The CALICE Collaboration - Calorimeter for LC
The particle colliders play a central role in the search for new particles and the study of their properties and every new experiment requires significant advances on the detectors to face the new challenges.
Experiments for future linear colliders as ILC (International Linear Collider) or CLIC (Compact LInear Collider) must measure the jet energy with a resolution a factor two better than in the present experiments. Reconstruction techniques based on the Particle Flow Algorithm (PFA) could meet this challenge. This requires very highly granular calorimeters to distinguish between particles close by. New calorimeter systems could have hundred of millions of channels, a very huge number in comparison with the tens of thousands of channels in the present calorimeters at the LHC experiments. This imposes important technological chalenges in the associated electronics, mechanics and cooling.
CALICE (CAlorimeter for LInear Collider Experiment) is a R&D collaboration with more than 300 physicist and engineers from institutes of 17 countries from all over the world. It is undertaking a major R&D program into highly segmented calorimeters optimized for particle flow measurement of multi-jet final states.
Different electromagnetic (ECAL) and hadronic (HCAL) calorimeters are being developed using different technologies (Silicon,Scintillator,Gaseous detectors:GRPC,MICROMEGAS,GEM) and readout (analog, digital, semi-digital). Several prototypes have been tested at CERN and Fermilab testbeam facilities and more than 400 million of events have been recorded.
The CALICE Analog HCAL was the first device using the SiPM thechnology on a large scale, and the good results encourage other experiments (as CMS, BELLE-II , T2K) to use it in their detector upgrades. GRPC (s)DHCAL prototypes with 1x1cm2 readout pads and about half a million of channels represent a world record. The prototypes provide a proof-of-principle of the vialiblity of the technology in terms of construction, operation and performance. The unprecendent granularity of the prototypes allow also detailed tests of the simulation models.
CIEMAT participation in CALICE
CIEMAT is member of CALICE since 2007. The group participate in the SDHCAL (Semi-Digital Hadronic CALorimeter), that uses a gaseous detector, a GRPC (Glass Resistive Plate Chambers) or Micromegas as active medium, readout by 1x1cm2 pads, interleaved with stainless steel plates. The main novelty is the semi-digital readout which counts which and how many pads have a signal over a certain threshold. Three thresholds are used.
At the moment the group is the responsible for the SDHCAL mechanics and the DIF (Detector InterFace Boards) electronics, which interface the ASIC chips with the DAQ for configuration and readout, and participate in the test beam data analysis.
A 1m3 stainless steel structure made of 51 1x1m2 plates, to host up to 50 GRPCs or Micromegas, has been assembly at CIEMAT. The dead spaces has been minimize requiring stringent tolerances in planarity and thickness of the componets. 48 GRPC, equiped with their readout electronics, have been inserted and the prototype has been tested at PS and SPS test beam lines at CERN showing very good results.
The group is developing now the mechanics and DIF electronics for the larger prototypes (up to 3m) needed for a real detector.