Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen Magnet Safety System Magnet Safety System Specification Specification 10 th of April 2003 ATLAS “MSS Specification”
Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen 1 Introduction: 1 Introduction: 1.1 Introduction to CERN 1.1 Introduction to CERN � � 1.2 Introduction to ATLAS 1.2 Introduction to ATLAS � � 1.3 Subject of this specification 1.3 Subject of this specification � � 10 th of April 2003 ATLAS “MSS Specification”
Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen 1.3 Subject of this specification 1.3 Subject of this specification This specification concerns the details of the “Magnet Safety System”, or MSS, used to protect stem”, or MSS, used to protect This specification concerns the details of the “Magnet Safety Sy experimental magnets used in particle physics. Due to the nature of operation and cost of such of operation and cost of such experimental magnets used in particle physics. Due to the nature magnets, all measures must be taken to provide a system with the highest possible reliability highest possible reliability magnets, all measures must be taken to provide a system with the and availability. and availability. The object of this paper is to specify the MSS system of ATLAS on the base of a common project for all The object of this paper is to specify the MSS system of ATLAS o n the base of a common project for all four experimental magnets at the future LHC machine. This project is called the “Magnet Control four experimental magnets at the future LHC machine. This projec t is called the “Magnet Control Project”, or MCP. Project”, or MCP. The responsibility of the MSS is to detect anomalies endangering the safety of the magnet and/or the safety of the magnet and/or The responsibility of the MSS is to detect anomalies endangering personnel and to take appropriate action in order to bring the magnet to a secure state. agnet to a secure state. personnel and to take appropriate action in order to bring the m The overall definition of the MSS system can be seen in the paper “MSS Definition 1.0” in appendix r “MSS Definition 1.0” in appendix The overall definition of the MSS system can be seen in the pape 1.3.1. This paper defines exactly the functionality of MSS. 1.3.1. This paper defines exactly the functionality of MSS. From the From the updated updated work work packages relevant to packages relevant to the the experiment experiment, , it it is is seen seen that that responsibility responsibility for for developing, production, installation developing , production, installation and and operation operation is is the the responsibility responsibility of of CERN. CERN. 10 th of April 2003 ATLAS “MSS Specification”
Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen 2 Technical Specifications 2 Technical Specifications 2.1 General Description: 2.1 General Description: 2.1.1 Differential quench detection 2.1.1 Differential quench detection � � 2.1.2 Superconducting quench detection 2.1.2 Superconducting quench detection � � 2.1.3 Bridge quench detection 2.1.3 Bridge quench detection � � 2.1.4 Voltage measurements 2.1.4 Voltage measurements � � 2.1.5 Temperature measurements 2.1.5 Temperature measurements � � 10 th of April 2003 ATLAS “MSS Specification”
Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen 2.1.1 Differential quench detection 2.1.1 Differential quench detection V1=I * R QUENCH - L1*dI/ dt + V1'=(I * R QUENCH - L1*dI/dt) L1: 120 turns Differential Amplifier - + Level Time Galvanic isolation discriminator discriminator Alarm - V OUT =I * R QUENCH + G L2: 19 turns - V2'=( - L2*dI/dt)*G V2= - L2*d φ /dt 10 th of April 2003 ATLAS “MSS Specification”
Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen 2.1.2 Superconducting quench detection 2.1.2 Superconducting quench detection Current source I SOURCE Galvanic isolation R CONNECTION + Level Time R SUPRA discriminator discriminator - Alarm V= (R SUPRA +R CONNECTION ) * I SOURCE Level Time discriminator discriminator Warning 10 th of April 2003 ATLAS “MSS Specification”
Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen 2.1.3 Bridge quench detection 2.1.3 Bridge quench detection Z = Z APERTURE 1 APERTURE 2 Z Z R 1 R 2 R 1 Galvanic isolation Aperture 1 + Level Time discriminator discriminator - Alarm Level Time discriminator discriminator Aperture 2 Alarm R 2 10 th of April 2003 ATLAS “MSS Specification”
Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen 2.1.4 Voltage measurements 2.1.4 Voltage measurements � � Same module as for the differential measurement Same module as for the differential measurement 2.1.5 Temperature measurements 2.1.5 Temperature measurements � � Same module as for the superconducting quench measurement Same module as for the superconducting quench measurement 4- 4 -wire measurement wire measurement 10 th of April 2003 ATLAS “MSS Specification”
Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen 2.2 Main Parameters 2.2 Main Parameters 2.2.1 Machine States 2.2.1 Machine States 2.2.1.1 Inhibit 2.2.1.1 Inhibit � � The inhibition inhibition of of current current in in the the magnet magnet is is controlled controlled by by the the MSS, MSS, eventually eventually under under orders orders from from The MCS or DSS. MCS or DSS. 2.2.1.2 Start- 2.2.1.2 Start -up tests up tests � � All principal sub All principal sub- -systems systems, , including including the the MSS, must MSS, must be be tested tested and and found found ready ready during during this this phase; phase; otherwise “Normal Mode” “Normal Mode” cannot cannot be be reached reached. . Only Only minimal minimal magnet magnet current current is is allowed allowed. . otherwise 2.2.1.3 Normal mode 2.2.1.3 Normal mode � � In the the “Normal Mode” “Normal Mode” the the MSS MSS is is fully fully operational operational, , with with or or without without current current in in the the magnet magnet. . In 10 th of April 2003 ATLAS “MSS Specification”
Magnet Safety Systems – Magnet Safety Systems – Magnet Common Project Magnet Common Project E. Sbrissa, G. Olesen – – CERN/EP CERN/EP E. Sbrissa, G. Olesen 2.2.1.4 Slow discharge 2.2.1.4 Slow discharge � � The normal current run- -down mode is a “Slow Discharge”, also called a “Slow Dump” or SD down mode is a “Slow Discharge”, also called a “Slow Dump” or SD. For . For The normal current run minor problems or defaults occurring in magnet sub- -systems the same mode is generally also systems the same mode is generally also minor problems or defaults occurring in magnet sub prescribed (see section 2.2.2 for details). prescribed (see section 2.2.2 for details). In this case the stored magnet energy is dissipated in the run- -down units in diode down units in diode- -resistor resistor In this case the stored magnet energy is dissipated in the run combinations in parallel with the magnet parts, see also figures 1.2.2 combinations in parallel with the magnet parts, see also figures 1.2.2- -1.2.3. 1.2.3. The “Slow Discharge“ initiates the following actions: The “Slow Discharge“ initiates the following actions: Power Converter OFF Power Converter OFF � � Circuit Breaker OPEN Circuit Breaker OPEN � � These actions are sequential. These actions are sequential. The “Slow Dump” will stop physics data- -taking for a few hours. taking for a few hours. The “Slow Dump” will stop physics data 10 th of April 2003 ATLAS “MSS Specification”
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