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1.
《低温学》2016
A cryogen distribution system was installed and commissioned to transfer liquid nitrogen (LN2) and liquid helium (LHe) from storage dewars to superconducting radio-frequency (SRF) cavities for the 3-GeV Taiwan Photon Source (TPS) project. The cryogen distribution system comprises one distribution valve box (DVB), four control valve boxes (CVB) and seven sections of multichannel transfer line (MCL). The DVB distributes the LHe and LN2 to the CVB, and then to the SRF cavities through independent vacuum-jacketed transfer lines. The vaporized GHe and GN2 from the cryomodules are collected via the MCL. The cryogen distribution system was installed and commissioned from October 2014 to the end of March 2015. This paper presents the installation, pre-commissioning and commissioning of the cryogen distribution system, and describes the heat load test. Thermal acoustic oscillation (TAO) was found in the GHe process line; this phenomenon and its solution are also presented and discussed. 相似文献
2.
《低温学》1985,25(8):471-474
Rotating tests have been performed to evaluate continuous liquid helium transfer and the cryogenic environment established in a test rotor. The testing was related to high speed alternator development programmes and the rotating Dewar was designed to simulate a self-pumping liquid helium cooling system for superconducting rotors. Stable pumping to < 0.6 atm1 and stable helium level regulation were achieved at several different levels. The established pool was, within the limitations of steady state heat transfer, isothermal and there was no evidence of a warm bore condition. Within the rotating Dewar, heat transfer devices, level gauges and other instrumentation have been tested using onboard microprocessors to log, digitize and then transmit the data from the rotor. All of the cooling system functions required by large synchronous alternators were observed to be present and stable. 相似文献
3.
T.S. Datta S. Ghosh J. Antony S. Babu J. Chacko A. Choudhury G.K. Choudhuri D. Kanjilal S. Kar M. Kumar P. Patra A. Pandey A. Rai R. Mehta R.S. Meena B.K. Sahu R.G. Sharma A. Roy 《低温学》2009,49(6):243-248
The Inter-University Accelerator Center, New Delhi is involved in commissioning a superconducting linear accelerator (LINAC) as a booster to its existing 15 UD Pelletron accelerator. The booster consists of three LINAC modules, each containing eight superconducting Nb quarter wave resonators and a superconducting solenoid magnet. The first LINAC module preceded by a superbuncher with one cavity and followed by a rebuncher cryostat with two cavities was installed in 0° beam line of Pelletron and has been under operation for some time at the Center. The module is integrated with a liquid helium (LHe) refrigerator through a cryogen valve box and the distribution line. The performance tests of each component like the RF cavity, the cryomodule and the liquid helium distribution line were carried out independently prior to the beam acceleration test. After having many trial runs on this integrated cryonetwork system, beam acceleration tests were performed during 2007. The energy of silicon beam with charge state of +10 has been enhanced approximately from 130 MeV to 158 MeV using the first module with seven effective cavities and the accelerated beam was delivered at user’s scattering chamber. The present paper highlights the performance of the first module producing an accelerating beam duly bunched in the rebuncher. The performance of first LINAC cryomodule along with problems and the solution associated with the cryogenic system and the cavities encountered during the beam runs are presented in this paper. 相似文献
4.
Kazuhiro Kajikawa Hirotsugu Kuga Takuro Inoue Kazuki Watanabe Yushi Uchida Taketsune Nakamura Tsuyoshi Wakuda Kazuhide Tanaka 《Journal of Superconductivity and Novel Magnetism》2013,26(5):1537-1541
An electric pump composed of an MgB2 motor is combined with a superconducting level sensor using a thin CuNi-sheathed MgB2 wire to demonstrate the transfer of liquid helium. An impeller is attached to the lower end of a rotating shaft of the MgB2 motor and covered with an outer casing to form a kind of centrifugal pump. After that, the MgB2 motor with the impeller is located vertically inside a cryostat with an infill of the liquid helium. Another glass Dewar vessel is also prepared to receive the liquid helium transferred from the cryostat containing the MgB2 motor. The MgB2 sensor is used not only to detect the level of the liquid helium but also to control the electric pump on the basis of its pre-estimated calibration curve. By using the assembled pump system, the liquid helium is successfully transferred from the cryostat to the glass Dewar vessel via a transfer tube. The transfers of liquid hydrogen with the identical pump system will be carried out in the near future. 相似文献
5.
低温地面支持设备系统CGSE是用于冷却第二代阿尔法磁谱AMS02的磁体组件并将超流氦注入AMS02磁体杜瓦的低温设备系统。介绍用于CGSE系统中气氦管路阀箱和液氦管路阀箱,介绍了阀箱的技术要求、方案设计、结构特征,并进行了强度校核计算,两个阀箱的筒体和下封头的壁厚为4mm,上封头的壁厚为5mm,能满足两个阀箱承受0.1MPa外压的强度要求。 相似文献
6.
