Performance of a cerium fluoride crystal matrix measured in high-energy particle beams

A cerium fluoride matrix composed of nine longitudinally segmented towers, approximately 25X(0) long, has been tested in electron, muon and pion beams of momenta ranging from 10 to 150 GeV/c. The results are discussed in terms of light yield, electronic noise, energy and position resolution. In spite of serious imperfections in geometry and quality of some of the crystals, an electron energy resolution of similar to 0.5% has been obtained with a silicon photodiode readout, for energies above 50 GeV. The performance of cerium fluoride in a beam, its high density, high light yield and fast response, radiation resistance and ruggedness make it a very good candidate for high-resolution calorimetry at future colliders. The best conditions for production of large high-quality crystals are being studied in several firms over the world. Many CeF3 crystals, 2 x 2 cm(2) or 3 x 3 cm(2) in cross section and up to 28 cm long, were received in 1994 from four companies, some of them with excellent light yield and radiation hardness.