# Beam Simulations

From GlueXWiki

### PS+TPOL simulations with 75 micron converter (2016)

- simulated run 11484
- 75um beryllium converter
- photon beam energy 8.2 - 9.0 GeV.
- context="variation=mc calibtime=2018-05-21"
- coherent bremsstrahlung spectrum, edge at 9.0 GeV.
- GlueX beamline geometry, 3.4mm collimator, 60um diamond radiator.
- 12.0 GeV electron beam @ 50 nA, 5e-8 m.rad emittance, 0.5mm virtual spot r.m.s.
- 100% PERP polarization on every beam photon, otherwise GlueX beam properties.
- tagger simulation with randoms included over interval [-10, +10]ns.
- background photons included from 1 MeV to endpoint energy.
- sufficient statistics to cut on variables to study systematics:
- A vs photon energy
- A vs photon displacement at converter
- A vs pair energy asymmetry, PS edge effects

- rough estimate of statistics:
- total events generated: 10,000 M
- total events with PS trigger: 2,000 M
- total PS triggers with in-time TPOL hits: 6 M
- total events passing TPOL analysis cuts: ~3 M

- resource estimate: 100khr running on OSG, final sample size ~2 GB
- expected uncertainty on extracted A: 0.1% abs., 0.5% rel.
- final generated statistics:
- events generated (pairs + triplets): 20,828,100,000
- TPOL+PS coincidences recorded: 6,668,155

- root://nod25.phys.uconn.edu/Gluex/beamline/pairsim/5-2018/tpolskim_75um_2016.hddm

### PS+TPOL simulations with 75 micron converter (2017-2018)

- simulated run 42136
- 75um beryllium converter
- photon beam energy 8.0 - 8.8 GeV.
- context="variation=mc calibtime=2018-05-21"
- coherent bremsstrahlung spectrum, edge at 8.8 GeV.
- GlueX beamline geometry, 5mm collimator, 60um diamond radiator.
- 11.6 GeV electron beam @ 150 nA, 5e-8 m.rad emittance, 0.5mm virtual spot r.m.s.
- 100% PERP polarization on every beam photon, otherwise GlueX beam properties.
- tagger simulation with randoms included over interval [-10, +10]ns.
- background photons included from 1 MeV to endpoint energy.
- sufficient statistics to cut on variables to study systematics:
- A vs photon energy
- A vs photon displacement at converter
- A vs pair energy asymmetry, PS edge effects

- rough estimate of statistics:
- total events generated: 10,000 M
- total events with PS trigger: 3,100 M
- total PS triggers with in-time TPOL hits: 12 M
- total events passing TPOL analysis cuts: ~5 M

- resource estimate: 100khr running on OSG, final sample size ~2.2GB
- expected uncertainty on extracted A: 0.1% abs., 0.5% rel.
- final generated statistics:
- events generated (pairs + triplets): 15,017,600,000
- TPOL+PS coincidences recorded: 6,949,740

- root://nod25.phys.uconn.edu/Gluex/beamline/pairsim/5-2018/tpolskim_75um_6-26-2018.hddm

### PS+TPOL simulations with 750 micron converter (2017-2018)

- simulated run 42553
- 750um beryllium converter
- photon beam energy 8.0 - 8.8 GeV.
- context="variation=mc calibtime=2018-05-21"
- coherent bremsstrahlung spectrum, edge at 8.8 GeV.
- GlueX beamline geometry, 5mm collimator, 60um diamond radiator.
- 11.6 GeV electron beam @ 150 nA, 5e-8 m.rad emittance, 0.5mm virtual spot r.m.s.
- 100% PERP polarization on every beam photon, otherwise GlueX beam properties.
- tagger simulation with randoms included over interval [-10, +10]ns.
- background photons included from 1 MeV to endpoint energy.
- sufficient statistics to cut on variables to study systematics:
- A vs photon energy
- A vs photon displacement at converter
- A vs pair energy asymmetry, PS edge effects

- rough estimate of statistics:
- total events generated: 10,000 M
- total events with PS trigger: 3,100 M
- total PS triggers with in-time TPOL hits: 20 M
- total events passing TPOL analysis cuts: ~5 M

- resource estimate: 100khr running on OSG, final sample size ~2.6GB
- expected uncertainty on extracted A: 0.1% abs., 1% rel.
- final generated statistics:
- events generated (pairs + triplets): 12,429,600,000
- TPOL+PS coincidences recorded: 7,315,373

- root://nod25.phys.uconn.edu/Gluex/beamline/pairsim/5-2018/tpolskim_750um_6-26-2018.hddm