Minutes glast lab meeting, August 29, 2000

Present: Alec, Bill, Gwelen, Collen, Mat, Wilko


HDI encapsulation:
BIll reported that he is ready to test the Urelene. He prepared some small 
hybrids with chips and wire bonds. Within the next few days he will mix the
Urelene and encapsulate a test piece. In order to mix the Urelene one of the
components has to be warmed in an oven.

Right Angle Interconnect (RAI):
Alec presented a new RAI that he just finished. This kapton piece were cut of a 
BTEM kapton sheet and therefore has traces. A first look shows that it is very nice
with no glue on the traces and well aligned with respect to the hdi.
Front end chips will be placed on the hdi and detectors (or some other bond-able material) 
will be mounted so that the wire bonding on the RAI can be tested.
The bad news is that after the meeting Alec and Gwelen found a lot of broken traces.
The traces are partly cover by another layer of kapton and the break occurred 
at the edge of this layer. We speculate that the traces broke because of this extra layer
and not due to the bending radius. More visual inspections are under way.

Alec and Gwelen also looked into the IPC specification and calculated a bending radius
for the kapton of 200 mu which is 5 times smaller compared to the value that we assumed
so far. 

HDI:
Gwelen believes that the hdi qualifies as a multi chip module and the IPC specification
gives a minimum distance between chips of 1 mm. The current layout assumed a spacing of 0.5 mm.
If one goes along with the IPC it would mean that the chips has to be 0.5 mm shorter.

Resistivity:
Mat reported that he has setup 3 test pieces with silver glue to measure the degradation of the 
glue/glue-gold interface due to thermal cycling. He uses a Keithley 237 and measures IV.
Connecting and disconnecting a test piece to the Keithley results in a change of the measured 
resistance due to the contact resistance of the connection. The variation is about a 
few hundreds(?) of an Ohm. One could avoid that by using the four wire measuring 
method. The Keithley it self could do that but we had problems so far. Another possibility
is to use the Electro meter.
There are still some issues with the labview program.

Electronics testing:
Wilko reported that he is now concentrating on the pickup measurements of the BTEM
due to commands issued to the front-end chips.
Masa is setting up the single board test setup using a Logic analyzer so that 
he can start testing. 
For threshold scans of all channels we will use the VME-TEM system.

Wilko didn't do anything porting the vxWorks system to the PC. The plan is to wait
until we could get the Linux drivers for the VME interface. 


BTEM disassembly:
Alec said it will be very fast to prepare the tools.
Gwelen started to clean up the clean room.
Wilko will prepare a list of items to disassemble the BTEM, what to repair
and the testing procedures before it is assembled again.


Clean Room:
We decided to make the clean room clean again similar to the state it was during the
construction of the BTEM. Gwelen will generate an instruction how to enter
the clean room.

On the weekend there might be an power outage or glitches. Instruments that are not needed
should be switched of and even disconnected from the power plug.