Readout Status and Plans

M. Andrew, E. Choi, R. Conrad, S. Dubey, B. Kirby, B. Macek, H. Mehta, K. Nishimura, M. Rosen, X. Shi, L. Wood,

G. Varner, G. Visser

Feb. 6, 2014 B2GM Update

Executive Summary• Production ASICs in fabrication (~April)

• Intermediate board stacks (IRS3C ASIC) almost complete pulser, laser scans planned & then commission on CRT (March) [enough for 3x TOP modules]

• Pre-production board stack: Use same HV, Front board as Intermediate Master FPGA chosen, SCROD Rev. B in design Carrier Rev. E – basic layout/amplifier design Mechanics almost same (no Interconnect board)

• Passed Director’s Review, gearing up for CD-2/3 2

Preliminary answers to BPAC1. Quantifying effectiveness of timebase feedback

(stability)

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Preliminary answers to BPAC2. “Recovering” saturated pulse data and

demonstration of the timing thus achieved

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Preliminary answers to BPAC3. Codify a set of ASIC, Carrier, SCROD and full

board-stack test/qualification procedures

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Reminder: Subdetector Readout Module (a/k/a “the 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 iTOP module (512 channels)

Example IRS Boardstack

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boardstack versionsLEPS/SPring-8:

9 PCBs7 distinct designs (6 UH; 1

IU)IRS3B/spartan6

intermediate:8 PCBs

6 distinct designs (4 UH; 2 IU)

IRS3C/spartan6

pre-production prototype:7 PCBs

4 distinct designs (2 UH; 2 IU)IRSX/zynq

SCROD revA3

thermal walls,AKA spacers SCROD “fake” revB (mockup)

new stuff:

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Intermediate (IRS3C)

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Transition to pogo-pins: need precise assembly jigs (being designed)

1) Assembled board stack2) Alignment jig plate3) Angle plates

Intermediate Board Stack

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• Pogo pins and HVB

• Basic active divider works very well, vetted in LEPS beam test

• Repackage for pogo-pin interconnect and more compact layout

• Compact layout requires encapsulation for HV insulation

• The encapsulation also provides thermal coupling to a new design cooling bracket compatible with spacer-block clamped boardstack

• New HVB board layout in progress. Will be assembled and encapsulated at IU for preliminary tests.

• Vendor identified for production encapsulation, quote received.

• Pins: Mill-Max # 0926-1-15-20-75-14-11-0• Prototype in carriers (HVB & signal types)

machined from PEEK• Pin carrier flatness is an issue for assembly• Considering injection-molded carriers, or perhaps

mold pins in place (if Mill-Max can do this)• Signal integrity tested for pogo pins: Equivalent to

<1.8 nH inductor, which does not limit our signal bandwidth

Intermediate Board Stack

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• Front board (pogo-pin lands)• PMT pins are fully buried inside a 4mm thick PCB• Low insertion force pin receptacles contact PMT pins• Pin receptacles are press-fitted to PCB (maximizes HV

clearance and cleanliness, and simplifies assembly)• 7-layer sequential lamination (2×), blind via PCB routes

anode signals and HV bias to pogo-pin contact pads on rear side

• “Arbitrary” pitch and location adaptation between PMT’s and readout boardstack – a challenge, met

Front board layout (99% final)Design reviewed 12/2013To be submitted for fabrication this week

Mechanical prototype front board (received 11/13/2013)(No routing, no internal layers)

Intermediate Board Stack

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• Carrier Rev. D (c02, c13)

Intermediate Board Stack

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• Pulser, laser test stand upgrade

Intermediate Board Stack

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• Test schedule (gets to Fuji Hall and then onto CRT)

Toward Fuji Hall campaign

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• Repackaged Sci-Fi (75x, 75y scint fiber – no ribbon cables)

• 9U KLM readout firmware development (same)

3A @ 5V1.7A @ -3.3V

Readout ASIC status:Design completed/reviewed, in fabrication

• IRS2 ASIC

• 8 channels per chip @ 2.7-4 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

* IRS3C = IRS3B with low power-on current, ext. dynamic range

Timing Generator

50Wterm

IRS3/X ASIC

Die Photograph

~8m

m

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IRSX• Baseline ASIC for production (800 expected in pre-

production run)

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• High-speed, lower power/EMI LVDS outputs for fast, asynchronous signals

• Extended dynamic range comparator

• Lower-power Gray Code Counter and internal DLL demonstrated (TARGET7)

• IRS3D takes the internal improvements, but keeps IRS3C user I/O

2.6M transistors, 7.7k resistors (DACs)

TSMC Engineering Run• Incremental cost ~zero (reduced risk)

