CALICE: high granular calorimeters
High Granular Calorimetry for present and future colliders
To meet the high precision levels foreseen by lepton collider experiments, the detector detectors will be based on the Particle Flow (PF) techniques. These techniques consist of choosing the best information available to measure the energy of the final state objects (i.e. measuring the charged particles momentum at tracking devices better than in the calorimeters). Therefore, PF techniques rely on single particle separation. For this purpose, PF algorithms require highly granular and compact calorimeter systems featuring minimum dead material. The R&D of highly granular calorimeters for future linear colliders is conducted within the CALICE collaboration. The IFIC (AITANA) is a member of the CALICE collaboration since 2020, with A. Irles as institutional board representative of the IFIC in CALICE.
Members of the AITANA group are involved in the silicon-tungsten electromagnetic calorimeter, SiW-ECAL group. The SiW-ECAL team is composed by several groups from: France (IJCLab – ex LAL, OMEGA, LPNHE, LLR, LPSC), Japan (Kyushu University, KEK ), South Korea (SKK University) and Spain (the AITANA group from IFIC and the CIEMAT).
The design and R&D of this prototype is conducted by CALICE and it is oriented at the baseline design of the ILD ECAL. The ILD ECAL is a sampling calorimeter of 24X0 of thickness (in the barrel region) and it uses silicon (Si) as active material and tungsten (W) as absorber material. The choice of Si and W allows the construction of a very compact calorimeter made up of compact active layers with small cell size (high granularity) in the transverse and longitudinal planes. It will consist of an alveolar structure of carbon fiber into which the slabs made up of tungsten plates and active sensors will be inserted. The very-front-end (VFE) electronics will be embedded in the slabs. The silicon sensors will be segmented in squared cells of 5×5 mm², featuring a total of∼100 million channels for the ECAL of the ILD. To reduce overall power consumption, the ILD ECAL will exploit the pulsed bunch structure foreseen for the ILC: the lepton bunchs trains will arrive within acquisition windows of∼1-2 ms width separated by ∼200 ms. During the idle time,∼99% of the time, the bias currents of the electronics will be shut down. This technique is usually denominated power pulsing. In addition, as the PF techniques demands minimum dead material in the detector, the design of the ILD foresees the calorimeters (hadronic and electromagnetic) to be placed inside the magnetic coil that provides magnetic fields of 3-4 T.
A. Irles is the institutional representative of the IFIC at CALICE.
Currently, the SiW-ECAL team is building and testing in beam facilities a technological prototype featuring detector elements adapted for realistic lepton collider detector. The AITANA group plays a main role in the commissioning of the SiW-ECAL prototype for beam tests at DESY and at CERN and we are also in the center of the the analysis and software coordination efforts.
In addition, we are also investigating the timing capabilities of the detector and the impact of a high precise time measurement on the reconstruction. This activity is performed in synergy with the detector optimization tasks done in our group and involve also the R&D in ultra fast silicon sensors as LGADs.
Around the world with CALICE
The SiW-ECAL Technological Prototype