Speaker
Hiroyuki Takahashi
(Uni Tokyo)
Description
We are developing a multi-grid-type MSGC with the global-local-grouping
(GLG) readout method for neutron scattering applications. In this method,
avalanche charge is divided into two ways. A half charge is used for
indicating the coarse position of the incident radiation. And the other half
charge is used for locating the detailed position of the incident radiation. In
this way, the position is determined by two-stage identification method. If
we could discriminate 9 rough positions and 9 fine positions, 81 different
positions are identified, whereas the readout line can be multiplexed to 9 +
9 = 18. Therefore, the advantage of the method is to decrease the number
of readout lines by less than 1/4 in this case. This is crucial for neutron
scattering applications since the detector must be operated in a pressure
vessel, as a result, the connection between the detector and the readout
circuit placed outside the vessel is not so easy. The drawback of the GLG
method is to decrease the charge by 50% and to increase the detector
capacitance by 4 times in the above case. However, the total capacitance
viewed by a preamplifier is not only the detector capacitance. Actually when
the pressure vessel is used, the feedthrough connector adds a certain
amount of the capacitance. Thus the drawback of the GLG method is
somehow relieved. We have developed a 6.4cm x 6.4cm multi-layer GLG-
MSGC plate with Toshiba’s Au/Ti multi-layer layer technology. Anode pitch
and cathode pitch were selected to be 0.8mm which is suitable for neutron
applications. The plate was successfully operated and the local and the global
position identification was ensured.
Author
Hiroyuki Takahashi
(Uni Tokyo)
