Speaker
Description
Scintillation light recording is a versatile readout approach for MPGDs which exploits the high granularity of pixellated imaging sensors or the high sensitivity and time resolution of photomultiplier tubes (PMTs). As an alternative to camera- or PMT-based optical readout, we report on the optical readout of GEMs and Micromegas with silicon photomultipliers (SiPMs). The compact dimensions, high sensitivity and good time resolution of SiPMs enable novel readout approaches when combined with MPGDs.
An array of 16 SiPMs was used for optical readout of a triple GEM detector. The signal waveforms from each individual sensor were recorded with a digitiser and signal amplitudes and integrals were extracted during offline analysis. A centre-of-gravity algorithm utilising weights determined from the amplitudes of SiPM signals was used to reconstruct the position of events. Different detector geometries are investigated to improve optical signal sharing across multiple readout channels.
To demonstrate the time resolution achievable with SiPM-based readout of MPGDs, an array of four SiPMs was used to optically read out a glass Micromegas detector in a PICOSEC Micromegas configuration. This detector is characterised by a thin drift region of 200 µm used for preampfification and a bulk Micromegas integrated on a transparent substrate coated with indium tin oxide (ITO). The possibility to reconstruct hit locations was investigated and the time resolution achievable with this combination of a precise timing detector with SiPM readout was measured.
To complement the abovementioned studies of optical readout with SiPMs, scintillation light spectra were measured for a range of gas mixtures based on Ar and He combined with CF$_{4}$ and other quenchers. While CF$_{4}$-based mixtures emit ample visible light which can be directly recorded with conventional SiPMs, the UV light emitted in other gas mixtures can be converted to the visible range with wavelength shifters (WLSs). Optical readout with different gas mixtures is demonstrated, illustrating the versatility of this readout approach.
| Name of the speaker | Florian M. Brunbauer |
|---|---|
| Eligible for the Georges Charpak Young Scientist Award. | yes |