TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb R. Denz TE-MPE-CP on behalf of the QPS team QPS Upgrade and Re-commissioning

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade – rationale  : Non-destructive discovery of aperture symmetric quenches in LHC main dipoles –Late detection of a quench in a main dipole –Upgrade of existing protection system required in order to detect timely aperture symmetric quenches  : Incident in sector 3-4 –Extent the existing protection system in order to be able to detect and interlock potential problems in the magnet interconnections and main bus-bar splices

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade building blocks Phase 1: required for re-start of LHC Phase 2a: required for MB training to 7 TeV Phase 2b: required for MQ training to 7 TeV Phase 3: enhanced diagnostics + repair, test and re-test of QPS electronics in sector regular maintenance of QPS & EE systems

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade – aperture symmetric quenches  Safe detection of symmetric quenches by comparing total voltage drops across magnets –System can share the instrumentation cables with the suspicious splice detection system –Additional interlock cabling for triggering of quench heater power supplies required  Multiple magnet evaluation scheme for main dipoles minimizing number of provoked quenches –3+1 magnet reference (interleaved with next unit): 1 st and 2 nd quench  trigger quenching magnet 3 rd quench  trigger remaining magnet of the three connected triggers  Interleaved two magnet evaluation scheme for quads  System reacts as well on “normal” quenches  detection threshold must be slightly higher to clearly distinguish different cases (U TH = 200 mV, 10 ms) K. Dahlerup-Petersen

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb Symmetric quench detection layout

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb Symmetric quench detection electronics  New design based on flash FPGA  Analog input stages and A/D converters on magnet potential, evaluation logic on local crate potential  Basic design finished  prototype production on the way  Redundant system with interlocks wired in 1 out of 2 configuration  Type tests –Detection logic & reaction time –Noise immunity (EMC) –Radiation tolerance of components e.g. ADC converters –Communication interface J. Steckert

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade - suspicious splice detection  Provide a system to be able to detect and localise “bad splices” representing a potential risk for the LHC integrity in the LHC main circuits (RB, RQD and RQF)  A splice developing a resistance in the order of n  equivalent of 100  V or kA) is regarded as potentially dangerous at high current (  see presentation A. Verweij) –System should interlock the concerned circuits Baseline threshold U TH = 300  V, 10 s –System should provide data for enhanced diagnostics via the QPS supervision –System can only access the superconducting circuits via existing voltage taps routed to the IFS box connectors (diode voltage taps), there is no access to a single splice  New layer of protection electronics exceeding the original scope of QPS –Detection of non-recoverable faults  new procedures required

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb Suspicious splice detection system type DQQBS  Re-use of existing design for the protection of HTS leads in LHC –Solution endorsed by management after QPS review end of 2008 –1200 units installed in LHC (equipment code DQQDC) Very few hardware problems revealed during commissioning Stable operation once system has been commissioned  2016 new units required for upgrade –Only minor hardware changes Increased isolation strength of DC-DC converters Replacement of obsolete components –New firmware under development (already used for testing) –Upgrade covers so far RB, RQF and RQD circuits –Upgrade can be extended to cover insertion region magnets Re-cabling of existing current lead protection system or installation of additional equipment

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb Suspicious splice detection electronics  Design based on ADuC834 TM micro-converter with 24 Bit  ADC –Two input channels with ±12.5 mV and ±250 mV voltage range 2 nd channel used for inductive compensation connected to external 1:10 voltage divider shared with symmetric quench detection –Baseline detection threshold is 300  V (10 s integration time) Redundant system with interlocks wired in 1 out of 2 configuration  Radiation tests (CERN TCC2, CERN CNGS, PSI) promising –Devices will withstand radiation levels expected for mid dipole position –ADuC834 TM micro-converter, DC-DC converters, SRAM, instrumentation amplifiers, fieldbus couplers …  To make full use of the capabilities of the system dedicated powering cycles are required –Powering cycle form injection current up to 2 or 3 kA with intermediate steps every 200 A –Sampling frequency = 5 Hz –Offline analysis of acquired data  expected resolution < 1 n 

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb Feasibility tests with prototype units in sector 1-2 Z. Charifoulline, B. Flora

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade - integration of new QPS electronics into LHC  Local Protection Unit type S to be installed in the existing QPS rack type underneath dipole B in each LHC half cell –Protection electronics associated to circuits RB, RQD and RQF –Suspicious splice protection system (phase 1) –Symmetric quench protection system (phase 2) –Potential to earth measurement (phase 3) –Fieldbus coupler linking to QPS supervision (phase 1)  Crate will be connected to existing infrastructure –Acquiring signals from 4 dipoles and 2 quads –WorldFip fieldbus and QPS internal interlocks (patches required) –One crate per LHC half cell, 54/55 per sector  Crate will be powered via a dedicated AC-DC power supply –Power supply fed by existing 230 V 50 Hz single phase UPS  Impact on existing QPS electronics is minimized

