Re: HV distribution update

["Fernando J. Barbosa" <barbosa@jlab.org>]

Hi Elton,

That's a good idea.

On the FDC, one wire plane is fed from 4 HV channels (sense), with the 
wires close to the beam grouped less densely than the wires away from 
the beam. Dan has looked at this and performed some calculations based 
on rates. The HV is distributed via the PCBs (HVTBs). Dan has also 
looked at failure scenarios but it is worth reviewing this issue again.

On the CDC, there is more freedom to choose which wires are connected to 
one HV channel through the HVB card. The limitation is on the length of 
the cables connecting the straws to the card. I don't recall seeing a 
study on the failure modes for the CDC in this regard but I believe 
Curtis and Yves are looking at this.

Regards,
Fernando



Elton Smith wrote:
> Hi Fernando et al.,
>
> With the new arrangement of HV cards, has anyone looked at the impact on
> tracking from the dead region when a channel trips off? If not, it might
> be useful to go through an exercise of failure scenarios with a given
> mapping for the HV.
>
> Thanks, Elton.
>
>
> -------------------------------------------------------------------
> Hello everyone,
>
> I have updated the HV distribution document (GlueX-doc-967, also
> accessed through the electronics wiki) to reflect the HV connectors and
> HV power supply modules specified for construction. I have also
> forwarded the connector specs to Bill and Slava.
>
> The FDC has been impacted by grouping a larger number of wires (sense
> and field) which now requires 4 HV channels per wire plane, instead of
> 6. In this manner, one FDC package requires one +HV module and one -HV
> module with two multi-pin HV connectors.
>
> The CDC requires 6 multi-pin HV connectors, instead of 4, because each
> HVB is fed by a +HV channel.
>
> Regards,
> Fernando
>
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