F. Millet, S. Claudet, G. Ferlin, A. Perin, R. Rabehl, G. Riddone, L. Ronayette, L. Serio, M. Soubiran, L. Tavian
The LHC machine, composed of eight sectors with superconducting magnets and accelerating cavities, requires a complex cryogenic system providing high cooling capacities (18 kW equivalent at 4.5 K and 2.4 W at 1.8 K per sector produced in large cold boxes and distributed via 3.3-km cryogenic transfer lines). After individual reception tests of the cryogenic subsystems (cryogen storages, refrigerators, cryogenic transfer lines and distribution boxes) performed since 2000, the commissioning of the cryogenic system of the first LHC sector has been under way since November 2006. After a brief introduction to the LHC cryogenic system and its specificities, the commissioning is reported detailing the preparation phase (pressure and leak tests, circuit conditioning and flushing), the cool-down sequences including the handling of cryogenic fluids, the magnet powering phase and finally the warm-up. Preliminary conclusions on the commissioning of the first LHC sector will be drawn with the review of the critical points already solved or still pending. The last part of the paper reports on the first operational experience of the LHC cryogenic system in the perspective of the commissioning of the remaining LHC sectors and the beam injection test.
{"title":"Commissioning the cryogenic system of the first LHC sector","authors":"F. Millet, S. Claudet, G. Ferlin, A. Perin, R. Rabehl, G. Riddone, L. Ronayette, L. Serio, M. Soubiran, L. Tavian","doi":"10.1063/1.2908500","DOIUrl":"https://doi.org/10.1063/1.2908500","url":null,"abstract":"The LHC machine, composed of eight sectors with superconducting magnets and accelerating cavities, requires a complex cryogenic system providing high cooling capacities (18 kW equivalent at 4.5 K and 2.4 W at 1.8 K per sector produced in large cold boxes and distributed via 3.3-km cryogenic transfer lines). After individual reception tests of the cryogenic subsystems (cryogen storages, refrigerators, cryogenic transfer lines and distribution boxes) performed since 2000, the commissioning of the cryogenic system of the first LHC sector has been under way since November 2006. After a brief introduction to the LHC cryogenic system and its specificities, the commissioning is reported detailing the preparation phase (pressure and leak tests, circuit conditioning and flushing), the cool-down sequences including the handling of cryogenic fluids, the magnet powering phase and finally the warm-up. Preliminary conclusions on the commissioning of the first LHC sector will be drawn with the review of the critical points already solved or still pending. The last part of the paper reports on the first operational experience of the LHC cryogenic system in the perspective of the commissioning of the remaining LHC sectors and the beam injection test.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908500","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58365314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Vanapalli, M. Lewis, G. Grossman, Z. Gan, R. Radebaugh, H. T. Brake
High frequency operation of a pulse tube cryocooler leads to reduced regenerator volume, which results in a reduced heat capacity and a faster cooldown time. A pulse tube cryocooler operating at a frequency of 120 Hz and an average pressure of 3.5 MPa achieved a no-load temperature of 50 K. The cooling power at 80 K was about 3.35 W with a cooldown time from 285 K to 80 K of about 5.5 minutes, even though the additional thermal mass at the cold end due to flanges, screws, heater, and thermometer was 4.2 times that of the regenerator. This fast cooldown is about two to four times faster than that of typical pulse tube cryocoolers and is very attractive to many applications. In this study we measure the cooldown time to 80 K for different cold-end masses and extrapolate to zero cold-end mass. We also present an analytical model for the cooldown time for different cold-end masses and compare the results with the experiments. The model and the extrapolated experimental results indicate that with zero cold-end...
