Speaker
Dr
Harry van der Graaf
(National Institute for Nuclear Physics and High-Energy Physics, The Netherlands)
Description
Conventional readout systems for Time Projection Chambers (TPCs)
based on wire chambers have certain limitations concerning counting
rate and spatial resolution. We have built a new type of TPC which
will not suffer from these limitations.
Our mini-TPC consists of a MediPix chip, a Micromegas and an cathode
plane. With the proper gas mixture and voltages it is possible to
detect single (primary) electrons left in tracks of minimum ionizing
particles. The information we obtain from the measurement has two
key components.
First it is possible to measure the position of the track to much
higher resolution than with conventional TPCs. Secondly, by
analyzing the track-density of primary electrons, the energy loss
function (dE/dx) can be measured.
A coincidence setup composed of three scintillator-photomultiplier
detectors defines a trigger signal for, in this case, cosmic muons.
This signal is used to read out the MediPix chip at the correct time
so the muon track can be measured. The data obtained from the cosmic
muons has been analyzed for track resolution and energy loss. These
results will be presented along with various further developments.
In the near future it will be possible to create a medipix-
micromegas combination in a monolithic form using wafer scale post
processing. Trials on dummy wafers and their gas amplification tests
will be presented.
The combination of a CMOS pixel device, a Micromegas and a thin
layer of gas can be used as vertex detector. This Gas On Slimmed
SIlicon Pixel (GOSSIP) device potentially outperforms Si
MAP/strip/pixel detectors in parameters like counting rate,
radiation hardness and power dissipation.
Primary author
Dr
Harry van der Graaf
(National Institute for Nuclear Physics and High-Energy Physics, The Netherlands)
