residual radiation cooldown: main injector bruce c. brown fermilab all experimenters meeting 19...
Post on 17-Jan-2016
218 Views
Preview:
TRANSCRIPT
Residual Radiation Cooldown: Main Injector
Bruce C. BrownFermilab All Experimenters Meeting
19 March 2012
2Bruce C Brown -- All Experimenters Mtg
Outline
Datao Residual Radiation at Bar Coded Locationso BLM Data each 2.2 sec Main Injector Cycle
Fit Residual Radiation using BLM datao Assume a set of half life valueso Weight BLM data by half life, do linear fit (simple matrix inversion only)
Identify Important Isotopes (activation study)Examine Cooldown Predictionso Collimator Areao ANU Operationo Effects from SeaQuest Operation
19 March 2012
3Bruce C Brown -- All Experimenters Mtg
Residual Radiation near MI Collimators
H230
Q230D
V231
Q232D
V301
C301
V303
C303
H304
V305
H306
V307
C307
H308
C308
V309
H230
1
10
100
1000
20110308 20120202
Resi
dual
Rad
iatio
n on
Con
tact
(mr/
hr)
19 March 2012
Formulas for FittingThe 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.
19 March 2012 Bruce C Brown -- All Experimenters Mtg 4
5Bruce C Brown -- All Experimenters Mtg
Losses LI232 Since Oct 2006
10/10/2006 2/22/2008 7/6/2009 11/18/2010 4/1/20120
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
a(week avg) b(312.30D) c( 27.70D) d( 5.59D)
Aver
age
or W
eigh
ted
LI232
Loss
(mr/
sec)
19 March 2012
Activation for MI Steel Samples(Normalized to BLM rate)
Compare Normalized Activation of MI Steel Sample
Sample Half Life Average Ratio days Shielded Unshield
/AverageShielded
Br-76 0.675 19639.73Co-60 1925.8 138487.1Cr-51 27.7 284194.5 100.5783Fe-52 0.344792 1266.819 201.9571Fe-59 44.5 327404.6Mn-52 5.591 79053.71 102.5272Mn-54 312.2 639444.8 99.31633Mn-56 0.1074 6771619 4.545409Na-24 0.62329 4104.662 59.35237Sb-122 2.7 552517.2 1.914643Sb-124 60.2 202194.8Sc-44m 2.44 5385.168 260.7752Sc-46 83.83 16852.09 215.3617Sc-47 3.341 10350.71 131.7161Sc-48 1.82 2048.755 108.3398V-48 15.98 47371 149.0295Sc-44 0.165417 10380 278.141
7Bruce C Brown -- All Experimenters Mtg
Residual Radiation w/ Fit at Q232D
19 March 2012
8Bruce C Brown -- All Experimenters Mtg
Cooldown Prediction – D230D
0 50 100 150 200 250 300 350 4001
2
3
Residual Radiation Decay for Q230D Using Fit from February 2012
2 Weeks Full Rate 2 Weeks 1/2 Rate 2 Weeks 1/4 Rate 2 Weeks 0 Rate 1 Week 1/2 Rate 1 Week 1/4 Rate 1 Week 0 Rate
Days after Shutdown Begins
Resi
dual
Rad
iatio
n N
orm
aliz
ed to
Ra
te a
fter
Yea
r
19 March 2012
9Bruce C Brown -- All Experimenters Mtg
Cooldown Prediction – Q230D
0 5 10 15 20 25 30 35 40 45 501.8
2
2.2
2.4
2.6
2.8
3
3.2
3.4
Residual Radiation Decay for Q230D Using Fit from February 2012 Use Mn-54, Cr-51, Mn-52, Mn-56
2 Weeks Full Rate 2 Weeks 1/2 Rate 2 Weeks 1/4 Rate 2 Weeks 0 Rate 1 Week 1/2 Rate 1 Week 1/4 Rate 1 Week 0 Rate
Days after Shutdown Begins
Resi
dual
Rad
iatio
n N
orm
aliz
e to
Ra
te a
fter
Yea
r
19 March 2012
10Bruce C Brown -- All Experimenters Mtg
Compare Cooldown Fits
Q230DV231Q232DV303 H304 V305 H306 V307 V309
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
Isotope Ratios at Correctors
Mn56/Mn54 Mn52/Mn54 Cr51/Mn54
Equi
libriu
m A
ctiva
tion
Ratio
C301 C303 C303 C3070
10
20
30
40
50
60
70
Isotope Ratios at Collimators (Shielded)
Mn56/Mn54 Mn52/Mn54 Cr51/Mn54
Equi
libriu
m A
ctiva
tion
Ratio
19 March 2012
11Bruce C Brown -- All Experimenters Mtg
Predictions for Nova EraOperation 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.
19 March 2012
12Bruce C Brown -- All Experimenters Mtg
Activation Study for SeaQuest
Observe Losses for Current Operation at 3E11 pTypical 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
19 March 2012
13Bruce C Brown -- All Experimenters Mtg
Losses for Operation 8 – 11 March
19 March 2012
Beam21
LI520D
LI522A
LI521A
14Bruce C Brown -- All Experimenters Mtg
Typical Rates for 1E12 protons/cycle
Assume we run 1 SeaQuest cycle per minute and take losses measured March 8-11, compare to 10 week average of some collimator region BLM’s
19 March 2012
Location mR/sec/1E12LI520A 0.409090909LI520B 54.81481481LI520C 157.7104377LI520D 18.21548822LI520E 10.94276094LI521B 18.49158249LI522A 0.777777778
Location mR/sec LI230 2.5874 LI303 55.2515 LI307 9.8107 LI309 48.5938
Resonant Extract Area Collimator Area
Residual Radiation Measurements following a week or two of operation are needed
15Bruce C Brown -- All Experimenters Mtg
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
19 March 2012
16Bruce C Brown -- All Experimenters Mtg
ReferencesSome Console Applications for Displaying Main Injector BLM Measurementshttp://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 Regionhttp://beamdocs.fnal.gov/AD-public/DocDB/ShowDocument?docid=4046
19 March 2012
top related