Yellow Report Detector Forward-IR

Meetings bi-weekly (sometimes weekly): Mondays @ 1:30pm EST

Weekly meeting Indico: https://indico.bnl.gov/category/284/

Current status of group:

1) Current Yellow Report Document on Overleaf: https://www.overleaf.com/project/5e2e4b1fb24ba1000124924a

2) Simulations have been carried out for most of the far-forward detectors (details below), and results presented at numerous meetings.

3) Currently in discussion with the integration and machine folks to add the more realistic vacuum and machine components to move simulations forward.

Some basics:

1) Protons are detected at a range of energies and x_L values, using a combination of three detectors (Roman Pots, B0 Spectrometer, Off-momentum detectors).

• For protons with x_L >~ .6, Roman Pots and B0 are relevant.
• For protons with x_L ~< .6, Off-momentum detectors and B0 are relevant.

2) Neutrons + photons are accepted in the ZDC. We are considering additional photon detection in the B0 as well.

Detector systems

1) Roman pots

The Roman Pots detectors have been studied extensively and some basic parameters are now understood.

• Fast timing ~ 30-40ps
• 500um x 500um pixels sufficient.
• multiple redundant layers, at least 2 stations.
• Must be placed between 25 and 35m from IP.
• AC-LGAD technology well-suited.

2) B0 spectrometer

• Will need timing information (no spec yet), probably a separate layer.
• Need high-performance spatial resolution - translates to small pixels of 50um x 50um, or less. MAPS are a good option.
• Need multiple layers for tracking.

3) Off-momentum detectors

• Same basic requirements as Roman Pots.

4) Zero-Degree Calorimeter

• 60cm x 60cm hadronic calorimeter
• Need good energy resolution (currently assuming ALICE phocal numbers)
• Need charged particle veto in front.
• Neutron and photon detection, so a preshower would be useful.

Other detector discussions.

• Possible PID.
• Sensors between ZDC and B1apf for negative pions.
• Photon detection in the B0 detector for veto of nuclear breakup.

Basic Acceptances:

Neutrons:

• Assume uniform acceptance for 0<θ<4.5 mrad
• The real acceptance is a bit better than this, in reality, but the extra bit is not uniform in phi.
• Resolution
• Assume an overall energy resolution of σ_E/E=(50%)/√E ⨁ 5%
• Assume angular resolution of σ_θ=(3 mrad)/√E

Protons:

• Assume uniform acceptance for 6<θ<20 mrad – “B0 spectrometer”
• For protons with p_z/(beam momentum)>.6 – “Roman pots”
• 275 GeV: Assume uniform acceptance for .5<θ<5.0 mrad
• 100 GeV: Assume uniform acceptance for .2<θ<5.0 mrad
• 41 GeV: Assume uniform acceptance for 1.0<θ<4.5 mrad
• For protons with .25<p_z/(beam momentum)<.6 – “Off-momentum Detectors”
• Assume uniform acceptance for 0.0<θ<2.0 mrad
• for 2.0<θ<5.0 mrad, only accepted for |φ|>1 radian