instrumentation of the very forward region of a linear collider detector

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June 24, 2022 LC Workshop Paris Instrumentation of the very Forward Region of a Linear Collider Detector Wolfgang Lohmann DESY (Zeuthen) Report from the FCAL workshop in Prague (April 16) Some results from SLAC (N. Graf and T Maruyama)

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Instrumentation of the very Forward Region of a Linear Collider Detector. Wolfgang Lohmann. DESY (Zeuthen). Report from the FCAL workshop in Prague (April 16) Some results from SLAC (N. Graf and T Maruyama). The very Forward Calorimeter Collaboration Recent meeting in Prague, April 16. - PowerPoint PPT Presentation

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Page 1: Instrumentation of the very  Forward Region of a Linear Collider Detector

April 24, 2023 LC Workshop Paris

Instrumentation of the very Forward Region of a Linear

Collider Detector

Wolfgang LohmannDESY (Zeuthen)

Report from the FCAL workshop in Prague (April 16) Some results from SLAC (N. Graf and T Maruyama)

Page 2: Instrumentation of the very  Forward Region of a Linear Collider Detector

see: PRC R&D 01/02

The very Forward Calorimeter Collaboration

Recent meeting in Prague, April 16.

Page 3: Instrumentation of the very  Forward Region of a Linear Collider Detector

Functions of the very Forward Detectors

•Fast Beam Diagnostics (BeamCal)

•Detection of Electrons and Photons at very low angle –

extend hermiticity

•Shielding of the inner Detector

IP

VTX

•Measurement of the Luminosity (LumiCal)

LumiCal BeamCal

300 cm

FTD

L* = 3m

Page 4: Instrumentation of the very  Forward Region of a Linear Collider Detector

•Measurement of the Luminosity

Goal: 10-4 Precision (LEP: 3.4 exp.; 5.4 theor.)

Gauge Process:

Physics Case: Z for Giga-Z , Two Fermion Cross Sections at high Energy, Threshold Scans

• Technology: Si-W Sandwich Calorimeter

• MC Simulations

• Alignment with Laser Beams

e+e- e+e- ()

10-4 10-4

Optimisation of shape and segmantation

• Close contacts to Theorists (Cracow, DESY)

Page 5: Instrumentation of the very  Forward Region of a Linear Collider Detector

•Measurement of the Luminosity

Inner Radius of Cal.: < 1-4 μm

Distance of Cals.: < 60 μm

Radial beam position: < 0.7 mm

Requirements on Alignment

and mechanical Precision(rough Estimate)

LumCal

LumCalIP

< 0.7 mm

< 4 μm

Page 6: Instrumentation of the very  Forward Region of a Linear Collider Detector

Laser Alignment SystemJagiellonian Univ. CracowPhotonics Group

reconstruction of the laser spot (x,y) positionon CCD camera

•Measurement of the Luminosity

• Simple CCD camera,• He-Ne red laser,• Laser translated in 50 mm steps

Page 7: Instrumentation of the very  Forward Region of a Linear Collider Detector

•Measurement of the Luminosity

Simulations with BHWIDE e+e- e+e- ()

RL

6.10m

15 cylinders * 24 sectors * 30 rings = 10800 cells28 cm

8 cm

Rings

)]}ln()([,0max{T

ibeami E

EEconstW

i

ii

WWX

X

))(( rad

)(radgenrec

Page 8: Instrumentation of the very  Forward Region of a Linear Collider Detector

Simulation: Bhwide(Bhabha)+CIRCE(Beamstrahlung)+beamspred

Events selection: acceptance, energy balance, azimuthal and angular symmetry.

Energy and Angular resolution

Page 9: Instrumentation of the very  Forward Region of a Linear Collider Detector

Some systematics in Reconstruction !

