Speaker
Description
Highly compact and finely segmented electromagnetic calorimeters are required for applications in the LUXE experiment at DESY and at future electron–positron colliders as luminometers. A small effective Molière radius and high spatial granularity are essential for resolving electromagnetic showers in high-occupancy environments. At collider detectors, such calorimeters precisely define the fiducial volume and need little space.
A silicon–tungsten sampling calorimeter is being developed within the FCAL and DRD Calo collaborations. Its construction poses a significant technological challenge, since the gaps between the tungsten absorber plates must be kept as small as possible in order to preserve the intrinsic compactness of tungsten. The active layers therefore have to integrate the silicon pad sensors, signal routing, high-voltage distribution and mechanical support within a very limited thickness.
The basic active unit is a highly compact silicon sensor plane in which the pad sensor is connected to thin Kapton fan-outs carrying signal and bias lines and embedded in a lightweight mechanical support. The sensors are read out at their edges by dedicated front-end ASICs such as FLAME or FLAXE, providing analogue amplification, digitisation and fast data transmission while keeping the electronics outside the sensitive area. The absorber stack is assembled with precisely manufactured tungsten plates and thin active layers in a mechanically controlled structure designed to maintain small and uniform inter-layer gaps.
The design, assembly and integration procedures developed for these modules are presented, together with experience from the construction of a multi-layer prototype. The completed system has been operated in electron beams at DESY, providing a validation of the mechanical integration, sensor connectivity and full readout chain of this highly compact calorimeter concept.