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Radiation monitoring: what do we have and what do we need?M. Calviani, M. Brugger, P. Peronnard, J. Saraiva, G. Spiezia (EN/STI)
R2E/Availability Workshop October 2014
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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SummaryUse of the monitoring systemBrief summary of Run I experienceRadMon development Injectors monitoringRequirements from usersWhat would be needed for Run II
October 2014
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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What do we use the monitoring for
Measurement of radiation levels in the machines:High energy hadron fluence (HEH)Total ionizing dose (TID)1. Understanding of the radiation field in the
tunnel and shielded areas and support for simulation extrapolation
2. Important service to equipment groups for failure analysis
3. Input/requirement for equipment design
October 2014
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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What would happen if don’t have it Cannot correlate equipment failure with radiation
levels risk of changing equipment w/o solving the problem
Cannot anticipate need for equipment upgrades – rad-tolerant
Cannot study radiation impact of changing operational parameters
Cannot dissociate the possible radiation source Limited info on eventual radiation quantity
responsible for degradation (TID, NIEL, HEH)October 2014
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Types of detectors employed
October 2014
• RadMons/RadFETs (HEH/cm2, Gy(SiO2))• Radiation levels close to equipment of interest, non
necessary “standard” locations• Time profile available
Dedicated detectors
• BLM (Gy – cumulated)• Provide loss distribution (dynamic view)• Total dose
Other detectors with high granularity
• TLD/HLD (Gy – cumulated)• Integral dose at the location of interest
Passive dosimetry
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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LHC RadMon coverage
October 2014
LHCCritical
areas (UJ, RR, US, UX, RE, UA)
DS and start of ARC
LSSExperiments
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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RadMon locations in DS/ARC
October 2014
DS/ARC (from cell 7 to 20) RadMon are placed
below the interconnect between the last MB/MQ of a given cell
Equipment below MB/MQ!
MB MB MQ
MB MB MQMB
MB
MBcell i cell i+1
cell i cell i+1
Dedicated LHC-MD extraction of an operative ratio between BLM dose and expected HEH from RadMons = ~1 SEU count/mGy
Tunnel equipment (QPS, CRYO, BLM or EPC)
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Experience from Run I (1/5)Nice summary of Run I observation is available here
Radiation levels summarized with the use of different types of detectors (RadMons, BLMs, FGCs, etc.)
October 2014
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Experience from Run I (2/5)Lesson: Important to follow-up machine
operational parameters (TCL/RR)
October 2014
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Experience from Run I (3/5)
October 2014
Lessons:BLM analysis fundamental for the DS/ARCWhen BLM/RadMon available, good
agreement between them
Point 4
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Experience from Run I (4/5)
October 2014
Very important to follow-up radiation monitoring following operational variationsSometimes just scaling is risky...
Predictions2012
Observations end 2012
Decreased: TCL closed
Increased: tight collimators
Increased: higher cum. lumi
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Experience from Run I (5/5)
October 2014
We should not forget the p-Pb and Pb-Pb runs Due to the Bound-Free Pair Production (BFPP), even for
short runs, radiation levels can be up to 5 times those of a “standard” pp run
DS cells most affected
~7 months
~3 days
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Open points in view of Run II
October 2014
25 ns operation uncertainties:Evolution of beam-gas levels during 25 ns
operation still to be fully clarifiedDuring Chamonix 2012 it was stated that
pressure will not increase more than 2x with respect to 50 nsHowever – experience showed that pressure
variation depends strongly on real operational parameters
Still an open point
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Open points in view of Run IILHC Point 4 and Point 6UX45: radiation levels in 2012 higher than
expected from 2011 triggered TE/CRG relocation activitiesHow the situation will evolve with 25ns
operation?UX65: still calm, as no special equipment
might increase the beam-gas interactionMonitoring has been improved
October 2014
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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RadMons developments
October 2014
During LS1 more than 100 RadMons have been installed in machines450 in total Injectors, target area, experimental areas..
