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	Detector Update Status September 1998

Splicing:
	The first problems with the splicing machine were solved by
polishing the glass fixtures that hold the fibers. That allows the light
to be more focused on the fiber joint and we have successfully spliced
fibers of different width and multi-clad to single-clad ones. The first
quantitative measurements of transmission after splicing shows a 84%
transmission for multi-clad fibers. The transmission is dependent on
the heating time and it has a maximum for 18s of heating time. The other
parameters like horizontal and vertical pressure do not seem to affect
the splicing transmission. The quality of the polish finishing in the
fiber ends is crucial for a good splicing, for that to be achieved ice
polishing is the only method that gave good results.
	The transmission efficiency for these setting is between 95-
99%, better than the average fiber connectors.
	The transmission very weakly dependent(less than 2%) on the
presence of epoxy on the fiber joint.
	A second set of glass fixtures, that can accomodate the new 
batch of wider fibers(0.83mm) has been ordered with the additional
specification of polished surfaces as above.
	Before she left, Jennifer spliced about 200 of the 448 needed
for the full prototype. The additional work requires a tecnician for
about 3 days. 

Detector Frames:
	Alluminum frames for the UVX planes have been done by the EDM
process on the Fermilab machine shop. Plastic frames have been casted
from those, but the final plastic frames are not done yet. There is
a need to dye the frames in order to avoid cross-talk. Estimated 
delivery of the frames are for the first week of October.
	Assembly of the fibers in the frames will start once the
frames are finished. Assembly work should require one tecnician for
3-4 days.

Efficiency:
	The UU' plane efficiency was measured using cosmic rays on a
two plane prototype with 16 channels. The measured efficiency of 98% 
can be understood in terms of the plane geometric acceptance, so in
principle the plane is 100% efficient.

Cables and Electronics:

	An inspection on the location of the pots on the tunnel shows
that there is no space on the existing trays for our cables. We have
therefore to arrange for the instalation of additional trays for our
signal cables. These trays also could be used to support the low
voltage cables for the amplifiers and step motors.

	We are still seeking for an amplifier option for the MAPMT.
I contacted Hamamtsu but they do not provide amplifiers for these
tubes. A former option from LeCroy, HQV802-M has good characteristics
but the price is too high(~70$/channel).
	I have made contacts with the muon group in order to adapt 
their LED pulser calibration to our needs. The main modification
we need to do is to use a different fiber for the light distribution.
They use a 1mm fiber which is too big and would require a major
change in the MAPMT mask to accommodate that.

Trigger Scintillator:

	We have tested several PMTs for the trigger scintillator. The old
Level0 PMTs were found and tested as well. The L0 PMTs have lower gain
compared to other PMTs tested(EMI and Hamamatsu). The question remaining
is the efficiency measurement for a 1/2 inch scintillator, that is the
planned thickness of our trigger scintillator.
	We have made 3 prototype trigger counters using 1/2 inch Bycron
BC408 scintillator. Each of the above has a different light collection
strategy, using either MC clear fibers(square and round) or acrylic light
guide.
	First measurements using radioactive sources confirm that the
electrons form the source are being stopped on the scintillator, so either
a test beam or a cosmic ray setup is needed in order to measure the efficiency
of each setup. At the moment a cosmic setup is being pursued.



	Gilvan