sPHENIX HCal discussion

[Itaru Nakagawa <itaru AT bnl.gov>]

Hi all,

On 2015/10/22 1:02, Jamie Nagle wrote:
> Hello John (cc same sPHENIX lists),
>
> Our group in Colorado has divided up some of the pCDR chapters for 
> reading and will be sending comments later today.   Here I am just 
> sending comments on Chapter 8 - Data Acquisition and Trigger.   This 
> Chapter has some significant issues and may need some major 
> restructuring in order not to raise red flags to a review committee.
>
> Sincerely,
>
> Jamie
>
> 1.  First, my recommendation is that all Chapters should start with a 
> few sentences before the first subsection (e.g. 8.1) that lays out 
> what is covered in the Chapter and a brief summary.    Here is a list 
> of the key points I would have expected in the DAQ and Trigger Chapter
>
> In this Chapter we detail the architecture of the sPHENIX data 
> acquisition system and the requirements to achieve a 15 kHz data 
> accept and archive rate even in high multiplicity Au+Au at 200 GeV 
> collisions and with > 90% livetime.   In the case of Au+Au collisions, 
> we expect to record with only minimum bias triggers (i.e. a simple 
> interaction trigger) of order 100 billion events in a 22-week running 
> period.    There are also selective jet and photon triggers that can 
> sample additional physics from the entire luminosity.  In p+p and p+A 
> collisions at 200 GeV, selective triggers are detailed utilizing the 
> EMCal, HCal, and potentially from the tracking system.   ???

I actually consulted before. I have a plan to implement the trigger 
capability to the tracker, mainly for
high multiplicity events just like as I did for FVTX. Although I am not 
assigned to edit the trigger section,
can I edit the section by myself? If you have any request to add another 
features to the tracker trigger,
I am absolutely open to listen your request. Please let me know.

c)    Multiplicity trigger - this section will be opaque to the reader.  
The Figure 8.4 does not indicate p+p, nor does the text detail what 
physics is being pursued.    What might be quite interesting is a 
Level-1 silicon trigger that gives a z-vertex in Au+Au -- since we 
really need that....

The z-vertex reconstruction capability hasn't been considered yet, but I 
this is my concern as well.
If z-vertex can be a help to get rid of trigger bias by the multiple 
collision in the high multiplicity trigger.
I think it will be a matter of having power enough FPGA in LL1 to 
accommodate LUT which allows us
the sophisticated online tracking. Let me know if I am wrong.

Regards,
-itaru