Stripped

LumiCal acolinearity

resolution

Page 10: Instrumentation of the very  Forward Region of a Linear Collider Detector

•Fast Beam Diagnostics (BeamCal)

e+ e-

• 15000 e+e- per BX 10 – 20 TeV

• 10 MGy per year Rad. hard sensors

Technologies: Diamond-W Sandwich

Scintillator crystals

• e+e- pairs from beamstrahlung are deflected into the LCAL

GeV

Gas ionisation chamber

Page 11: Instrumentation of the very  Forward Region of a Linear Collider Detector

Schematic views

Heavy crystals W-Diamond sandwich

sensorSpace for electronics

Page 12: Instrumentation of the very  Forward Region of a Linear Collider Detector

•Fast Beam Diagnostics (BeamCal)

detector: realistic segmentation, ideal resolutionsingle parameter analysis, bunch by bunch resolution

first radial moment first moment in 1/r thrust value total energy angular spread E(ring ≥ 4) / Etot (A + D) – (B + C) (A + B) – (C + D) E / N

forward / backward calorimeter

Observables

Page 13: Instrumentation of the very  Forward Region of a Linear Collider Detector

•Fast Beam Diagnostics (BeamCal)

detector: realistic segmentation, ideal resolutionsingle parameter analysis, bunch by bunch resolution

---24

60.4

0.0010.002

---0.7

4.32.7

0.20.5

1.52.1

uncertainty. Beam Diag. nominal

None None

0 μm 360 μm

Horizontal waist shiftVertical waist shift

5 nm 0.1 nm

0 0

Beam offset in xBeam offset in y

? ?

0.03 mm mradEmittance in y Ave. Diff.

? ?

10.0 mm mradEmittance in x Ave. Diff.

~ 10 %~ 10 %

300 μmBunch length z Ave. Diff.

Shintake Monitor

5.0 nmBunch width y Ave. Diff.

~ 10 %~ 10 %

553 nmBunch width x Ave. Diff.

Page 14: Instrumentation of the very  Forward Region of a Linear Collider Detector

Multi Parameter Analysis

σx σy σz Δσx Δσy Δσz

0.3 % 0.4 % 3.4 % 9.5 % 1.4 % 0.8 %

0.3 % 0.4 % 3.5 % 11 % 1.5 % 0.9 %

0.9 % 1.0 % 11 % 24 %

5.7 % 24 % 1.6 % 1.9 %

1.8 % 1.1 % 16 % 27 % 3.2 % 2.1 %

Page 15: Instrumentation of the very  Forward Region of a Linear Collider Detector

First Look at Photons

nominal setting(550 nm x 5 nm)

σx = 650 nmσy = 3 nm

Page 16: Instrumentation of the very  Forward Region of a Linear Collider Detector

•Detection of Electrons and Photons

Includes seismic motions, Delay of

Beam Feedback System, Lumi

Optimisation etc.

Realistic beam simulation

Efficiency to identify energetic electrons and photons(E > 200 GeV)

Fake rate

√s = 500 GeV

Page 17: Instrumentation of the very  Forward Region of a Linear Collider Detector

High Energy Electron Detection in NLC LUMONN. Graf and T. Maruyama (SLAC)

• Beampipe radius: IN 1 cm, OUT 2 cm• Detector: 50 layers of 0.2 cm W + 0.03 cm Si Zeuthen R- segmentation

OUT IN

• Generate 330 bunches of pair backgrounds.• Pick 10 BX randomly and calculate average BG in each cell, <E>background

• Pick one BX background and generate one high energy electron.• EBG + Eelectron - <E>background, in each cell• Apply electron finder.11 cm

LUMON

Page 18: Instrumentation of the very  Forward Region of a Linear Collider Detector

High Energy Electron Detection

250 GeV e-BG

Si Layers

Pair Background 250 GeV Electron

Ebg + Eelectron - <Ebg>

Dep

osite

d En

ergy

(arb

. Uni

ts)

Page 19: Instrumentation of the very  Forward Region of a Linear Collider Detector

Electron finder

Cut at 450.

250 GeV e-

Background

2 distribution

Use first several layers as shield. Use towers past layer 10 as seeds for a fixed-cone algorithm to cluster cells.

- physical size of shower doesn’t change - simplifies geometry handling - single pass through the data

Cuts on cluster width and longitudinal shower 2.

