Electron-Proton/Ion Collider Experiment

FarForward

EPIC Far-Forward Detector Subsystem Collaboration

Detector Subsystem Lead:

  • Alex Jentsch (ajentsch@bnl.gov)

Detector Subsystem Technical Contacts:

  • Zero-Degree Calorimeter: Yuji Goto (goto@bnl.gov)
  • B0 Tracker and EMCAL: Zvi Citron (zvi.citron@gmail.com)
  • Roman pots and Off-Momentum Detectors: Alex Jentsch (ajentsch@bnl.gov)

Meetings: INDICO on Tuesdays @ 9:00am EDT, unless noted otherwise via email.

File:ATHENA FF layout Nov 2021 v1.pdf

Far-Forward Sub-systems

  • B0 Silicon Tracker & Photon Tagger

The B0 tracker and photon tagger currently consists of 4 silicon tracking layer, with 2-3 layers being comprised of MAPS (< 20um spatial resolution), and 1-2 layers being comprised of AC-LGADs spaced evenly by 30cm inside the B0pf magnet bore in IP-6. After the silicon tracking system, either a silicon EM preshower, or a full PWO4 crystal EMCAL will be installed, depending on available space. Should engineering constratints preclude the latter, an upgrade or alternating technology implementation will be proposed (e.g. running periods with one or the other system installed).

The detector will need to be inserted/removed on the IP-side of the magnet bore. The detector space is warm and open to air, so routing the cabling and cooling components will be a little less challenging. The detector can slide in and out of the bore using a rail system like many other forward vertex trackers, e.g. STAR FST in the Forward Upgrade.

The below figure shows the basic angular acceptance for 100 GeV protons in the B0 tracking detector, with the current considerations for the available space. The space occupied by the electron components are still under design, so the acceptance loss in that region is still not finalized.

The below figure shows the baseline acceptance for the B0 detector for 100 GeV protons. The left pane is the generated proton sample, the middle pane is is the accepted protons, and the right pane is the occupancy in the first layer of the silicon.

File:B0 acceptances 100 gev.png


  • Roman Pots

Location: Station 1 @ z = 26m, station 2 at z = 28m

The Roman Pots detector subsystem consists of two stations, each with two layers, of AC-LGAD sensors bump bonded to ASICs, and surrounded by RF shielding foils. The whole package is then injected (vertically only) directly into the beam-line vacuum. The detectors will be injected a few millimeters from the beam (at 10Sigma), with the distance determined by the optics configuration in use for that run period. Currently the detector is ~12cm tall and ~26cm wide in total.

  • Off-Momentum Detectors

Location:

2 stations (separated by 2m) right after B1apf, inserted as Roman Pots detectors into beam line (horizontally).


The off-momentum detectors (OMD) are designed to capture charged particles (e.g. primarily protons) from nuclear breakup, where the protons have a different magnetic rigidity than the beam being used. These protons are then bent outside the beam pipe vacuum at some point along the drift. Implementing the OMD as horizontal Roman Pots detectors allows for a smoother transition for acceptance between the conventional Roman Pots detector, and the OMD.

  • Zero-Degree Calorimeter

The Zero-Degree Calorimeter (ZDC) is designed to capture neutrons and photons from various nuclear breakup and incoherent nuclear events. The EPIC ZDC consists of both a PWO4 and imaging W/Silicon EMCAL section, as well as an imaging and sampling Pb HCAL system.

The image below shows a 100 GeV neutron showering in the combined ECAL + HCAL used for the full ZDC.

