mapmt readout workshop / introduction

MaPMT Readout MaPMT Readout Workshop / IntroductionWorkshop / Introduction

MaPMT Readout MaPMT Readout Workshop / IntroductionWorkshop / Introduction

MaPMT Workshop Imperial College26/27 June 2003

Franz MuheimUniversity of Edinburgh

MaPMT Workshop, Imperial College, 26/27 June 2003

F. Muheim 2

Workshop Agenda & GoalsWorkshop Agenda & Goals Outline of MaPMT project Reports/Presentations

– MaPMT/Beetle studies

– Photo detector integration issues

– Possible Readout schemes

– Level-1 Electronics, PINT results

– Plans for this summer Define MaPMT read-out project

– Produce list of tasks necessary to get job done

– Identify conflicting requirements

– Prioritise different options (if possible)

– Planning of schedules and milestones

– MaPMT plans and schedule Hope for lots of fruitful discussions


F. Muheim 3

MaPMTs for LHCb RICHMaPMTs for LHCb RICH Multianode Photo Multiplier Tubes

– Single photo tube containing8x8 array of 64 dynode chains 2.1 mm pixel size, 0.2 mm gap

– Bialkali photo cathode, UV glass window QE = 22 % at = 380 nm

Lenses– with one flat and one curved surface – Increases active area fraction to 85% – effective pixel size 3.0 mm

Readout Electronics – ASIC preamplifier chip with pipeline – Readout architecture L0 & L1

Mechanics– Photo detector mounts & motherboard– Magnetic field shielding, mu-metal


F. Muheim 4

MaPMT/Beetle ProjectMaPMT/Beetle Project MaPMT R7600-03-M64 with 8 dynode stages

– gain: 50000 HV 800 V Front-End electronics

– Beetle1.2 chip

– single photon equivalent 60 mV (2 mip)

– signal / noise ratio 40

– analogue or binary readout mode

MaPMT R7600-03-M64 with 12 dynode stages – gain: 300’000 HV 800 V

– Beetle1.2-MaPMT chip with gain adaption

– single photon equivalent 30 mV (2 mip)

– signal / noise ratio 40

– analogue or binary readout mode


F. Muheim 5

MaPMT Plans & ScheduleMaPMT Plans & Schedule Read out the 8 dynode stage MaPMT

– with Beetle1.2 in analogue and binary mode– using the Heidelberg board restricted to 12 channels

Jan - June 03 Read out the 12 dynode stage MaPMT

– with Beetle1.2MA0 in analogue and binary mode– using the Heidelberg board, restricted to 12 channels

April - June 03

Read out all 64 channels of one or more MaPMTs – with the Beetle1.2/Beetle-MA0 in analogue and binary mode– with Beetle PCBoard

July 03 - Testbeam

– Prepare and operate a cluster of MaPMTs in a testbeam, read out with the Beetle1.2 or Beetle-MA0 chip

May - Sep 03


F. Muheim 6

Electronic Cost Comparison Electronic Cost Comparison Main Inputs

– 232 modules with 16 MaPMTs, 8 Beetle chips, 1024 channels– 220 SFr/optical link, 190 SFr/ 4 copper links 5kSFr/ L1 board

Binary Electronics – 232 optical links, 30 L1 boards 1250 kSFr

Analogue Electronics– 4x1856 copper links, 116 L1 boards 2100 kSFr– TDR cost for comparison 1600 kSFr– difference to binary 850 kSFr

Digital Electronics– 1856 optical links, 78 L1 boards 1970 kSFr– difference to binary 720 kSFr– Cost differences are understood– data links costs are rather robust O(50 kSFr) – optimisation for L1 board necessary O(100 kSFr)– absolute cost of L0 electronics needs to be reassessed


F. Muheim 7

Major Issues Major Issues MaPMT/Beetle studies

– BoardBeetle July 03

– Testbeam 13 Aug - 9 Sep

MaPMT type decision– 8 vs 12 dynode stages Sep 03

Binary vs analogue/digital readout– cost versus risks (common mode, comparator)

– only decision possible now is analogue or digital

– proposal - analogue or digital as baseline June 03

Design of L0 motherboard – includes cooling, on critical path Jan 04

– report from meeting at CERN 22.5.03

Software – Performance studies, robustness Sep 03


F. Muheim 8

Overall Schedule Overall Schedule 1 year old,

– produced for June 2002 review, need to update July 2002 Resume design of Beetle chip done Oct 2002 Resume Motherboard design starting now 1 Mar 2003 Choose MaPMTs Mar 2003 Start tendering not started 1 Oct 2003 Place MaPMT Order Jan 2004 L0 F/E Electronics and Motherboard (MB)

design completed Mar 2004 Start Photodetector testing July 2004 10% of MaPMTs delivered Jan 2005 L0 - F/E Electronics and MB R&D completed Mar 2006 100% of MaPMTs delivered and tested Mar 2006 100% production and testing of L0 and L1 units June 2006 100% of photodetector modules assembled


