sPHENIX HCal discussion

["Huang, Jin" <jhuang AT bnl.gov>]

Hi Megan and all

 

Yes, in simulation, photo-electron per ADU conversion factors of 32/5 and 16/5 are currently used for inner and outer HCal, respectively, following the original design at the test beam era:

• Out: https://github.com/sPHENIX-Collaboration/macros/blob/master/common/G4_HcalOut_ref.C#L189
• In: https://github.com/sPHENIX-Collaboration/macros/blob/master/common/G4_HcalIn_ref.C#L260

 

> Now that factor is 32 for both inner and Outer electronics. My conclusion is that we need to update this factor to 32 for outer HCal in the outer HCal simulation.

 

First a caution :  from the preamp block diagram below, changing high gain channel’s gain does not necessarily change the gain for the nominal operation at the low gain channel. Nonetheless, I think the general statement is correct, the photo-electron per ADU conversion factors should be (High gain of 32)/(single photon peak at high gain mode in ADU). Nonetheless, John probably can best comment on it.

 

 

 

One more thing: as you can see, some of the HCal digitization factors in simulation are based on guess work of the past. If we have measurement of the actual value, e.g. pedestal width, gains, photon yield, please make an pull request to have them updated.

 

Cheers

 

Jin

 

 

______________________________

 

Jin HUANG

 

Physicist, Ph.D.

Brookhaven National Laboratory

Physics Department, Bldg 510 C

Upton, NY 11973-5000

 

Office: 631-344-5898

Cell:   757-604-9946

______________________________

 

From: Megan Connors <meganeconnors AT gmail.com>
Sent: Thursday, March 24, 2022 5:02 PM
To: Huang, Jin <jhuang AT bnl.gov>; Haggerty, John <haggerty AT bnl.gov>; sphenix-hcal-l AT lists.bnl.gov
Subject: Gain Factors in HCal Simulation

 

Hi Jin and John,

 

I'm hoping you can help clarify a question that came up during the calibration meeting today. Shuhang showed the slide below that includes a 5/16 factor. I believe the 5 comes from the single pixel peak of 5 ADC we measured. The 16 is the factor between high and low gain. The test beam paper we state that the factor is 16 for the outer HCal and 32 for inner. Now that factor is 32 for both inner and Outer electronics. My conclusion is that we need to update this factor to 32 for outer HCal in the outer HCal simulation. Does this all sound correct to you? Any other insight to these factors in the simulation are appreciated.

 

 

Best,

-Megan

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