File:ZDC EICroot neutron shower.png

Acceptance Summary

Caption text
Detector Acceptance Notes
Zero-Degree Calorimeter (ZDC) 𝜽 < 5.5 mrad (πœ‚ > 6) About 4.0 mrad at Ο• ~ πœ‹
Roman Pots (2 stations) 0.0* < 𝜽 < 5.0 mrad (πœ‚ > 6) 0.65 < 𝑝_(𝑧, π‘›π‘’π‘π‘™π‘’π‘œπ‘›)/𝑝_(𝑧, π‘π‘’π‘Žπ‘š) < 1.0 -- *10Οƒ cut
Off-Momentum Detectors (2 stations) 0.0 < 𝜽 < 5.0 mrad (πœ‚ > 6) Roughly 0.3 < 𝑝_(𝑧, π‘›π‘’π‘π‘™π‘’π‘œπ‘›)/𝑝_(𝑧, π‘π‘’π‘Žπ‘š) < 0.6
B0 Detector 5.5 < 𝜽 < 20.0 mrad (4.6 < πœ‚ < 5.9) Silicon tracking + EM preshower

Services and Support

Updated: 10/3/2022

Roman Pots

  • Detector packages are comprised of AC-LGADs, sandwiched with ASIC readout which is bump-bonded to the back of the sensor, and read out using ribbon cables. It's not clear if thee readout will be per-ASIC, or if 4 ASICs will be readout together (there are 4 ASICS per sensor). Supplying power to the ASICs is still being discussed.
  • Cooling will be achieved via thermal strips made of thin copper, which are bonded to the back of the ASICs, and cooled external to the vacuum using a small LN2 dewar. The EICROC ASICs are expected to have 1-2 mW/channel power dissipation, which amounts to about 100 W per layer in the Roman Pots of required cooling. The detector does not need to be operated below room temperature.
  • Shielding will be comprised of thin, high-Z foils (likely Au), which will serve the purpose of protecting the detector from stray RF from the beam. Work is also being done to find a solution to the impedance impact on the machine.

Off-Momentum Detector

  • Same basic considerations as for the Roman Pots.

Zero-Degree Calorimeter

  • The ZDC is comprised of 4 independent subsystems in the following order: PbWO4 crystal EMCAL, W/Silicon imaging EMCAL, Pb/Sci imaging EMCAL, Pb/Scintillator sampling HCAL.
  • The PbWO4 EMCAL and Pb/Sc HCAL will both be readout with either standard PMTs or SiPMTs, depending on spatial constraints and operating risk (SiPMs in this area of the machine will potentially suffer unacceptable radiation load - needs further study). The imaging readout components are still unknown.

B0 Tracking System

  • The tracking system is comprised of 2 layers (disks) of ITS3 silicon MAPS, 1 layer (disk) of AC-LGADs, and 1 final layer (disk) of ITS3 MAPS. The ITS3 MAPS will be readout at the outer ends of the sensor planes, while the AC-LGADs will be readout the same way as for the RP/OMD. The ribbon cables can be brought to the outer edge of the sensor planes, and routed along the outer wall of the magnet bore.
  • Cooling can be achieved using air or CO2, with channels/copper tubing carrying the coolant integrated with the tracking disks, similar to the forward silicon tracking disks in the main detector.

B0 preshower

  • A silicon preshower/shower max detector is one option for EM calorimetry in the B0 magnet bore. The detector will be comprised of 2X0 of Pb as a converter, and then 2 layers of silicon, with one being ITS3 MAPS, and one being AC-LGADs, with readout being the same as for the tracking system.

B0 PbWO4

  • A PbWO4 crystal calorimeter is one option for EM calorimetry in the B0 magnet bore. The detector is comprised of PbWO4 crystals, mounted into the B0 bore. Readout will be achieved either via SiPMTs, or regular PMTs. SiPMTs are ideal for size, but potentially challenging given the proximity to the beam, and potential slow neutron damage. More study is needed to identify the best technology.
  • There are two options for the ordering of the PbWO4 and the tracking system. Putting the EMCAL second makes the spatial constraint most-challenging. Placing the EMCAL first allows the readout to be mounted on the outside of the EMCAL, saving space, and making maintenance on the EMCAL easier, but the impact on the tracking system needs to be carefully studyied.

