Spurious PE entries in Hcal hits at around 817 PE

[EinarElen]

As noted by @jpasc27 and @mrsolt, we seem to have some odd entries in the HCal rechits with occasional photoelectrons > what you get at max ADC (see Jessica's talk at the 2023 spring collaboration meeting slide 5).

As far as I understood it, Jessica does not take the maxPE hits from the veto processor so this should be unrelated to LDMX-Software/Hcal#58. It also looks like the hits always have the same value, which wouldn't make sense if it was LDMX-Software/Hcal#58. Unclear if it is related to LDMX-Software/ldmx-sw#1348

I tested this quickly with a neutron gun while working on the HCal DQM today and can confirm that I'm getting the same thing.

All of the RecHits included in the figure above are from the Back HCal.

[EinarElen]

Some details on one of the RecHits in question...

HcalHit { id: 18000414,  energy: 55.9885MeV, time: 36.5234ns, amplitude: 0, pe: 817}

Hit ID corresponds to section 0, layer 1, strip 20 so nothing looks immediately suspicious here other than the 0 amplitude.

{<ldmx::HcalAbstractID> = {<ldmx::DetectorID> = {static SUBDETECTORID_MASK = 63, static SUBDETECTORID_SHIFT = 26,
      static SUBDETECTOR_PAYLOAD_MASK = 67108863, id_ = 402654228}, static BAR_TYPE_MASK = 7, static BAR_TYPE_SHIFT = 23, static HCAL_PAYLOAD_MASK = 8388607},
  static SECTION_MASK = 7, static SECTION_SHIFT = 18, static LAYER_MASK = 255, static LAYER_SHIFT = 10, static STRIP_MASK = 255, static STRIP_SHIFT = 0}

Looking more closely:

• isADC -1700121632 (hmm...)
• isNoise false
• minpe 0 (really odd if the other end has 800!)
• xpos -6847.9707 (!!)
• ypos 25
• zpos 879 (think that matches the layer above more or less)

Given the xpos value, I now very much think that this is the same issue as LDMX-Software/ldmx-sw#1348. Interesting to see that these entries might have bogus values for isADC!

[EinarElen]

Last comment can be ignored, isADC is always containing junk :(

This does mean that isTOT is always false, since it is defined as !isADC

[tvami]

I tested this quickly with a neutron gun while working on the HCal DQM today and can confirm that I'm getting the same thing.

@EinarElen can you show what you did to reproduce this? I'm wondering if this issue is gone now with having all the initializations fixed?