1. LINAC4 Vacuum Control System Review
J. De la Gama, Vacuum Controls,

2. Vacuum Control System Overview
LINAC 4 Description
LINAC 4 Vacuum Control System
Gas Injection
Interlocks and Alarms rules
Interlocks logic
References
J. De la Gama, Vacuum Controls,
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3. LINAC4 Description
Linac4, the new 160 MeV CERN H- injector, is presently being constructed at CERN Building 400 with the goal of improving the LHC injection chain with a new higher energy linac. A dynamic pressure in the low 10-7 mbar is therefore requested all along the machine, starting from the RFQ.
LINAC4 Vacuum Requirement
The Linac4 vacuum system has to respond to the three criteria of reliability, robustness and minimal downtime in case of failure during operation.
Together with these criteria, ultimate pressure is the essential technical parameter for the vacuum system. Specification values vary along the longitudinal coordinate, where the most constraining requirement is the large pressure drop between the LEBT and the RFQ (<5.10-7mbar).
Pressure in the LEBT, up to mbar, is regulated by gas injection, to optimize space charge compensation. Accelerating structures and TL: < mbar.
G.Vandoni.
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4. Total: 13 VRGPT (TPG300) 52 signals 44 VRPI 88 signals
Linac4 Vacuum Controls
Hardware Spec:
6 Vacuum Sectors
SOURCE – 3x VRGPT (TPG300)
RFQ – 2x VRGPT (TPG300) & 9x VRPI
CHOPPER – 2x VRGPT (TPG300) & 4x VRPI
DTL – 2x VRGPT (TPG300) & 5x VRPI
CCDTL – 2x VRGPT (TPG300) & 14x VRPI
PIMS – 2x VRGPT (TPG300) & 12x VRPI
DONE!!
DONE!!
DONE!!
DONE!!
Total:
13 VRGPT (TPG300)
44 VRPI
52 signals
88 signals
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5. Gas Injection
Fixed turbomolecular pumping groups with backing dry scroll pumps are used to
evacuate the heavy gas load from source and LEBT gas injection, where pressure and gas species is not compatible with ion pumps.
A Residual Gas Analyzer (RGA)is separately pumped.
LEBT, Its function is to transport the beam from the ion source and match it to the RFQ input parameters, gas injection is ensured by a regulated gas dosing valve, one smaller scroll pump evacuates the differential gas on the line.
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J. De la Gama, Vacuum Controls,

6. Interlocks and Alarms rules
Chopper Valve
RF Valve
Penning gauge
Ion Pump
Condition:
IF (Penning gauge signal OK) THEN (Ion Pumps can operate )
1 SIG>RF
VRP Lev1B
VRP Lev1A
VRP Lev1A
VRP Lev1A
VRP Lev1A
REL2/4
J. De la Gama, Vacuum Controls,

7. Interlocks logic
Alarms for RF
Each VVS is controlled by 4 devices that can give the interlock signal.
A sector valve can be opened if ALL devices are ready.
A sector valve is closed when there is an interlock trigger of 3 of the 4 devices
The VVS-1 and VVS+1 will be closed.
In this way two sectors are isolated .
In LINAC4 it is used the same configuration and logic than in LHC.
J. De la Gama, Vacuum Controls,

8. Next Steps…
Cabling, installation and commissioning for Half-sector Test
Installation and commissioning for CDDTL, CDTL & PIMPS
VRPI Calibration (32 devices)
Documentation Update
J. De la Gama, Vacuum Controls,

9. References Presentation Interlock LHC (Gael Girardot)
Hardware Configuration. (S. Blanchard & K.Radwan)
Racks Layout
Technical Description of the LINAC 4 Vacuum System (G. Vandoni)
Thanks to J. Yanez, F. Aragon, K. Radwan, Gia, Helder, Fabien, Philippe, A. Gutierrez and S. Blanchard for your help and support.
J. De la Gama, Vacuum Controls,