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         Requirements for SCT glues and a plan of investigation
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  1. Introduction

   Below are given the requirements and plans for establishing what glues
  are to be used in module production. PLEASE send us NOW your comments 
  on these, and in particular:
      * details of tests you have already carried out
      * a list of items you can have ready for irradiation in the 
        coming PS run starting on 31st AUGUST.
  
  2. Requirements

  The SCT silicon strip modules require glues for adhering together various 
 surfaces, with four specific examples having particular importance. These
 are given below, and there may be others.

 (a) Detector to coated TPG-baseboard
 (b) ceramic to coated TPG baseboard
 (c) Hybrids to BeO facings
 (d) ASICS to the hybrid surface
 
  The details concerning electrical and thermal conductivity must be 
 clarified and defined for (a) and (d). In connection with radiation hardness,
 all such interfaces must be studied after they receive the full SCT irradiation
 dose of 3*10^14 p/cm^2. We refer to this as the F(ull)A(TLAS)IR(radiation)
 dose[FAIR].

  In each case the glues must fulfil the following criteria:
     (a) be unaffected by irradiation up to the FAIR dose
     (b) allow all the necessary thermo-mechanical  properties
     (c) have an application process compatible with module construction


  3. Plan of investigation

   (a) Irradiation programme

  Each glued system after the FAIR dose must be tested for sustained : 
   (i)  adhesive strength, 
   (ii) mechanical properties, and moduli
   (iii)electrical performance in the case of silicon detectors and ASICs

 
   (b) Thermo-mechanical performance

  Each glued system should be subjected to measurements of:
   (i)  combined thermal conductivity
   (ii) composite thermal and humidity expansion
   (iii)mechanical moduli as a function of thermal cycling


   (c) Application evaluation

   Each glue application requires specifications of :
    (i)  application procedure
    (ii) curing temperature
    (iii)curing time
    (iv) any special precautions, either due to nature of glue
         or in silicon wafer case due to sensitivity of component items

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