July 2006ALCWS Vancouver Very Forward Instrumentation of the Linear Collider Detector On behalf of...

July 2006 ALCWS Vancouver

Very Forward Instrumentation of the

Linear Collider DetectorOn behalf of the

Wolfgang Lohmann,DESY


Univ. of Colorado, Boulder, AGH Univ., INP & Jagiell. Univ.

Cracow,JINR, Dubna,

NCPHEP, Minsk,FZU, Prague,

IHEP, Protvino,TAU, Tel Aviv,DESY, Zeuthen

see: PRC R&D 01/02 (2002)

‘Old’ Kernel

“Vinča“ Institute of Nuclear Sciences, Belgrade

Royal Holloway, London,BNL, Brookhaven, NY,

LAL, Orsay

New Members

Goal-Design and R&D for:

•Luminometer •BeamCal•PhotoCal


Current design (Example LDC, 20 mrad):

Luminometer

BeamCal

Technology: Tungsten/Si (C) sandwich

TPC

ECA

L

HCAL

July 2006 ALCWS VancouverCollaborationHigh precision design

• High granularity and multi-channel (104)

• High occupancy – machine and physics backgrounds

• High radiation environment (radiation hard sensors/electronics)

• Readout of every bunch (fast electronics, fast analyzes, high volume storage)

•High precision alignment

Fast, robust and reliable

Detector performance

Challenges

15000 e+e- per BX

10–20 TeV

~10 MGy per yeardL/L = 10-4

0

0.0020.004

0.006

0.0080.01

0.012

0.0140.016

0.018

0.0E+001.5E-043.0E-044.5E-046.0E-04

dr (cm)

dz

(cm

)

ΔL/L=10-4

Align

r ~μm

Z ~100μm

r

zIP

July 2006 ALCWS VancouverCollaboration

High precision design

Min Max

R ~10 cm ~25 cm

θ 33 mrad 80 mrad

Energy (GeV)

Eve

nts

DESY-PRC2006

Requires theoretical cross-section with the necessary precision; contacts to theory groups in Zeuthen, Cracow, Katowice theory groups (two loop calculation)

Measurement of L

L = N /

Count Bhabha events

From theory

N

Goal: Precision ~10-4

Eve

nts

, (rad)

July 2006 ALCWS VancouverCollaboration

High precision design

e+

e-(0)

e- e+

Deflection of Bhabhas due to the field of the opposite beam shifts

~2%

~0.5% shift in the lumi measured

Systematic Effects

Beam polarisation

Bunch charge effects


Occupancy

Remnant background from Beamstrahlung

+background from two photon events

(under work)x [cm]

+Bhabha signal

LumiCal

July 2006 ALCWS VancouverCollabortionHigh precision design DESY-PRC2006

15

layers (z)

11 layers

(z)

4 layers

(z)

10 cylinders (θ)

60 cylinders (θ)64 cylinders

120 sectors

30 rings

Every second ring:

Parameter Pad Performance Strip Performance

Energy resolution 25% 25%

resolution 3.5 * 10-5 rad 2.1 * 10-5 rad

resolution 10-2 rad 10-3 rad

~ 1.5 * 10-6 rad ~2.1* 10-7 rad

Electronics channels

25,200 3720 (with bonding sectors)

13,320 (without bonding)

)( GeV )( GeV

StripPad

e-

Maximum peak shower

LumiCal, present understanding


BeamCal

Low angle electron veto:

Background suppression in search channels.

e.g.


BeamCal

Determination of beam parameters from beamstrahlung depositions on BeamCal:

2 mrad 20 mrad

Question: how many sensor planes are really

needed?Full GEANT4 simulation:Parameters: x and y

Seems sufficient to read out a few planes only

( around 10 X0)


BeamCal sensor tests

Energy deposition from beamstrahlung pairs in BeamCal.

10-20 TeV and more depending on the beam parameters.

Dose of up to 10MGy/a

20X0

6X0

2X0

Shower particles energy spectra

Test of sensors in an electron beam of 10

MeV energy (DALINAC, TU Darmstadt)


GEANT4 Simulation

Deposited energy density

Deposited energy inside

the sensor


exit windowof beam line

collimator (IColl)

sensor box (IDia, TDia, HV)

Faraday cup (IFC, TFC)

The Setup

July 2006 ALCWS Vancouvertypical spectrum of an E6 sensor

Sr90 source

Preamplifier

Sensor box

Trigger box

&Gate

PA

discr

discr

delay

ADC

Sr90

diamond

Scint. PM1

PM2

Measurement of reference spectra

signal


•2 samples from E6•1 MGy•5 MGy

•2 samples from IAF•1 MGy•5 MGy

•2 Si samples•both drew high currentsafter ~50 kGy.

E6_4p after ~5 MGy

PROGRAM


Results

Si sensor, 10 nA (ECAL standard)

high leakage current after

50 kGy

Beam current, set to 10, 20, 50 and 100 nA,

(Faraday cup)


Results

Diamonnd sensor

(produced by E6)

Diamond sensor (produced by

Fraunhofer IAF)


The Testbeam Crew

not on the photo:W.Lange

Thanks to: INTAS, Worldlab and the TU Darmstadt


- 5 bunch trains per second (5 Hz)- 3000 bunches within one train

- One bunch every 300ns, 150ns possible- Each bunch to be registered- High dynamic range (1:10k)- 10 bit ADC

- Data per train ~1 Gb (transmission during train ~1 Tb/s, during break ~3 Gb/s)

- Radiation hardness to be considered- Compact detectors: low power little space for multi-channel electronics

Readout- the challenges


PHD, 8

MSc/ Diploma, 4

PostDocs, 2

Simulation50%

Hardare50%

Simulation90%

Hardware10%

CollaborationHigh precision design DESY-PRC2006

DESY PRC Report May 2006

2006

2008

2006

5

3

8

13

6

2

9

2

5

7

051015

USA

Serbia & Montenegro

Russia

Poland

Israel

UK

Germany

France

Czech

Belarus

People signing the 2006 PRC report (60)


Conclusions

•From similations: Design of calorimeters in the forward region relatively advanced •However, many topics not yet addressed or completed (cross talk, occupancy, pile-up of events ….)

•Radiation hard sensors not yet understood - we consider ‘backup materials’, like special silicon and GaAs•Read-out electronics will be a challenge -different from ‘standard’ calorimeters, fast digitisation and processing, large amount of ‘raw data’

Effort on hardware development will be increasend!

July 2006ALCWS Vancouver Very Forward Instrumentation of the Linear Collider Detector On behalf of...

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