micro-scint

Microfluidic scintillation detectors

A novel type of particle detector based on scintillation, with precise spatial resolution and increased radiation resistance is being studied. It consists of a single microfluidic channel filled with a liquid scintillator and designed to define an array of optically separated scintillating waveguides each independently coupled to a photo-detector.

A standard microfabrication process was optimized to fabricate structures with high aspect ratios (up to 1:30) in thick layers, of the order of 200 μm, of the SU-8 negative-tone photoresist. These structures define dense arrays of microfluidic channels that are filled with liquid scintillators and optically coupled to pixelated photodetectors. The photoelectric yield of this assembly was measured to be of the order of 1.65 photoelectrons per minimum ionizing particle (MIP) traversing the liquid scintillator contained in the 200 μm deep microchannels. This number is in full agreement with theoretical calculations and is comparable to the yield of small diameter scintillating fibres.

Initially developed for HEP applications, the same technology is under investigation to obtain thin beam monitors interacting as little as possible with particle beams for hadrontherapy online monitoring in cancer treatment. Such detectors are expected to provide the required resolution with a significantly thinner device with respect to the ones based on other state-of-the-art technologies. This will allow performing online measurements which are not possible with the existing techniques.