Agenda of SCT links meeting

 14:00-18:00   1st December '99

 Bat 40-RC-10

1. Specifications of Opto-packages. T. Weidberg
2. Progress reports on opto-packages
• Taiwan, Ming Lee Chu
• OSU, KK Gan
• Marconi, T. Weidberg
3. Radiation tests and plans. I-M Greggor and G. Mahout.
4. Fibre routing and MT connector purchase. J. Troska and N. Uno
5. Harness production and test equipment. J. Troska
6. Opto-flex cables. T. Weidberg
7. Opto-package cover. J. Fraser.
8. Opto-flex to Al tape solder conenction. R. Millea.
9. ASIC status.
• DRX12. D. White
• BPM4-B. N. Kundu
• BPM-12. N. Kundu
10. OptoIF and BOC status. M. Goodrick
11. Opto plug-in for forward system tests. F. Hartjes

Minutes

1. Specifications of Opto-packages. The updated radiaton specifications are avaialable here. The draft specsifciations for the opto-packages are available here. These have been discussed during the recent video meetings with Taiwan. These should become final official specifications before the market survey for the opto-packages is launched in January. The draft specs are avalilable here.
2. Progress report on pacakages.

 (a) Ming Lee Chu reported on the progress in Taiwan. They have made ATLAS style opto-packages. One package so far has been made with  Truelkight VCSELs and a Centronic   PIN   diode . Unfortunately the PIN was damaged and it was too big for the current PCB so the PIN bias line was shorted to ground. The package was taken to Oxford and mounted on a dog-leg/opto-hybrid with VDC and DORIC4. The VCSEL performance was excellent. A new package will be amde which fits the Centronic PINs. Improvements will also be made to the grounding to reduce cross-talk. The packages should be availlable for testing in early January. The packages will be radiation tested with 30 MeV protons in Taiwan. Some of the next batch of Marconi packaages will also be tested in the same machine. Ming Lee also discussed ideas for making a small, simple and cheap fibre connector of the volition type. This will take 4 months to develop. If successfull then packages could be made with short pig-tails. The volition style connector would be used to connect the fibres comming from the package to th the fibres in the ribbon. If this does not work, then a back up option would be for Tawian to produce a fibre harness with opto-packages (i.e they would mount fibres from ribbons into their packages). See copies of the transparencies for more details.
 (b) KK Gan reported on the OSU developments. This is a two piece design in ceramic. Hybrid Tek screened the gold traces (10 micron gold). Unfortunately the surface was not flat enough to mount the VCSELs with surface mount technology. New pacakges will be made in Aluminia which is expected to be sufficiently flat to get goid adhesion for the VCSELs. The new pacakges are expected to be delivered in January. See copies of the transparencies for more details.
 (c) Tony Weidberg reported on the first of the Marconi phase 2 packages. The first device ahd a broken PIN diode bond wire but the next two pacakages were fully functional and work very well. A report on these tests is avaiolable here. 10 more packages will be available in late December/early January and the remaining 50 packages will be available in late January or early Feburary. See copies of the transparencies for more details.
3. Radiation tests. John Dowell reported on the radiation tests of two of the Marconi phase 2 packages. The packages were irradiated to a fluence of 3 10**14 p/cm**2  with 24 GeV p at the CERN PS. One package was annealed for 69 houts at 20 mA. The LI curves show a ~ 1mA shift ion threshold current and a small decrease in slope efficiency. Such a change would be expected for the VCSELs therefore the indication is that the package itself is radiation hard. See copies of the transparencies for more details.
4. Fibre routing and MT connector purchase. Jan Troska outlined the fibre routing numerology and the positions of the patch panels. This defines the number of MT conenctors required. The numbers are summaried here and are available as a  a note.
5. Harness production and test equipment. Jan Trsoka outlined the current status. The project has been split into barrel and forward. The specifications have been agreed. The VME modules required are being designed or are already in production. See copies of the transparencies for more details.
6. Opto Links for the System  test. Jan Troska discussed different options. It was agreed that we should aim to integrate the opto-packages into a real harness. The first harness should contain dog-legs of the opposite handedness to the current system test dog-legs. This should be reviewed in Feburary and if neccessary we should produce some opto-apckages on existing style dog-legs. For the forward system tests it was proposed that we should extend the opto-plgin board to provide strain relief for the fibres. It was proposed that we should use oversleaving on the bare fibres (barrel and forward). See copies of the transparencies for more details.
7. Opto-flex cables.  A proposal for the mechanical design from Eric Perin was shown. The dog-leg is fixed to the bracket in an adjustable way that can accommodate the lack of precision in the position of the connector on the module pig-tail. Mechanical trails will be performed with dog-legs and dummy modules mounted onto the prototype sector. ESPI measurements in an environmental chamber in Oxford will be used to determine the distortions when the system is cooled down. If the distortions are too large then loops will be inserted into the low mas tapes to accommodate the contraction on cool-down. A proposal to remove unwanted lines on the dog-leg and conenctor was made. The new design will be made available on the web for detailed comments. See copies of the transparencies for a picture of a plastic cover used for the system tests.
8.  low mass tape to opto-flex connection. Tony Weidberg reported on the progress in the design and tests. Follwoing a suggestion by Marko Mikuz a simplified design for the connection which does not require a bridge piece is being considered. Rob Millea is performing systematic trials of the connection. A few samples have been successfully soldered using a pulsed thermode. The next steps will require us to purchase a pulsed thermode and do high statistics studies. See copies of the transparencies for more details.
9. Opto-package cover. Janet Fraser reported on ideas for the cover for the opto-package. See copies of the transparencies for more details.
10. ASIC status. Tony Weidberg reported on the ASIC status.

(a) VDC radiation tests have been completed successfully. DORIC4A still needs to be radiation tested.
(b) BPM-4B is due back in December. This should be the same as BPM-4A except that the output current should be asjustable.
(c) DRX-12 is due back in Decmber. This should be the final prototype.
(d) BPM-12 should be submitted on 2nd December. There are many changes compared to BPM4-B. See copies of the transparencies for more detauls.
11. OptoIF and BOC status. Maurice. Goodrick reported on the status of the MITEL VCSEL and PIN arrays. 12 channel arrays are now available on small PCBs suitbable for surface mouting (with a reflow machine). The schedule for OptoIF, BOC0 and BOC1 was presented. See copies of the transparencies for more details.
12. Opto plug-in for forward system tests. Fred Hartjes reported on the current status. The VCSEL perofrmance as good but the PIN responsivity was only 0.13 A/W. This is under investigation. See copies of the transparencies for more details.