18/6/03GS/ALICE Forum1 LVPS - Grounding Meeting of LVPS TF on Tuesday 17/6 Overview of TPC, TRD and TOF subsystem with F. Szoncso/TIS-GS Review of subsystems SPD, SSD, HMPID, DiMuons (Tk & Trig) Grounding scheme of each subsystem Wiener PL500radiation testing, status and plans (ESS) CAEN dc/dc converterradiation testing (ESS group & CMS team) AREMproradiation testing Latest calculations of radiation levels

18/6/03GS/ALICE Forum2 TPC Grounding

18/6/03GS/ALICE Forum3 TRD Grounding

18/6/03GS/ALICE Forum4 TOF Grounding

18/6/03GS/ALICE Forum5 HV PS LV PS Subdetector Support - Safety Ground Vessel (if any) FEE Screen (if any) Equipment Rack - Safety Ground Copper links (if any) Grounding - (Over)simplified generic model GS/ Mains 1M  Mains Ground Trasf Optical Links Mains Ground

18/6/03GS/ALICE Forum6 Status of Grounding Preliminary grounding plans shown –TPC, TRD, TOF, SPD, SSD, HMPID, DiMuons First overview of large systems by TIS does not reveal inconsistencies or violation of safety rules Plans comply with guidelines (isolation of subsystems, etc) –HMPID: problem of metallic pipes Not (yet) all mapped to generic template –Simplified functional scheme needed for operational verification Are guidelines an overkill ? –Follow established best practices in large detectors –Proof of principle: test with slice of real system (by end 2003)

18/6/03GS/ALICE Forum7 Status of LV Power Supplies (I) Wiener (PL500 & variants) Power & Radiation tolerance –Joint effort in ESS to develop rad tolerant configuration for LHC experiments –Power block validated for ATLAS & CMS radiation levels in exp. hall –Standard embedded microprocessor (controls all operations) sensitive to very low levels –Recently tested new device may be more tolerant Controls –Modification required (switching of individual channels) –Control (OPC server) not yet finalized –Very slow response from supplier –Action: draft a common ALICE requirement document (L. Jirden) and get help of ESS group to raise interest in supplier and expedite delivery

18/6/03GS/ALICE Forum8 Status of LV Power Supplies (II) CAEN dc/dc converter (SASY, EASY) –Radiation test with ≈ 20MeV neutrons (CMS team) –Fluence up to >> 10 years LHC –4 SEU observed, analysis under way –Radiation tolerance seems to be more than adequate for the levels expected in ALICE –EMI of input power cables to be measured –Final validation of prototypes by ≈ end 2003 AREMpro –Low power units for SDD (and possibly SSD) –Radiation tested with neutrons - spectrum up to ≈ 20MeV –No problems found for fluence >> 10 years LHC

18/6/03GS/ALICE Forum9 Latest calculations of radiation levels (B. Pastircak) Charged hadrons contribution included in tables Fluence includes normalization of NIEL to 1 MeV neutrons Higher fluence values for SPD inner layer (mainly) Outside ITS –TPC FE (inner radius) TID ≈ 0.65krad –fluence (1MeV n eq) ≈ cm -2 (p,  > 20MeV) ≈ cm -2 –Other subdet locations with (p,  > 20MeV) >> 10 8 cm -2 Levels at rack locations are very low –TID ≈ 1 rad –fluence (1 MeV n eq.) << 10 8 cm -2 –==> standard commercial equipment can be used

18/6/03GS/ALICE Forum10 Status of LV Power Supplies (III) Some thoughts on Wiener LVPS ALICE requires individual channel control as in PL500 F12 –not requested by other LHC experiments (see eg ATLAS LVPS MS) –small number, relatively uninteresting business opportunity ? What if Wiener does not deliver “ALICE” PL500s ? –(Nearly) all subsystems have voltage regulators on FE load –Radiation levels in ALICE hall are expected to be so low that industry standard products (wide range) may be used. Advantages and drawbacks: Estimated cost ≈ 1 Euro/W (< 3x lower than HEP units) Outstanding reliability Simpler functionality (remote setting, ramping, etc) Developments needed: market survey, test, control s/w (OPC server etc) –Should somebody look into this possibility ?

18/6/03GS/ALICE Forum11 Conclusion Good progress in implementation of grounding plan Progress in dc/dc converter testing Questions on prototyping and availability of LVPS –Essential controls not yet available –ALICE specific requirements may be niche market –Action: common ALICE requirements document –Single source dependence Commercial “rad soft” equipment can be used at rack locations