3. Outline Introduction to LHC Power Converters Remaining Inventory
Observed Availability
New inventory – FGClite
Cumulative & SEE Effects
Maintenance Expectations
Improving Availability

4. LHC Power Converters (1/3)
≈1050 in LHC radiation areas

5. LHC Power Converters (2/3) Inventory
Thurel, CERN’12

6. LHC Power Converters (3/3) Power & Control
After Todd, TWEPP’12
Control Part – FGC
S. Uznanski
Power Part – Voltage Source
Y. Thurel

7. Observed Availability in 2012
Hardware failures leading to a beam dump from Post Mortem
After Todd, Evian’12
All faults: Post Mortem, EPC Equipment and RadWG
New controller needed: FGClite

8. FGClite (1/3) Technical Concept
Dedicated design methodology:
No microcontrollers/DSP as computationally intensive tasks moved to the gateway
Extensive radiation testing to select/validate all electronic components
Highly available Gateway/FGClite communication required

9. FGClite (2/3) Challenges
Reliable communication infrastructure
FGClite infrastructure (TE-EPC):
Robust FGClite hardware
Robust Gateway software and hardware
World FIP (BE-CO):
FGClite/Gateway communication modules
Robust repeaters, cabling, etc…
Field Bus functional tests (BE-CO):
High speed, high temp, long cables, 30 days
Not sufficient statistics

10. FGClite (3/3) Installation
FGClite project planning
2015
2015/16
2016/17
First Beam & Physics
Increasing failure rate
FGC2 not acceptable
FGC2 OK ?
nOK
FGClite
Production/Burn-in ? OK
FGClite burn-in & installation
Infant mortality failures
FGClite operational
FGC2
≈ 1700 units
≈1050 units
Number of FGCs
≈650 units
FGClite
Time
2015: FGC2 will be used after LS1 for the first months as its failure rate will be acceptable
2015/16: FGC2 will start failing due to increasing radiation levels thus FGClite will be installed
2016/17: Operational FGClite will exhibit much lower failure rate than FGC2 after infant mortality issues are addressed.

11. Estimated reliability post-LS1
Radiation environment
Radiation Levels
Røed,
CERN’12
Brugger,
CERN Oct. 14
Accumulated dose
SEE related

12. Long term supply of components: Preventive maintenance:
Maintenance Plan
Long term supply of components:
Batches of components (1600x FGClite)
1400x production
1100x in operation
20% spares
30x Pre-series
20x Rad Testing
150x future repairs (storage in controlled atmosphere?)
50x prototyping
Preventive maintenance:
Rotation of devices as a function of accumulated dose:
Each FGClite has an embedded radiation monitor (SRAM-based)
Based on dose measurement, a rotation of devices will be done
~10% in hottest locations swapped every LS
~10% in hottest locations swapped every year
Expected access:
Infant mortality failures (2016) higher
Operational FGClite (>2016) same as for the FGC2

13. Improving Availability
Availability limited by electronics exposed to radiation
Further optimization would require changing the gateway/front-end communication
to get higher throughput

14. Conclusions Remaining/New inventory analyzed Cumulative/SEE Effects
Relocation done where possible
Most of the equipment will remain in affected environments
Cumulative/SEE Effects
TID can become problematic for HL-LHC if no mitigation
Rotation of the FGClites will be needed in long term
Failures due to SEEs will be addressed in the FGClite
Maintenance expectations
Supply of components will cover spares/prototyping/testing needs
Preventive maintenance will be done as a function of TID
Improving availability
Number of exposed components is strictly limited with the FGClite
Additional improvements would require higher throughput communications