General EEEMCal Meeting Summary 2/25/22

PARTICIPANTS: Carlos, Irina, Renee, Silvia, Vardan, Vladimir, Tanja, Olivier, Hamlet

R&D UPDATES

READOUT

• JLab prototype tests 2022: planning to test SiPM array configurations

• Array of 16 SiPM (Hamamatsu S14160-3010PS) per PWO block based on BCAL/Hall D array configuration
• Array of 16 SiPM (Hamamatsu S14160-6050HS) per SciGlass block based on BCAL/Hall D array. As an alternative considering the Hamamatsu provided 4x4 array.

• IJCLab-Orsay: planning tests in 2022 of reading out SiPM with ASIC

MECHANICAL DESIGN

• Concept idea of an insert for the EEEMCAL to reach to the highest eta ~-3.7.

• In this concept design the insert is installed at the location of the EEEMCAL and is fixed in place.
• The EEEMCAL is installed behind the insert and can be removed by sliding it out.
• To address any gaps in homogeneous electron detection in the backward direction (EEEMCAL and barrel EMCAL) in this design additional EMCal capabilities around the insert at larger radii may be necessary.

• Discussion of the concept idea of an insert for the EEEMCAL

• Increase of acceptance needs to be balanced with feasibility of cluster analysis across boundaries
• How does having an insert impact the physics?
• Is there a way to split open the EEEMCAL into two pieces (clam shell design) and merge the insert with the EEEMCAL?
• How does the fixed insert impact the beamline - is it even allowed to have the blocks close to vacuum pipe?
• Geant Mesh could be a good option for simulating complex designs in GEANT4 - works directly from CAD drawing step file
• If splitting EEEMCAL in two pieces this may have less of an impact on clusters, and so physics, than having a separate insert - needs to be verified

• Action items

• Check if insert EEEMCAL is ok for beamline
• Check if EEEMCAL can be split apart in the middle and incorporate the insert
• Simulation of impact of insert vs splitting EEECAL in two pieces on physics

PROTOTYPES

DESY

• Preparing for prototype test in May - the overall plan:

• long horizontal scans at various vertical positions with the PbWO4 using CAEN QDC and Digitizer in parallel (3 days)
• The same thing with FADC250 triggered and streaming readout (3 days).
• Then switch to simpler scans swapping the central crystals with the SciGlass and PbWO4 alternating at various temperatures (4 days).
• If there is time, rotate the calorimeter to study the effect of incident angle (1 day).
• A lower priority would be to place various thicknesses of absorber before the calorimeter (1 day).

• Assuming 1 day for setup and 1 day to clean up and pack the entire test is expected to take 2 weeks.

JLAB

• Next prototype beam tests are planned for the fall 2022 - the overall plan:

• measure energy resolution of 40cm long SciGlass in 3x3 array prototype
• measure energy resolution with SiPM readout for 4x4 arrays of SiPMs per block (10um pixel for PWO, 50um SciGlass) based on BCAL design from Hall D for a 3x3 prototupe with PWO 20cm long crystals and a 3x3 SciGlass prototype
• commission the Crytur 3x3 prototype with Crytur PWO crystals and in-house designed arrays of SiPMs

• Crytur prototype preparations - investigating options for reducing power/heating

• presently testing a reduction by factor 16
• discussion about options for outside cooling

• water cooling - chiller
• dry air - need to check with Hall D

• planning tests at JLab on test bench before installing in the hall - could be as soon as May

RADIATOR SPECIFICATIONS

• Discussion of list of specifications for PWO and SciGlass

• include resistance to hadron radiation - how to quantify?
• current measurements are carried out at 18degC
• current measurements are carried out for 100ns integration gate
• add emission peak for both PWO and SciGlass
• transmission longitudinal and transverse captures uniformity of material
• resolution not part of the specifications to vendor, but measurements with prototype are needed
• quote all specifications for the radiation length that the calorimeter will use and leave open spaces or put question marks where specification values are still being determined

• Projectivity of SciGlass blocks

• Sasha Bazilevsky gave a presentation on pi0/gamma discrimination (https://indico.bnl.gov/event/14906/contributions/60352/attachments/39871/66237/athena_pi0g_16feb22.pdf) that suggests that both PWO and SciGlass in EEEMCAL are showing excellent and adequate performance. To improve SciGlass performance it seems that projectivity can help.

NEXT MEETING: FRIDAY 18 MARCH AT 8:00AM ET