Program to develop a Kapton-PG/Be hybrid for the ATLAS SCT
(Draft by KEK, UCSC, QMW, ...)


Scope: develop an alternative to the baseline BeO hybrid by a bridge of
PG/Be with a Kapton hybrid.

Advantages: 

(1) Savings in radiation length (see the tables by R.Apsimon presented
    at the Santa Cruz meeting), maximum difference by 0.15% Xo(with 0.5 mm
    Beryllium) in the 1.3 % Xo of the Barrel module (overlap included)

(2) Superior thermal properties in hybrid by PG, comparable thermal
    properties by Beryllium
	
(3) Superior electrical conductivity by Copper (about 3 times with an
    equivalent radiation length of Gold)
	
(4) One piece construction of hybrids and Kapton cables (i.e.,
    wraparound and pig- tail), which has two advantages:
	
    - the width of the hybrid is not limited by the width of
      connections of the hybrid and the cables,
	  
    - eliminating the soldering process of the hybrid and the Kapton
      cables, which saves the assembly cost/man power and the vulnerable
      connection of the Kapton soldering (for any bending near the 
      solder may damage the Copper traces)


Tasks and volunteers:

1) Kapton hybrid   
   
   1.1) for CAFE-M and ABC

Definition of pigtail and wrap-around           A. Carter/ N. Unno
Layout of Kapton hybrid                         UCSC
Fab' of Kapton                                  KEK / UCSC
Loading of Kapton hybrid                        UCSC / KEK
Support card(s)                                 UCSC
Testing of Kapton hybrid                        UCSC / KEK / QMW

   1.2) for ABCD

Definition of pigtail and wrap-around           A. Carter/ N. Unno
Layout of Kapton hybrid                         KEK / Oslo
Fab' of Kapton                                  KEK / UCSC
Loading of Kapton hybrid                        KEK / UCSC
Support card(s)                                 UCSC
Testing of Kapton hybrid                        KEK / UCSC / QMW

2) Bridge

If PG is proven mechanically acceptable, PG is the choice of the bridge
(unless radiation length increases considerably)

   2.1) PG

Thermal simulations                             T. Kondo
Layout of bridge                                QMW / KEK
Encapsulation of PG                             A. Carter / Bill Miller
Fab. of PG bridge                               A. Carter

   2.2) Be

Thermal simulations                             T. Kondo
Layout of bridge                                KEK / QMW
Fab. of Be bridge                               KEK

3) Module(s)

PROPOSE to assemble 2 modules and irradiate one and beam test both

Thermal simulation and layout of PG heat spreader 	T. Kondo
Design BeO stiffener of PG/Be "ear"             	KEK
Layout of module, electrical and thermal connections 	KEK / QMW
Fab. of PG heat spreader                             	KEK / RAL
Supply of 2*4 detectors                              	KEK / UK
Assembly of module(s)                                	KEK / UK
Electrical Test of modules                           	KEK / UCSC 
							RAL / Cambridge
Thermal Test of modules                              	KEK / RAL / Oxford

4) Time scale

Tasks 1) and 2) 				End of October
Task 3)						End of November
KEK beam test					Jan. 98