17 Reticle Layout

IRS3CTARGETX

IRSXIRS3D

We will own the masks, can make rest of production fab with Engr Run

Expect 836 of each (though yield near edge of wafer may be low)

Pre-production Board Stack

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• SCROD Rev. B

Pre-production Board Stack

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• Carrier Rev. E

Pre-production Board Stack

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• Amplifier and calibration signal path• Two-stage amplifier enables high speed response

(600 ps risetime) with low gain operation of PMT• First stage is a load resistor and noninverting

voltage amplifier, for better matching to characteristic impedance of the anode signal routing line

• Second stage inverts the signal (necessary for IRSX readout polarity)

• Calibration signal summed (when enabled) with main signal – no switches in main signal path

• Calibration signal bussed across 8 (or possibly 16) channels; switches chosen for minimal loading on disabled channels

• 3.5V power supply limits output swing to protect the ASIC against latchup

CAL switch – one possiblescheme, now prototyping

Simplified signal path schematic

Pre-production Board Stack

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• Amplifier and calibration signal path

Typical raw single-pe PMT pulseHVB @ −3200 V25 Ohm load20 GS/s (RTO1044)measured risetime: 140 ps

Typ. amplified single-pe pulseHVB @ −3200 VVoltage on 10 pF load (IRSX eq.)20 GS/s (RTO1044)Measured risetime: 565 ps[NOTE: different event & channel]

1 ns/div

1 m

V/d

iv50

mV

/div

PMT gain ~ 5×105

High Speed Link Board?

8k channels1k 8-ch. ASICs

64 SRM “board stacks”

64 DAQ fiber transceivers

32 FINESSE8 COPPER

FTSW clock, trigger, programming

Waveform sampling ASIC

Clock jitter cleaners

64 SRM

8 COPPER

32 FINESSE

UT3 Trigger module

16 FTSW

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Calibration requirements

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1. Subtract storage cell pedestal (avg. ~2000 ADC +/- 100’s counts)2. Linearity correction (optional)3. Individual sample time offset correction

Data Analysis in Hardware

• Basic beam test analysis implemented in FPGA

– Fully pipelined architecture for maximum performance

• Initial measurements: 570k waveforms/sec

– Fiber, memory access will reduce max rate; studies underway now

• Testbench development for detailed performance analysis with replayed data underway

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Schedule

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• Intermediate BS readout of Fuji prototype

Schedule

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• Pre-production board stack completion

Schedule

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• Production test procedures and division of labor (@ S. Carolina & Pittsburgh)

Summary• Into the end-game for production

• Remaining issues: Choice of SCROD FPGA (made) IRSX as baseline (IRS3D, IRS3C as backup) Confirming pogo-pin interface Confirming final amplifier configuration Final power cabling

• Intermediate board stacks for validating thermo-mechanics of pre-production designs

• Key milestones are: operation in CRT, completing pre-production board-stack, and establishing/validating production testing procedures 28

Insufficient time/laser scanning resources before LEPS beamtest – subsequent testing in Hawaii

29Module under test w/ reference SL-10 MCP

Stage for x-y control of illumination fiber (picosecond laser)

FTSW, COPPER, CAMACPicosecond laser

Inside Dark Box

Dark box too small – being rebuilt

Event sampling

• Storage: 64 x 512 (32k per ch.)

• Sampling: 128 (2x 64) separate transfer lanes

Recording in one set 64, transferring other

(“ping-pong”)

• Wilkinson ADC (64 at once)• 64 conv/channel (512 in

parallel)

Belle II iTOP Counter• A highly constrained cylinder• 3-key elements

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(1)

(2)

(3)

• Operate within Belle-II Trigger/DAQ environment

• >= 30kHz L1 trig• Gbps fiber Tx/Rx• COPPER backend• Timing trigger• iTOP: 8k channels• 16 iTOP modules• 4x 128-channel SRM/iTOP module (64x total)

SuperKEKB RF clock

Readout Electronics -- requirements

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Belle II back-end

• COPPER (COmmon Pipelined Platform for Electronics Readout)• Used in Belle, J-PARC experiments• FINESSE (Front-end Instrumentation Entity for Subdetector Specific

Electronics)

Schematic Drawing of the COPPER

FIFOFIFO

FIFOFIFO

FIFOFIFO

FIFOFIFO

MemoryMemory

CPUCPU

Bridge

Local Bus PCI Bus

Det

ecto

r Si

gnal

s

FINESSEFINESSE

FINESSEFINESSE

FINESSEFINESSE

FINESSEFINESSE

Trigger inputTrigger interrupt

BridgeBridge

Mezzanine Cards

PCI Mezzanine Cards

ControlControl BridgeBridge

Upgraded forBelle II

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