HRS Analysis

PREX Main

Portal for HRS, Counting Mode, Optics, data and simulation notes and meetings

Useful Notes

• Weekly Meetings - Monday 2:30 PM
• Hall A monte carlo portal
• G4HRS Simulation - Documentation, Github
• HAMC Simulation - Notes, tech-note, formulae, Github
• Carbon contamination study: Note, Kiad's thesis

HRS Analyses

• Bob's October 2019 analysis plan, Kent's October 2019 plan, Ryan's October 2019 Update (most useful starting point), Ryan's FOM calculation for CREX notes
• Notes from Tyler: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Analyses Projects

• Optics Database Tuning - Ryan, Siyu, etc.
• Acceptance Function + APV Extraction - Ryan, Chandan, Bob, etc.
  • PREX I notes from Bob
  • Average Q^2 from Analyzer and Simulation - Devi, Ryan, Dustin
  • Inelastic backgrounds and contamination - Ryan, Devi, etc.
  • Radiative corrections for APV extraction - ?
  • Carbon contamination - Hanjie
• AT extraction, verification in Analyzer and Simulation - Ryan, Devi, etc.
• Rescattering, Pole Tip backgrounds, and more - Devi, Bob, etc.
• Reproduce phi distribution from HRS data with simulation

Outstanding Issues

• Super-elastic tail in G4HRS simulation but not in the Analyzer data
• Related, questionable quad magnetic field implementation in G4HRS (see some of Tyler's notes above for reference)
• Raster / BPM corrections for Analyzer Database
• Consider two ways of tuning HRS database w/ & w/o septum co-tune
• Are radiative corrections handled properly in G4HRS
• Target implementation is simplistic in G4HRS (and needs to be update to do diamond foil + Pb simultaneously)
• Inelastic states may need additional attention in G4HRS
• Difficult to recreate the hard collimator cut seen in the data with G4HRS

Carbon Contamination

Goal is to estimate relative cross-sections, acceptance with radiative effects, and then cross-check by comparing rates between the carbon target and lead targets

• Obtain counting mode data for lead and carbon targets to understand rates/thicknesses and provide a starting point
• Simulate the ideal carbon and lead targets and make sure we can predict accurately the rates and asymmetries that are measured
• Once those targets are ideally implemented in the simulation make a diamond+lead simulation for the front piece and the back piece (separately if needed, G4HRS generator will need code updates) to get radiation affects/contamination impacts on ideal lead
• Produce fractional rate and asymmetries per lead target
• Question: How much of an impact is radiative tail in carbon/lead sandwich and changes in carbon thickness (flakes fall off?) and how do these affect the ability for us to simply subtract out an asymmetry of carbon from lead based on carbon thickness measurements? (corrections to simplistic A_lead == A_measured - A_carbon_foils... i.e. how much of a correction do we apply to A_carbon_foils from the fact that there is radiation of the beam while it travels through the lead part of the target sandwich)

Target Density Fluctuations

Lead targets had density fluctuations and other changes over time that need to be understood in more time-resolved detail and studied carefully.