Fabrication and beam test of a silicon-tungsten electromagnetic calorimeter

Abstract

A : A silicon-tungsten (Si-W) sampling calorimeter, consisting of 19 alternate layers of silicon pad detectors (individual pad area of 1 cm 2 ) and tungsten absorbers (each of one radiation length), has been constructed for measurement of electromagnetic showers over a large energy range. The signal from each of the silicon pads is readout using an ASIC with a dynamic range from −300 fC to +500 fC. Another ASIC with a larger dynamic range, ±600 fC has been used as a test study. The calorimeter was exposed to pion and electron beams at the CERN Super Proton Synchrotron (SPS) to characterise the response to minimum ionising particles (MIP) and showers from electromagnetic (EM) interactions. Pion beams of 120 GeV provided baseline measurements towards the understanding of the MIP behaviour in the silicon pad layers, while electron beams of energy from 5 GeV to 60 GeV rendered detailed shower profiles within the calorimeter. The energy deposition in each layer, the longitudinal shower profile, and the total energy deposition have been measured for each incident electron energy. Linear behaviour of the total measured energy (E) with that of the incident particle energy (E 0 ) ensured satisfactory calorimetric performance. For a subset of the data sample, selected based on the cluster position of the electromagnetic shower of the incident electron, the dependence of the measured energy resolution on E 0 has been found to be σ/E = (15.36/ E 0 (GeV) ⊕ 2.0)%. K: Calorimeter, electromagnetic shower, silicon pad detectors, longitudinal profile, energy resolution.

Development and characterization of a large area silicon pad array for an electromagnetic calorimeter

“…active silicon layers. The primary objective of the FOCAL detector is to provide optimum position and energy resolution of the photons and separate from 0 up to 200 GeV [14,15] of incident energy for the incoming particles. FOCAL consists of two different types of silicon detector layers, high granularity layers (HGL) and low granularity layers (LGL).…”

“…This plot assures minimal contribution from the FEE chain in the RMS value of figure 9D. A Prototype Si-W sampling type electromagnetic calorimeter was built with 19 layers of alternating 6x6 array of silicon pad detectors and tungsten absorber/converter as a very next step [15]. As shown in figure 11A, the experimental setup was installed at the H6 beamline facility at CERN-SPS [35].…”

“…In the calorimeter, tungsten as a passive absorber initiates the EM shower, which subsequently progresses along with the depth of the calorimeter with fractional (∼ 2%) energy absorption in the 2021 JINST 16 P09026 active silicon layers. The primary objective of the FOCAL detector is to provide optimum position and energy resolution of the photons and separate 𝛾 from 𝜋 0 up to 200 GeV [14,15] of incident energy for the incoming particles. FOCAL consists of two different types of silicon detector layers, high granularity layers (HGL) and low granularity layers (LGL).…”

Development and characterization of a large area silicon pad array for an electromagnetic calorimeter

“…In the calorimeter, tungsten as a passive absorber initiates the EM shower, which subsequently progresses along with the depth of the calorimeter with fractional (∼ 2%) energy absorption in the active silicon layers. The primary objective of the FOCAL detector is to provide optimum position and energy resolution of the photons and separate 𝛾 from 𝜋 0 up to 200 GeV [14,15] of incident energy for the incoming particles. FOCAL consists of two different types of silicon detector layers, high granularity layers (HGL) and low granularity layers (LGL).…”