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SC strand and cable measurement instrumentation

Internal review of superconductors and magnet laboratories, CERN May 19, 20, 2009. SC strand and cable measurement instrumentation. Mechanical testing of superconductors lab. 103 Low-temperature electrical testing of superconductors lab. 163.

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SC strand and cable measurement instrumentation

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  1. Internal review of superconductors and magnet laboratories, CERN May 19, 20, 2009 SC strand and cable measurement instrumentation Mechanical testing of superconductors lab. 103 Low-temperature electrical testing of superconductors lab. 163

  2. Instrumentation of lab. 103(Mechanical testing) • PC controlled(-able) instruments • Cable Measurement Engine (2x+3x): QBasic, DAS-8PGA card. • Cable Inspection System (2x+5x)Pattern recognition video system for Rutherford-type cables. • EMPA mandrel movement optical monitoring system. • Cable thermal contraction measurement bench. • Coulometer (2x). • Developed for and very extensively used during the LHC cable production

  3. Test stations lab. 163(Low-temperature electrical testing) As built for LHC • 4x IC- strand NbTi • 1x M(H)-strand • 2x rrr/RC • 1x Fresca • --------------------------- • 1x Com. with Cryo Present • 2x IC- strand NbTi • 1x IC- strand Nb3Sn • 1x Heat transfer • 1x M(H)-strand • 1x rrr/RC • 1x Fresca • --------------------------- • 1x Com. with Cryo Next: 1 of alternatives • 2x IC- strand ITER • 2x IC- strand Nb3Sn • 1x M(H)-cable/IC-HTSc • 1x M(H)/loss-strand • 1x rrr/RC • 1x Fresca1x Heat transfer • --------------------------- • Com. with Cryo 7 + 1 pits available in 163

  4. Testing electronics NbTi Ic-strand example

  5. Control computer • 10x somewhat obsolete SunBlade or SunUltra • Problems very rare, not supported at CERN anymore – replacement. • Links: HD cross mount, server regime, afs calls. • Rather unreliable coax Ethernet • Problems not rare, also for Cryo remote controls. • Under upgrade since months. • Ethernet as noisy as mains – could be isolated, WiFi? • LabView 5.1 through 7.1 • TB updated but not yet a problem in real life. • Protected mains installed for Controls • Their use somewhat random. Protected mains for test stations? Local UPS?

  6. Control bus • IEEE-488 bus • 6x RS 232 20 mA loop terminated by an RS 232-to-IEEE-488 convertor serving typically 7 parallel working instruments in each station. • Difficult management of READs and WRITEs for the control program in order to avoid blocking of the bus. • We learned how to work in this condition but higher performance IEEE-488 bus would make operation more fluent. • Nb3Sn IC-strand, HT, and FRESCA on direct IEEE-488.

  7. Instruments conducting the test • Mixture of: • Current supplies: 1 mA to 32 kA • V-meters: nV, mV, and mV ranges • Switches: nV to kA • DI/Os: 5 V, 24 V • Automates PLC: M(H), Cryo communications • Quench security • Most of them fulfill their function and do not have TB replaced yet • From time to time some burn and need replacement, typically during summer – air temperature 35 C. • All stations use the same instruments: Sufficient internal redundancy in case of failure. CERN Electronics Pool offers some of them. All instruments still manufactured. Failure of any electrical instrument, with the exception of the multi-kA power supplies for the Nb3Sn IC-strand, M(H)-cable and FRESCA should not result in more than few-days stoppage. • Sensors & Heaters • Available: Small stock of GRT, Cernox, CLTS, and Pt100 sensors, MINCO foil heaters. • Low stock of LHe level meters. • Stock TB revised.

  8. PXI upgrade option NbTi Ic-strand example Cost:About 6000÷15 000 EUR/station & partial re-programming of the LabView code & partial re-cabling. Essential gain: Smoother communication, possible replacement of 2.5 instruments.

  9. Two current supplies to look at • 5 pieces of 1 kA battery powered current supplies for IC-strand test (TE/MSC) • Need maintenance: battery replacement, revision of charger electronics and of cooler, adjustment/replacement of water interlock. • Power supply for M(H) test • ISR original material. • Need for bipolarity, better control of current, reliability, smaller volume. • Would better be replaced by a new one.