{"title":"MODELING AND EXPERIMENTS ON FAST COOLDOWN OF A 120 Hz PULSE TUBE CRYOCOOLER","authors":"S. Vanapalli, M. Lewis, G. Grossman, Z. Gan, R. Radebaugh, H. T. Brake","doi":"10.1063/1.2908503","DOIUrl":"https://doi.org/10.1063/1.2908503","url":null,"abstract":"High frequency operation of a pulse tube cryocooler leads to reduced regenerator volume, which results in a reduced heat capacity and a faster cooldown time. A pulse tube cryocooler operating at a frequency of 120 Hz and an average pressure of 3.5 MPa achieved a no-load temperature of 50 K. The cooling power at 80 K was about 3.35 W with a cooldown time from 285 K to 80 K of about 5.5 minutes, even though the additional thermal mass at the cold end due to flanges, screws, heater, and thermometer was 4.2 times that of the regenerator. This fast cooldown is about two to four times faster than that of typical pulse tube cryocoolers and is very attractive to many applications. In this study we measure the cooldown time to 80 K for different cold-end masses and extrapolate to zero cold-end mass. We also present an analytical model for the cooldown time for different cold-end masses and compare the results with the experiments. The model and the extrapolated experimental results indicate that with zero cold-end...","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908503","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58365327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Throttle cycle coolers, operating with mixed refrigerants have been already used at refrigeration temperatures down to 70 K. An industrial single-stage, oil lubricated compressor can be used to provide both, a relatively low cost and long operational time. Application of nonflammable mixed refrigerants is important for safety, transportation, service and maintenance. However, it is more difficult to provide a required refrigeration performance and long-term reliability due to properties of nonflammable components. The paper presents experimental and modeling data for single-stage coolers operating in a temperature range of 80 to 150 K. The nonflammable components were selected to develop mixed refrigerants for the desired temperature ranges. A gas refrigerant supply technology is used for a single-stage cooler design. The minimal achievable temperature is restricted by the freezing point of the mixture. Selected gas refrigerant technology restricts the maximal refrigeration capacity. However, it allows a ...
{"title":"Development of jt Coolers Operating at Cryogenic Temperatures with Nonflammable Mixed Refrigerants","authors":"A. Khatri, M. Boiarski","doi":"10.1063/1.2908574","DOIUrl":"https://doi.org/10.1063/1.2908574","url":null,"abstract":"Throttle cycle coolers, operating with mixed refrigerants have been already used at refrigeration temperatures down to 70 K. An industrial single-stage, oil lubricated compressor can be used to provide both, a relatively low cost and long operational time. Application of nonflammable mixed refrigerants is important for safety, transportation, service and maintenance. However, it is more difficult to provide a required refrigeration performance and long-term reliability due to properties of nonflammable components. The paper presents experimental and modeling data for single-stage coolers operating in a temperature range of 80 to 150 K. The nonflammable components were selected to develop mixed refrigerants for the desired temperature ranges. A gas refrigerant supply technology is used for a single-stage cooler design. The minimal achievable temperature is restricted by the freezing point of the mixture. Selected gas refrigerant technology restricts the maximal refrigeration capacity. However, it allows a ...","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908574","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58365205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In cooperation with Industrial Research Ltd (IRL), Cryomech, Inc. is developing a low cost high frequency pulse tube cryocooler. The valveless compressor, developed at IRL, employs two S.S. diaphragms and a novel kinematics driven mechanism. The pulse tube cold head has co-axial configuration. It is separated from the compressor with a SS flexible line of 1 meter long. The test results demonstrate a very small orientation effect of the cold head (<3 K at any orientation). This pulse tube cryocooler provides flexibility for user's integration. It can provide 108W at 77K with an electric input power of 3.7 kW in the primary test.
