Speaker
Bernhard Matthias Flierl
(Ludwig-Maximilians-Univ. Muenchen (DE))
Description
Full track reconstruction for charged particles in thin gaseous
detectors can be achieved using a Time-Projection-Chamber like (TPC)
readout and analysis method.
This method has proven to be very successfull for thermal neutron
detection in gaseous electron multiplier (GEM) detectors,
based on the full track reconstruction of the charged
Helium and Lithium ions
produced in a thin $^{10}$B conversion layer building
the cathode of the triple GEM detector.
An improvement from FWHM 3.4 mm to 0.25 mm
of the spatial resolution of the interaction point of the neutron
in the $^{10}$B layer has been observed using an
Ar-CO$_2$ gas mixture as detector gas.
For the achievable track resolution the driftvelocity and thus
the composition of the drift gas is of big importance.
A self-consistent algorithm allows for optimized results
without the development of gas-parameters, as otherwise usual,
in prior test experiments with well known angle of incidence of the ions.
Simulations predict, that by application of this method the spatial
resolution for minimal ionizing particles can be improved as well.
For verification a compact cosmic muon telescope has been commissioned,
which consists of three triple GEM detectors with two-dimensional
strip readout of 0.4 mm pitch in x and y and one detector
with a single strip readout layer of 0.25 mm pitch.
All strips are read out by APV25 frontend boards.
Muon tracks are reconstructed using the TPC-like method in one of the detectors
and are then compared to the predicted track from the other three detectors
defined by the center of charge position in every detector.
A strong dependence of the composition of the detector gas is expected.
We report on our study of Argon and Helium based noble gas mixtures with
carbon-dioxide as quencher.
Primary author
Bernhard Matthias Flierl
(Ludwig-Maximilians-Univ. Muenchen (DE))
