DAQ:
The Australians discussed the BEAST DAQ. Their initial plan is
to adapt a system used for data taking at TRIUMF beam tests.
The system which runs on a LINUX PC should be able to
handle rates up to 300 Hz. The system will be debugged at Melbourne
and then moved to KEK in September. One question not yet settled
is which type of CAMAC/PC interface cards are needed.
It is possible that CAMAC/GPIB board could work. Or it may be Kinetic
systems CAMAC/PC 2927 or 2915 module will be
necessary to handle high rates.
The accelerator information will be available
by the VME network shared memory. Leon will discuss
with Sakai-san how to access this information.
Initially at low accelerator luminosity, the BPM will provide a
trigger. As the luminosity improves, a discriminated sum of
drift tube signals will provide a trigger.
Sahu provided another summary of the channel count.
There are about 100 DC levels, 20 ADC pulses to be digitized.
There are 24 DC levels from
diodes, 20 RTD levels from temperature measurements in diodes
and on the beampipe. There are 53 DC
levels from the drift tubes and 7 pulses to be digitized.
There are 20 MOSFETs for active dose monitoring.
For the moment, we assume that the CsI(Tl) and EFC crystals
will be read out independently and if necessary correlated with
accelerator information. The SVD group will take care of
the readout of the SVD quadrant in the electronics hut.
A module inventory is needed fairly soon. An initial guess is
that an additional 4 scalars, 3 Octal discriminators, 1 trigger
register, and 4 2249 ADCs are needed. A Datway Display is also needed
for DAQ. The Australian group will need a subset of these modules for their DAQ tests.
Drift tubes:
All the PCB boards and electronic components for
drift tube readout have arrived. The boards are being populated.
Diodes:
The diode signals were found to be too small in the radiation damage
tests. This is due to the small active area 0.5 cm x 0.5 cm and the
small depletion depths of O(50-70) mu m of the Hamamatsu diode model.
Better Hamamatsu diodes (model S 2744-08)
with larger active areas and 300 mum depletion
depths will be used instead. A batch of 30 of these
were obtained from Tamai-san and then sent to Hawaii.
No changes to the readout electronics
are required in order to use these diodes although the
box and holders have to be modified.
The second PCB readout prototype arrives tommorow.
MOSFETs:
The MOSFETs are located on the inner layer
of the BEAST next to the diodes
and on the front face of the CsI(Tl) crystals. About 20
are needed for BEAST. There are 32 which have been calibrated
as a function of radiation dose in Australia.
These will be sent to Hawaii and attached to the mechanical structure.
Structure:
Rosen presented updated drawings of the BEAST structure. The CsI(Tl)
supports and outer beast ring will be made from fiberglass
unistrut. Non-magnetic materials (delrin, fiberglass, composites) will be
used wherever possible.
One of the backward endcap crystals may need to be moved or
removed to satisfy the space constraints of the concrete shield.
The inner BEAST support structure was narrowed to allow personnel
access.
The support for the beampipe is not yet decided. One possibility is to
use the same support structure ("bed") that supports the inner layer
of BEAST. Details of this still have to be worked out.
Rosen also discussed positioning mounts for BEAST and the beampipe.
Simulation:
Rodriguez reported an update on the simulation of standalone BEAST.
He is now generating single tracks and simulating their interactions.
Bozek presented results on the z and phi distributions of backgrounds.
He noted that the background properties versus z and phi
are significantly different without the solenoidal detector field.