david emschermann cbm collaboration meeting - gsi – 12/04/2010 trd geometry in cbmroot and...

David Emschermann David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010CBM Collaboration Meeting - GSI – 12/04/2010

TRD geometry in CBMrootTRD geometry in CBMrootand conclusions and conclusions

for detector module for detector module designdesign

David EmschermannDavid Emschermann

Institut für Institut für KKernphysikernphysik

Universität MünsterUniversität Münster


OutlineOutline

• the TRD layout in CBMroot Dec09the TRD layout in CBMroot Dec09• signal extraction from the TRD signal extraction from the TRD modulesmodules• quadratic chambers and their quadratic chambers and their rotationsrotations• pad structure inside the modules pad structure inside the modules • pad hit ratespad hit rates• arrangement of FEBs on the modulesarrangement of FEBs on the modules• dual sided MWPC prototypes dual sided MWPC prototypes • layout of TRD modules in TRD1 layer layout of TRD modules in TRD1 layer 11• summary and outlook summary and outlook


The TRD in CBMrootThe TRD in CBMroot

• 33 stations a 4 layers, stations a 4 layers, 1212 layers layers totaltotal

• 1110 m²1110 m² surfacesurface• 1,2million 1,2million channelschannels

• positions in positions in z:z:

station 1 - station 1 - 5,1m5,1m station 2 station 2 – 7,4m – 7,4m station 3 – station 3 – 9,6m 9,6m

TRDTRD


Signal extraction and ratesSignal extraction and rates2D readout2D readoutdual MWPC,dual MWPC,central PPcentral PP

3D readout3D readoutsingle MWPC,single MWPC,with 50% driftwith 50% drift

3D readout3D readoutsingle MWPC,single MWPC,with 33% driftwith 33% drift

AA AA DD AA DDAA

33 33 33 33 33 33 66 44 44 44thicknessthickness(12 mm)(12 mm)

1 time unit1 time unit 3 time units3 time units 2,6 time units2,6 time units timingtiming100 kHz/cm²100 kHz/cm² 30 kHz/cm² ?30 kHz/cm² ? 40 kHz/cm² ?40 kHz/cm² ? raterate

At fixed gas thickness, can we build detectors with At fixed gas thickness, can we build detectors with a thin drift volume for hit rates below ~30 kHz/cm²?a thin drift volume for hit rates below ~30 kHz/cm²?

AA AA AA AA

DataDataflowflow


Choice of detector Choice of detector technologytechnology

In CBMroot we assume the following:In CBMroot we assume the following:

• the TRD surface is divided into the TRD surface is divided into quadratic modulesquadratic modules• the modules allow for signal readoutthe modules allow for signal readout perpendicular to the pad planeperpendicular to the pad plane


A module with 1 cm² pad A module with 1 cm² pad sizesize

50 c

m50 c

m

92 x 23 pads (5 x 20 mm)92 x 23 pads (5 x 20 mm)

S sizeS size


Station 1 – CBMroot Dec09Station 1 – CBMroot Dec09

8x S + 12x M + 36x L sized chambers8x S + 12x M + 36x L sized chambersin each layerin each layer

Approximate size of pads in cm²Approximate size of pads in cm²

Approximate border of 30 kHz/cm² particle rateApproximate border of 30 kHz/cm² particle rate


Station 2 – CBMroot Dec09 Station 2 – CBMroot Dec09

8x S + 12x M + 80x L sized chambers8x S + 12x M + 80x L sized chambersin each layerin each layer


Station 3 – CBMroot Dec09 Station 3 – CBMroot Dec09

144x L sized chambers in each layer144x L sized chambers in each layer


Quadratic detector modulesQuadratic detector modules

We build quadratic detectors in 3 different We build quadratic detectors in 3 different sizes:sizes:

1.1. 50 cm x 50 cm – Small size chambers50 cm x 50 cm – Small size chambers2.2. 75 cm x 75 cm – Medium size chambers75 cm x 75 cm – Medium size chambers3.3. 100 cm x 100 cm – Large size chambers100 cm x 100 cm – Large size chambers