Cryomech, Inc.与Industrial Research Ltd (IRL)合作，正在开发一种低成本的高频脉冲管制冷机。IRL开发的无阀压缩机采用了两个S.S.隔膜和一个新颖的运动驱动机构。脉冲管冷头具有同轴结构。与压缩机之间用1米长的SS软线隔开。试验结果表明，冷头的取向效应非常小(在任何方向都< 3k)。这种脉冲管制冷机为用户的集成提供了灵活性。在77K时可提供108W功率，初级试验输入功率3.7 kW。
{"title":"DEVELOPMENT OF A LOW COST HIGH FREQUENCY PULSE TUBE CRYOCOOLER","authors":"C. Wang, A. Caughley, D. Haywood","doi":"10.1063/1.2908521","DOIUrl":"https://doi.org/10.1063/1.2908521","url":null,"abstract":"In cooperation with Industrial Research Ltd (IRL), Cryomech, Inc. is developing a low cost high frequency pulse tube cryocooler. The valveless compressor, developed at IRL, employs two S.S. diaphragms and a novel kinematics driven mechanism. The pulse tube cold head has co-axial configuration. It is separated from the compressor with a SS flexible line of 1 meter long. The test results demonstrate a very small orientation effect of the cold head (<3 K at any orientation). This pulse tube cryocooler provides flexibility for user's integration. It can provide 108W at 77K with an electric input power of 3.7 kW in the primary test.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908521","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58364982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
HTS leads are increasingly used on superconducting magnets. In most cases the magnet leads are shielded from the magnetic field by iron or the magnet is actively shielded, so that the stray field at HTS leads is low. There are magnets where the HTS leads must be located in a magnetic field. The two general types of HTS leads that are commercially available are either leads fabricated from bulk HTS materials or leads fabricated from oriented HTS materials that have one or two planes of favorable current density. This paper will discuss how two types of leads are affected by magnetic field. The warm end temperature of the HTS lead is a key lead performance factor.
{"title":"USING HIGH TEMPERATURE SUPERCONDUCTING LEADS IN A MAGNETIC FIELD","authors":"A. GreenM., H. Witte","doi":"10.1063/1.2908480","DOIUrl":"https://doi.org/10.1063/1.2908480","url":null,"abstract":"HTS leads are increasingly used on superconducting magnets. In most cases the magnet leads are shielded from the magnetic field by iron or the magnet is actively shielded, so that the stray field at HTS leads is low. There are magnets where the HTS leads must be located in a magnetic field. The two general types of HTS leads that are commercially available are either leads fabricated from bulk HTS materials or leads fabricated from oriented HTS materials that have one or two planes of favorable current density. This paper will discuss how two types of leads are affected by magnetic field. The warm end temperature of the HTS lead is a key lead performance factor.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908480","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58365281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Rowe, A. Tura, J. Weisend, John Barclay, S. Breon, J. Demko, M. Dipirro, J. Kelley, Peter Kittel, A. Klebaner, A. Zeller, M. Zagarola, S. V. Van Sciver, A. Rowe, J. Pfotenhauer, Tom Peterson, J. Lock
An AMR test apparatus has been developed for testing magnetic regenerators at temperatures ranging from room-temperature to 20 K. Near 300 K, no-load temperature spans over 80 K have been produced using regenerators composed of two and three different magnetocaloric materials. Modifications to the apparatus have been performed to allow testing at cryogenic temperatures. Initial tests near 80 K using magnetic fields of 5 T are presented using an AMR composed of Gd5Si0.33Ge3.67. A no-load temperature span of ∼8 K is achieved. The operating point is established using liquid nitrogen flow through the shell-side of the warm heat exchangers of the AMR. Design characteristics of the test apparatus, problems encountered, and modifications for improving experimental results are discussed.
{"title":"CRYOGENIC TESTING OF AN ACTIVE MAGNETIC REGENERATIVE REFRIGERATOR","authors":"A. Rowe, A. Tura, J. Weisend, John Barclay, S. Breon, J. Demko, M. Dipirro, J. Kelley, Peter Kittel, A. Klebaner, A. Zeller, M. Zagarola, S. V. Van Sciver, A. Rowe, J. Pfotenhauer, Tom Peterson, J. Lock","doi":"10.1063/1.2908486","DOIUrl":"https://doi.org/10.1063/1.2908486","url":null,"abstract":"An AMR test apparatus has been developed for testing magnetic regenerators at temperatures ranging from room-temperature to 20 K. Near 300 K, no-load temperature spans over 80 K have been produced using regenerators composed of two and three different magnetocaloric materials. Modifications to the apparatus have been performed to allow testing at cryogenic temperatures. Initial tests near 80 K using magnetic fields of 5 T are presented using an AMR composed of Gd5Si0.33Ge3.67. A no-load temperature span of ∼8 K is achieved. The operating point is established using liquid nitrogen flow through the shell-side of the warm heat exchangers of the AMR. Design characteristics of the test apparatus, problems encountered, and modifications for improving experimental results are discussed.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908486","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58365297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over the past few decades, the pulse-tube cryocooler has advanced from a curiosity to one of the most attractive systems for providing reliable cryogenic cooling; it is now used in aerospace, medical and superconductor applications. This technology development has been enabled by the simulation tools that are available for regenerator, compressor, and inertance tube design. However, a dedicated design tool for the pulse-tube component in a pulse-tube cryocooler and the associated flow transitions between the pulse tube and the regenerator and the pulse tube and the inertance network is not currently available.This paper describes the development of a two-dimensional, axisymmetric computational fluid dynamic (CFD) model of the pulse-tube and its associated flow transitions. The model is implemented in the commercial CFD package FLUENT. The CFD simulations are sufficient to calculate and delineate the various loss mechanisms; these are reported as a percentage of the acoustic power that is present at the co...
