He3 / H3 e,e'p experiment E12-14-011
The SRC Tritium Experiment (E12-14-011) is an (e,e'p) experiment in Hall A, comparing the momentum distribution of protons in tritium and helium-3. These nuclei have a large proton-neutron asymmetry, but are also isospin-mirror nuclei, meaning that the proton distribution in tritium can tell us about the neutron distribution in helium-3.
Contents
During the experiment
The information that was more relevant for activities during the data-taking period will be moved from this page to the following new page:
Beam Energy Calibration
Done by D. Higinbotham (This is a 'pass-dependent' statement)
Use the Tiefenbach energy multiplied by 1.0025(5)
(That is, replace the value Ebeam in db_run.dat by 1.0025xEbeam)
Target Information
- Tritium Target Tech. Note
- Target Ladder Alignment Survey January 2018
- Information from Jesse
- Target Densities (TGT-CALC-17-020)
Target | density [g/cm3] |
---|---|
Hydrogen | 0.002832 |
Deuterium | 0.005686 |
Tritium | 0.003065 |
Helium-3 | 0.002 |
HRS Angles, Surveys, and Mispointings
- Spectrometer Surveys
LVDT retults
Kinematics | Run number | L mispointing [mm] | R mispointing [mm] | LHRS angle [deg] | RHRS angle [deg] |
---|---|---|---|---|---|
Fast | 100085 | 1.18245 | -0.70915 | 20.8837 | 48.8207 |
Hydrogen | 100100 | 0.9882 | -0.7113 | 17.8017 | 48.8207 |
Slow | 100532 | 0.48765 | -0.65395 | 20.8812 | 58.5031 |
Fast2 | 100658 | 0.49145 | -2.9875 | 20.8812 | 48.8187 |
Hydrogen2 | 100685 | 0.8831 | -3.00255 | 17.8053 | 48.8188 |
HRS Momenta
Values taken from db_run.dat file.
Kinematics | Run number | LHRS p_cent [GeV] | RHRS p_cent [GeV] |
---|---|---|---|
Fast | 100085 | 3.54334 | 1.48051 |
Hydrogen | 100102 | 3.54334 | 1.4805 |
Slow | 100532 | 3.54331 | 1.246 |
Fast2 | 100658 | 3.5433 | 1.48051 |
Hydrogen2 | 100685 | 3.5433 | 1.4805 |
Other information
- Kinematics MORE DETAILS HERE
These are the nominal values we got by optimizing in simc (these are not the actual values from the experiment)
Kinematics | LHRS momentum [GeV] | LHRS angle [deg] | RHRS momentum [GeV] | RHRS angle [deg] |
---|---|---|---|---|
Fast | 3.543 | 20.88 | 1.4805 | 48.80 |
Slow | 3.543 | 20.88 | 1.246 | 58.50 |
Parallel (Hydrogen) | 3.543 | 17.80 | 1.4805 | 48.80 |
- BCM calibration
- run number: 100172
- target: carbon foil
- currents and attenuator values:
- 3uA ---> 140
- 7uA ---> 163
- 12uA ---> 184
- 18uA ---> 204
- 22.2uA ---> 214
- These are nominal values for the beam current. Gotta get the actual values from epics info.
- See example in the halog, entry number: 3505501
- Unser calibration
- run number: 100451
- target: dummy
- current values: 0,2,0,3,0,5,0,10,0,25,0,40,0,60,0,80,0,90,0,100,0,2,0,3,0,5,0,10,0 uA
- Ideally we would have completed two full cycles from 0 to 100 uA, but the beam came back and we decided to go back to production.
- See example in the halog, entry number: 3499263
Root files on Tape
Actual raw data: /mss/halla/triton/raw/
July 10th, 2018 /mss/halla/triton/prod/coinc_eep/pass2.1/all/
Documentation
- Run List
- For collimator cut
- Experiment seminar slides
- Run and online analysis slides
- Raster
- HRS DAQ Resources
- Simulation
- Tel Aviv University SRC group
- MySQL Database
Reference Reading
- Proposal for E12-14-011, approved by PAC-42
- Hall-A NIM paper (2004)
- Tech notes on HRS optics calibration
- Hall A Coordinate systems (Ye Zhihong PhD thesis)
- HRS info