluid helium flow is critical for the Soft X-ray Spectrometer (SXS) onboard Astro-H, to achieve a life time of the liquid helium over 5 years. The superfluid film flow must be sufficiently small, compared to a nominal helium gas flow rate of the SXS . For this purpose, four devices composed of a porous plug, an orifice, a heat exchanger, and knife edge devices will be employed based on the experience of the X-ray microcalorimeter (XRS for X-Ray Spectrometer) onboard Suzaku. The porous plug is a phase separator of the liquid and gas helium. A potential film flow leaking from the porous plug is suppressed by the orifice. Almost all the remaining film flow evaporates at the heat exchanger. The knife edge devices stop the remaining film flow by using atomically sharp edges. In this paper, we describe the principle and design of these four devices.     

Improving the performance of a quadrupole time-of-flight instrument for macromolecular mass spectrometry

We modified and optimized a first generation quadrupole time-of-flight (Q-TOF) 1 to perform tandem mass spectrometry on macromolecular protein complexes. The modified instrument allows isolation and subsequent dissociation of high-mass protein complexes through collisions with argon molecules. The modifications of the Q-TOF 1 include the introduction of (1) a flow-restricting sleeve around the first hexapole ion bridge, (2) a low-frequency ion-selecting quadrupole, (3) a high-pressure hexapole collision cell, (4) high-transmission grids in the multicomponent ion lenses, and (5) a low repetition rate pusher. Using these modifications, we demonstrate the experimental isolation of ions up to 12 800 mass-to-charge units and detection of product ions up to 38 150 Da, enabling the investigation of the gas-phase stability, protein complex topology, and quaternary structure of protein complexes. Some of the data reveal a so-far unprecedented new mechanism in gas-phase dissociation of protein oligomers whereby a tetramer complex dissociates into two dimers. These data add to the current debate whether gas-phase structures of protein complexes do retain some of the structural features of the corresponding species in solution. The presented low-cost modifications on a Q-TOF 1 instrument are of interest to everyone working in the fields of macromolecular mass spectrometry and more generic structural biology.     

智能型电梯运行性能测试分析仪研制

为解决电梯检验和安全评价过程中电梯运行性能的快速高精度现场测试分析问题,研制智能型电梯运行性能测试分析仪。通过三轴加速度传感器和声级计测量电梯的运行信号,采用32位嵌入式系统实现信号处理和数值分析,获得电梯的运行加加速度、加速度、速度、位移、振动、噪声等性能参数,三轴加速度非线性误差低于0.1%,频率响应相对偏差低于1%,声级计相对误差低于0.3%。应用试验结果表明:该仪器实现了电梯运行性能的便捷可视化测量和现场快速准确分析,为电梯安全保障领域提供国产化解决方案。     

Comparison of ejector predicted performance by thermodynamic and CFD models

This paper presents a systematic comparison of ejector performance predictions by a thermodynamic and a CFD model for different operating conditions. The dimensions of the ejector were determined by the thermodynamic model and used in the CFD model. The thermodynamic model predicts higher entrainment ratios for double choking operation and somewhat different values of the critical and limiting pressure ratios. The CFD model validates the similarity solutions characteristic of ejectors using perfect gases. It also shows that the position of the shock varies linearly with the compression ratio in qualitative agreement with the assumption used in the thermodynamic model. Finally, the isentropic and mixing efficiencies obtained by the two approaches are favorably compared.     

Measured and predicted effect of flowrate and tube spacing on horizontal tube absorber performance

The presented model applies to absorption in a falling film of constant thickness of a binary mixture with only one component in the vapour phase. The mathematical formulation with partial differential equations is based on very general assumptions. The model is validated for a horizontal tube absorber. The absorber is simplified to a series of vertical falling films with mixing conditions in between. The dimensionless absorber operating conditions are: Gz = 0.1–10, Le = 0.002 or 0.004, Λ = 0.01 or 0.02, Bi ≈ 5, θ_c ≈ −0.2, N_c = 0.1. The absorber consists of 10 cooled tubes, measurements were obtained at tube spacings: 0, 3, 15 and 24 mm and with sheet, droplet and jet flow in between the tubes. The correlation between predicted and measured absorption outcomes is very strong. On average the predicted outcomes equal the measured ones within the scatter, if the diffusivity is taken 0.3 times the established correlation and varies with x and y.     

仪器仪表标尺自动生成系统的设计与实践

用VB6．0作为开发平台开发“仪器、仪表标尺自动生成系统”，探讨分析了中小企业实用软件的开发路线，并且提供了源程序共同提高。     

虚拟仪器平台婴儿培养箱校准试验装置设计

该文提出一种虚拟仪器平台婴儿培养箱测控系统。设计基于RS-485接口和Mod Bus通信协议的氧含量测量模块、湿度测量模块和温度测量模块以及基于RS232接口的噪声测量模块。应用虚拟仪器开发平台Lab VIEW构建数据采集与控制系统,系统由PC机和完成测控功能的智能测控节点组成,各智能测控节点通过USB和RS485串行总线与PC机通信,通过PC机中的虚拟仪器界面实现人机交互、状态监测、数据分析、数据记录与保存以及系统管理任务。试验表明:根据JJF 1260——2010《婴儿培养箱校准规范》和GB 11243——2008《医用电气设备:第2部分婴儿培养箱安全专用要求》,该测控系统能够高效、准确地完成测量任务。     

盾构刀盘驱动三级行星齿轮系统固有特性及灵敏度分析

建立了三级行星齿轮传动系统的平移-扭转耦合动力学模型,模型考虑了时变啮合刚度、各级中行星轮位置相角的时变性、啮合综合误差、阻尼等影响因素。基于特征值问题求解了系统结构的固有频率和振型,并将其系统振动模式归为三类：扭转耦合振动模式、平移耦合振动模式、行星轮振动模式。研究了不同振动模式下固有频率对系统参数的灵敏度。研究结果表明,在一些系统参数敏感点处,参数的微小变化不仅导致固有频率灵敏度、模态能量的大幅变化,也将引起能量在各级间发生转移,使得振动特性剧烈变化。     

基于虚拟仪器技术的网络性能测评系统的设计

介绍了虚拟仪器的概念及虚拟仪器的形成，提出了一种新的网络性能测评系统的设计方法——基于虚拟仪器技术的网络性能测评系统的设计，介绍了该系统的数据采集、网络性能分析、数据显示、数据库管理和主控模块等功能模块的设计和软件设计，并给出了该系统的应用实例。