This paper describes the cryogenic system of the International Thermonuclear Experimental Reactor (ITER) Correction Coils (CC) test facility, which consists of a 500 W/4.5 K helium refrigerator, a 50 kA superconducting transformer cryostat (STC) and a background field magnet cryostat (BFMC). The 500 W/4.5 K helium refrigerator synchronously produces both the liquid helium (LHe) and supercritical helium (SHe). The background field magnet and the primary coil of the superconducting transformer (PCST) are cooled down by immersing into 4.2 K LHe. The secondary Cable-In-Conduit Conductor (CICC) coil of the superconducting transformer (SCST), superconducting joints and the testing sample of ITER CC are cooled down by forced-flow supercritical helium. During the commissioning experiment, all the superconducting coils were successfully translated into superconducting state. The background field magnet was fully cooled by immersing it into 4.2 K LHe and generated a maximal background magnetic field of 6.96 T; the temperature of transformer coils and current leads was reduced to 4.3 K; the inlet temperature of SHe loop was 5.6 K, which can meet the cooling requirements of CIC-Conductor and joint boxes. It is noted that a novel heat cut-off device for High Temperature Superconducting (HTS) binary current leads was introduced to reduce the heat losses of transformer cryostat. 相似文献
7.
Tsunehiro Takeda Masayoshi Okamoto Kazuhiro Atsuda Akihiro Kobayashi Takashi Owaki Keishi Katagiri 《低温学》2008,48(1-2):6-11
We developed a helium circulating system that re-liquefies all the evaporating helium gas and consumes far less power than conventional systems, because warm helium gas at about 40 K collected high above the surface of the liquid helium in the Dewar is used to keep the Dewar cold, and because cold helium gas just above the liquid helium surface is collected and re-liquefied while still cold. A special transfer tube with multi-concentric pipes was developed to make the system operate efficiently. The system can produce up to 35.5 l/D of liquid helium from the evaporated helium using two 1.5 W@4.2 K GM cryocoolers. 相似文献
8.
《低温学》2017
Soft X-ray Spectrometer instrument (SXS) is one of the primary scientific instruments of ASTRO-H. SXS has a cold detector that is cooled to 50 mK by using a multi-stage Adiabatic Demagnetization Refrigerator (ADR). SXS Dewar containing ADR provides 1.3 K heat sink by using liquid helium in nominal operation. After liquid helium is dried up, 4 K heat sink is provided by using mechanical coolers. Both nominal operation and cryogen free operation were successfully demonstrated. This paper describes the test result of cryogen free operation and cool-down performance from room temperature by using only mechanical coolers without liquid helium. The coolers on the Dewar cooled down cold mass from around 300 K to 4 K with 260 W electric power in 40 days. Cold mass is 35 kg in 4 K area including the helium tank, ADR and detector assembly. 相似文献
9.
EAST超导托卡马克的纵场和极向场磁体均采用NbTi超导材料,由3.8 K超临界氦冷却.在托卡马克实验运行时,极向场的放电脉冲和等离子体破裂产生的交流损耗带来的热负荷增加,经过超临界氦流带到低温系统控制阀箱内的液氦槽和过冷槽,造成槽内的液氦蒸发量增加.蒸发的氦回到制冷机中,从而影响制冷机的稳定运行.通过对实际超临界管道和液氦槽、过冷槽中换热过程建立换热模型,进行热工分析,分析液氦槽和过冷槽中的压力等参数的变化,指导低温系统的设计. 相似文献
10.
We are developing a new cryogenic neutrino detector: electron bubble chamber, using liquid helium as the detecting medium, for the detection of low energy p-p reaction neutrinos (<420 keV), from the Sun. The program focuses in particular on the interactions of neutrinos scattering off atomic electrons in the detecting medium of liquid helium, resulting in recoil electrons which can be measured. We designed and constructed a small test chamber with 1.5 L active volume to start the detector R&D, and performed experimental proofs of the operation principle. The test chamber is a stainless steel cylinder equipped with five optical windows and ten high voltage cables. To shield the liquid helium chamber against the external heat loads, the chamber is made of double-walled jacket cooled by a pumped helium bath and is built into a LN2/LHe cryostat, equipped with 80 K and 4 K radiation shields. A needle valve for vapor helium cooling was used to provide a 1.7-4.5 K low temperature environments. The cryogenic test chamber has been successfully operated to test the performance of Gas Electron Multipliers (GEMs) in He and He + H2 at temperatures in the range of 3-293 K. This paper will give an introduction on the cryogenic solar neutrino detector using electron bubbles in liquid helium, then present the cryogenic design and operation of liquid helium in the small test chamber. The general principles of a full-scale electron bubble detector for the detection of low energy solar neutrinos are also proposed. 相似文献
11.
