PID Cherenkov Session at CM 22/2

Status of the Gluing Lab at HIM, Ahmed Ali, HI-Mainz

Ahmed showed the plans for gluing two radiator bars
together. First gluing tests will be performed using
glass samples and samples from Nikon bar after dicing.
As next step the optical table will be installed.

Status of the DiRICH back-plane, Carsten Schwarz, GSI

The changed electrical plug configuration of the Photonis
MCP-PMTs need the design of a new back-plane. On one side
the MCP-PMTs are connected to the back-plane with samtec
plugs on the other side the DiRICH is plugged in. The new
Back-plane will also include a HV divider with SMD parts.
Carsten showed plugs and possible geometrical configurations.

Evaluation of the PANDA Barrel DIRC particle identification
efficiency using physical events, Arturo Abril Martinez, Uni.Complutense

Arturo studied the improvement of the signal to background
ratio for the Barrel DIRC by calculate the efficiency of the
reconstruction for pion and kaon tracks. He used the channel
pbar+p in Ds+ and Ds- for the signal and pbar+p in K=K-pi+pi-
for the background. In all cases the DIRC information improves
the signal to background ratio.

Simulation of B-field effects inside MCP-PMTs, Merlin Boehm, FAU Erlangen

Merlin simulated the movement due to the Lorentz force of
electrons within the MCP-PMT in an external magnetic field.
The geometrical shift was shown for different tilt angles of
the tube. The charge cloud centroid gets significantly shifted
at high B-fields and tilt angles. This needs to be taken into
account for simulations & data analysis in the later experiment.

Latest measurements of MCP-PMTs and first data of 9002220, Katja Gumbert, FAU

Beside of the update on the lifetime measurements, she showed
results of the width of the charge cloud dependent on the voltages at
photocathode and channelplate. Then Katja looked into the conditions
when a tube gets into escalation mode - firing like hell. The escalation
depends on the Bfield and HV and is not stable: There is a higher risk with
illumination and after escalating, the escalation
starts earlier. Therefore, if a sensor escalates, it needs
to be switched off and to cool down a while. Also the new
Photonis 9002220 was escalating at he highest HV. The gain, QE
and the homogeneity of the new tube is ok.

Disc-DIRC and GCS Status Update, Michael Dueren, Uni Giessen

The Giessen Cosmic Station was used to measure prototypes of the
Endcap Disc DIRC. A full scale radiator was equipped with an
additional ROM. Detaching the previous ROM showed a broken optical
bonding of the middle FEL. The middle bar was drenched in optical oil
which slowly crept down from MCP-PMT coupling. Reason for separation
is not clear. The Broken FEL has been replaced and the ROM reassembled.
Michael showed also plans for  Cherenkov measurements with
SiPM-Matrices.