predicting residual radiation using beam loss data – early results bruce c. brown 10 march 2010...
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Predicting Residual Radiation using Beam Loss Data – Early Results
Bruce C. Brown10 March 2010
Main Injector/Recycler Group Meeting
Bruce C. Brown -- MI/RR Group Meeting 2
Personal Note
Early operation of the Main Injector was at modest intensities and very high transmission (Think Tevatron, not the Booster or Main Ring) but in 2004, we were preparing for NuMI operation at about x10 intensity. I have been seeking since then to understand losses: mechanisms, residual radiation, monitoring.
Can we relate: protons lost to Residual Radiation, to BLM readings, to radiation safety limitations?
Can we control the loss locations?3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 3
Today’s Outline
• Primary Goal – Predict Residual Radiation• How to relate Residual Radiation to BLM’s• Some Results• Preliminary Conclusions• Issues with BLM data in Datalogger• Proposed additional efforts – Data cleanup for BLM – faulty readings– How much loss is important?– Lost Protons vs. BLM readings– Exploring BLM pedestal with I129 or I130
3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 4
Predicting Residual Radiation
We need to predict residual radiation so that:
We can plan tunnel access work Will we need time for cool down? Can we predict cool down for shutdown? We know long term trends Will the current loss rate make work difficult?
3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 5
Relating Residual Radiation to BLM Data Logs of LI(T) for losses - since 11Oct06 Residual Radiation at Bar-Coded location since 10Oct05 We access the tunnel after about 1 hour or more. We find
that the lifetimes of interest are about 2.5 hours. We will store sums of LI(T) for 10 minute intervals
Create half life weighted integrals (I is isotope, TM is measurement time).
3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 6
Relating Residual Radiation to BLM Assume geometry of loss is constant:
Constant pattern for creating ionization in BLM Constant pattern for creating residual radiation at bar-coded locations
Measured Residual Radiation is linear in weighted BLM Sums
Note that we are dividing by the half life so the coefficient relates the residual radiation to the weighted loss rate . This is a linear fit so we can perform it with existing data. However, if long half life isotopes were produced well before the BLM data record, we will need to add a term to take care of it. We have a plan.
3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 7
Console Application I130
Guan Wu is developing a program to implement a fitting procedure:
It reads data from the data logger tables, applies some cuts (more to be developed) and sums them to a convenient set of ‘Quanta’ and stores the results in Sybase.
It plots data logger or Quanta results for examination It provides a fit as shown above.
He is doing the work so I will do the talking !! 3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 8
Fit Results at V105 Corrector
3/10/2010
1070000000 1090000000 1110000000 1130000000 1150000000 1170000000 1190000000 12100000000
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V105 Residual Radiation vs. Integral of LI105
MeasFit
Linux Time (sec)
Resi
dual
Rad
iatio
n at
V10
5 (m
R/hr
)
Bruce C. Brown -- MI/RR Group Meeting 9
Fit Results at H104,Q104D
3/10/2010
1070000000 1090000000 1110000000 1130000000 1150000000 1170000000 1190000000 12100000000
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Q104D Residual Radiation vs. Integral of LI105
MeasFit
Resi
dual
Rad
iatio
n at
Q
104D
(mR/
hr) LIfetime Coeffi-
cient312 days 0.10395.591 days 0.08612.5789 hrs 0.8271
1070000000 1090000000 1110000000 1130000000 1150000000 1170000000 1190000000 12100000000
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H104 Residual Radiation vs. Integral of LI104
MeasFit
Resi
dual
Rad
iatio
n at
H10
4 (m
R/hr
)
LIfetime Coefficient312 days 0.03125.591 days 0.04372.5789 hrs 0.2565
Bruce C. Brown -- MI/RR Group Meeting 10
Fit Results at V621 Corrector
3/10/2010
10400000001060000000108000000011000000001120000000114000000011600000001180000000120000000012200000000
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V621 Residual Radiation vs. Integrals of LI621
MeasFit
Resi
dual
Rad
iatio
n at
V62
1(m
R/hr
)
Bruce C. Brown -- MI/RR Group Meeting 11
Results at 610We get useful results even at low loss
1070000000 1090000000 1110000000 1130000000 1150000000 1170000000 1190000000 12100000000
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H610 Residual Radiation vs. Integral of LI610
MeasFit
Resi
dual
Rad
iatio
n at
H61
0 (m
R/hr
)
1070000000 1090000000 1110000000 1130000000 1150000000 1170000000 1190000000 1210000000012345678
Q610D Residual Radiation vs. Integral of LI610
Series1Series3
Resi
dual
Rad
iatio
n at
Q
610D
(mR/
hr)
3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 12
Residual Radiation Fit at LAM52A1Previously at 3000 mR/hr now 300 mR/hr
3/10/2010
1070000000 1090000000 1110000000 1130000000 1150000000 1170000000 1190000000 12100000000
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LAM52A1 Residual Radiation fit to LI522A Integrals
MeasFit
Unix Time (seconds)
Resi
dual
Rad
iatio
n at
LA
M52
A1
(mR/
hr)
Bruce C. Brown -- MI/RR Group Meeting 13
Residual Radiation at Primary Collimator – Q230D
3/10/2010
11200000001130000000114000000011500000001160000000117000000011800000001190000000120000000012100000000
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Q230D Residual Radiation fit to LI230 Integral Loss
MeasFit
Unix Time (seconds)
Resi
dual
Rad
iatio
n at
Q23
0D (m
R/hr
)
LIfetime Coefficient312 days 0.2145.591 days 0.20412.5789 hrs 0.4257
Bruce C. Brown -- MI/RR Group Meeting 14
Residual Radiation at V309Last corrector in Collimation Region
3/10/2010
11200000001130000000114000000011500000001160000000117000000011800000001190000000120000000012100000000
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V309 Residual Radiation fit to LI309 Integral Loss
MeasFit
Unix Time (seconds)
Resi
dual
Rad
iatio
n at
V30
9 (m
R/hr
)
LIfetime Coefficient312 days 0.37525.591 days 0.53852.5789 hrs 0.5227
Bruce C. Brown -- MI/RR Group Meeting 15
Residual Radiation at V109Why the poor fit to recent data?