LHC: ARC P1-2-5-8 + relocations for R2E
RadMon v5 LHC
RadMon v6 Experimental areas (n_TOF, AD) Injection lines
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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RadMons development Features of v6:
Remote configurability Self-diagnostic Radiation resistance 3 times higher New sensors
October 2014
Advantages with respect to v5:Resolution improved by a factor of 10Reduced number of tunnel access to change
settingsLonger life-time
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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RadMons development Overall resolution improvement – factor of 3 to 10 TID limit 3x times larger
October 2014
Sensor Sensitivity*Resolution
Range(Prev) (New-V6)
Fet100 50 rad/mV
300 rad
20 rad
1Mrad
Fet100Bias
14 rad/mV NA 6
rad 0.4
Mrad
BPW (3)
4·109
n/cm2/mV3·1010 n/cm2
6·109
n/cm21013
n/cm2
BPW(1)
1·1010 n/cm2/mV
7·1010 n/cm2
2·1010 n/cm2
5·1014 n/cm2
Toshiba 2·106 n/cm2/count
2·108 n/cm2
2·108 n/cm2
2·1011 n/cm2
Cypress 1.5·105(8·105)
n/cm2/count NA1.5·107(8·107)
n/cm2
4·1011 n/cm2
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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BatMon – versatile instrument
October 2014
Where versatile installation is requiredE.g. PLC failures in LHC Point
4 and 6 requiring urgent checks1. Validation of the relocation
strategy2. Measure R-factor in critical
area via voltage change3. Measurement requests for
machine studies
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Injector’s radiation monitoringR2E up to 2012 concentrated on the LHC, in
order to mitigate radiation effects for Run 1However issues are present in the injector
chain as well, simply “less visible” In order to guarantee machine availability
also in the future, it’s important to dedicate resources on it as well
Info available at http://r2e-injectors.web.cern.ch/
October 2014
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Issues with present radiation monitoring
October 2014
BLMs (ACEM – Aluminum Cathode Electron Multipliers)
Saturation in critical areas, of no use for loss distribution Not calibrated to dose Ongoing campaign to install LHC-type BLMs in PSB
(not PS) important to be able to evaluate cumulative dose
SPS ionisation chambers – low granularity (1 every 32 meters)
HLD (not online system) Radiation Surveys
Depends on activation, cannot directly relate to rad levels for equipment
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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PSB example (RS vs. HLD)
October 2014
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PS example (RS vs. HLD)
October 2014
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Injector monitoring - future
October 2014
Requirements: Appropriate BLM coverage with sufficient granularity in
PS/PSB/SPS RadMon installation extension Passive dosimetry Important to follow-up this measurements and improve
analysis speed
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Requirements from users
October 2014
A weekly report was published during 2011/2012, providing radiation levels in critical areasService to users in support of the RadWG
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Requirements from users
October 2014
However: It was a manual system, requiring full support
from the MCWG teamDifficult for users to understand levels if
equipment away from the detector location interpretation/extrapolation from MCWG team needed
Loss scenarios can modify radiation levels distributions
Investment should be made to try to automatize it!
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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Requirements from users
October 2014
An attempt of realizing an online system was performed in collaboration with EN/ICE
Dedicated support of EN/ICE requested to revise the system
LHC R2E Dashboard
Complex to maintain, since as of now data requires manual manipulation
M. Calviani: Radiation monitoring - R2E/Availability Workshop
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What will be needed for Run II1. Reactivation of the MCWG analysis team
2. Dedicated support from the BLM team to provide cumulated doses on a weekly basis
3. RadMon team to continue support the detectors
4. Continue keep track of the detectors inventory (Layout DB?)
5. Support of the groups for fast reporting on equipment failures
6. Continue improving on radiation monitoring in the injectors
October 2014
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Fundamental to follow-up on these, at the moment done manually!
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ConclusionsMonitoring is and will be an important aspects of the R2E (and Availability) activities In the LHC and in the Injector chain It is now required as a service rather than
studiesPowerful instrument that allow providing a service to equipment owners in understanding radiation-related failures
October 2014