EPIC Far-Forward Tasks Table

EPIC Software Framework Implementation

  • Description: Initial inclusion and testing of Far-Forward systems in EPIC simulation framework.
  • Work Start: October 2022
  • Expected Duration: 2-4 months
  • Required Expertise: Medium/High
  • Task assigned to: A. Jentsch (initially)
  • Notes:The initial work should be done by experts, but this initial work will likely conclude quickly. After that, we will need to do (lots of) testing.
  • Contact: Alex Jentsch (ajentsch@bnl.gov)
  • Links:

Machine-Detector Interface

RP/OMD Impedance Study

  • Description: Work with machine group to analyze impedance impact of base Roman Pots/Off-Momentum Detector design, and iterate on design as needed.
  • Work Start: July 2022
  • Expected Duration: 6-12 months
  • Required Expertise: High
  • Task assigned to: A. Jentsch, Y. Furletova, C. Videbaek, A. Blednykh, C. Hetzel
  • Notes: Work done by machine engineers and scientists together.
  • Contact: Alex Jentsch (ajentsch@bnl.gov)
  • Links:

Vacuum System Impact on FF Detectors

  • Description: Work with machine group to study impact of the vacuum design on the detector acceptances and backgrounds.
  • Work Start: Summer 2022
  • Expected Duration: 6-12 months
  • Required Expertise: High
  • Task assigned to: A. Jentsch, Y. Furletova, C. Videbaek, A. Blednykh, C. Hetzel
  • Notes: Work done by machine engineers and scientists together.
  • Contact: Alex Jentsch (ajentsch@bnl.gov)
  • Links:

Sub-system Studies

B0 Calorimetry study

  • Description: Include B0 EMCAL in DD4HEP. Work on spatial constraints of engineering structure needed for PWO4 EMCAL, including cabling, PMTs, etc. Study possibility of HCAL system.
  • Work Start: September 2022
  • Expected Duration: 6-8 months
  • Required Expertise: Low/Medium
  • Task assigned to: Michael Pitt <michael.pitt@cern.ch>, Sakib Rahman <rahmans@myumanitoba.ca>, Sasha Bylinkin <alexander.bylinkin@gmail.com>
  • Notes:
  • Contact: Alex Jentsch (ajentsch@bnl.gov)
  • Links:

B0 ACTS vs. GenFit Tracking Study

  • Description: Study of ACTS tracking in the B0 tracker. Comparisons to be made with GenFit, and study of material thickness carried out.
  • Work Start: October 2022
  • Expected Duration: 6-8 months
  • Required Expertise: Medium
  • Task assigned to: Shujie Li <shujie@jlab.org> and Sakib Rahman <rahmans@myumanitoba.ca>
  • Notes:
  • Contact: Shujie Li <shujie@jlab.org>, Sakib Rahman <rahmans@myumanitoba.ca>, Alex Jentsch (ajentsch@bnl.gov)
  • Links:

Roman Pots/OMD Reconstruction Algorithm

  • Description: Refine reconstruction approach for Roman Pots/OMD using advanced matrix method, polynomial expansion method, ML, or some combination.
  • Work Start: August 2022
  • Expected Duration: 6-8 months
  • Required Expertise: Low/Medium/High
  • Task assigned to:
  • Notes:This is a larger task, so a less-experienced person could easily get involved, and be overseen by experts. We have applied for R&D funds to help get someone new involved.
  • Contact: Alex Jentsch (ajentsch@bnl.gov)
  • Links:


Zero-Degree Calorimeter - Reconstruction of Final-State Particles with EMCAL (photons)

  • Description: Detailed study of reconstruction with full FoCAL ZDC system of photons. Study of charged-particle vetoing.
  • Work Start: October 2022
  • Expected Duration: 6-8 months
  • Required Expertise: Low/Medium
  • Task assigned to: Two Graduate Students or a postdoc
  • Notes: To be overseen by the RIKEN group et al.
  • Contact: Yuji Goto (goto@bnl.gov)
  • Links:

