Speaker
Description
Highly compact and granular electromagnetic calorimeters are required for precision measurements in luminometers at future Higgs factories and for the determination of positron multiplicity and energy spectra in the laser–electron scattering experiment LUXE, which probes strong-field QED. In luminometer applications, where Bhabha scattering serves as the reference process, a compact calorimeter with a small Molière radius enables a precise definition of the fiducial volume, reduces the required space, and improves the separation of high-energy electromagnetic showers from low-energy background. In laser–electron scattering, the wide range of positron multiplicity makes a compact calorimeter suitable for both counting and energy measurement. A sandwich-type calorimeter has been designed and partially constructed, consisting of tungsten absorber plates interleaved with thin silicon sensor planes in 1.2 mm gaps. Each sensor plane comprises a 90x90 mm² silicon pad sensor segmented into a 16× 16 matrix, flexible Kapton PCBs, and a carbon-fiber support, with a total thickness of less than 1 mm. The readout system employs 32 channel FLAME ASICs with charge integrating analogue front-end electronics and 10-bit ADCs. A prototype equipped with up to 11 detector planes was tested with 1 - 6 GeV electron beams at the DESY-II synchrotron. Preliminary results on the energy, position, and angular resolution, the Molière radius, and the longitudinal shower development are presented. The current status of the prototype development and the performance expected from simulations will also be discussed.