Würzburg 2018 – scientific programme

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ST: Fachverband Strahlen- und Medizinphysik

ST 2: Detector Physics

ST 2.3: Talk

Tuesday, March 20, 2018, 17:00–17:15, Phys-HS P

Detection of Cherenkov Light from Compton-Scattered Electrons for Medical Applications — •Reimund Bayerlein, Ayesha Ali, Ivor Fleck, Waleed Khalid, Ayman Salman, Albert Walenta, and Ulrich Werthenbach — Universität Siegen

Modern nuclear medicine and radiation therapy require imaging systems for higher energy gamma rays up to several MeV. Especially monitoring dose delivery in radionuclide or proton/ion therapy would benefit from the ability to image high-energetic gamma rays.

Since Compton-scattering dominates in this energy-region, the momentum information of the gamma is lost. However, using a two-layer detection system (Compton Camera) where the high-energetic Compton-electron is detected in coincidence with the scattered gamma, the origin of the photon can be narrowed down to the surface of a cone. In order to perform this challanging measurement, a new concept is introduced using Cherenkov light from Compton-electrons in the optically transparent scattering layer. Coincident detection of Cherenkov photons on an array of Silicon Photomultipliers (SiPM) enables a reconstruction of the characteristic Cherenkov cone and allows to draw conclusions on the momentum information of the incident gamma.

Results of coincident Cherenkov light detection on a 4x4 SiPM-array with sub-nanosecond timing resolution will be presented. The spatial distribution of Cherenkov photons from collimated electrons in PMMA on the detector-array was investigated. The distribution of the number of photons per incident electron was studied using pulse-integral spectra.