The Impact of BeamCal Performance at Different ILC Beam Parameters and Crossing Angles on \tilde{tau} searches

The ILC accelerator parameters and detector concepts are still under discussion in the world-wide community. As will be shown, the performance of the BeamCal, the calorimeter in the very forward area of the ILC detector, is very sensitive to the beam parameter and crossing angle choices. We propose here BeamCal designs for a small (0 or 2 mrad) and large (20 mrad) crossing angles and report about the veto performance study done. As illustration, the influence of several proposed beam parameter sets and crossing-angles on the signal to background ratio in the stau search is estimated for a particular realization of the super-symmetric model.Comment: Talk given by V. Drugakov at the Linear Collider Workshop "LCWS06'', 9-13 March 2006, I.I.Sc Bangalore, Indi

Potential and challenges of the physics measurements with very forward detectors at linear colliders

The instrumentation of the very forward region of a detector at a future linear collider (ILC, CLIC) is briefly reviewed. The status of the FCAL R and D activity is given with emphasis on physics and technological challenges. The current status of studies on absolute luminosity measurement, luminosity spectrum reconstruction and high-energy electron identification with the forward calorimeters is given. The impact of FCAL measurements on physics studies is illustrated with an example of the sigma(HWW).BR(H - GT mu(+)mu(-)) measurement at 1.4 TeV CLIC.37th International Conference on High Energy Physics (ICHEP), Jul 02-09, 2014, Valencia, Spai

ECFA Detector R&D Panel, Review Report

Two special calorimeters are foreseen for the instrumentation of the very forward region of an ILC or CLIC detector; a luminometer (LumiCal) designed to measure the rate of low angle Bhabha scattering events with a precision better than 10$^{-3}$ at the ILC and 10$^{-2}$ at CLIC, and a low polar-angle calorimeter (BeamCal). The latter will be hit by a large amount of beamstrahlung remnants. The intensity and the spatial shape of these depositions will provide a fast luminosity estimate, as well as determination of beam parameters. The sensors of this calorimeter must be radiation-hard. Both devices will improve the e.m. hermeticity of the detector in the search for new particles. Finely segmented and very compact electromagnetic calorimeters will match these requirements. Due to the high occupancy, fast front-end electronics will be needed. Monte Carlo studies were performed to investigate the impact of beam-beam interactions and physics background processes on the luminosity measurement, and of beamstrahlung on the performance of BeamCal, as well as to optimise the design of both calorimeters. Dedicated sensors, front-end and ADC ASICs have been designed for the ILC and prototypes are available. Prototypes of sensor planes fully assembled with readout electronics have been studied in electron beams.Comment: 61 pages, 51 figure

Performance of fully instrumented detector planes of the forward calorimeter of a Linear Collider detector

Detector-plane prototypes of the very forward calorimetry of a future detector at an e+e- collider have been built and their performance was measured in an electron beam. The detector plane comprises silicon or GaAs pad sensors, dedicated front-end and ADC ASICs, and an FPGA for data concentration. Measurements of the signal-to-noise ratio and the response as a function of the position of the sensor are presented. A deconvolution method is successfully applied, and a comparison of the measured shower shape as a function of the absorber depth with a Monte-Carlo simulation is given.Comment: 25 pages, 32 figures, revised version following comments from referee

A precision luminometer for future linear collider experiments

The FCAL collaboration develops the technologies of compact and fast calorimeters to measure the luminosity at Linear Collider experiments both with high precision using small angle Bhabha scattering, and bunch-by-bunch using beamstrahlung pairs. Beside the luminosity measurement, the capability of detecting high energy electrons at low angles is important for many search experiments. A small Molière radius facilitates the measurement of Bhabha events in the presence of background and allows the detection of single high energy electrons on top of the widely spread background of beamstrahlung. A multi-plane prototype of a compact precision luminometer was studied in an electron beam with energies between 1 and 5 GeV at DESY. The results for the longitudinal and the transverse shower profiles are compared with Geant4 simulations of the setup. Very good agreement was obtained. The effective Molière radius of the prototype was determined. Again, very good agreement between data and Monte Carlo simulations was found. The value of the Molière radius approached the technological limit. A dedicated multi-channel ultra-low power readout ASIC is under development in 130 nm CMOS, comprising an analogue front-end and fast 10-bit ADC in each channel, followed by fast serialization and data transmission. In addition, an ASIC with a dual readout scheme allowing for a fast feedback to the accelerator and simultaneous data taking and calibration is under development. The paper summarizes the results on design optimization, beam-tests and the status of the readout ASICs

Beam test results with ultra thin LumiCal detector planes

A new design of a detector module of submillimeter thickness for an electromagnetic calorimeter is presented. It is aimed to be used in the luminometers LumiCal and BeamCal in future linear e+e− collider experiments. The module prototypes were produced utilizing novel connectivity scheme technologies. They are installed in a compact prototype of the calorimeter and tested at DESY with an electron beam of 1 GeV–6 GeV. The performance of eight detector modules in a prototype of a compact LumiCal is studied