  10. Calibration • Multimeters • The 21 DMMs and 15 nV-meters Keihley, which are the core of the DAQ should be regularly calibrated. • Last systematic calibration done in 2000. • Temperature sensors • LakeShore Germanium and Cernox sensors used. Last calibration campaign done in 2002 and 2004 – actual status TB verified. • Similar concerns the 1.5 kA DCCTs

  11. EM noise & Co. • TBD: De-coupling from mains and from Ethernet for sensitive measurements: • Double conversion UPS + separation transformer + WiFi(?). • TBD: Installation of filters on cranes and verification of EM emission useful • TBD: Protection of sensitive instruments against draughts in winter, and from overheat in summer • Temperature driven auto-calibrations TB added.

  12. Cabling and others • Signal and control cabling • needs revision - connectors in particular (10 years in operation). • Ventilation inside instrument racks - cleaning/revision • Maintenance/upgrade of cooling water circuits • More de-mineralized water needed? • Utility water circuit TB purged, interlocks changed/adjusted. • Water-cooled cables TB revised. • Mechanical tooling needs revision small repairs/re-placements/cleaning

  13. FRESCA particular • SC current transformer for FRESCA • Transformer and its control electronics to be re-assembled and put into operation, some development of the electronics expected. • Warm instrumentation cabling • Diverse provisional cabling TB replaced by a definitive one. • Sample holders • Diverse sample holders TB inventoried and documented.

  14. Control programs (CP) • The LabView based control software proved rather reliable and efficient during the extensive 5-year testing of superconductors for the LHC, and afterwards. • CPs sontrol all (or almost all) test parameters and can run reasonably unattended over hours to complete series of tests: All use programmable sequencers – agendas. • Built-in LHC-tailored quality control • IC-strand verifies instrument configuration. • Either have on-line automatic analysis of the test result, or they do not need it. • Many use reference sample as aid for on-line validation. • They all rely on final off-line acceptance of data by educated follower. • Interactions of the CP • Interaction with Cryogenics • Interaction with Database • Calls to afs • Mail, phone alerts

  15. Upgrade of the CPs desirable • Diverse upgrades desirable for CPs: • LHC-type control features TB revised/removed/extended: Sample ID control, assumptions about sample parameters, assumptions about test procedure. • Bi-directional-relation with the LHC database TB updated. • Change of all READs and WRITEs and bus sequencing in case of RS232 loop removal. • Periodic auto-calibration should be introduced in CPs. • New requirements on test algorithm for all tests: IC-strand, M(H), rrr, RC. • Algorithm extended for non-standard tests: Rc used for rrr of BB, rrr used for r(T) of SnAg.

  16. Sources of Control programs TE/MPE, TE/MSC (LHC/MMS): • IC- strand NbTi • IC- strand Nb3Sn • Daq & data evaluation in M(H) • rrr • RC test • RC follow-up • Data evaluation for Fresca • Heat transfer • Communication with Cryogenics • Data storage, retrieval, and post-processing • CME modifications • Cable thermal contraction EN/ICE • Data acquisition in M(H) • Data acquisition for Fresca Outside CERN: • Cable Measurement Engine • Cable Inspection System • Mandrel Monitoring EMPA

  17. Database from the user’s point of view • LHC production period • Highly efficient and specialized Database at the center of the LHC-centered activity of the section:Data storage, contract follow-up, test sample flow, test reference data, and test data approval and tracability. • Limited diversity of tests and samples × very high number of tests. Database inter-linked with testing programs. Concise paper logging - all information available from the DB. • Current status and future • Unlike the LHC production: Diversified samples, Nb3Sn dominant. • We urgently need ‘new’ database • The Database TB re-established in all its roles according to changed activities of the Section. • Actual state of the Database and its links to other SW TB inventoried. • Data approval procedures, automatic data tracability and test logging TB re-established/enhanced. • To offer fast read and load from daq & post-processing SW. • Well and simply organized flat files in right place are valuable complement ideal for creativity and raw data manipulation. • The database is to be accessed primarily from inside CERN and by interfaces written in different languages. External-to-CERN access must not impose restrictions on the in-house function of the database. • The users are TRAINED EXPERTS, who do their best to do good job – DB kind to users.

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