120740000
FGLD: a novel and compact micro-pattern gas detector
Abstract A new gas detector which combines in the same structure the gas amplification mechanism and the position sensitive readout, named the field gradient lattice detector (FGLD), is being developed at CERN. The detector, reminiscent in geometry of a multi-wire proportional chamber but with a different field configuration can be fabricated as two or more layers of micro-patterned parallel tracks on a variety of substrate materials. Two preliminary proof-of-concept designs without position sensitivity have been fabricated as copper tracks of 50 μ m width and 150 μ m pitch on polyimide in a 3D geometry and on epoxy in a 2D geometry. They have been shown to detect the 5.9 keV X-rays of an 55 Fe source with a stable gain ranging from 500 to 5000 in a 3 mm drift chamber containing an argon carbon-dioxide gas mixture. The elegance and compactness of the FGLD design make it a very attractive gas detector solution both economically and mechanically. Most interestingly, the 3D FGLD design on flexible polyimide should greatly simplify the mechanical challenges of gas chamber assembly in planar and cylindrical detector designs.
119630665
Fast readout of GEM detectors for medical imaging
Abstract We describe the design and implementation of a fast data acquisition (DAQ) system for Gas Electron Multiplier (GEM) trackers applied to imaging and dosimetry in hadrontherapy. Within the AQUA project of the TERA foundation a prototype of Proton Range Radiography of 30×30 cm 2 active area has been designed and built to provide in-beam integrated density images of the patient before treatment. It makes use of a pair of GEMs to record position and direction of protons emerging from the target. A fast data acquisition rate close to 1 MHz will allow obtaining a good resolution in-beam proton radiography in a few seconds. A dedicated fast front-end circuit for GEM detectors (GEMROC by AGH-Crakow University) is read by the FPGA based DAQ card (GR_DAQ), developed by the AQUA group. The same system is under evaluation (within the ENVISION European project) to realize the in-vivo dosimetry, based on detecting secondary light particles during the treatment of the patient.
96911852
THE CRYSTAL BALL AT MAMI