T. X. Zhao L. Q. Liu J. Gao L. Y. Xiong Q. J. Xu J. Y. Zhai W. H. Lu C. H. Li Y. Sun Z. L. Hou Z. G. Zong L. Zhang 《Journal of Superconductivity and Novel Magnetism》2010,23(6):1095-1099
In order to obtain the design, manufacture and operation experiences on the Superconducting Radio Frequency (SRF) cryomodule for the International Linear Collider (ILC), a test cryomodule for 1.3 GHz single 9-cell SC cavity was designed by IHEP (Institute of High Energy Physics) and TIPC (Technical Institute of Physics and Chemistry) jointly. This cryomodule will be used as a horizontal test facility for a 1.3 GHz 9-cell SC cavity. The cryogenic system for the cryomodule was also designed, which will be operated at 2.0 K with saturated superfluid helium. The major requirements, design, simulation results of the cryomodule are reported in the paper. This key component of a superconducting accelerator test unit will be built in the near future at IHEP. 相似文献
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13.
M.L. Mallory H.P. Hilbert H.W. Laumer 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,241(1):14-16
A procedure for testing the vacuum integrity of very large stainless steel weldments used at cryogenic temperatures has been developed at Michigan State University. This development, which uses large quantities of liquid nitrogen, is a modification of a technique commonly applied to small devices and involves cooling the cryostat's liquid helium vessel (bobbin) to liquid nitrogen temperature, and then proceeding immediately with leak testing. This method was applied to the K800 superconducting magnet helium vessel, which seemed leak tight at room temperature, but was found to have an easily detectable helium leak when cooled. After repairing the leak, retesting revealed no leaks, where upon the K800 cryostat construction was completed; i.e. the bobbin was wrapped with superinsulation, a liquid nitrogen radiation shield was added, and the assembly was inserted into the vacuum jacket. The final leak test occurred when the cryostat was cooled to liquid helium temperature and was found to be helium leak tight. 相似文献
14.
A versatile cryogenic test bed, based on circulating cryogenic helium gas, has been designed, fabricated, and installed at the Florida State University Center for Advanced Power Systems (FSU-CAPS). The test bed is being used to understand the benefits of integrating the cryogenic systems of multiple superconducting power devices. The helium circulation system operates with four sets of cryocooler and heat exchanger combinations. The maximum operating pressure of the system is 2.1 MPa. The efficacy of helium circulation systems in cooling superconducting power devices is evaluated using a 30-m-long simulated superconducting cable in a flexible cryostat. Experiments were conducted at various mass flow rates and a variety of heat load profiles. A 1-D thermal model was developed to understand the effect of the gas flow parameters on the thermal gradients along the cable. Experimental results are in close agreement with the results from the thermal model. 相似文献
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氦气净化技术是国家大科学工程北京正负电子对撞机重大改造(BEPC-Ⅱ)中低温系统的关键技术之一.在充分调研国内外大型低温系统氦气净化技术的基础上,结合自身情况,创造性提出氦气储罐内部处理及真空置换方案,一次性充入氦气,将储罐内氦气不纯度控制在40 vpm之内,同时辅之以80 K外置低温吸附器对氦气储罐内以及冷箱和超导设备端的氦气进行净化.高效而又经济的解决了BEPC-Ⅱ低温系统中的氦气纯度问题,成功地进行了制冷机的验收测试和超导设备的调试及运行. 相似文献
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18.
Development of mechanical cryocoolers for Astro-H/SXS 总被引:1,自引:0,他引:1
Yoichi Sato Hiroyuki Sugita Takao Nakagawa Masahide Murakami Shoji Tsunematsu Katsuhiro Narasaki 《低温学》2010,50(9):500-506
The Soft X-ray Spectrometer (SXS) is a high-resolution spectrometer with an X-ray micro-calorimeter array onboard the Japanese X-ray astronomy satellite Astro-H, planned for launch in 2013. The micro-calorimeter is operated at cryogenic temperature of 50 mK provided by the Adiabatic Demagnetization Refrigerator (ADR) with a heat sink of 1.3 K liquid helium stored in the SXS Dewar. To extend the liquid helium lifetime to over 3 years in orbit, two types of mechanical cryocoolers are installed: 20 K-class double-staged Stirling (2ST) coolers and a 1 K-class Joule-Thomson (JT) cooler. Improvement of mechanical cryocoolers has been investigated and verified for higher reliability and cooling performance. The engineering model (EM) of upgraded mechanical cryocoolers was fabricated for a long lifetime test. The required cooling power of 200 mW at 20 K for the 2ST cooler and 10 mW at 1.7 K for the JT cooler are achieved by EM test. 相似文献
19.
Eric T. Swartz 《Journal of Low Temperature Physics》1995,101(1-2):249-252
With the increasing stress on consumable budgets, the goal of decreasing helium consumption of cryogenic system components has become a major issue. Although much progress has recently been made (improvements in helium Dewar technology and high Tc magnet leads are good examples) the potential to improve efficiency is greater when the entire cryogenic system is viewed as an interacting unit. 相似文献