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{\large {\bf Electronics}}\\[2mm]
Revised Cost Estimates
}}\\[7mm]
\makebox[2.5cm][l]{Author:} R.A. Hunt\\[2mm]
\makebox[2.5cm][l]{Date:} 1 September 1993\\[2mm]
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\centerline {\bf Revised Estimates for Channel Amplifiers and Control}
\bigskip\noindent
{\bf Introduction}
\smallskip\par
Estimates presented in June 1993 were based on an assumption that
the final 320 channel array would be simply an extension of the 32 channel
prototype. This used the original amplifier design which now included
remote control for gain, pole zero and discriminator threshold. The amplifier
was supported by a control module which processed the analogue output and
also controlled the selection of the channel within an event.  
\smallskip\par
After further investigation it now appears that we can obtain a higher density
and lower cost by rearranging the functions of a control module into groups
of eight and shifting certain system features into Camac.
A revised layout would fit 32 amplifier channels into a Eurocrate
along with four modules to control selection of channels in an event
and four modules to convert amplitude to time. The pile-up
indication would be placed directly within Camac along with an interface for
remote control.
These two Camac modules would each handle 32 channels.
\smallskip\par
Redesign of the system is mainly concerned with re-packaging
existing functions to get
a better balance between keeping interconnections at a minimum but saving
on common support circuits by grouping similar functions together.
\smallskip\par
In the revised scheme the amplifier has been extended to include the
analogue processing circuit along with the gate generation circuit. The analogue
output from the amplifier is then less dependent on the time relation of its
digital discriminator output and this eases the task of both selecting a set
of channels within an event and converting amplitude into a digital value.
\smallskip\par
There are now five parameters within each amplifier which are under remote
control: Gain, Pole Zero, Discriminator, Gate Width and Integrator Time
Constant.
These are controlled by a Camac Control Interface module which is
connected in a daisy chain fashion to 32 amplifiers. Non-volatile devices are
used at each amplifier to ensure that the current settings are preserved
following a power interruption.
\smallskip\par
The remaining functions of the Channel Control are re-packaged into three
modules with an overall reduction in the cost and an increase in density.
The generation of Walk signals and the associated Accept levels to mark
channels within an event are grouped into an eight channel unit while the
Conversion of Amplitude to Time is separated in another eight group unit.
\smallskip\par
This rearrangement makes better use of common circuitry at a slight increase
in the number of interconnections. The overall result will reduce costs by
around 20\% and enable 32 channels to be placed in a single crate.
Detection of Pile-Up from 32 channels is arranged directly in a Camac
module which is read immediately after the TDC output has been processed
\vfill\eject
\bigskip\noindent
\bigskip\noindent
{\bf Extended Amplifier}
\smallskip\par
The component and production costs for building an Amplifier are estimated at
 \pounds 176 for each unit. This includes the charge of \pounds 3200
 for rearranging 
the PCB layout and manufacture of 320 boards. The total cost of building 320
Amplifiers is then \pounds 56320
\bigskip\noindent


\bigskip\noindent
{\bf Walk and Accept module}
\smallskip\par
The component cost is \pounds 240 and the ancillary cost is \pounds 60. The
PCB artwork is estimated at \pounds 25 and the final assembly cost is
\pounds 45. These estimates give a unit cost of \pounds 370 and a total
cost of \pounds 14800 for 40 units.
\bigskip\noindent
\bigskip\noindent
{\bf Conversion module}
\smallskip\par
The component cost is \pounds 170 and the ancillary cost is \pounds 60. The
PCB artwork is estimated at \pounds 25 and the final assembly cost is
\pounds 45. These estimates give a unit cost of \pounds 300 and a total
cost of \pounds 12000 for 40 units.
\bigskip\noindent

\bigskip\noindent
{\bf Pile-Up Recording Interface}
\smallskip\par
The component cost of this module is expected to be  \pounds 500
giving a final cost for 10 units
\pounds 5000
\bigskip\noindent

\bigskip\noindent
{\bf Channel Control Interface}
\smallskip\par
The component cost of this module is expected to be  \pounds 400
giving a final cost for 10 units
\pounds 4000
\bigskip\noindent

\bigskip\noindent
{\bf Sample-hold/Integrator}
\smallskip\par
We have been quoted \pounds 63 for the Silena Sample/Hold sub-circuit based
on a quantity of 100 and it is estimated that for a quantity of 320 the price
might be reduced to \pounds 45. An alternative Integrator board is priced at
\pounds 25 based on a quantity of 320 units.
\bigskip\noindent

\bigskip\noindent
{\bf Powered Crates}
\smallskip\par
The component costs for building a crate with power supply is estimated at
\pounds 1149 for component and ancillary costs and \pounds 500 for 
production giving a unit cost of \pounds 1649.
Only 10 units will be required to house 320 channels in the revised scheme
this yields a total cost of \pounds 16490.
\vfill\eject
\bigskip\noindent
{\bf Summary and Comparison}
\smallskip\par
The original estimate
%\magnification=\magstep 1
$$\vbox{\halign{
#\hfil\quad&
#\hfil\quad&
#\hfil\quad&
#\hfil\quad\cr
{\bf Channel Amplifier}&\pounds 161& 320 off&\pounds 51520\cr
{\bf Channel Control}&\pounds 179& 320 off&\pounds 57280\cr
{\bf Channel Interface}&\pounds 150& 20 off&\pounds 3000\cr
{\bf Powered Crate}&\pounds 1649& 20 off&\pounds 32980\cr
&&&\cr
{\bf Sub total}&&&\pounds 144780\cr
&&&\cr
}}$$
\bigskip
The revised estimate
%\magnification=\magstep 1
$$\vbox{\halign{
#\hfil\quad&
#\hfil\quad&
#\hfil\quad&
#\hfil\quad\cr
{\bf Channel Amplifier}&\pounds 176& 320 off&\pounds 56320\cr
{\bf Walk and Accept}&\pounds 370& 40 off&\pounds 14800\cr
{\bf Convert Amplitude/Time}&\pounds 300& 40 off&\pounds 12000\cr
{\bf Pile-Up Recorder}&\pounds 500& 10 off&\pounds 5000\cr
{\bf Parameter Control}&\pounds 400& 10 off&\pounds 4000\cr
{\bf Powered Crate}&\pounds 1649& 10 off&\pounds 16490\cr
&&&\cr
{\bf Sub total}&&&{\bf \it \pounds }108610\cr
&&&\cr
}}$$
\bigskip
Additional costs unchanged by revision
%\magnification=\magstep 1
$$\vbox{\halign{
#\hfil\quad&
#\hfil\quad&
#\hfil\quad&
#\hfil\quad\cr
{\bf Sample/Hold Silena}&\pounds 45& 320 off&\pounds 14400\cr
&or&&\cr
{\bf Integrator}&\pounds 25& 320 off&\pounds 8000\cr
}}$$
\bigskip
\bigskip
\centerline{\bf R Hunt and D Savory 1st September 1993 }

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