Zero-Degree Calorimeter - Reconstruction of Final-State Particles with HCAL (neutrons)

  • Description: Detailed study of reconstruction with full FoCAL ZDC system of neutrons, including shower reconstruction in imaging layers.
  • Work Start: August 2022
  • Expected Duration: 6-8 months
  • Required Expertise: Medium
  • Task assigned to: Postdoc -
  • Notes: To be overseen by the RIKEN group et al.
  • Contact: Yuji Goto (goto@bnl.gov)
  • Links:

Zero-Degree Calorimeter - Calibration

  • Description: Matching for energy measurement using various ZDC components to test-beam and ALICE FoCAL data, and implementation of calibration table for use in full RECO in simulations.
  • Work Start: October 2022
  • Expected Duration: 6-8 months
  • Required Expertise: Low/Medium
  • Task assigned to:
  • Notes: To be overseen by the RIKEN group et al.
  • Contact: Yuji Goto (goto@bnl.gov)
  • Links:

Detector Backgrounds

Detector Background Simulations - Beam Remnant and Secondary Interactions with machine

  • Description: Study of impact from secondary showers produced from collisions with machine by beam remnant.
  • Work Start: October 2022
  • Expected Duration: 3-6 months
  • Required Expertise: Low/Medium
  • Task assigned to: Graduate Student
  • Notes: Part of a larger effort to study backgrounds.
  • Contact: Alex Jentsch (ajentsch@bnl.gov)
  • Links:

Detector Background Simulations - Slow neutrons

  • Description: Study of impact from slow neutrons on detector electronics in B0 and ZDC - leveraging information from eRD effort on neutrons.
  • Work Start: October 2022
  • Expected Duration: 3-6 months
  • Required Expertise: Low/Medium
  • Task assigned to: Graduate Student
  • Notes: Part of a larger effort to study backgrounds.
  • Contact: Alex Jentsch (ajentsch@bnl.gov)
  • Links:

Detector Background Simulations - Beam Halo

  • Description: Study of impact of beam halo protons on rates in the Roman Pots/OMD.
  • Work Start: October 2022
  • Expected Duration: 6-8 months
  • Required Expertise: High
  • Task assigned to: Alex Jentsch, Yulia Furletova, and EIC accelerator experts
  • Notes: Part of a larger effort to study backgrounds.
  • Contact: Alex Jentsch (ajentsch@bnl.gov)
  • Links:

Physics Benchmarks

EPIC FF Software Tests - DVCS

  • Description: DVCS study using FF EPIC simulations, using EPIC exclusive MC generator.
  • Work Start: October 2022
  • Expected Duration: 2-4 months
  • Required Expertise: Low/Medium
  • Task assigned to: Graduate Student
  • Notes: Required testing for FF EPIC simulations. Will need three energies to cover Yellow Report studies.
  • Contact:
  • Links:

EPIC FF Software Tests - TCS

  • Description: TCS study using FF EPIC simulations, using EPIC exclusive MC generator.
  • Work Start: October 2022
  • Expected Duration: 2-4 months
  • Required Expertise: Low/Medium
  • Task assigned to: Graduate Student
  • Notes: Required testing for FF EPIC simulations. Will need three energies to cover Yellow Report studies.
  • Contact:
  • Links:

Pion/Kaon Structure Studies

  • Description: Study meson structure capabilities, with special attention paid to tagging of negative pions, and reconstruction of lambdas.
  • Work Start: October 2022
  • Expected Duration: 3-6 months
  • Required Expertise: Medium
  • Task assigned to: Graduate Student + postdoc
  • Notes: More-challenging than average study, so someone with expertise on the Sullivan Process and tracking in the lattice required.
  • Contact:
  • Links:
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