Evaluation and testing of advanced low-voltage power supplies 12th Workshop on Electronics for LHC and Future Experiments 25-29 September 2006, Valencia, Spain Bruno Allongue, CERN, PH-ESS September 27, 2006

Agenda Introduction Equipment evaluated Measurements Corrective actions Conclusions 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Background Low-voltage detector power supplies Low-noise, high-efficiency Switching technology for efficiency and low-volume Installation close to the detectors To avoid distribution over long cables (~120m) Installation close to the detector implies Significant stray magnetic fields (ex. CMS) < 1.8 kGauss Radiation (ex. ATLAS TRT) TID - 140Gy over 10 years Neutrons - 1012 1 MeV equivalent neutrons/cm2 over 10 years Protons - 2*1011 >20MeV protons/cm2 over 10 years 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Typical topology for switching power supply Design principle 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments Typical topology for switching power supply

Proof of concept Work done over several years by CERN and industry to identify potential problems in typical low-voltage power supply architectures Magnetic field tolerance “Classical” soft-iron screening Novel technology – high permeability toroidal transformers Radiation tolerance Opto-couplers Weak components identified Power transistors Need for very conservative under-rating Efficient cooling Direct water cooling Air cooling 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Equipment evaluated The proof-of-concept process was followed at the end of 2005 by a formal invitation to tender from CERN on behalf of a sub-set of LHC experiments’ subdetectors Tender included Detailed electrical specifications Environmental specifications Magnetic field and radiation tolerance Remote control functions OPC server Two suppliers were selected Wiener (Germany) CAEN (Italy) Both suppliers offered similar architectures Radiation and magnetic field sensitive elements as far as possible installed outside the hostile area Control Active power factor correction Tolerant power conversion in the hostile area Sample equipment was evaluated against the tender specification 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Radiation & magnetic field tolerance 3. “Maraton” 12ch 50A DC-DC (3kW) Wiener “Maraton” 27 Sep. '06 - ba Radiation & magnetic field tolerance Water cooled μP 230VAC, single phase 1. AC-DC (w. PFC) 3. “Maraton” 12ch 50A DC-DC (3kW) 385VDC 2. Control & monitoring 12th Workshop on Electronics for LHC and Future Experiments μP Ethernet OPC Server

Radiation & magnetic field tolerance CAEN “EASY” Air cooled 27 Sep. '06 - ba 400VAC, Three-phase μP 3. “EASY A3486 AC/DC” 2ch 48V/40A/2KW 1. Harmonic filter 400VAC 48VDC 2. Control & monitoring 4. “EASY crate" with “EASY DC/DC ” ex. 12ch 9A/45W μP 12th Workshop on Electronics for LHC and Future Experiments Ethernet OPC Server

Measurements Electrical Environmental Controls Regulation Efficiency Static Dynamic Efficiency Noise and ripple Turn ON and turn OFF Protections Overcurrent Overvoltage Stability EMC (Harmonic emissions) Environmental Magnetic field tolerance Radiation tolerance Controls Check the OPC server for conformity to specifications (IT/CO) 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Electrical tests Instrumentation Test set up PC DC output 27 Sep. '06 - ba PC HP 6050 A Electronic load DVM Keithley 2000 Oscilloscope Philips PM 3394 Power analyzer Infratek 106A DC output Output characteristics measured by oscilloscope and DVM Controller USB or ETHERNET 30m cable length with C=300uF AC input DUT Test set up 12th Workshop on Electronics for LHC and Future Experiments

Results (Harmonics emissions) Wiener Maraton 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Without harmonics filter Results (Harmonics emissions) CAEN EASY 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments Without harmonics filter With harmonics filter

Environmental categories – two specifications 27 Sep. '06 - ba Spec A ALICE LHCb ATLAS-TRT 12th Workshop on Electronics for LHC and Future Experiments Spec B Radiation is present at a level below 4Gy and 1011 1 MeV equivalent neutrons/cm2 over 10 years, of which approximately 10% are above 20MeV. Stray magnetic fields are present at a level up to 180mT. CMS

Environmental Magnetic field tolerance Tests at CERN PH-ESS magnet for components tests (1.8kGauss, 15cm gap) Bigger magnet (MNP22) for systems tests (8kGauss, 50 cm gap) Both systems conform to specifications 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Environmental Radiation Protons at Neutrons at Gammas PSI – Louvain la Neuve Small diameter beam (8 – 10 cm) Focus on components Uppsala Large beam Test large system (e.g. CAEN EASY modules) Neutrons at Prospero (1Mev Neutrons reactor) Gammas Cassacia (ATLAS Muons) 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Radiation tolerance Uppsala 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Radiation tolerance PSI 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Corrective actions required Wiener Change optocouplers (NIEL problem) Change power transistors due to implementation of PFC Qualification of components CAEN Spikes on reset lines (Transients on optocouplers with hadrons) Low pass filter implementation Sensitive components (Amplifiers, EPROM) Change of components 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Summary Qualified radiation and magnetic field tolerant detector power supplies are available to the four LHC experiments from two suppliers Purchase and support contracts have been set up, production is underway and installation has started Lessons learned Qualification of COTS equipment is a very long, costly and painful process Close collaboration between users, power supply and radiation tolerance specialists at the earliest possible stage is of prime importance to minimize time and cost 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments

Acknowledgements F.Anghinolfi (CERN) G.Blanchot (CERN) F.Faccio (CERN) R.Richter (MPI) C.Rivetta (SLAC) PH/ESS colleagues 27 Sep. '06 - ba 12th Workshop on Electronics for LHC and Future Experiments