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{\large {\bf Update}}\\[2mm]
Silicon Detector Developments
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\makebox[2.5cm][l]{Author:} Brian Fulton\\[2mm]
\makebox[2.5cm][l]{Date:} 27 April 1992\\[2mm]
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Distribution: \parbox[t]{12cm}{
WNC,NMC,PVD,BRF,RAH,JSL,WDMR,GT,DLW\\
(with Agenda for meeting of 29 April 1992.)
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{\large {\bf Silicon Detector News}} \\[1cm]
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Letters were sent out to manufacturers at the beginning of 
March.   There have been a number of follow-up discussions 
since then.   The present state is:
 
\begin{itemize} 

\item	Q-Par Angus\\[2mm]
 
Order placed.   Two prototype 50$\times $50 mm surface barrier 
detectors to the Japanese design due for delivery in the next 
couple of weeks.   One device will have "low" sheet 
resistance (~1k$\Omega $ per square) and one "high" resistance 
(~15k$\Omega $ per square) to allow us to check the trade off 
between good resolution (high resistance) and short 
collection times (low resolution).
 
 
\item  Micron\\[2mm]
 
Quotation received for prototype 50$\times $50 mm ion implanted 
detector to the Japanese design.   No order placed as yet.
 
An alternative design detector has been given on loan for 
tests.   This is a flight test device made to a NASA 
specification.   It is essentially a double sided strip detector 
with the stips on each side connected via discrete interstrip 
resistors laid down on the PCB mount.   Position 
information obtained from standard resistance division and 
energy from summing the signals on each side.   Strip pitch 
is 500 microns with 125 strips on each side (60$\times $60 mm).   
Thickness 140 $\mu $m.
 
\newpage
\item	Canberra\\[2mm]
 
Response received from Paul Burger at the factory with 
some questions and these discussed with the UK sales 
engineer (Sally Davies).   Awaiting response to these.   Also 
discussed with Sally Davies the possibility of obtaining 
devices such as the Micron/NASA design from them.   They 
do double sided strip detectors already (called PAD detectors 
in their vocabulary) and may be able to put the interstrip 
resistors in place.   Awaiting a response on this.   In any 
case, they would appear to be a suitable source for PSSSD's 
and DSSSD's in future.
 
 
\item	Hamamatsu\\[2mm]
 
Order placed for 60$\times $60 mm ion implanted detector to the 
Japanese design (it is in fact the device made for RIKEN but 
without the inter connector resistive strips).    Due for 
delivery in May.   This will allow us to check their "quality" 
and also see the effect of distortion without the inter 
connector strips.
 
 
 
 
 
\item	Intertechnique\\[2mm]
 
Discussion with their sales engineer (Mary Laport).   She 
has promised to send us a sample detector of the design they 
have made for the Italian group for testing (50$\times $50 mm ion 
implanted but without the inter contact resistive strips).   
Also discussed the strip detector idea with her and they will 
get back on this.
 
 
\end{itemize} 
 
 
It looks like we will have a number of devices to test within 
the next month or so.   I have mentioned to Garry Tungate 
that we could use any "spare" beamtime for this if there are 
gaps in the schedule.   [I will also put in a request to the next 
Programme Panel meeting for detector test time].   The main 
decision looks likely to be whether we go for the 
interconnected strip detector design or the resistive charge 
division.   Some discussion on this would be welcome.   If 
we do go for the resistive charge division then we will also 
have to decide on a suitable resistance value - a choice linked 
to the tests on charge collection times and the decision on 
whether to go for gated integration in the electronics.\\[1cm]
 
 
 
Brian Fulton


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