{"title":"Optimal Pulse-Tube Design Using Computational Fluid Dynamics","authors":"R. Taylor, G. Nellis, S. Klein","doi":"10.1063/1.2908505","DOIUrl":"https://doi.org/10.1063/1.2908505","url":null,"abstract":"Over the past few decades, the pulse-tube cryocooler has advanced from a curiosity to one of the most attractive systems for providing reliable cryogenic cooling; it is now used in aerospace, medical and superconductor applications. This technology development has been enabled by the simulation tools that are available for regenerator, compressor, and inertance tube design. However, a dedicated design tool for the pulse-tube component in a pulse-tube cryocooler and the associated flow transitions between the pulse tube and the regenerator and the pulse tube and the inertance network is not currently available.This paper describes the development of a two-dimensional, axisymmetric computational fluid dynamic (CFD) model of the pulse-tube and its associated flow transitions. The model is implemented in the commercial CFD package FLUENT. The CFD simulations are sufficient to calculate and delineate the various loss mechanisms; these are reported as a percentage of the acoustic power that is present at the co...","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908505","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58365340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Takahashi, K. Kamiya, H. Nakagome, T. Numazawa, P. Shirron, D. Wegel
We are developing a multi-stage continuous adiabatic demagnetization refrigerator (CADR) for milli-gravity experiments, which can provide cooling at ultra low temperatures. One of the greatest features of the ADR is that it doesn't depend on gravity. The CADR is designed to provide the high cooling power, 10 μW at 50mK and 100 μW at 100mK. The CADR is planned to conduct a cooling test under the milli-gravity condition in airborne flight experiments. This paper describes the developmental status of the CADR for milli-gravity experiments.
{"title":"DEVELOPMENT OF A CRYOGEN-FREE CONTINUOUS ADR SYSTEM FOR MILLI-GRAVITY EXPERIMENTS","authors":"K. Takahashi, K. Kamiya, H. Nakagome, T. Numazawa, P. Shirron, D. Wegel","doi":"10.1063/1.2908577","DOIUrl":"https://doi.org/10.1063/1.2908577","url":null,"abstract":"We are developing a multi-stage continuous adiabatic demagnetization refrigerator (CADR) for milli-gravity experiments, which can provide cooling at ultra low temperatures. One of the greatest features of the ADR is that it doesn't depend on gravity. The CADR is designed to provide the high cooling power, 10 μW at 50mK and 100 μW at 100mK. The CADR is planned to conduct a cooling test under the milli-gravity condition in airborne flight experiments. This paper describes the developmental status of the CADR for milli-gravity experiments.","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908577","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58365546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The characterization of a multistage Pulse Tube cycle refrigeration system has been partially performed on the Northrop Grumman High Capacity Cooler (NG HCC) cryocooler by the Air Force Research Laboratory. This cooler's design uses two pulse tube cold ends in parallel. The nominal 85 K cold end is thermally strapped to the regenerator housing of the nominal 35 K cold end in order to boost 35 K cooling capacity. The cooler was tailored to support long wave infrared (LWIR) HgCdTe focal plane arrays and their associated optical systems, but this particular refrigeration system can also support a variety of short or medium wave infrared sensing as well as high temperature superconducting electronics applications. The results are presented for both steady state and transient performance envelopes for this cooler on and off the design point of 2 Watts of cooling at 35 K and 17 Watts at 85 K. When it is off the design point the load is up to 15 Watts of cooling at “35 K” and 50 Watts on the “85 K” sides. Testin...