• Use rectangular pads with fixed width of 5 Use rectangular pads with fixed width of 5 mmmm

allowing a fixed chip-chip spacing on the allowing a fixed chip-chip spacing on the FEBsFEBs

• Scale the pad size by variing the pad Scale the pad size by variing the pad lengthlength

• Rotate the chambers by 90° between Rotate the chambers by 90° between layers layers

to obtain 2D position informationto obtain 2D position information• Odd layers (1,3) with vertical padsOdd layers (1,3) with vertical pads• Even layers (2,4) with horizontal padsEven layers (2,4) with horizontal pads


Rotating the modules – pad Rotating the modules – pad viewview

odd layers (1,3)odd layers (1,3) even layers (2,4)even layers (2,4)

vertical padsvertical pads horizontal padshorizontal pads

5mm x 20mm pads5mm x 20mm pads


Detail of modules (S size)Detail of modules (S size)

A chamber can contain pads of different sizes,A chamber can contain pads of different sizes,here 5mm x 15mm (green) and 5mm x 20mm (yellow).here 5mm x 15mm (green) and 5mm x 20mm (yellow).

layer 1layer 1 layer 2layer 2


Station 1 - hits per padStation 1 - hits per pad

Based on interpolated data from the TSR.Based on interpolated data from the TSR.

Scale the pad size to yield 100 kHz hits per pad maximum.Scale the pad size to yield 100 kHz hits per pad maximum.

CyranoCyranoBermannBermann



CyranoCyranoBermannBermann



sizesize66%66%scaledscaled CyranoCyrano

BermannBermann


Chip count for Dec09 Chip count for Dec09 geometrygeometry

• for the full CBM TRD in Dec09 layoutfor the full CBM TRD in Dec09 layout 81984x 16 channel ASICs or81984x 16 channel ASICs or 41552x 32 channel ASICs41552x 32 channel ASICs

16 channels / chip16 channels / chip



92 pads92 pads

• some channels are lost at the two ends of some channels are lost at the two ends of each roweach row => need to optimise channels/chip for all => need to optimise channels/chip for all detectors detectors

22

22

22

22

22

22

S sizeS size


Channels per chipChannels per chip

• with upcoming 5 mm pad width layout thewith upcoming 5 mm pad width layout the chambers have 92, 142 or 192 pads per chambers have 92, 142 or 192 pads per rowrow• pad number not always even multiple of pad number not always even multiple of 16 or 3216 or 32

192 pads192 pads

32 channels / chip – 16 cm chip spacing32 channels / chip – 16 cm chip spacing



L sizeL size


Positioning front-end Positioning front-end boardsboards

• the neighbor hit trigger requires data exchange the neighbor hit trigger requires data exchange between ajacent pads (ASICs)between ajacent pads (ASICs)• it therefore makes sense to place chips reading it therefore makes sense to place chips reading pads of the same row on the same FEBpads of the same row on the same FEB• due to fixed pad width (5 mm) there is a common due to fixed pad width (5 mm) there is a common chip-to-chip spacing for all TRD chamberschip-to-chip spacing for all TRD chambers• there is too little space on chambers with small there is too little space on chambers with small pads to place the FEBs parallel to the pad planepads to place the FEBs parallel to the pad plane


FEB size and arrangementFEB size and arrangement

• what will be the size ofwhat will be the size of the chip carriers?the chip carriers?• what will be the widthwhat will be the width of the FEBs?of the FEBs?• vertical orientation of vertical orientation of the FEBs allows forthe FEBs allows for higher density of chipshigher density of chips• data collection from anddata collection from and distribution to FEBs isdistribution to FEBs is possible on dedicatedpossible on dedicated buses:buses:• slow control bus (blue)slow control bus (blue)• optical readout bus (red)optical readout bus (red)


Detector back-panelDetector back-panel

• the bus bar length the bus bar length scales with the pad scales with the pad length of the different length of the different detector chamber detector chamber typestypes

• interface board interface board designdesignwith standard layoutwith standard layout

