1. Consolidation and development of the CERN radiating cable infrastructure in PS and TT2
F. Chapron
IT/CS

2. Agenda What is the use of the radiating cable at CERN ?
What needs to be done and how ?
Work in PS
Work in TT2

3. What is the use of the radiating cable at CERN ?
More than 50 km of cable at CERN
Almost all tunnels and experiments
Used to carry multiple signals
CERN safety services:
TETRA signals used mainly by the CERN fire brigade.
Indoor localisation system (indirectly)
External safety services:
the TETRAPOL signals from the Swiss and French safety organisations
General public mobile services:
GSM (2G), UMTS (3G) and LTE (4G) signals
Special users like the TIM (“Train d’Inspection sur Monorail”) or remote maintenance robots access CERN intranet via a secured and controlled access (CERN APN).
Radiating cable
TI8 injection tunnel

4. What needs to be done and how ?
Due to the aging of the cable and the high exposure to radiation in some locations, the infrastructure must be renewed before it stops working.
If the radiating cable is broken, mobile communications are not possible anymore
A global PLAN project (number 10046) was created for the approval process, but it is including many sub-projects which will be described in specific ECRs
To allow a smooth transition (without cutting the mobile and radio services) :
Deployment of a new cable during E-YETS, YETS and LS2
Replacement of the existing cable during LS3
Who does what ?
IT-CS: inputs for coordination, material supplying, ECRs drafting (with EN/EL and EN/ACE), cable connectors and terminations, commissioning
EN-EL: coordination and supervision of cable pulling
Where and when?
E-YETS: PS and TT2 (first ECRs already circulated for approval)
YETS: Booster
LS2: SPS, LHC3/LHC7 and aside the LHC experiments (at collimator locations)
Schedule for other locations (Linac, CTF2,3, AD, ISR, Ntof) to be evaluated

5. Work in PS during E-YETS
ECR number v.0.1
Status: under approval (submitted beginning of July)
Few comments but no blocking point. The ECR to be updated.
Extension of coverage in PS cross galleries
Currently there is no mobile coverage in the PS cross galleries
A New TETRA emitter will be placed in 359/R-009
A coax cable will be pulled from 359/R-009 to a radio frequency splitter in room 353/S-202 (location to be identified)
Pulling of a radiating cable in each of the four PS cross galleries
Placed on the ceiling displaced from the middle to preserve the reservation for the line of sight SURVEY
Stopping just before the fire protection doors
Cross of the fire door at the end of tunnel 1
Addition of a cable in PS ring
Attach, with clamps, a second cable above the internal yellow girder (from ring centre), similar to the installation of the existing cable on the external yellow girder.
To cross the eight (8m) sections where there are (CV) pipes by connecting radiating cable segments by a flexible, small diameter coax cable.
3D integration still to be done

6. Courtesy to P. Lelong for the drawing

7. Work in PS during E-YETS
Constraints
When pulling the cable the path will be blocked
In PS cross tunnel, the cable pulling requires one week of work for each tunnel
In PS ring, the cable pulling requires one week of work for each of the eight section
Pulling of a small coax cable from emitter in to the PS (via cable trays).
Radiations at some places
Junction between TT2 and PS ….

8. Work in TT2 during E-YETS
ECR number v.0.1
Status: under approval (submitted beginning of July)
Few comments but no blocking point. The ECR to be updated.
Addition of a radiating cable
Interconnected with the PS ring infrastructure
Extension of infrastructure up to lift in building 269 (A-TT2-E location)
The second cable will follow the same path and as much as possible, at a distance of 30 cm from the existing cable
At the end of TT2 tunnel, the cable will be split to cover TTL2 tunnel
Extension of coverage in the safety exit (ladder) in TTL2 with antenna

9. Work in TT2 during E-YETS
Cable path in details

10. Work in TT2 during E-YETS
Cable path in details

11. Work in TT2 during E-YETS
Constraints
One fire door to cross
When pulling the cable the path will be blocked.
The work will last up to 1 month
Known co-activity with the renewal of fire detection system
Sorted out…

12. Thanks

13. Current radiation studies
Since May 2016, new radiation tests are being performed on the “new” LF cable in CHARM in “operational mode”
Objective:
Identify any impact on “live” signals when the cumulative radiation dose increases
Redo mechanical tests with a thinner accuracy than the previous tests
Test the resistance of the clamps to radiation.

14. What is a radiating cable?
Is a cable used to carry radio signals in buildings
It’s like a “long” antenna connected to an emitter.
It is made of two coax cables isolated by foam and protected by a jacket.
Made for certain frequencies with better longitudinal loss (-3dB/m) and coupling loss
The external coax cable has holes equally distributed all along which allow to broadcast the signal in a “clean” way
Typically affix to the wall/cable trays with clamps
At CERN, there 4 types of cables with their respective clamps
CQG50 : installed in 2002/2003 mainly in LHC and SPS
CQA50, CQB50, CQD50: installed in 1996 mainly in injector chain.
Holes
Foam
Longitudinal loss
Coupling loss
Jacket
Coax cables

15. What is the issue ? Picture in SPS1
Mechanical tests have been performed in 2010 on samples (jacket + foam) after radiation
EDMS doc: v.1
For samples exposed to more than 100 kGy, the foam starts crumbling away with low compression.
If the LF cable is manipulated, there is a high risk of short-cut preventing normal LF operation
Any repair will introduce additional power loss
The foam losing its dielectric feature, first the longitudinal loss value of the cable will degrade (problematic for LHC), and the then coupling loss
The external jacket also gets “burned”
Radiation effects on other components was not tested (connectors, clamps)
Normal aging of the cable
Thirty (30) years under normal environmental in-tunnel conditions
External damages
Severe event like a fire destroying the cable can prevent communications in large tunnel sections
Local damage (cable hit by “machines”)
Local repair can be performed but will affect the max propagation distance
100 KGy
Foam radiation tests
Picture in SPS1

16. Work in PS during E-YETS
Integration of the cable in PS cross galleries
View from ring centre with tunnel 5 on the left and tunnel 7 in front.
View from ring centre with tunnel 3 on the left and tunnel 7 on the right.
View from ring centre with tunnel 3 on the left and tunnel 7 on the right.
Tunnel 1 on the right and tunnel 5 in front.

17. Other topics Frequencies Materiel supply Commissioning
Already broadcasted in all PS and TT2 (except extensions)
Safety signals
TETRA:
Duplex frequencies: / MHz ; / MHz ; / MHz ; / MHz ; / MHz / MHz
Simplex frequency: MHz, MHz, MHz
TETRAPOL:
French safety network: / MHz
Swiss safety network: / MHz
Public mobile signals
GSM: from 876 MHz to 959 MHz
UMTS: from 876 MHz to 959 MHz
LTE: from 791 MHz to 862 MHz
Materiel supply
New cable for which radiation resistance is being tested in CHARM
Commissioning
Ejection of a signal with frequency generator and validation that propagation with RF analyser
Interconnection with TETRA and mobile emitters (short disruption)

18. Conclusion
The radiating cable infrastructure is the only means to have mobile communications in tunnels for the fire brigade and standard users
The work in PS and TT2 will be done without service cut for end-users during the E-YETS
The main constraint is the blocking of paths when pulling the cable