Daresbury Aug 2005Jean-Sébastien Graulich Detector DAQ Overview and Needs Jean-Sebastien Graulich, Univ. Genève o Introduction o Detector Systems Overview.
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Daresbury Aug 2005Jean-Sébastien Graulich Detector DAQ Overview and Needs Jean-Sebastien Graulich, Univ. Genève o Introduction o Detector Systems Overview o Implementation Proposals FEE, Trigger and Architecture o Conclusions MICE DAQ and Controls Workshop
Daresbury Aug 2005Jean-Sébastien GraulichSlide 2 Introduction Normal Detector DAQ is synchronised with MICE Beam We want RF ON and RF Off Data (50/50 ?) We need calibration data For each run We want RF Noise data Dedicated Run
Daresbury Aug 2005Jean-Sébastien GraulichSlide 3 DDAQ vs CM Detector DAQ Synchronised with the beam Very fast reaction time (~ s) High transfer rate (~50 MB/s) Read and Store, no time for on-line processing Limited User Interface Run Control only (Slow) Control and Monitoring Continuous and permanent Very reliable (Safety issue) Deal with a lot of ≠ hardware Read and Check Calibration, manage alarms at ≠ levels, soft interlocks, take actions, log history, etc. Extended UI Set many parameters, manage complicate initialisation procedures, etc. Why separate Particle Detector DAQ and Control Sensor DAQ ?
Daresbury Aug 2005Jean-Sébastien GraulichSlide 4 Concept Schematic MICE Beam Line MICE Cooling Channel MICE Detectors Detector DAQ Slow Control Data Storage Monitoring Data Log Run Control UI MICE User Interface Environment RF Phase
Daresbury Aug 2005Jean-Sébastien GraulichSlide 5 Definitions and assumptions Definitions Machine Cycle: 50 Hz (20 ms) Injection/Extraction cycle of ISIS MICE Target Cycle -> Spill Cycle Beam ON / RF ON Beam ON / RF OFF MICE RF Cycle RF duty factor: 10 -3 ~100 s ramping up/down time Most efficient cycle: ~1ms long RF pulse every second Assumptions (from TRD) The aim is to collect 600 good muons per spill Instantaneous rate = 0.6 MHz (1.7 s between 2 muons) A good muon is a traversing muon (~ 1/6 in phase with RF) 10 6 muons per setting is required (1700 spills, 30 min) -> 2 spills/second (~1ms long)
Daresbury Aug 2005Jean-Sébastien GraulichSlide 6 Readout Cycle Particle-by-particle readout is not possible: Readout takes a few 100 s (depends on the data size) Readout time ≠ Conversion time Readout time driven by the slowest VME crate => Detector Data has to be buffered in the FEE modules Buffer size ~ 600 muon events => Readout performed at the end of the spill Normal DAQ Event triggered by Start of Spill Normal DAQ Event ≠ Particle Event
Daresbury Aug 2005Jean-Sébastien GraulichSlide 7 The ADC problem EEEEven simple gated ADC is a problem Conversion time > ~3 s = 2 x the average time between two muons GGGGated ADC => maximum 300 muons/spill If buffer size high enough (common is 30 evts!) AAAAlternative: Flash ADCs The full waveform is digitised for the whole spill Sampling rate > 200 MHz (1 sample/ 5ns) 200 10 6 sample/channel/spill If 8 bits data -> 200 MB/ch (or nearly 400 GB/ch/run) => Data size problem No time to transfer No space to store => Need zero suppression NNNNobody works on that !!!
Daresbury Aug 2005Jean-Sébastien GraulichSlide 8 Detector System Overview 5 detector systems 2 Tracker modules (5 Sci.Fi stations) 3 TOF stations CKOV1 Upstream CKOV2 Downstream EmCal
Daresbury Aug 2005Jean-Sébastien GraulichSlide 9 Sci.Fi Tracker Main requirements: Efficiency, Spatial Resolution, low sensitivity to RF bg Number of channels: 4096 ADC per tracker = 8192 ch 8192 TDC channels under development (AFE-T) Front End Electronic: Analog to Digital: AFE II VME (digital data buffer): VLSB (512 ch/module) Word size: 10 bits for ADC, Probably ~12 bits for TDC 13 bits for the channel number (+ data overhead) Average Data Size Without zero suppression (no TDC): 24 kB/μ With zero suppression and TDC: 0.25 kB/μ
Daresbury Aug 2005Jean-Sébastien GraulichSlide 10 Sci.Fi Tracker Constraints Important limitations: Read out has to be synchronised with the beam microstructure Built in the AFE board, designed for D0 100 ns muon burst every 320 ns (Compared to D0: 150 ns burst every 400 ns) Looks OK AFE Conversion time: ~6.5 microseconds 600 muons/spill is NOT possible New assumption: Maximum 150 muons per spill (2h/run)
Daresbury Aug 2005Jean-Sébastien GraulichSlide 11 TOF Main requirements: Time resolution ~70 ps, high rate (2.5 MHz in TOF0) Number of channels: (48 + 32 + 32) TDC = 112 ch 112 ToT (Time over threshold) for time walk correction Front End Electronic: CAEN 1290 Word size: 16 bits/ch Average Data Size 0.1 kbyte/muon Time Walk
Daresbury Aug 2005Jean-Sébastien GraulichSlide 12 TOF FEE Proposed FEE module: Multi-Events, Mutli-Hits Not tested yet
Daresbury Aug 2005Jean-Sébastien GraulichSlide 13 Event Integrity How to retrieve particle event integrity ? Easy at the DAQ Event Level What about the Particle Event Level ?
