CALICE - CAlorimeter for the Linear Collider with Electrons

Staff: Nigel Watson, Miriam Watson, (+honorary) Tony Price

Students: Alasdair Winter

We have been developing a technological prototype of a novel calorimeter to measure electromagnetic energy with unprecedented precision at the next generation, high energy e+e- machine, the International Linear Collider (ILC).

The detector studies for a digital ECAL using MAPS technology will continue in the medium term, characterising both their radiation hardness and suitability in e.m. showers using testbeam data, and to quanity their performance in physics simulations with the ILD/CLIC detector models.

CERN Test Beam (proposal, memo) Photos of test beam prototype UK simulation/physics Further information

Following on from involvement in the LEP experiments, the next step in our group's programme is two-fold, requiring both the Large Hadron Collider (LHC) at CERN, widely expected to discover the Higgs boson in whatever form it takes, and the ILC (e+e-). The ILC is essential for a full understanding of the properties of the Higgs boson, or the alternative mass generating process. The complementarity of the LHC and the ILC arises because of their very different environments, the latter being optimal for precise, detailed measurements. There is very widespread support for this project, both worldwide and within the UK, where we are collaborating closely with Cambridge, CCLRC (RAL-PPD), Manchester, Imperial College, RHUL and UCL. A detailed motivation for such a highly segmented and performant calorimeter is presented here. Our R&D work aims to understand how the difficult technical and cost optimisation issues can be addressed without unduly sacrificing performance for understanding the origin of mass and the unification of fundamental interactions. Together with colleagues from 34 institutes/9 countries, we will design and start testing the prototype calorimeter in a test beam by late 2004 (at DESY), with further test beam running during 2005 (expected at Fermilab).

ECAL prototype diagram

The entire electromagnetic calorimeter proposed for the LDC (nee TESLA) detector comprises a cylinder of length 5.5m, internal radius 1.9m, and annular thickness of 20cm. It is constructed from 40 layers of tungsten absorber interleaved with active silicon wafers. It consists of approx. 38 million channels of data to be read out in less than a microsecond. The ECAL prototype itself (pictured, left) will be approx. 30x30x20 cm in size, comprising 30 layers of silicon wafers, 324 diode pads per layer, totalling more than 9000 channels. Behind this will be placed a variety of sampling hadron calorimeter technologies, in a 38 layer iron sandwich structure, length of side approx. 100cm. Beams of high energy particles will be fired at the combined ECAL + HCAL prototype (pictured, left) to emulate the conditions within a detector at the linear e+e- collider. The data will be digitised, stored for analysis and comparison with detailed simulations of the system, from which we can extrapolate to the physics performance of the entire calorimeter.

The UK groups:

  • Design and build the data acquisition system and associated DAQ and run control/monitoring software.
  • Simulate performance of the test beam prototype, hadronic modelling
  • Study luminosity energy spectra measurements
  • Develop reconstruction algorithms, leading to improved energy flow methods
  • Will be active in all aspects of test beam operation and data analysis

At Birmingham, our current effort is devoted to simulation of the calorimeter and hadronic interaction modelling, to be extended to data analysis (when available) and investigations of software reconstruction algorithms.

Further information


Last significant change: 15-Jan-2006, N.K. Watson