(1) Radiation Tests.
    (a) PIN diodes.
    John Wilson reported on the continuation of the PIN Diode irradiation tests.
    Bulk silicon and epitaxial silicon PIN diodes were tested. Three packages
    for each type of PIN diode were tested and each package contained 3 PIN
    diodes. Results from the first irradiation at the Birmingham Dynamitron
    with up to 1.5 10**14 n/cm**2 were reported by Steve Oglesby at a previous
    meeting. These devices were subsequently irradiated with about 2 10**14
    n/cm**2 at ISIS. The performance of the epitaxial PIN diodes was very good
    as there was a small but acceptable increase in dark current and no
    significant further degradation of the response. The tests confirmed that
    the bulk silicon diodes are not radiation hard. 
    The PIN diodes were then irradiated with 3 10**14 protons at the PS. The
    full analysis of this data has not yet been performed but the first look at
    the raw data showed that the epitaxial PIN diodes showed no significant
    degradation. See the copies of the transparencies for more details.
    The measurements performed so far were all DC and Kurt Borrer suggested
    that rise and fall times should be measured. He suggested that this could
    be done with coax cables terminated into 50 Ohms and using a digital scope
    in averaging mode to reduce the noise. John Wilson will try to perform
    these measurements.
    
    The 120 PIN diodes on ceramic substrates for the high statistics radiation
    and lifetime tests have been ordered with GEC and delivery is expected in
    December. There was a first discussion of the required fluences and a
    proposal was made to irradiate half the devices to 2 10**14 n/cm**2 and the
    remaining half to 6 10**14 n/cm**2 at ISIS. The PS will not be available
    until September '98 so Allan Clark will look into the possibility of using
    300 MeV pions at PSI.
    
    (b) LDC and DORIC
    Four of each of the LDC and DORIC have been irradiated to 2 10**14 n/cm**2
    at ISIS. All chips showed correct functionality after the irradiation and
    Dave White's measurements of currents and voltages on the chips showed no
    significant variations with radiation. Dave's current all electrical set-up
    is not sufficiently sensitive to determine if there has been an increase in
    noise but this will be looked at when chips are bonded up to GEC packages.
    These chips have subsequently irradiated with 3 10**14 p/cm**2 at the PS.
    Another set of 3 chips of each type were also irradiated at the PS and
    these ones the DC voltages were applied. If these tests are successful then
    a very low dose rate irradiation will be performed with a Gamma source at
    Birmingham.
    
    
(2) Packaging
    (a) on-detector opto-electronics.
    Tony Weidberg showed the proposed changes to the GEC package and assembly
    scheme. The new device would have a minimum area silicon base plate and all
    the chips and decoupling capacitors would be placed on an alumina tile.
    This saves cost as it minimises the area of the silicon baseplate. It also
    minimises material and number of wire bonds as it would remove the need for
    an extra opto-board. In order to simplify handling of the devices and hence
    reduce costs, GEC proposed a "fibre last" assembly scheme in which fibres
    were inserted into the v-groves to measure the performance and then
    removed. We would then install the fibres during the assembly sequence.
    Concern was expressed about the reliability of this procedure and at the
    possible losses in assembly. These issues will be discussed when we visit
    GEC next week.
    (b) off-detector packaging.
    Tony Weidberg showed a photograph of the MT conectorised 8 way PIN diode
    array produced by AME (Norway) for the Stockholm Liquid Argon group. Such
    an array might be suitable for the ROD PIN diode receivers. To use this
    type of array we would need to spend some NRE to develop 12 wide arrays or
    to use 8 wide fibre ribbons.

(3) VCSEL plans
    There was an agreement with GEC to package VCSELs from Sandia in a similar
    way to the LEDs. Since then Kevin Lear has left Sandia to work for a spin
    off company Micro Optical. Tony Weidberg reported that he had talked to
    Kevin Lear and he was interested in producing devices for us but we would
    need to spend a significant sum of money on NRE. Efforts were being made to
    find this money. There will also be an atempt made at the Stockholm Optical
    Links Workshop to find other manufacturers prepared to sell us bare VCSELs.
      
(4) CMS Links.
    Allan Clark reported on discussions with Franocis Vasey and Stefanini. They
    have good results on radiation hardness of the laser diodes but some
    concerns with the InGaAsP PIN diodes. The devices are packaged with active
    alignment into monomode fibre by ITALTEL. There are plastic and ceramic
    packages. Work with a second source will start in the near future. The ROM
    cost is 180 FS/link.
    
(5) Overview of plans for '98.
    There was a discussion of a provisional program of work to complete
    the development of the links however no firm agreements were made.
    
(6) MOU
    There is no agreement on who will provide the deliverables but the
    following list of what was required and the proportion of spares was
    agreed:
    
    Item                          Number Required for SCT        +spare fraction       
    Optoelectronic package                   4088                      10% (*)
    with two LEDs and one PIN
    diode
       
    8m lengths of rad-hard 12 way            1022                      10%
    ribbon fibre with MT connectors
        
    80m radiation soft 12 way                1022                       5%  
    ribbon fibre with MT connectors
    
    PIN diodes+receiver amplifier+           8176                       10%
    control system for ROD end of 
    data link
    
    LED (or VCSELs) for sending TTC data     4088                       10%
    +BiPhase mark encoding ASIC+control
    electronics
    
(*) The spares fraction would have to be determined after more understanding     
    of assembly losses and reworkability issues. 
    
    
(7) AOB.
    John Dowell reported on the meeting on fibres held at CERN on 13/14 August.
    See copies of the transparencies for information on this subject.
        
(8) The date of the next meeting was fixed for 23rd October, to be held at
    Oxford or RAL.