From: Ken Bell [Ken.Bell@cern.ch]
Sent: 29 April 2003 13:38
To: Jordan Nash; Dave Cockerill; Bob Brown
Cc: Martin Sproston
Subject: Re: FW: Rack Requirements for EC HV

Hi Jordan,

Martin & I have just done a quick pessimistic "ab initio" calculation.
* Assume 2 endcaps fully autonomous & in different racks
* Assume Bob's independent Dynode & Anode HV per quadrant
* Assume the multiway HV connectors developed for ATLAS ECAL
  (04.31.52 series in CERN stores)

==> Per EE Quadrant
    1 2U Anode  distributuion unit
    1 2U Dynode distributuion unit

==> Per endcap
    4 x 4U of HV distribution
    1 x 10U of one Nimbin & airflow  (Struck/ISEG NIM HV supplies)  

==> 26U per endcap  (cf 56U per CMS Rack)

==> One EE HV rack per endcap, svp.    


Ah, and if we very pessimistically go for one SHV per supercrystal
(which we anyway can't afford...)
then we reckon we can get 3 rows of 13 across inna 2U distribution
unit, so 78 supercrystals per quadrant need 4U Anode & 4U Dynode,
so our distribution needs double to 32U per endcap,

==> 42U per endcap needed including HV supplies.

So we're STILL safe with 

************************************
  One EE HV rack per endcap, svp.
************************************

OK ???

Regards - Ken "No idea where 6-10 racks came from!".

On Tue, 29 Apr 2003, Brown, RM (Bob)  - PPD wrote:

> Ken/Martin, can we do a quick back-of-the-envelope estimate for Jordan?
> 
> 6-10 racks sounds rather generous.
> 
> Bob. 
> 
> -----Original Message-----
> From: Jordan Nash [mailto:Jordan.Nash@cern.ch]
> Sent: 29 April 2003 11:27
> To: Dave Cockerill; Bob Brown
> Subject: Rack Requirements for EC HV
> 
> 
> Dear Dave and Bob,
>    Could one of you point me to how I could verify the Rack and Crate 
> requirements for
> the Endcap High Voltage system.  At the moment something like 6-10 Racks 
> are reserved
> for EC HV and I want to verify what is actually required, and what the 
> envisioned layout
> might be
> Many Thanks
> Jordan
>