Daresbury Aug 2005Jean-Sébastien GraulichSlide 14 SoS EoS DAQ Gate Normal DAQ Trigger Good Muons (TOF0xTOF1xTOF2) Muon Trigger to AFE II Muon Trigger to TDC AFE Gate Clock Programmable delay Progr. Width TDC Event Window DAQ and Muon Triggers
Daresbury Aug 2005Jean-Sébastien GraulichSlide 15 Data Structure RUN # m Number of DAQ Events == Number of spills Environment data DAQ Event j-1 DAQ Event j DAQ Event j+1 Tracker # of Events Event k-1 Event k Event k+1 Number of Hits Ch_0001 ; Data_0001 ………… Ch_8192 ; Data_8192 TOF # of Events Event k-1 Event k Event k+1 Number of Hits Hit1_Ch ; Hit1_Data ………… Hitn_Ch ; Hitn_Data
Daresbury Aug 2005Jean-Sébastien GraulichSlide 16 CKOV1 Main requirement Energy resolution: Threshold between pion and muons Number of channels: 4 TDC ch 4 QDC ch Front End Electronic: TDC : CAEN 767 ? QDC : ?? Word size: TDC : 20 bits/ch ADC : probably 10 bits Average Data Size ~ 25 bytes/muon (15 kB/spill)
Daresbury Aug 2005Jean-Sébastien GraulichSlide 17 CKOV FEE Possible FEE module: Also Multi-Events, multi-Hits -> Same Event Integrity check Not tested yet
Daresbury Aug 2005Jean-Sébastien GraulichSlide 18 CKOV2 Main requirement Low energy threshold Number of channels: 12 TDC ch 12 QDC ch Front End Electronic: TDC : CAEN 767 ? QDC : ?? Word size: TDC : 20 bits/ch ADC : probably 10 bits Average Data Size ~ 75 bytes/muon (60 kB/spill)
Daresbury Aug 2005Jean-Sébastien GraulichSlide 19 Muon Identifier (EmCal) Main requirement Energy resolution Number of channels: 240 QDC ch ~60 TDC ch Front End Electronic: Not chosen (see ADC Problem) Word size: ??? Average Data Size I guess ~ 1kB/muon
Daresbury Aug 2005Jean-Sébastien GraulichSlide 20 Data Volume Summary All detectors: 25 kB/μ (1 kB/μ if zero suppression in the tracker) 7 MB/spill (if 2 x 150 μ/spill) 25 GB/run (if 10 6 μ/run) How many runs ? 2 hours/run 50% overhead (setting changes) 80% efficiency 1 year, 7/7, 24/24 (just to get an idea) => ~ 2500 runs Need storage space for ~ 60 TB/year
Daresbury Aug 2005Jean-Sébastien GraulichSlide 21 Event types Normal DAQ Event ~ Spill Calibration Events (Can be Single Gated !) Pulser events Full readout, full event building Pulses generated by the DAQ Cosmic/source events ? Partial readout, partial event building Pedestal events ? Only ADC readout, full event building Special muon event with dedicated beam ?? Special DAQ Events Start of Spill (SoS) and End of Spill (EoS) can be used to check the synchronisation between subsystems. No readout, full event building Each different Event Type requires a dedicated trigger receiver IO channel in each crate !
Daresbury Aug 2005Jean-Sébastien GraulichSlide 22 Trigger Receiver Need at least 6 inputs SoS and EoS Events Normal DAQ Events Calibration Events: Pedestal, pulser and source/cosmics 7 outputs 6 Individual busies One common busy More I/O = more flexibility One module per crate ! Possible Choice: CAEN V977
Daresbury Aug 2005Jean-Sébastien GraulichSlide 23
Daresbury Aug 2005Jean-Sébastien GraulichSlide 24 “VME” Processors Needed to collect data locally, at the crate level. Could be VME processor or External PC External PC under Linux connected with a VME to PCI optical link is easy, flexible and widespread Easier if all VME have the same interface Possible choice: CAEN V2718
Daresbury Aug 2005Jean-Sébastien GraulichSlide 25
Daresbury Aug 2005Jean-Sébastien GraulichSlide 26 DAQ Architecture
Daresbury Aug 2005Jean-Sébastien GraulichSlide 27 Conclusions Detector data Readout must be performed at the end of the spill Data has to be buffered in FEE Maximum 150 muons/spill (2h/run) Due to Conversion time in AFE II of Sci.Fi Tracker Charge Measurement in the Muon Identifier (EmCal) is an issue A Detector DAQ conceptual scheme already exists Based on HARP experience It’s Time to write Specifications !