Status of Forward Calorimetry R&D: Report from the FCAL Collaboration Bruce A. Schumm Santa Cruz Institute for Particle Physics University of California, Santa Cruz Americas Workshop on Linear Colliders Fermi National Accelerator Laboratory May 12-16, 2014

February 25, 2016 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 hermeticity Challenge: Fast readout (Wolfgang Lohmann)

February 25, 2016 Detector Workshop Terascale 3 Luminosity Measurement Precise measurement of the luminosity (10 -3 at ILC, 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 (Wolfgang Lohmann)

February 25, 2016 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-back Bunch-by-bunch at ILC (Wolfgang Lohmann)

AWLC-14 Fermilab 5 Bruce 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)

February 25, 2016 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 (Wolfgang Lohmann)

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February 25, 2016 Detector Workshop Terascale 8 Beam-test Results Scan across a pad boundary BeamCal sensor LumiCal sensor Wolfgang Lohmann

AWLC-14 Fermilab 9 Bruce Schumm Heading Oleksandr Borysov

AWLC-14 Fermilab 10 Bruce Schumm Heading Oleksandr Borysov

AWLC-14 Fermilab 11 Bruce Schumm Testbeam Prototype Structure Status and PLans Oleksandr Borysov

AWLC-14 Fermilab 12 Bruce Schumm Heading Marek Idzik

AWLC-14 Fermilab 13 Bruce Schumm Heading Marek Idzik

AWLC-14 Fermilab 14 Bruce Schumm Radiation Damage Studies Marek Idzik

AWLC-14 Fermilab 15 Bruce Schumm Heading Marek Idzik

AWLC-14 Fermilab 16 Bruce Schumm Heading Marek Idzik

February 25, 2016 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 Wolfgang Lohmann

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 beam is 5 x 5 mm 2 for sensor. The mean positions mx i 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. Leszek Zawiejski

AWLC-14 Fermilab 22 Bruce Schumm Radiation Damage Studies SLAC Experiment T506: Electromagnetically-Induced Radiation Damage to Solid State Sensors Tungsten radiators Sensor Beam

AWLC-14 Fermilab 23 Bruce Schumm Example Radiation Damage Result Further T506 goals: Explore different Si sensor technologies (p-type, float-zone Explore GaAs sensors Higher doses N-type bulk Magnetic Czochralski Exposures up to 220 mrad Including (accidental) annealing

AWLC-14 Fermilab 24 Bruce 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

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AWLC-14 Fermilab 26 Bruce Schumm Heading