Aachen 2019 – scientific programme

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T: Fachverband Teilchenphysik

T 44: Gasgefüllte Detektoren

T 44.5: Talk

Tuesday, March 26, 2019, 17:05–17:20, ST 3

Developement of a low background low energy X-ray detector for IAXO — •Tobias Schiffer, Klaus Desch, and Jochen Kaminski — Uni Bonn

Gaseous detectors and especially micropattern gaseous detectors like MicroMegas are commonly used in particle physics. Due to their high granularity they achieve a very high spatial resolution. An appropriate way to maximise this is a pixelised readout chip, like the Timepix3 ASIC, with a perfectly aligned gas amplification stage (InGrid) on top. This GridPix3 (the successor of GridPix) is also able to detect single primary electrons giving a good energy reconstruction for X-rays.

The search for solar axions and chameleons with helioscopes like the International Axion Obeservatory (IAXO) experiment requires detectors with very low background rates and high detector efficiency, since the expected rates are in the order of one per day and cm² or less in the region of 2 to 7 keV.

To achieve very low background rates the selection of special radiopure materials is required as well as a veto system for offline suppression of background events is necessary. In addition to gain a high detector efficiency an, in the low energy X-ray regime, highly transparent entrance window is important. This can be achieved by using utra thin (300 nm) vacuum-tight silicon nitride windows.

The challenges of building such a detector and the current developements will be presented.