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Status of Forward Calorimetry R&D: Report
from the FCAL Collaboration
Bruce A. SchummSanta Cruz Institute for Particle Physics
University of California, Santa Cruz
Americas Workshop on Linear Colliders
Fermi National Accelerator Laboratory
May 12-16, 2014
April 21, 2023 Detector Workshop Terascale 2
Example Very Forward Region of the ILD and a CLIC Detector
Optimisation of the design of the very forward region of LC detector •Precision luminosity measurement•Fast feedback and beam tuning•Detector hermeticityChallenge: Fast readout
(Slide: Wolfgang Lohmann)
April 21, 2023 Detector Workshop Terascale 3
Luminosity Measurement
• Precise measurement of the luminosity• (10-3 at ILC, 10-2 at CLIC)• Low angle physics• New challenge: Beamstrahlung
Gauge process for the luminosity measurement: Bhabha scattering
e+e- e+e- (
L = N /
Count Bhabha events
From theory
(Slide: Wolfgang Lohmann)
April 21, 2023 Detector Workshop Terascale 4
Beam Tuning and electron tagging
BeamCal (+Pair Monitor)• Fast luminosity estimate using beamstrahlung
(bunch-by-bunch at ILC)• Beam parameter estimation• Fast feedback to the machine• Low angle electron tagging
Beam parameter determination and fast feed-backBunch-by-bunch at ILC
(Slide: Wolfgang Lohmann)
AWLC-14 Fermilab 5Bruce Schumm
FCAL Collaboration Goals and Activities
FCAL aims to generate complete designs of both forward detection elements (LumiCal, BeamCal)
Challenges include: Alignment and precision, data throughput, radiation hardness
Current activities include
•Sensor development
•Prototypes for full beam testing
•Application-specific electronics development
•Alignment systems
•Radiation damage studies
•Simulation for instrumentation design and physics studies (not discussed here)
April 21, 2023 Detector Workshop Terascale 6
Sensors Development
Characterisation of a GaAs sensor on the probe-station
Silicon sensor prototype for LumiCal
p on n, strip pitch 1.8 mm
40 sensors available
Institutes: IFJ PAN Cracow, DESY, Tel Aviv (TAU)
Electrical characterization done, matches quality criteria
Compensated GaAs
Institutes: Tomsk, DESY-JINR collaboration (BMBF supported)
Electrical characterization at JINR and DESY, 30 sensors of sufficient quality
(Slide: Wolfgang Lohmann)
AWLC-14 Fermilab 7Bruce Schumm
Heading
Marek Idzik
AWLC-14 Fermilab 8Bruce Schumm
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(Slide: Oleksandr Borysov)
20
Olga Novgorodova Szymon Kulis
April 21, 2023 Detector Workshop Terascale 9
Beam-test Results
Scan across a pad boundary
BeamCal sensor
LumiCal sensor
(Slide: Wolfgang Lohmann)
Veta Ghenescu, Itamar Levy
AWLC-14 Fermilab 10Bruce Schumm
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(Slide: Oleksandr Borysov)
Konrad Elsener
AWLC-14 Fermilab 11Bruce Schumm
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Oleksandr Borysov
AWLC-14 Fermilab 12Bruce Schumm
Testbeam Prototype Structure Status and PLans
(Slide: Oleksandr Borysov)
AWLC-14 Fermilab 13Bruce Schumm
Radiation Damage Studies
Marek Idzik
AWLC-14 Fermilab 14Bruce Schumm
Heading Marek Idzik
AWLC-14 Fermilab 15Bruce Schumm
HeadingMarek Idzik
Now measured! ENOB = 9.3 bits
AWLC-14 Fermilab 16Bruce Schumm
Heading Marek Idzik
April 21, 2023 Detector Workshop Terascale 17
Dedicated BeamCal Readout
• 180 nm TSMC technology• 10 bit SAR ADC • 4 channel version in summer 2014• Assembled sensor planes for beam tests after 2015
(Slide: Wolfgang Lohmann)
Angel Abusleme
18
Mechanical aspects of LumiCal alignment
Leszek Zawiejski
19
The design of the LAS system The alignmen system may include two components: ● IR laser + PSD system:infra-red laser beam and semi-transparent position sensitive detectors ● FSI system: tunable laser(s), beam splitters, isolator, Fabry-Perot interferometer, retroreflectors, fibers, collimators, photodetectors, lens
FSI - Frequency Scanned Interferometry):The absolute distance measurements between LumiCal’s
IR Laser + PSD
Leszek Zawiejski
20
Position Sensitive Detectors
Laser beam position measurements
An example: beam profile signals from the X-strips along the moving beam.The available aperture for laser beamis 5 x 5 mm2 for sensor. The mean positions mxi were obtained from a Gaussian fit to observed signals
Fluctuations increasing with distance along the laser beam. They can be related to:laser instability with an increase of beam diameter and noise of the sensor.Data from laser working since hours show smaller fluctuations
Light transmission: above 85% for > 780 nm
Leszek Zawiejski
21
Summary
● The accuracy received in preliminary measurements of the beam position was less than 20 micrometers, using the layout of 6 semi-transparent sensors. An improvement of the conditions of measurement (like thermal insulation) will lead to a smaller value.
● For beam test measurements and further development of the prototype a new complete system (PSD with readout and DAQ) seems to be necessary. Question is if this will be possible? Another option which can provide the measurement of transverse displacements is optical system RASNIK (Red Alignment System NIKHEF)
● FSI elements which recently were collected allow to build a simple prototype.The FSI studies will be continued after finished some tests performed by the producer for tunable laser.
● Several steps are planned during such studies, leading towards the final prototype.This will be continued inside the AIDA2 project.
(Slide: Leszek Zawiejski)
AWLC-14 Fermilab 22Bruce Schumm
Radiation Damage Studies
SLAC Experiment T506: Electromagnetically-Induced Radiation Damage to Solid State Sensors
Tungsten
radiatorsSensor
Beam
Beam
AWLC-14 Fermilab 23Bruce Schumm
Example Radiation Damage Result
Further T506 goals (multi-year program):•Explore different Si sensor technologies (p-type, float-zone…)•Explore GaAs sensors (should start soon!)•Higher doses
• N-type bulk
• Magnetic Czochralski
• Exposures up to 220 mrad
• Including (accidental) annealing
AWLC-14 Fermilab 24Bruce Schumm
Summary and Conclusions
Large, international group collaborating well towards development of forward calorimetry
Good progress towards prototype BeamCal and LumiCal systems
Challenging questions of alignment (prototype mechanical stack, alignment system development) and data rate (electronics development) being met
In good shape for potential drive to build detectors for a realized Linear Collider
AWLC-14 Fermilab 25Bruce Schumm
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AWLC-14 Fermilab 26Bruce Schumm
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