1. Radiation monitoring and follow up during LHC commissioning
Presented by T. Wijnands (TS/LEA)
Contributions : SC/RP, AB-ATB, CMS BRM group, speakers at the 6th LHC Radiation workshop
All proposals presented here are open for debate !

2. Outline Radmon for equipment groups
Radiation Monitoring (including Radmon) for LHC commissioning
5 March 2008
ELTC days

3. RADMON radiation monitors
T. Wijnands, C. Pignard, D. McFarlane, A. Nyul, A. Prevenas
(2 FTEs + 2 Technical Students)
CERN, TS Department
5 March 2008
ELTC days

4. RadMon Radiation Monitors
350 RadMon devices in LHC tunnel, underground areas, caverns
To measure radiation levels at the location of equipment on line
To check radiation levels against simulations
To verify performance of equipment under irradiation
To provide early warnings and feedback to EICs in case of danger
5 March 2008
ELTC days

5. RadMon devices Integrated radiation sensors – 200 Gy
Remote radiation sensors – 200 kGy
5 March 2008
ELTC days

6. Radmon system Tunnel Monitors are all installed and commissioned
CMS, ATLAS, CNGS installations before “summer” 2008
Standard AB/CO controls infrastructure
Fixed displays (equip monitor) PM
Timing
TIMBER, METER for logging
ROOT Expert program
In CCC :
Dose rate (dose)
Hadron flux (fluence)
1 MeV neutron fluence
We are very confident that all this will work because it did so in the SPS (3 years), CDF-Tevatron (1 year), CNGS, Proton Test beams, Neutron test beams, Nuclear reactors, Gamma sources ….
5 March 2008
ELTC days

7. TSL :174 MeV Neutron Irradiation
LHC BLM chamber
RADMON
D. Kramer, M. Stockner, C. Pignard, T. Wijnands
5 March 2008
ELTC days

8. Example SPS : high radiation along M2 beam line
Bending Magnet M2 beam line wrong
5 March 2008
ELTC days

9. Outline Radmon for equipment groups
Radiation Monitoring (including Radmon) for LHC commissioning
5 March 2008
ELTC days

10. LHC Radiation Monitoring systems
Several systems, various groups, different objectives :
RAMSES
BLMs
Radmons
Passive dosimetry
BCM/BSC (experiments)
See presentations in 6th LHC radiation workshop :
5 March 2008
ELTC days

11. Radiation measurements at startup
We prefer a joined approach for LHC radiation issues :
global rather then individual solutions
share experience in the field
share shiftwork
increase measurement resolution
shorter turnaround time in case of radiation problems
Discussed with D. Forkel-Wirth, S. Roesler, H. Vincke, A. Ferrari, R. Hall Wilton, …
5 March 2008
ELTC days

12. How to get organized ? Front Office Back Office LHC Operations
1 x EIC with experience in radiation matters
1 x Radiation expert
Front Office
Simulations Shielding and Monitoring
MC Simulations
Shielding
Analysis Radiation data
Modify monitoring
Feedback to EICs
Radiation Damage Effects
Performance equipment under radiation
Radtol equipment designs
Radiation Tests
New System architectures
Back Office
5 March 2008
ELTC days

13. When do we care about radiation in the CCC ?
In general :
Increase in beam intensity
Optics change
Change in energy
Collisions
Phase
Description
Radiation
Areas to check
A.1
Injection and first turn
yes
UJ88, UJ22, UA87, UA23
A.2
Circulating pilot no
ARC, UX45, IR7
A.3
450 GeV initial commissioning
UA67, UA63, UP62, UP68
A.4
450 GeV optics
ARC, DS
A.5
Increasing intensity
Help !
A.6
2 beam operation - colliding beams at 450 GeV
LSS1, LSS5, RRs, UX15, UXC55
A.7
Snap-back and ramp
IR3
A.8
Bringing beams into collision
A.9
7 TeV optics
A.10
Squeeze
LSS, RRs
A.11
Physics runs
UJ14, UJ16, UJ53, UJ57
5 March 2008
ELTC days

14. What can go wrong ? measured > or < expected
No further increase in beam intensity
Try to find and eliminate the cause in CCC
Inform equipments groups concerned
Monitor error rates in equipment
Perform detailed (MC) analysis
(to be able to compare simulations & measurements)
Improve local radiation monitoring
Slowly further increase beam intensity
measured >> or << expected
This may halt the LHC for several months (i.e CNGS) !
Find the cause
Design shielding and/or change equipment architecture
5 March 2008
ELTC days

15. Example : beam on TI8 TED UA Shielding TI8 TED UX85 UJ88
Simulation by H. Vincke SC/RP
5 March 2008
ELTC days

16. Radiation measurements at end TI8
UJ88
TI8
4R8
UA87
UJ88
UA87
Next to TDI
5 March 2008
ELTC days

17. TI8 Radiation measurements
4 x 72 x 3e10 on TI8 TED
Few tens of counts on Radmons in UJ88 (nbr 8,7,6)
Nothing (?) on Radmons in UA87 (nbr 5,4,3)
IAMs for integrated dose (< 1 rad)
BLMs for loss patterns (spatial & temporal)
What can go wrong ?
Few 106 hadrons above 20 MeV in UA87
What to do ?
Reinforce UA87 shielding
Fill up all holes
Perform MC simulations
Modify radiation monitoring
Study equipment failures
5 March 2008
ELTC days

18. Summary
Recommend to use available Radiation diagnostics (including Radmons) in LHC operation
Combining BLM, RAMSES, Radmon, BCM/BSC, passive measurements will prove beneficial for all concerned
So far everyone is willing to contribute but consolidation (i.e. manpower) is required
Proposal is to distinguish between:
Radiation damage effects
Simulation, shielding and data analysis
Radiation diagnostician in charge in CCC
5 March 2008
ELTC days

19. Conclusions Radiation issues in the LHC will much more complex :
Large amount of equipment will be exposed
Some (electronic) equipment very sensitive
MC simulations of the machine are incomplete
Locating the radiation source may prove difficult
Consequences of damage to equipment considerable
We recommend to start now and to put the infrastructure in place :
To reduce impact on LHC operations
To minimize the problems related to activation
What could be done if we start now :
Review simulations, assumptions, back up solutions, radtol designs …
Improve radiation measurements in critical areas
Detailed plan for LHC commissioning phase
5 March 2008
ELTC days