OLYMPUS Collaboration DESY 30/August/2010 Rome group activity since last meeting (4) DESY 30/August/2010 Olympus Collaboration meeting Salvatore Frullani / INFN-Rome Sanità Group 1
GEM electronics: Outline Since last meeting only activity done has been during test beam in DESY 19-27 August (before: material sent to DESY; after: summer vacations) Results obtained during test (no futher analysis has been possible due to vacations) Points to be solved working with all system connected in lab MWPC electronics: Information needed on radiation environment where front end cards should be installed DESY 30/August/2010 Olympus Collaboration meeting 2
Test beam in July has been also the first opportunity to connect all the system: HV, GEM chamber, FEC, VME than results has to be considered as the first essay on the system. Several problems have prevented to test the complete system at lab before test beam period. People: Evaristo Cisbani (INFN-ISS), Juergen Diefenbach (Hampton), S.F. (INFN-ISS), Massimo Gricia (INFN-ISS), Paolo Musico (INFN-Genoa), Roberto Perrino (INFN-Bari) DESY 30/August/2010 Olympus Collaboration meeting 3
4
5
6
7
8
Electronics Components GEM FEC ADC+VME Controller DAQ 2D Readout 49.5 mm Main features: 80 mm 8 mm Use analog readout APV25 chips (wire-bonded on standard PCB, no ceramics): proven to work in COMPASS Up to 16 FEC ZIF connector on the GEM side (no soldering on readout foil) Minimum electronics components (front-end + VME custom module) Copper connection between front-end and VME Up to 10 m or +? DESY 30/August/2010 Olympus Collaboration meeting 9
Slow Control HV management is not trivial! 7 HV levels must rump up/down coherently DESY 30/August/2010 Olympus Collaboration meeting Low pass filters 1 0
First and main problem to understand: Noise Configuration: 1 FEC connected to GEM output to the test board and then to the oscilloscope. Reset, Clock and trigger from VME master at 20 MHz. Other 3 FEC connected to the GEM and readout bus but not powered. FEC with LV on and disconnected from the chamber shows RMS = 8 mv FEC with LV on and connected to the chamber shows RMS = 55 mv Tried to reduce the RMS by checking the cross-grounding between various components of the system: LV, HV, DAQ, FE, Chamber. Shorting two-by-two of the respective local grounds does not affect the RMS. DESY 30/August/2010 Olympus Collaboration meeting 1 1
Disconnect HV pins from chamber one-by-one: RMS goes from ~50 to 15 mv!!! Source of noise likely coming from HV supplier Put decoupling filter (1 MOhm resistors) between HV cable pins and chamber RMS drops to 13 mv The filter is effective. Decided to keep it in place. Different situation respect to last year test beam with Gassiplex chip. Gassiplex electronics adjusted for RICH readout (strips about 10 cm) while present FEC adjusted (?) for longer strips (Compass 30x30cm2- SBS 40x50 cm2) possible explanation : adjustment of chamber capacity. DESY 30/August/2010 Olympus Collaboration meeting 1 2
1 3
All FEC connected to GEM and VME controller 1 4
Pedestal no beam without mapping readjustement 1 5
Pedestal after mapping no beam Pedestal after mapping with beam_latency 10 1 6
Beam on first and fourth FEC 1 7
Beam off 1 8
Beam on again different clock phase 1 9
Beam on another phase 2 0
Cable lenght from FEC to VME (oscilloscope) 2 1
Cable lenght 2 2 2
3 m 10 m 13 m 2 3
Outlook The system seems working with data acquired and treated by all components Problem to be solved noise, probably due to a wrong impedence matching between FEC and GEM chamber Firmware to be completed and make flexible to different configurations and checks Full test in lab during next month of September, foreseen new test beam at CERN (within RD51) or/and DESY in October DESY 30/August/2010 Olympus Collaboration meeting 2 4
MWPC readout PCOS4 system LeCroy-ISS design for HERMES Monitor MWP Chambers: 400 channels each -> 25 PCOS4 cards + 2 backplanes 14 slots + ½ VME module For 6 chambers: 2400 channels -> 150 fec + 12 backplanes + 3 VME modules + 1 VME controller + 1 fanout module Readout electronics and some spare Electronics needed for RICH SBS then we must guarantee a use in safe condition Conditions used for HERMES MWPC and RICH must be reproduced: temperature control, switches and relays for low voltage power supply, patch panels and all other services DESY 30/August/2010 Olympus Collaboration meeting 2 5
MWPC readout electronics Essential to measure the radiation field where the electronics should be put. Difference with HERA should be considered when beam is lost: different current (factor 3-4 higher for DORIS but less charge stored), different lenght (HERA 6.3 km DORIS 300 m) for possible impact on detector and electronics To be measured in order to test cards under same radiation field DESY 30/August/2010 Olympus Collaboration meeting 2 6