From: Mark Raymond [m.raymond@imperial.ac.uk]
Sent: 14 October 2005 09:27
To: Lodge, AB (Tony); Bell, KW (Ken); Shepherd-Themistocleous, CH
(Claire); Matthew Ryan (E-mail)
Cc: Cockerill, DJA (David); Greenhalgh, RJS (Justin); Brown, RM (Bob) -
PPD
Subject: Re: 

Attachments: Prot_res_studies.pdf

Hi Tony,

Your summary looks OK to me. If you are sure that there is no way to put the series
resistor on the anode side of the blocking capacitor then fair enough, but there is
a small advantage to putting it there as you saw in my note (attached again in case
someone else has not yet seen it), particularly if we wanted to increase its value 
for sparking protection reasons.

Cheers, Mark.



At 16:39 13/10/2005, Lodge, AB \(Tony\) wrote:
>Hi All,
>I would just like to summarise my understanding of the agreements reach 
>during Marks visit to RAL last week, concerning the HV Filter Cards and 
>components.
>Agreements were as follows:
>
>1/ We would use the following RS Comps recommended alternatives for the 
>HV Resistors.
>                 a) 10Mohm HV (RS176 - 7956) would be replaced by 
>10Mohm  HV (RS 484-4595).
>                 b) 22Mohm HV (RS176 - 8000) would be replaced by 
>22Mohm  HV (RS 484-4602).
>                 c) 10Mohm LV (RS135 - 667) would be replaced by 10Mohm 
>HV  (RS 484-4595).
>                 d) 1nf HV Filter Capacitors would remain the same  
>(RS177-316).
>                 e) 1nf HV blocking Capacitor (RS177-316) would be  
>replaced by 470nf HV (RS 117-300).
>
>It should be noted that RS Components Sales representative has informed 
>me that the recommended alternatives are in fact the same components, 
>but just different packing quantities and therefore different stock numbers.
>
>2/ The 100 ohm series resistor would be a 100 ohm LV (RS131 - 132) type 
>resistor. This resistor will be located on the LV (VFE) side of the 
>blocking capacitor.
>
>3/ The PCB ident would be re-done and started at R1, C1 through to Rn, Cn etc.
>
>4/ The card would have the following name CMS ECAL EE HV Filter Card 
>Version 1.0. ( these being the first pre-production HV Cards).
>
>I propose to try and visit the PCB company next week to get them 
>started on the Artwork changes as stated above.
>I will also purchase all of the necessary components to manufacture the
>105 HV Cards(plus some more spare resistors and capacitors) for next 
>years Test Beam work.
>I will also request the company to manufacture the 105 HV Cards with 
>the components supplied by us.
>
>I will us FK75100 as the project number to fund this work, unless 
>otherwise instructed.
>
>If anyone disagrees with this summery and production plans they should 
>contact me ASAP, otherwise I will proceed as stated.
>
>Further discussions will be necessary to discuss the proposed future 
>plans for Radiation Testing of HV components, but It was agreed that 
>these discussions would not affect the agreements reached and stated 
>plan of action.
>
>Regards Tony.

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  Mark Raymond
  Blackett Laboratory
  Imperial College       phone: +20 7594 7799
  London SW7 2BW         fax: +20 7823 8830
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