3/10/2010
1070000000 1090000000 1110000000 1130000000 1150000000 1170000000 1190000000 1210000000
-10
0
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V109 Residual Radiation vs. Integrals of LI109
MeasFit
Resi
dual
Rad
iatio
n at
V10
9 (m
R/hr
)
tau E
312.3 day 0.1241
5.590 dat 1.7324
2.579 hr -2.626
Chisqr 2.183
Bruce C. Brown -- MI/RR Group Meeting 16
Various Fit Results using 3 Isotopes
3/10/2010
Location BLM 312.3 day 5.591 day 2.5789 hr chisqr312.3 5.591 2.5789
V105 LI105 1.0843 1.3421 0.9249 14.653V621 LI621 0.373 0.3916 0.2069 3.576V109 LI109 0.1241 1.7324 -2.626 2.183 Q230D LI230 0.214 0.2041 0.4257 6.668 V309 LI309 0.3752 0.5385 0.5227 15.132 LAM52A1 LI522A 0.236 0.2738 -0.0172 153.681 H104 LI104 0.0312 0.0437 0.2565 0.518 Q104DS LI104 0.1039 0.0861 0.8271 1.799 V609 LI609 3.2885 1.328 2.5358 4.733 S408 LI408 1.8541 1.1733 1.5016 3.269
Bruce C. Brown -- MI/RR Group Meeting 17
Preliminary Results
• The Proposed Fit seems to provide a useful description of the residual radiation based on the BLM integrals.
• Coefficient of 1E+4 implies 1 mRad/sec of BLM loss yields 10 mR/hr on typical object in the tunnel
• Using three isotopes provides a useful description for present purposes. Will explore alternative options later. Software handles 5 now.
• Better review of the data logger information may produce better fits.
• Should be able to provide cool down curve prediction for shutdown planning.
3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 18
Issues with BLM results in Datalogger
• We know that Main Injector Cycles without a prepare for beam will result in storing the same result again and again. If this was due to a high loss abort, the data may show high loss (fix code ready to tweak).
• Present 600 second sums have a few unphysical points. Will have to explore how to remove them. At present simply cut after reviewing data.
• The pedestal is not a zero so the integrals may have added or missing Rads. Pedestal of 2 Rad may create 10 mR/hr residual radiation.
3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 19
Lost Proton Measurement
The Beam Loss Monitors have a measured calibration in Rads. This relates the ionization detected to the radiation field which produced that ionization
The loss geometry varies around the ring but fortunately the regular placement of BLM detectors (above beam height on the wall at the downstream end of each quadrupole) makes the characteristic response to lost protons somewhat regular
Using the integral around the ring, a nominal response is 0.66 Rads/1E12 Protons lost at 8 GeV. Extinction scans produce a number about half of this.
3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 20
Today’s Outline
• Primary Goal – Predict Residual Radiation• How to relate Residual Radiation to BLM’s• Some Results• Preliminary Conclusions• Issues with BLM data in Datalogger• Proposed additional efforts – Data cleanup for BLM – faulty readings– How much loss is important?– Lost Protons vs. BLM readings– Exploring BLM pedestal with I129 or I130
3/10/2010
Bruce C. Brown -- MI/RR Group Meeting 21
S408 Residual Radiation
3/10/2010
1060000000 1080000000 1100000000 1120000000 1140000000 1160000000 1180000000 1200000000 12200000000
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S408 Residual Radiation fit to Integral of LI408
MeasFit
Unix Time (seconds)
Resi
dual
Rad
iatio
n at
S40
8 (m
R/hr
)
Bruce C. Brown -- MI/RR Group Meeting 22
Residual Radiation at V609Note old radiation levels here
3/10/2010
1060000000 1080000000 1100000000 1120000000 1140000000 1160000000 1180000000 12000000000
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V609 Residual Radiation fit to LI609 Loss Integral
MeasFit
Linux Time (seconds)
Resi
dual
Rad
iatio
n at
V60
9 (m
R/hr
)