sPHENIX HCal discussion

[Michael Lenz <mlenz AT rcf.rhic.bnl.gov>]

Thank you Ed!  Then unless there are any objections, I will start 
loading the new inner HCAL with tiles starting tomorrow (just need more 
tile retainer clips).  I will chart where each tiles resides. The covers 
(as I said earlier) should be done by Friday (God willing !) :-)


On 12/18/2017 12:47 PM, Edward Kistenev wrote:
> Hi, everyone.
>
> I may already confirm that tiles are consistent within 20% even before they 
> are out of the boxes. Tiles are all labeled, label is scannable using your 
> smart phone, it is also linked to the data base entry on a server at UNIPLAST 
> (VLADIMIR). One may immediately see all data on geometrical dimensions of 
> tile, measure of luminosity and measure of light attenuation in scintillator 
> on his/her screen.
>
> In the last few days I made an efoort to quickly calibrate tiles from one of 
> the boxes (using tiles from Small-30 subset, meaning HInner, tile #30 in 
> Richie’s parlance). I used two different setups and two different sets of 
> SiPM’s coupled to DT5702 CAEN DAQ board. Both SiPM sets (from GSM and 
> recently from Sean) were supposed to be matched within  the set. As it 
> happened both sets are either not matched and/or the individual channels  in 
> DT5702 are mismatched too (even when all controls are set to the same 
> numbers). Likely the biggest part of the problem is mismatch in the CAEN 
> channel’s calibration (preamps and/or bias generators). When tiles are moved 
> one-by-one through the same input channel of the board the measured light 
> emission in response to cosmic exitation is nearly the same for every tested 
> tile (10 tiles).
>
> What is not yet tested  is uniformity of LED light delivery to tiles but that 
> can be done even with tiles loaded into detector.
>
> Conclusion 1:  with good probability tiles in the boxes could be installed 
> into detector even without further testing (unknown 20% ( 6% rms) in tile 
> average luminosity) - wisual inspection and dust removal from fiber area 
> should be sufficiens.
>
> Conclusion 2:  unfortunately "as is" both setups which I used - one around 
> GSM built SiPM interface board and second with individual SiPM’s installed on 
> individual tiles  in a way similar to how it will be done in the future HCal are not 
> ready - need quite a bit of work.
>
>                         Edward
>
>                         
>
> On Dec 18, 2017, at 11:16 AM, Michael Lenz <mlenz AT rcf.rhic.bnl.gov> wrote:
>
> I will be happy to install all tiles in the new inner as soon as they are 
> available and I have a map of where they go. I am working on covers now and 
> should be done by Friday.