PREX CREX Target Studies

See also, Target Density Variation Check

The PREX and CREX targets operated at very high currents with a lot of power deposition and radiation. The targets performed very well, up until their destructions (due to degradation of carbon foils in Pb target case, and until the copper frame was blasted and caused Ca48 to melt in the first unfortunate Calcium target's case).

To make sure that things are all right we did some special studies of the Pb and ideal-Ca40 targets at various times to make sure we could claim that the target system introduced no unwanted effects in the Asymmetry measurements.

Pb Target Density studies during PREX

• Here - Sanghwa and co did some careful studies of the Pb target's density vs. time and as a result of different amounts of current or total charge (across the experiment)
  • That page also contains a mention of Weibin's simulations for verifying those study's results, which have also been followed up with further
  • Weibin's more recent HAPLOG and slides

Target studies during CREX / Cameron's DNP 2020 Target Talk

• DocDB Entry 470

Questions that needed to be addressed:

• Temperature and Radiation in the hall during Target Degradation
• Main detector signals effect during Target Degradation
• Raster Frequencies to minimize L-R Correlated Noise
• Raster Size effect on regression analysis
• Beam Current effect on regression analysis
• CFD Simulations of Target Heating vs. Diamond Thermal Conductivity

• DocDB entry with all of my notes and plots I used in analyzing the data to make conclusions: Here
  • Includes 3 documents with summary of runs, some sample plots, and links to HALOGs, etc. - Runplan Doc, Data taking notes, Analysis Doc
  • Also includes tarballs with lots of plots used in analyzing data mentioned in that document

Assorted Documents

• Silviu's 2017 ERR Talk on the PREX Target System
• PREX/CREX Target Manual
• Kiadtisak's thesis, mentioning target from PREX 1, etc.
• Tao's target-end-of-life cut description HAPLOG
• Sanghwa's collaboration meeting update on target behavior and special counting mode studies
• Weibin's target contamination studies (background fractions)
• Weibin's simulation study of radiation changes due to target size changes
• Weibin's optics study cross-check (not exactly relevant to this topic)
• Siyu's target thickness check
• Chandan's target thickness effect on Q2 double check
• Chandan - More studies of Q2 changes during PREX
• Chandan's Q2 systematics results
• Important HALOG mentioning raster frequency update to be maximally cancelling