LAV thresholds requirements Paolo Valente
LAV answers for Valeri’squestions (old) • List of hardware to control (HV, LV, crates, temperatures, pressure, etc) , including number and nature of channels, refresh rate, etc. Answer: 2496 crystals: • 2496 HV channels (in 32 or 48 boards, see next slides) + HV crates status, fan, temperature… • 2496×2 thresholds (in 32 custom VME boards) + Wiener TEL62 crate status, fan, temperature • Foreseen control interfaces, in particular for non standard equipment • The custom Time-over-Threshold discriminator VME boards will have a CPU and a CANOpen interface: • firmware will be developed by LAV team • Part of the software probably also will be developed by LAV team (a custom OPCServer?...) • We will have more details as soon as the front-end electronics project for LAV will be completed (and we will have the final boards with the CPU, remote control of thresholds, etc.) • Special and non-standard requirement for user interface, alarms, actions, etc. • Nothingreallyspecialy for the LAV stations, theycould be consideredastwelveindependentcalorimeters • The onlyspecial care to be paidisthatevenONE dead or notproperlyworkingchannelcan be a problem for the experiment • How your requirement will evolve beyond the 2011 run up to the final set-up • For a synchronizationrun in 2011 wewillhavealreadyhalf of the stations in finalconfiguration (apart from front-end electronics) • The HV system can be practicallyfinal by then • The LV system (threshold and front-end boards control) will be needed for just a fewpre-prodcutionboards • What will be your participation in the DCS preparation • As much as we can… we are man-power limited
LAV answers for Valeri’squestions (new) • Do you only set the threshold?… Answer:No, we want to set and read back the actual threshold value • 2496×2 thresholds to be set and actual values to be readout • Actual threshold should match the required value(in a given band, see next) taking into account known offset (stored in the DB) for each channel • A newset of thresholds implies: • Starting a newrun • New entries in the configurations and conditions DB’s • …how often? • New thresholds would be probably needed in order to tune the efficiency of each single block inside the LAV’s, after having estimated the response with data. • This is something we expect change quite slowly (certainly not once per spill), since sufficient statistics should be collected for measuring efficiency (with muons from the beam halo or photon/electrons from a selected sample…), • Presumably this will be performed (at least during stable data-taking) by an automatic calibration task: I estimate very roughly a new set of thresholds every few hours, to start with, that would become a new set every day (or few days), in stable conditions.
LAV answers for Valeri’squestions (new) • Do you need reading them? Answer:Yes • How often? Dead band? • Can be a slow readout, of order of minutes: a drift due mainly to temperature effects is expected. • Dead band should be a fraction of 1 mV(if typical thresholds range between few to 10-15 mV, 1-2% should be fine) • In addition, an asynchronous readout command could be useful, in order to read e.g. at run initialization or every given number of spills • Do you need alarms? • Yes, if (readout value-required value) >> readout error. Probably, something in the range of 0.5 mV • Do you need trending, archiving? • Yes, at least at the level of the online archive • Average values per run would be probably enough for offline conditions DB
LAV answers for Valeri’squestions (new) • CANbus technology • Rationales behind the choice • A working solution already exists, even though applied to a different piece of hardware, LHCb GEM HV… • Expertise available • …moreover the same electronics design team is available (Gianni Corradi, LNF) • Your vision of sharing of the job • Programming of firmware inside the board will be done by the Frascati team • A test setup with PVSS could be arranged in Italy, either in Rome or Frascati… • …certainly with the driving force and intelligence from the central DCS team • We are looking for young people for actual programming, even though I expect a great part of the job will be the massive configuration of the final system, probably a little less work will be required for a test setup • Schedule • As soon as first production boards will be available (we are waiting them for end of May 2011)… • …but also subject to finding some help in Italy
Mapping CAN channel Crate (CAN node) Station Layer VME Board (CAN node) … … Crystal channel 1 VME Board = 1 Layer for first stations