Residual Radiation Cooldown : Main Injector

1. Residual Radiation Cooldown: Main Injector Bruce C. Brown Fermilab All Experimenters Meeting 19 March 2012

2. Outline Data • Residual Radiation at Bar Coded Locations • BLM Data each 2.2 sec Main Injector Cycle Fit Residual Radiation using BLM data • Assume a set of half life values • Weight BLM data by half life, do linear fit (simple matrix inversion only) Identify Important Isotopes (activation study) Examine Cooldown Predictions • Collimator Area • ANU Operation • Effects from SeaQuest Operation Bruce C Brown -- All Experimenters Mtg

3. Residual Radiation near MI Collimators Bruce C Brown -- All Experimenters Mtg

4. Formulas for Fitting The BLM system records (for each monitor) a loss integral (LI) for each MI Cycle. We sum these over ten minute intervals (Ts = 600 sec) – to quantas, LIj. For each isotope we sum these quantas weighted by the half-life The fitting hypothesis assumes that the measured residual radiation at measurement time, TM is a linear sum of the weighted quata sums over the set of isotopes The physics of the loss pattern and isotope production, loss monitor geometry, bar code monitor location geometry and Geiger tube energy response multiply to create one linear constant EI. Bruce C Brown -- All Experimenters Mtg

5. Losses LI232 Since Oct 2006 Bruce C Brown -- All Experimenters Mtg

6. Activation for MI Steel Samples(Normalized to BLM rate)

7. Residual Radiation w/ Fit at Q232D Bruce C Brown -- All Experimenters Mtg

8. Cooldown Prediction – D230D Bruce C Brown -- All Experimenters Mtg

9. Cooldown Prediction – Q230D Bruce C Brown -- All Experimenters Mtg

10. Compare Cooldown Fits Bruce C Brown -- All Experimenters Mtg

11. Predictions for Nova Era Operation of the Main Injector Complex for the NovA era will achieve 700 kW operation by accelerating the similar intensities with higher repetition rates. The losses will be similar and much of the loss will be at the same locations. The weighted loss rate LW for any isotope will reach an equilibrium for the new rate at 2.2/1.3 of the current (nearly) equilibrium rate. Long Half Life isotopes will continue to build toward equilibrium. Measured Residual Radiation results from the sum of the specific activities, SA of produced isotopes weighted by geometry effects and the energy response of the measurement instrument (Geiger Counter). Since iron is typical of the materials we activate, we look at the chart of identified isotopes and see that the only long lived isotope not included in previous studies is Co-60 with a half life of 1925.8 Days (5.27 years). Comparing the ratio of SA for Co-60 with that for Mn-54 we predict that when starting a shutdown after achieving equilibrium, we expect 13.8/63.9 = 21.6% enhancement of the long lived components (ignoring differences in geometry or energy response) . Planning for a long shutdown in the Nova era will be impacted primarily by the 70% higher loss rate (assuming same loss fraction) with little impact from build-up of long half life isotopes. Bruce C Brown -- All Experimenters Mtg

12. Activation Study for SeaQuest Observe Losses for Current Operation at 3E11 p Typical activation data and loss rates will predict residual radiation due to SeaQuest slow spill operation at 1E12 or at 1E13 ppp and expected repetition rate. Could try to use 8 GeV activation data but 120 Gev will be somewhat different physics and geometry Will wait for measurements, then scale with rate Bruce C Brown -- All Experimenters Mtg

13. Losses for Operation 8 – 11 March LI522A LI520D Beam21 LI521A Bruce C Brown -- All Experimenters Mtg

14. Typical Rates for 1E12 protons/cycle Assume we run 1 SeaQuest cycle per minuteand take losses measured March 8-11, compare to 10 week average of some collimator region BLM’s Resonant Extract Area Collimator Area Residual Radiation Measurements following a week or two of operation are needed Bruce C Brown -- All Experimenters Mtg

15. Acknowledgments This work had been built on the efforts of many individuals and groups at the lab. Some of them include: • Guan Wu (MI Dept) for Application Program Support • Operations and MI Department for vigilant tuning • APC Energy Deposition Gp (Nikolai Mokhov and colleagues) • Vernon Cupps (retired) for Activation Measurements • Everyone who contributed to the MI BLM System Bruce C Brown -- All Experimenters Mtg

16. References Some Console Applications for Displaying Main Injector BLM Measurements http://beamdocs.fnal.gov/AD/DocDB/0032/003299/002/Beams-doc-3299.html Residual Radiation Monitoring in the Main Injector with the ROTEM RAM DA3-2000 Radiation Survey Meter http://beamdocs.fnal.gov/AD/DocDB/0035/003523/001/Beams-doc-3523.html Measuring correlations between beam loss and residual radiation in the Fermilab Main Injector.http://lss.fnal.gov/archive/2010/conf/fermilab-conf-10-368-ad.pdf Activation of Steel and Copper Samples in the Main Injector Collimator Region http://beamdocs.fnal.gov/AD-public/DocDB/ShowDocument?docid=4046 Bruce C Brown -- All Experimenters Mtg