Page 20: Instrumentation of the very  Forward Region of a Linear Collider Detector

Electron Detection Efficiency

1

2

3

45

6

X (cm)

Y (c

m)

Efficiency (%)

Energy (GeV)50 100 150 200 2500

10

20

30

40

50

60

70

80

90

100

Point 6Point 5Point 4Point 3Point 2Point 1

GeV

Page 21: Instrumentation of the very  Forward Region of a Linear Collider Detector

Background Pileup

What happens if we do not havesingle bunch time resolution?

The detection efficiency does not degrade quickly, but the fake rake increases.

Fake rate (all cluster energies):1 bx 5%2 203 404 47

Fakes are concentrated in hotspots, not uniform in phi.Expect rejection to improve with further study.

20

15

10

5

0

Fake

Rat

e (%

)

7654321

No. of Bunches

2.0 - 2.5 cm 2.5 - 3.0 3.0 - 3.5 3.5 - 4.0 4.0 - 4.5 4.5 - 5.0

Page 22: Instrumentation of the very  Forward Region of a Linear Collider Detector

Different surface treatments :#1 – substrate side polished; 300 um#2 – cut substrate; 200 um#3 – growth side polished; 300 um#4 – both sides polished; 300 um

Diamond; Size: 12x12 mm 2

Metallisation: 10 nm Ti + 400nm AuCurrent (I) dependence on the voltage (V)Ohmic behavior for ‘ramping up/down’, hysteresis

Charge collection distance issaturated to 60 m at ~300V

Sensor prototyping, Diamonds

Page 23: Instrumentation of the very  Forward Region of a Linear Collider Detector

Sensor prototyping, Diamonds

Charge Collection distance vs. dose#1 – substrate side polished; 300 um #2 – cut substrate; 200 um

Page 24: Instrumentation of the very  Forward Region of a Linear Collider Detector

Oscillograms of Tetrod-BJT Amplifier

20ns/div

20ns/div

Preamp output

Shaper output

Preamplifier Characteristics

Page 25: Instrumentation of the very  Forward Region of a Linear Collider Detector

Sensor prototyping, Crystals

Light Yield from direct coupling

and using a fibre

~ 15 %

Plastic scintilator

Study with heavy crystals(Cerenkov light) is going on

Page 26: Instrumentation of the very  Forward Region of a Linear Collider Detector

Sensor prototyping, C3F8 Gas Ionisation Chamber

Beam Test,e- beam, 10-40 GeV (IHEP)

Pads for charge collection

Pressure vessel

Page 27: Instrumentation of the very  Forward Region of a Linear Collider Detector

Offers for GaAs

LPI group Lebedev Physical Institute, Moscow

IHEP, ProtvinoNCPHEP, MinskSIPT, TomskICBP, Puschino

Page 28: Instrumentation of the very  Forward Region of a Linear Collider Detector

Summary

• BeamCal has a great potential for fast beam diagnostics

• MC Simulations to optimise the Design of the forward calorimeters are progressing • Different Detector Technologies for BeamCal are under study

• Tests with Sensor Prototypes and preamplifier have been started

• After about one year we will present a Design• The goal is to start after with the construction and test of a prototype

Page 29: Instrumentation of the very  Forward Region of a Linear Collider Detector

Charge collection distance measurements

&

Gate

PA

discr

discr

delay

ADCSr90

PM1

PM2

diamond

Scint.

Qmeas. = Qcreated x ccd / LUsing electrons from a Sr90 source

(mips)

Page 30: Instrumentation of the very  Forward Region of a Linear Collider Detector

Charge collection distance measurements

The sensors are not irradiated

Upper curve is ramping up HV,Lower ramping down.

Charge collection distance issaturated to 50 m at ~300V

Page 31: Instrumentation of the very  Forward Region of a Linear Collider Detector

Sensor prototyping and lab tests

Current (I) dependence on the voltage (V)

Ohmic behavior for ‘ramping up/down’, hysteresisResistance in the order of 100 TOhm

Current decays with timeAfter 24 h nearly 1/2

Page 32: Instrumentation of the very  Forward Region of a Linear Collider Detector

• Two photon event rejection

•Detection of Electrons and Photons

(Severe background for particle

searches)

• Electromagnetic fakes

1% from physics 2% from fluctuations

• essential parameters:Small Molière radius

High granularity

Longitudinal segmentation

e+e- e+e-