• decoupled from thedecoupled from thechamber geometrychamber geometry

station 1 layer 1station 1 layer 1

chamber with 1cm² chamber with 1cm² padspads


FEB communicationFEB communication

• optical readout board (ORB, optical readout board (ORB, red)red)• detector control board (DCB, detector control board (DCB, blue)blue) can act as interface to the can act as interface to the outsideoutside


ORB and DCBORB and DCB

Zoom on FEB spacing for chambers with 40 mm pad lengthZoom on FEB spacing for chambers with 40 mm pad length


Dual sided MWPCs - Dual sided MWPCs - picturespictures

MuBu:MuBu:Münster-Münster-BucharestBucharest


MuBu prototype chambersMuBu prototype chambers

• can stand high rates, tested at 100k can stand high rates, tested at 100k hits/cm²/shits/cm²/s• central pad plane with double-sided MWPCcentral pad plane with double-sided MWPCBut:But:• signal extraction possible only in plane signal extraction possible only in plane (2D)(2D)• at maximum 2 pad rows in one moduleat maximum 2 pad rows in one module• resulting in modules with large aspect resulting in modules with large aspect ratioratio• geometrical acceptance only 66% with geometrical acceptance only 66% with 1cm² pads1cm² pads


The “real size” TRD The “real size” TRD prototypeprototype

TRD station 1TRD station 1

pads too pads too large:large:(4cm²)(4cm²)

beam hole isbeam hole istoo small: too small: onlyonly12cm x 5cm12cm x 5cm

need a need a realistic TRD realistic TRD geometrygeometry


MuBu module modificationsMuBu module modifications

Following modifications are required to fit the Following modifications are required to fit the MuBu chambers into the CBMroot geometry:MuBu chambers into the CBMroot geometry:

• assume two rows of pads in one detector moduleassume two rows of pads in one detector module• use 5mm wide rectangular padsuse 5mm wide rectangular pads• scale pad size 1 cm², 2 cm², 4 cm², 8 cm² …scale pad size 1 cm², 2 cm², 4 cm², 8 cm² … resulting in different width of modulesresulting in different width of modules• extend the module length from 36 cm to 50 cmextend the module length from 36 cm to 50 cm

• group the modules into quadratic segmentsgroup the modules into quadratic segments• rotate segments between even and odd layersrotate segments between even and odd layers for good position resolution on both dimensionsfor good position resolution on both dimensions


Dual MWPCs in TRD1 – layer Dual MWPCs in TRD1 – layer 11

Layer 1 – vertical padsLayer 1 – vertical pads

48x/24x chambers - 1cm²/2cm² pads48x/24x chambers - 1cm²/2cm² pads

1cm²1cm²

2cm²2cm²

pad

siz

ep

ad

siz

e

50 c

m50 c

m


Dual MWPCs in TRD1 – layer Dual MWPCs in TRD1 – layer 22

Layer 2 – horizontal padsLayer 2 – horizontal pads

48x/24x chambers - 1cm²/2cm² pads48x/24x chambers - 1cm²/2cm² padsqu

ad

rati

c s

eg

men

ts r

ota

ted

qu

ad

rati

c s

eg

men

ts r

ota

ted


Staggered arrangement Staggered arrangement

• Staggered arrangement of dual sided MWPCsStaggered arrangement of dual sided MWPCs• 8 quadratic => 72 rectangular modules8 quadratic => 72 rectangular modules• 576 MuBu modules in TRD1 and TRD2576 MuBu modules in TRD1 and TRD2• thickness of each layer increases by a factor 2thickness of each layer increases by a factor 2• electronics on front- and back-side of layerselectronics on front- and back-side of layers


Detailed view of detectors Detailed view of detectors

• full coverage of the active area - many extra framesfull coverage of the active area - many extra frames• same number of pads as with quadratical chamberssame number of pads as with quadratical chambers

MWPCs with 2 rows of 1cm² padsMWPCs with 2 rows of 1cm² pads

MWPCs with 2 rows of 2cm² padsMWPCs with 2 rows of 2cm² pads


Summary & OutlookSummary & Outlook

• Dual sided MWPCs could cover 2% of the Dual sided MWPCs could cover 2% of the totaltotal TRD surface (in the inner part of TRD1 and TRD surface (in the inner part of TRD1 and TRD2)TRD2) • For the remaining 98% of the TRD, we need For the remaining 98% of the TRD, we need to find a solution and build large area to find a solution and build large area prototypesprototypes

• We need to settle the chamber technologyWe need to settle the chamber technology (rate capability vs signal extraction, drift (rate capability vs signal extraction, drift region?)region?)