F. Muheim 9

Status of MaPMT Project Status of MaPMT Project Large effort has started for MaPMT project in 2003

– Measurements of 8-dynode stage MaPMTs signal shape

with Beetle1.2 has highest priority

– Measurements with Beetle1.2MA0 are promising

More effort is needed

– Need to catch up delays, 7 months for L0 Motherboard

MaPMT is baseline

– More effort available

– Need to re-think organisation of MaPMT project now

– Many important decisions need to be taken soon


F. Muheim 10

Backup SlidesBackup Slides


F. Muheim 11

Multianode Photo MultiplierMultianode Photo Multiplier

MaPMT Single photo tube containing

8x8 array of 64 dynode chains 2.1 mm pixel size, 0.2 mm gap

Gain: 3.105 at 800 V Bialkali photo cathode,

QE = 22 % at = 380 nm UV glass window, was borosilicate,

QE dE increased by 50 %

Wavelength [nm]

QE [%]


F. Muheim 12

Quartz LensesQuartz Lenses MAPMT active area fraction:

38% (includes pixel gap) Increase with quartz lens with

one flat and one curved surface to 85%

effective pixel size 3.0 mm

400 mrad

0 mrad

no lens lens

lens lens

Demagnification(f -d)/f 2/3


F. Muheim 13

3x3 MaPMT Cluster Test3x3 MaPMT Cluster Test Measurements with

– MaPMT: HV = -1000V Data

– subtract cross-talk and common-mode

– Fit # of photo electrons per event:

Cherenkov ring, 6000 events Observe in data background

npe= 6.96 0.33 0.26 p.e. Expect from simulation npe=

6.49 0.17

Single channel spectrum


F. Muheim 14

Electronics Costs Electronics Costs Major cost differences in

– data links– L1 boards

L0 Electronics – 232 modules – 16 MaPMTs, 1024 channels, 8 Beetle chips – 4 data links per beetle, 128: 4 multiplexing, 40 MHz clock– cost very similar for all options

Binary Electronics – optical links to L1 board

– 32 : 1 multiplexing (1bit per data link)

– 232 optical links, 1 per module (was 2)

– costs from John Bibby

– cost per optical link 220 SFr, total 50 kSFr

– 30 L1 boards, 5 kSFr/board, total 150 kSFr

– L1 costs reduced by 300 kSFr wrt to TDR


F. Muheim 15

Analogue/Digital Electronics Analogue/Digital Electronics Analogue Electronics

– similar to VELO, with copper links over 60 m– link costs include driver, differential link receiver

and ADC (costs from Thomas Ruf)– 4 x 1856 links, 190 SFr / 4 links, total data links 350 kSFr– L1 board input: 64 links = 16 cables– 116 L1 boards, 5 kSFr/board, total L1 boards 580 kSFr

Analogue/Digital Electronics– similar to Inner Tracker, ADC at outer detector rim– need rad tolerant ADC (15kRad), – costs from Achim Vollhardt– 4:1 multiplexing with 8bit ADC– 1856 optical links, 252 SFr/link, total data links 470

kSFr – L1 board, input 96 optical links = 6 ribbons– 78 L1 boards, 5 kSFr/board, total L1 boards 390 kSFr


F. Muheim 16

Comparator ReviewComparator Review Phone Meeting of Beetle Users

– 30 April 03 – comparing of notes– digital switching noise, 80 MHz, on analogue lines

Comparator Discussion– closed loop of understanding– small differences resolved– conclusions remain the same– 3bits are marginal, – 5bits has comfortable margin

Comparator in Beetle1.2– 3 bits, no access to negative offsets

Comparator in Beetle1.3– 5 bits, different sign for Offset and Delta IDAC– will be submitted in June


F. Muheim 17

Allocation of PersonnelAllocation of Personnel Agreed at RICH group leader’s meeting CERN, 26 Feb 03 Immediate personnel requirements

– Setup of read-out and testing A) and B) Edinburgh

– Testing of BeetleMA0 B) Oxford

– Production of PCBoard for C) Imperial College

– Consulting for A) B) SW,JB,NS,DP

– Procurement strategy ok

– Design of L0 motherboard Cambridge, Oxford Genova

– Coordination FM Additional personnel required in May

– Cooling strategy Genova

– Higher channel occupancy CERN, Edinburgh

– Bleeder board for test beam Cambridge

– jigs UK/CERN

– moulded lenses Genova


F. Muheim 18

To Do List (on 28 April) To Do List (on 28 April) Read-out of 8-dynode MaPMT with Beetle1.2

– (re-)connect MaPMT done

– measure analogue spectra with LED done

– take data in binary mode July

Review of electronics cost– binary vs analogue vs digital read-out done

Comparator review done

Decision on binary vs analogue– cost versus risks (common mode) ???

Read-out of 12-dynode MaPMT with Beetle1.2 – testing of Beetle1.2MA0 done

– measure with LED analogue spectra done

– take data in binary mode July

mapmt readout workshop / introduction

Documents