1. WBS 1.03 Readout Systems Specifications, Design and Acceptance
Gary Varner
University of Hawaii

2. Gary Varner, Belle II Directors Review (Pre CD-2/3)
Talk Outline
Performance requirements
Technical status
Remaining R&D
Summary
16-17 January 2013
Gary Varner, Belle II Directors Review (Pre CD-2/3) 2

3. Common Readout: Structural Requirements
Operate within Belle-II Trigger/DAQ environment
>= 30kHz L1
Gbps fiber Tx/Rx
COPPER backend
Super-KEKB clock/timing
16-17 January 2013
Gary Varner, Belle II Directors Review (Pre CD-2/3) 3

4. Common Readout: Hardware Interface Requirement
Belle2link or equivalent (KLM, iTOP)
Integrated into Belle II DAQ infrastructure
16-17 January 2013
Gary Varner, Belle II Directors Review (Pre CD-2/3) 4

5. iTOP Requirement: single photon timing
Record single photon timing with MCP-PMT + system timing limited resolution
σ ~ 38.4ps
σ < 10ps
16-17 January 2013
Gary Varner, Belle II Directors Review (Pre CD-2/3) 5

6. iTOP Requirement: rate handling capability
Deadtimeless operation at >1MHz single hit operation; 30kHz fast-feature extraction
Use waveform samples to correct for intrinsic PMT cross-talk and charge-sharing
CFD+
CAMAC ADC/TDC
Waveform sampling
σ ~ 38.4ps
16-17 January 2013
Gary Varner, Belle II Directors Review (Pre CD-2/3) 6

7. iTOP Trigger Requirements
Few ns time resolution triggering
X. Gao et al., IEEE (NSS/MIC) proceedings, 2010, pp
90°
120°
40° e- e+
Single-track performance
2-4ns resolution desired for
SVD timing match
16-17 January 2013
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8. KLM scintillator: Trigger threshold and timing
High efficiency triggering, sub ns-level timing
Setting threshold at 7.5 pixels: SiPM noise  neutron bg rate even after 10 years of SiPM irradiation
16-17 January 2013
Gary Varner, Belle II Directors Review (Pre CD-2/3) 8

9. KLM scintillator : neutron degradation compensation
Waveform sampling to maintain/understand gain and MPPC response after neutron damage
16-17 January 2013
Gary Varner, Belle II Directors Review (Pre CD-2/3) 9

10. iTOP Readout Component Counts
64 DAQ and 64 trigger
fiber transceivers
32 FINESSE
8 COPPER
8k channels
1k 8-channel waveform ASICs
64 SRM
Precision timing requires 64 channels of high-precision clock distribution (<~ 20ps)
Approximately 30m runs
16-17 January 2013
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11. iTOP readout chip status: design completed/reviewed, in fabrication
IRS3/X ASIC
IRS2 ASIC
50W
term
~8mm
Timing Generator
Die Photograph
8 channels per GSa/s
Samples stored, 12-bit digitized in groups of 64
32k samples per channel (8us at 4GSa/s)
IRS3C (April 2013) usable for Belle II
Increased performance margin ASICs in fab:
IRSX with high-speed serial interfaces
IRS3D with enhanced dynamic range, same I/O
16-17 January 2013
Gary Varner, Belle II Directors Review (Pre CD-2/3) 11

12. iTOP Subdetector Readout Module
Example IRS Boardstack
IRS ASIC reads out 8 channels
Require 2 ASICs to read out 16 PMT channels
4 x ASICs per self-contained carrier board (32 channels)
4 x ASIC carrier boards arranged in compact boardstack (128 channels)
Combined readout electronics, mechanical support and cooling
4 boardstacks per quartz bar (512 channels)
16-17 January 2013
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13. iTOP Readout Performance
Measure time resolution in core distribution
Trailing tail expected from photoelectron backscatter within PMT
Also leading non-Gaussian tail due to small pulses
Single p.e. timing
Example 62ps measured time resolution
Requirement: <100ps
<= 50ps with higher gain
Measured Time Resolution Vs Pulse Height
Integrated Charge in MCP Laser Pulse Window
16-17 January 2013
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14. KLM Readout: Component counts
Scintillator
Legacy RPCs
DAQ and Trigger fiber
transceivers
20k channels
1.25k 16-channel
Waveform sampling
ASICs
144 SRM
16 FINESSE
4 COPPER
20k channels
Discriminator +
FPGA-based TDC
16 barrel,
16 Endcap (scint only)
Data Concentrators
Due to data sparseness, concentrate smaller number of fiber links
Approximately 30m cable runs
16-17 January 2013
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15. KLM Scintillator Readout Statush
Ubias Al
Depletion
Region
2 m
Substrate
Pre-amps and TARGET ASIC
Fabrication complete
16 channels
GSa/s
10-12-bit digitization
Very similar to IRSx family (looser specs)
TARGET6 (Dec. 2012) usable for Belle II
TARGETX provides TARGET7 improvements (+ trigger bug fix)
Noise is 500kHz − 2MHz not a problem: p.e. threshold reduces rate to < 1kHz while maintaining ~ 99% MIP efficiency
16-17 January 2013
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16. KLM scint Readout Final Form Factor
Ribbon cables and HV distribution placed on separate RHIC board
RHIC Board
MPPC Signals
Revised 10 Daughter Card Mother Board
TARGET6 Daughter Card with Transformers
TARGET6 daughter cards with transformers for common-mode noise reduction 16

17. KLM Readout Performance
will be installed inside the detector
were tested for radiation hardness at ITEP proton (200 MeV) beam.
Photo-electron peaks
obtained with irradiated amplifier
Amplifiers gain and noise measured
before (blue) and after (red) irradiation
No effect was observed with radiation doses 5 times higher than expected at Belle II.
16-17 January 2013
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18. KLM overall Readout: on-detector installation
RPC Readout
Scintillator Readout
16-17 January 2013
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19. Outstanding Electronics R&D
Finalize the production ASICs
IRSX/IRS3D with IRS3C as back-up
TARGETX with TARGET6 as back-up
Back-up ASICs have less performance margin/functionality
Finalize the production modules
Final electro-mechanics prototypes exist (iTOP)
Implement final FPGA choice (iTOP)
Need to complete studies for kaon tagging and full B reconstruction
Electrically Rev. 3 Readout works fine (KLM)
Mechanics of cabling
Full Data Concentrator/vertical slice test
16-17 January 2013
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20. Gary Varner, Belle II Directors Review (Pre CD-2/3)
Conclusion
iTOP and KLM Readout mature
Evidence – Performance achieved in beam and bench tests
Final ASIC and readout electronics add performance margin and improved electro-mechanical robustness
Costs are known and fit within funding profile
Evidence – Costs defined by bid/vendor quote/similar work
Fits funding profile
Ready for CD-2 and (conditional) CD-3 pending success of recently submitted ASICs
16-17 January 2013
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