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb Local protection unit type S – integration into dipole protection rack Local protection unit type S Power supply unit

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade - cabling  Cabling is one of the essential parts of the upgrade –Measurement cables –Interlock cables for quench heater power supply triggering Required by symmetric quench detection system –Local patches for fieldbus, interlock and powering (treated separately)  Use of existing cable trays – additional cable supports (CABLOFIL TM ) required in dispersion suppressor areas and to by-pass the jumpers –Half-cell 7 to 11 shared with beam instrumentation (courtesy BE-BI)  Exclusive use of magnet connectors D20 (MB) and D21(MQ)  Cabling requests (DIC) prepared by QPS team and submitted to EN-EL –Three levels of cross checking introduced in collaboration with BE-OP  Cables fully assembled and tested on the surface by contractor  Final checking after installation (layout, continuity and isolation) –Tools provided by ELQA team Careful checking of the cabling work is extremely important and needs adequate time allocated. Any non-conformity not revealed during these tests will cause inevitable delays at a later stage.

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade – basic cabling set-up (odd half-cell) G. Coelingh 240 km of cables (= Chamonix – Venezia) 4400 individual cables 7800 connectors 0 errors permitted Triggers Instrumentation MQ Instrumentation MB

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade - supervision  Supervision hardware –2100  2536 QPS fieldbus clients in LHC –Up to 60  75 per WorldFip segment –Up to 120  150 per front-end computer –Increased number of clients will require slight modifications of the QPS networks in the LHC tunnel  more repeaters and local patches  Supervision software –Three new equipment types associated to a new QPS controller type –~30000 new signals, no dead-bands on analog signals permitted –Increased data volume transmitted to LHC logging  Firmware development of new QPS controller type by TE-MPE-CP in close collaboration with EN-ICE  All other tasks performed by BE-CO and EN-ICE

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade – revised supervision layout

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade – status phase 1 electronics  Suspicious splice detection board (2500) and fieldbus coupler (500) –Technical specification and final manufacturing folder ready –Electronic components ordered and about 90% delivered –Purchase order for PCB production, circuit board assembly and test submitted to approval Pre-series expected for beginning of March Total before end of May (partial delivery in batches) –Functional test systems for circuit boards currently being commissioned  Local protection unit type S (450) –Technical specification to be sent out to firms in week 7  Power supply unit (500) –Final prototype testing, technical specification in preparation

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade – status phase 1 cabling  Cabling requests (DIC) for all sectors submitted to EN-EL  Cable assembly on the surface –Sector 4-5: completed and tested by contractor –Sector 5-6: 50% completed –Sector 2-3: cables cut  Installation of cable supports started in sector 4-5 and 5-6  Cabling of sector 4-5 to be started this week –Final testing of cables can start as soon a reasonable quantity is installed K. Dahlerup-Petersen

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb QPS upgrade – status phase 2 & 3  Cabling included in phase 1  Symmetric quench detection electronics –Prototype production to be launched soon –Prototype device is also required for validation of QPS supervision –Various type tests to be made Radiation PSI scheduled for mid March –Technical specification & procurement of components in April –Production in May / June  test & installation in July (earliest date)  Voltage to earth feeler –Design principle clear, further development as soon as resources are available (not on critical path)

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb Summary I  QPS update will enhance the diagnostic and protection capabilities significantly and provide a powerful tool for identifying potentially dangerous problems in the LHC superconducting circuits –Scanning of the superconducting circuits including the magnets (using already available tools) on a regular (weekly?) basis necessary –New systems need to be very carefully commissioned in order to guarantee proper function and limited number of false triggers  New QPS electronics is based on a modular design allowing installation and commissioning in three stages –Upgrade of the system to phase 2 and 3 does not require long interventions inside the LHC  The proper functioning of the new protection system depends strongly on the instrumentation and interlock cabling –Proper testing of all new cabling work is essential

TE-MPE-CP, RD, LHC Performance Workshop - Chamonix Feb Summary II  QPS update is on the critical path for the re-start of LHC –Suspicious splice detection must work prior to re-commissioning of LHC System can be realised based on existing QPS designs and infrastructures Still on time but no contingency reserve Tests with powered magnets end of 2008 proved feasibility –Development of symmetric quench detection system almost completed Prototype testing to be started soon  Production, installation and commissioning until re-start of LHC remains nevertheless challenging The members of the QPS team like to thank all their colleagues providing help during this challenging phase!