{"title":"MULTISTAGE PULSE TUBE REGRIGERATION CHARACTERIZATION OF THE NORTHROP GRUMMAN HIGH CAPACITY COOLER—AN UPDATE","authors":"J. Sutliff, T. Roberts","doi":"10.1063/1.2908689","DOIUrl":"https://doi.org/10.1063/1.2908689","url":null,"abstract":"The characterization of a multistage Pulse Tube cycle refrigeration system has been partially performed on the Northrop Grumman High Capacity Cooler (NG HCC) cryocooler by the Air Force Research Laboratory. This cooler's design uses two pulse tube cold ends in parallel. The nominal 85 K cold end is thermally strapped to the regenerator housing of the nominal 35 K cold end in order to boost 35 K cooling capacity. The cooler was tailored to support long wave infrared (LWIR) HgCdTe focal plane arrays and their associated optical systems, but this particular refrigeration system can also support a variety of short or medium wave infrared sensing as well as high temperature superconducting electronics applications. The results are presented for both steady state and transient performance envelopes for this cooler on and off the design point of 2 Watts of cooling at 35 K and 17 Watts at 85 K. When it is off the design point the load is up to 15 Watts of cooling at “35 K” and 50 Watts on the “85 K” sides. Testin...","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908689","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58365796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Bourcey, P. Campos, P. Chiggiato, P. Limón, A. Mongelluzzo, G. Musso, A. Poncet, V. Parma
The assembly of the approximately 1700 LHC main ring cryostats at CERN involved extensive welding of cryogenic lines and vacuum vessels. More than 6 km of welding requiring leak tightness to a rate better than 1.10−9 mbar⋅l⋅s−1 on stainless steel and aluminium piping and envelopes was made, essentially by manual welding but also making use of orbital welding machines. In order to fulfill the safety regulations related to pressure vessels and to comply with the leak-tightness requirements of the vacuum systems of the machine, welds were executed according to high qualification standards and following a severe quality assurance plan. Leak detection by He mass spectrometry was extensively used. Neon leak detection was used successfully to locate leaks in the presence of helium backgrounds.This paper presents the quality assurance strategy adopted for welds and leak detection. It presents the statistics of non-conformities on welds and leaks detected throughout the entire production and the advances in the us...
{"title":"LEAK-TIGHT WELDING EXPERIENCE FROM THE INDUSTRIAL ASSEMBLY OF THE LHC CRYOSTATS AT CERN","authors":"N. Bourcey, P. Campos, P. Chiggiato, P. Limón, A. Mongelluzzo, G. Musso, A. Poncet, V. Parma","doi":"10.1063/1.2908564","DOIUrl":"https://doi.org/10.1063/1.2908564","url":null,"abstract":"The assembly of the approximately 1700 LHC main ring cryostats at CERN involved extensive welding of cryogenic lines and vacuum vessels. More than 6 km of welding requiring leak tightness to a rate better than 1.10−9 mbar⋅l⋅s−1 on stainless steel and aluminium piping and envelopes was made, essentially by manual welding but also making use of orbital welding machines. In order to fulfill the safety regulations related to pressure vessels and to comply with the leak-tightness requirements of the vacuum systems of the machine, welds were executed according to high qualification standards and following a severe quality assurance plan. Leak detection by He mass spectrometry was extensively used. Neon leak detection was used successfully to locate leaks in the presence of helium backgrounds.This paper presents the quality assurance strategy adopted for welds and leak detection. It presents the statistics of non-conformities on welds and leaks detected throughout the entire production and the advances in the us...","PeriodicalId":80359,"journal":{"name":"Advances in cryogenic engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1063/1.2908564","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58365129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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