| Paper |
Title |
Page |
| WEPD038 |
Thermal and Structural Modeling of the TTF Cryomodule Cooldown and Comparison with Experimental Data
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2494 |
| |
- S. Barbanotti, P. Pierini
INFN/LASA, Segrate (MI)
- K. Jensch, R. Lange, W. Maschmann
DESY, Hamburg
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The study of thermal and structural behavior during cooldown/warmup of long SRF cryostats is important for both the XFEL and ILC, which base the design on the successful TTF design. We present the finite elements analysis of the main internal components of the cryomodules during the transient cooldown and warmup, comparing the data obtained with data taken at DESY on the linac.
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| WEPD039 |
Evolution of the Standard Helium Liquefier and Refrigerator Range designed by Air Liquide DTA, France
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2497 |
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- S. Crispel, G. Aigouy, A. Caillaud, F. Delcayre, V. Grabie
Air Liquide, Division Techniques Avancées, Sassenage
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The standard helium liquefier and refrigerator range, called HELIAL, designed by Air Liquide DTA, has been upgraded with significant improvement of efficiency as a result of technological development.. Indeed in the demanding high tech markets, (international laboratories, aerospace applications, synchrotrons, HTS applications…), cryogenic systems must provide increasingly high performances. The new HELIAL Evolution is equipped with Air Liquide's expansion turbines, well known for their extremely high reliability and efficiency,. The results of this development endowing the HELIAL Evolution with twice liquefaction capacity, are presented in this paper.
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| WEPD040 |
Outcome of the Commissioning of the Readout and Actuation Channels for the Cryogenics of the LHC
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2500 |
| |
- G. Fernandez Penacoba, C. Balle, J. Casas-Cubillos, J. De La Gama, P. Gomes, E. Gousiou, N. Jeanmonod, A. Lopez Lorente, E. Molina Marinas, A. Suraci, N. Vauthier
CERN, Geneva
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The installation of the Large Hadron Collider (LHC) at CERN has been completed and its commissioning is now in progress. The LHC is the largest cryogenic installation ever built. It includes 1700 superconducting magnets, a cryogenic distribution line (QRL) running parallel to the accelerator, 52 electrical distribution feedboxes (DFB) supporting the superconducting current leads that supply power to the magnets circuits, and 16 superconducting RF accelerating cavities. For its operation more than 10 000 sensors and actuators are required. The commissioning of this instrumentation includes the validation of both hardware (installed sensors, cabling, front-end electronics, communication field-buses) and software (databases extraction, programmable logic controllers programs, supervision coherence). At present point, having provided the cryogenic instrumentation for the operation in half of the LHC, more than 95% of the channels are working within specifications. This paper presents the commissioning strategy, tracking policy, and performance results after commissioning of the cryogenic instrumentation for the LHC.
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| WEPD041 |
Continuous Operation of Cryogenic System for Synchrotron Light Source
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2503 |
| |
- F. Z. Hsiao, S.-H. Chang, W.-S. Chiou, H. C. Li, H. H. Tsai
NSRRC, Hsinchu
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The availability of user time is an important index for the performance evaluation of a synchrotron light source. In NSRRC two cryogenic plants are installed for liquid helium supply to the superconducting magnets and the superconducting cavity of the electron storage ring. As a subsystem of the storage ring, the objective of continuous helium supply without interruption is important for the cryogenic plant. The target to shorten the recovery time of the storage ring, if the cryogenic plant trips, is another issue. Component failure and system maintenance are two main reasons interrupting operation of the cryogenic plant. This paper shows our strategy on the scheduled maintenance of either the cryogenic plant or the utility system to keep continuous liquid helium supply. Two tests to shorten the recovery time are presented: the first is liquid helium supply from both cryogenic plants simultaneously; the second is restarting the on-duty cryogenic plant with the other dewar providing helium to the superconducting devices.
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| WEPD042 |
Development of a Simulation Module for the Cryogenic System
|
2506 |
| |
- H. C. Li, S.-H. Chang, W.-S. Chiou, F. Z. Hsiao, H. H. Tsai
NSRRC, Hsinchu
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In NSRRC two 450W cryogenic systems were installed on the year 2002 and 2006, respectively. After long time operation some behavior and setting parameters of the cryogenic system did not satisfy our requirement because of the deterioration of electrical sensors and valves. To ask the manufacturer to solve those problems, it took lots of time in the communication of problem description and the modification of control program. A simulation module for the cryogenic system is thus developed to trace the procedure before and after modification of the control program. This paper details the simulation module and shows the usefulness of this module on evaluation of the software modification for cryogenic system.
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| WEPD043 |
Orbital Welding of QRL Line in Confined Environment
|
2509 |
| |
- E. P. Roussel
Air Liquide, Sassenage
- P. J.D. P. Mazoyer
ORBITAL, Vonnas
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AIR LIQUIDE DTA was in charge of design, manufacturing of element and installation of QRL line of CERN. The elements of this cryogenic line have been welded by orbital welding with an open weld head. A specific welding head has been developed for the project. Radial and axial clearances lead the design of the head. To install this cryogenic line, more than 15 000 orbital welds have been realized. This paper will present the technical requirements applicable to QRL line, different welding configuration, main step to qualify welding process. We will describe the results of non destructive examination: helium leak test, X-ray inspection and visual inspection.
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| WEPD044 |
Efficiency Analysis for the Cryogenic System at NSRRC
|
2512 |
| |
- H. H. Tsai, S.-H. Chang, W.-S. Chiou, F. Z. Hsiao, H. C. Li
NSRRC, Hsinchu
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Three superconducting magnets and one superconducting cavity for RF are cooled by two 450W liquid helium system at NSRRC. These two systems were made up of Claude cycle which is usually compared in their performance to that of the ideal Carnot cycle. This paper presents the efficiency analysis for the cryogenic system. Based on the analysis, the power transfer to the process change for the operation will be performed. In addition, it also shows the way to identify the problems when done the trouble shooting for part of erratic response of the plant. The carnot efficiency also provides an important index of the performance, especially when we done the process control.
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| WEPD045 |
Hydrogen Cryosorption on Multi Walled Carbon Nanotubes
|
2515 |
| |
- F. Xu, M. Barberio, P. Barone, A. Oliva, L. Papagno, V. Pirronello, R. Vasta
INFN Gruppo di Cosenza, Arcavacata di Rende (Cosenza)
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We present a Temperature Programmed Desorption (TPD) study on H2 adsorption on multiwalled carbon nanotubes (MWNT) at very low pressure (< 10-6 Torr) and temperature (12-30 K). Our results show a hydrogen take up limit in the range of 10-8 mol per gram depending on the adsorption temperature. We compare the MWNT cryosorption capacity with that of commonly used activated carbon and discuss the possibility of employing MWNT as cryosorber in large particle accelerators.
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