sPHENIX HCal discussion

[pinkenburg <pinkenburg AT bnl.gov>]

Hi Stefan,

I looked at the presentations and they are a bit opaque to me but I 
think I get the general idea. I would make the software a secondary 
thought - there will always be some mapping to translate a channel to 
row/column, even if it is some one to one. In terms of how to set up the 
channel numbers I would concentrate more on monitoring/debugging needs 
when using raw data. If e.g. you run some packet ddump and the channel 
number tells you directly where some given tower is located rather than 
going through some geometry translation, there is value in that - or if 
it is easier to make a connection between slow control and a given tower.

Not sure if this helps - whatever makes running the hcal easier and more 
bullet proof should be done. Software can always be recompiled if you 
got something wrong even after you are done taking data.

Chris


On 1/4/2022 9:10 PM, Stefan Bathe via sPHENIX-HCal-l wrote:
> Dear All, (specifically Xiaochun, Eric, Chris)
>
> Xiaochun asked in today’s HCal Meeting about the HCal channel mapping for his 
> Geant simulation.  As far as I can tell, this was last discussed in the 
> 8/27/19 HCal Meeting:
>
> https://indico.bnl.gov/event/6688/
>
> where both Eric and I gave presentations on our ideas of how to map hardware 
> channels to digitizer channels.  I think we basically agreed.  In the end, 
> though, I think, it might be up to the software group (Chris?) to decide 
> which numbers to assign to the channels.  I guess the two options would be to 
> either adopt the digitizer channel numbering (no additional map needed, but 
> geometrically more complex) or to have numbers simply increment in z and phi 
> (geometrically simple, but additional map needed).
> The other open question is where to start counting.  Naturally one would like 
> to start counting at phi = 0 (and at the South end, so along the z axis).  
> But the sector at phi = 0 (and at phi = 180 degrees) have their outer radius 
> combs vertical.  Therefore phi = 0 is in the center of a sector, not at the 
> edge.  This would introduce an offset with respect to the digitizer channel 
> number, which is ugly.  The answer to this question might also depend on 
> which sectors get plugged into which digitizer boards/crates, which Eric and 
> Steve would know.  (I’m saying this because it might make sense to start 
> counting at channel 0 of a digitizer board.)
>
> Regards,
> Stefan
>   
> -
> ---------------------------------------------------------------------------------
> Stefan Bathe
> Professor of Physics
> Baruch College, CUNY
> and RIKEN Visiting Scientist
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Christopher H. Pinkenburg       ;    pinkenburg AT bnl.gov
                                ;    http://www.phenix.bnl.gov/~pinkenbu

Brookhaven National Laboratory  ;    phone: (631) 344-5692
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