1 / 18

Electronic requirements for detectors

Use LHC systems to illustrate. Electronic requirements for detectors. functions required by all systems amplification and filtering analogue to digital conversion association to beam crossing storage prior to trigger deadtime free readout @ ~100kHz storage pre-DAQ calibration control

nanda
Télécharger la présentation

Electronic requirements for detectors

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Use LHC systems to illustrate Electronic requirements for detectors g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  2. functions required by all systems amplification and filtering analogue to digital conversion association to beam crossing storage prior to trigger deadtime free readout @ ~100kHz storage pre-DAQ calibration control monitoring CAL & Muons special functions first level trigger primitive generation optional location of digitisation & memory Generic LHC readout system g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  3. Pipeline memory buffer depth and trigger rate determine deadtime data often buffered in pipeline queueing problem “Deadtime free” operation APV25 NB ≈ 10, NP =192 @100kHz compare with deadtime from maximum trigger sequence = 1001… = 50ns/10µs = 0.5% g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  4. Bipolar atomic displacement carrier recombination in base gain degradation, transistor matching, dose rate dependence CMOS oxide charge & trap build-up threshold (gate) voltage shift, increased noise,… change of logic state = SEU All technologies parasitic devices created => Latch-up can be destructive Basic radiation effects on electronics g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  5. by 1997 some (confusing) evidence of radiation tolerance extra thin gate oxide beneficial tunnelling of electrons neutralises oxide charge Why 0.25µm CMOS? • negative effects attributed to leakage paths around NMOS transistors • cure with enclosed gate geometry 1Mrad VT vs toxide g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  6. technology thought to be viable for intermediate radiation levels (~300krad) but results much better than expected First results from 0.25µm CMOS (1997) g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  7. ATLAS Innermost: Pixels Inner: Silicon microstrips 6M channels Occupancy 1-2% Outer: Transition Radiation tracker gas filled 4mm diameter straw tubes 420k channels x-ray signals from e- above TR threshold occupancy ~ 40% CMS Innermost: Pixels Remainder: Silicon microstrips 10M channels Occupancy 1-2% Radiation hardness is a crucial point for trackers Tracking systems g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  8. ASDBLR amplifier/shaper/discriminator key points speed and stability, since high occupancy peaking time 7-8ns => reduce pileup baseline restorer => maintain threshold levels two level discriminator => electron identification ATLAS TRT readout g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  9. Amplifier =>tail cancellation and baseline restoration selectable for CF4 and Xe gas mixtures ATLAS TRT ASDBLR front end 4mm straw + Xenon based gas g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  10. Amplifier/discriminator + pipeline/sparse readout ABCD (BiCMOS) Binary readout simple small data volume but maintain 6M thresholds vulnerable to common mode noise Specifications ENC < 1500e Efficiency 99% Bunch crossing tag 1 bunch crossing Noise occupancy 5x10-4 Double pulse resolution 50ns after 3.5fC signal Derandomising buffer 8 deep Power <3.8mW/channel ATLAS SCT front end g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  11. CMS microstrip tracker readout 10 million detector channels Analogue readout synchronous system no zero suppression maximal information improved operation, performance and monitoring 0.25µm CMOS technology intrinsic radiation hardness Off-detector digitisation analogue optical data transmission reduce custom radiation-hard electronics g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  12. High speed signal processing is required to match the 40MHz beam crossings Low power consumption is essential - 2-3mW/channel Performance must be maintained after irradiation Start from CR-RC filter waveform form weighted sum of pulse samples zero response outside narrow time window small number of weights (>3) implementable in CMOS switched capacitor filter Impulse deconvolution at LHC Ideal CR-RC Sampled CR-RC waveform Deconvoluted waveform g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  13. Pulse shapes & noise APV25 1 MIP signal t [ns] ENC [electrons] • System specification • Noise <2000 electrons for CMS lifetime Inputcapacitance [pF] g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  14. ATLAS ECAL/Endcap HCAL Liquid Argon 190k channels signal: triangular current ~500ns fall (drift time) CD ~ 200-2000pF ATLAS Barrel HCAL Scintillating tiles 10k channels CMS ECAL PbWO4 crystals + APDs (forward: VPT) 80k channels fast signal t ~ 10ns CD = 35-100pF CMS Barrel/Endcap HCAL Cu /scintillating tiles with WLS 11k channels HPD readout Calorimeter systems • Requirements • large dynamic range • 50MeV-2TeV = 92dB = 15-16bits • precision • ≈ 12bits and high stability • precise calibration • ~ 0.25% • Radiation environment • few 100krad - Mrad • +high neutron fluxes (forward) g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  15. Amplifier close to photo-detector (APD or VPT) 4 gain amplifier + FPU gain selection 12bit 40MHz digitisation commercial bipolar ADC - rad hard 1Gb/s optical transmission 12bit (data) + 2bit (range) custom development using VCSELs 80,000 low power links Recent substantial changes in philosophy CMS crystal ECAL g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  16. Advantages c.f. copper: low mass, no electrical interference, low power, high bandwidth LHC requirements digital control ~40Ms/s digital data transmission ~1Gb/s analogue: 40Ms/s CMS Tracker Fast moving technological area driven by applications digital telecomms, computer links analogue cable TV requirements c.f. commercial systems bulk, power, cost, radiation tolerance ?? possible for some applications? Optical links in LHC experiments g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  17. Now dominate market, over LEDs narrow beam, high optical power, low electrical power, better matched to fibres Direct band gap material GaAs ~ 850nm GaAlAs ~ 600-900nm In, Ga, As, P ~ 0.55-4µm Forward biased p-n diode -> population inversion optical cavity => laser at I > Ithreshold often very linear response Fibres and connectors sufficient rad hardness trackers require miniature connectors care with handling compared to electrical Semiconductor lasers g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

  18. Edge emitting 1.3µm InGaAsP MQW laser diodes miniature devices required single mode fibre ~50mW/256 detector channels CMS Tracker analogue optical links Tx Rx same components for digital control BER << 10-12 easily achievable g.hall@ic.ac.uk www.hep.ph.ic.ac.uk/~hallg/

More Related