Speaker
Madhu Dixit
(Carleton University)
Description
The Micro Pattern Gas Detector (MPGD) readout TPC, proposed for the
International Linear Collider (ILC), will have to measure 200 track
points with a transverse resolution close to 100 microns. It will be
difficult to meet the resolution goal with conventional MPGD readout
techniques if 2 mm x 6 mm pads were used as was initially envisioned.
Reducing the pad width to improve resolution could add significantly
to the detector cost and complexity. The new MPGD readout concept of
charge dispersion has been shown to achieve excellent resolution
without resorting to narrower pads in cosmic ray TPC tests without a
magnetic field. We have recently tested two small prototype MPGD-TPCs
with charge dispersion readout in a 1 T superconducting magnet in a
test beam at KEK. Transverse resolution close to 50 microns was
achieved with 2 mm wide pads at 1 T for short drift distances. The
dependence of resolution on drift distance was as expected from
diffusion. With larger suppression of transverse diffusion at higher
magnetic fields, the resolution goal of 100 microns appears feasible
for the ILC TPC. The present status of charge dispersion MPGD-TPC
resolution studies will be presented.