• Tests of chambers with realistic dimensions Tests of chambers with realistic dimensions andand pad size are needed. Limiting factors are thepad size are needed. Limiting factors are the anode wire length, pad plane PCB size.anode wire length, pad plane PCB size.


Thank youThank you


BackupBackup


Pad sizes & pad capacityPad sizes & pad capacity

With a pad width of the order of 5 mm With a pad width of the order of 5 mm a particle track will induce signals on 3 adjacent pads.a particle track will induce signals on 3 adjacent pads.

The pad sizes vary in the range of :The pad sizes vary in the range of :5mm x 20mm = 100 mm² ~ 5 pF5mm x 20mm = 100 mm² ~ 5 pF5mm x 200mm = 1000 mm² ~ 25 pF5mm x 200mm = 1000 mm² ~ 25 pF

Comparable ALICE TRD pads:Comparable ALICE TRD pads:6,35mm x 90mm = 571,5 mm² ~ 15-20 pF6,35mm x 90mm = 571,5 mm² ~ 15-20 pF

Giving rise to the above estimated pad capacities forGiving rise to the above estimated pad capacities foridealideal wiretraces (+50% variation is easily possible). wiretraces (+50% variation is easily possible). Is this input capacitance variation worth notingIs this input capacitance variation worth notingduring the ASIC design?during the ASIC design?


Dual MWPCs in the center – Dual MWPCs in the center – L1L1

Layer 1 – vertical padsLayer 1 – vertical pads



Dual MWPCs in the center – Dual MWPCs in the center – L2L2

Layer 2 – horizontal padsLayer 2 – horizontal pads



Staggered detectors Staggered detectors


Rectangular prototypeRectangular prototype


Simulations and data ratesSimulations and data rates

As input to the data rate estimation MC wasAs input to the data rate estimation MC wasprovided by Elena for different collision energies,provided by Elena for different collision energies,up to 35 GeV.up to 35 GeV.

The data rate estimations agree very well between The data rate estimations agree very well between the different input MC sets.the different input MC sets.

We assume 3 firing pads per particle track @ 5mmWe assume 3 firing pads per particle track @ 5mmpad width.pad width.

132 Bits raw data are generated by a 1 channel 132 Bits raw data are generated by a 1 channel hit. (Timm) Then 100 kHz hit rate per pad are hit. (Timm) Then 100 kHz hit rate per pad are equal to 40 MBit/s data rate.equal to 40 MBit/s data rate.


Station 1 Layer 1Station 1 Layer 1

Bit

s/p

ad

Bit

s/p

ad

MBitMBit11



Bit

s/p

ad

Bit

s/p

ad

MBitMBit11


Data rates for 35 GeVData rates for 35 GeV

• data rate in station 1data rate in station 1• data rate in station 2data rate in station 2• data rate in station 3data rate in station 3

• all 3 stations combinedall 3 stations combined

2622 GBit/s2622 GBit/s 3396 GBit/s 3396 GBit/s 37763776 GBit/sGBit/s---------------------------- 9794 GBit/s9794 GBit/s= 1,22 TByte/s= 1,22 TByte/s============================

This saturates the bandwidth of CBM to the FLES.This saturates the bandwidth of CBM to the FLES.So we need to either reduce the TRD rate So we need to either reduce the TRD rate or build al larger FLES.or build al larger FLES.

david emschermann cbm collaboration meeting - gsi – 12/04/2010 trd geometry in cbmroot and...

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