2. The Stripping Foil Test Stand in the Linac4 Transfer Line
R. Noulibos, P. van Trappen, W. Weterings
CERN, European Organization for Nuclear Research, CH-1211 Geneva 23, Switzerland

3. Stripping Foil Test Stand
A stripping foil test stand will be installed in the Linac4 transfer line allowing tests with a 160 MeV H− Linac4 commissioning beam:
Testing from 2015, prior to final PSB installation (>2018)
The foil changing mechanism as well as the interlocking functions can be assessed;
Gain experience with these very fragile foils;
Test different foil materials and thicknesses;
Evaluate the lifetime of the foils and foil holders;
Measure the stripping efficiency and emittance growth of the beam through the stripping foil.
01/09/2014
W. Weterings

4. Layout & Instrumentation
Linac4 Layout
160 MeV
100 MeV
50 MeV
3 MeV
Dump
PIMS
CCDTL
DTL
Source
Transfer Line to PSB
Transfer Line
to PSB
Profile Monitors
Stripping Foil
Test Stand Location QF QD
QD from 2.5 T/m up to 9 T/m, the horizontal beam size (90%) can be varied from 2.5 mm to 3.7 mm respectively and the vertical beam size from 7.4 mm to 4.2 mm.
Beam can be transported to the main dump without any losses, provided that the downstream QF (L4T. MQF.0210) is switched off
BCT + BLM
BCT
Stripping efficiency is measured by current decrease between cross-calibrated Beam Current Transformers (BCT) and by taking the electrical signal from the foil holder.
Emittance growth is estimated using Secondary Electron Monitor (SEM) profile.
The upstream defocusing quadrupole (QD) is used to vary the beam size.
01/09/2014
W. Weterings

5. Test possibilities
Stripping efficiency by measuring the BCT current before and after the foil (resolution of 0.1 mA).
Beam losses at the level of few 109 protons are expected for 1014 H− nominal intensity from L4.
A rough estimate of the emittance growth through the stripping foil could be obtained by using the SEM profile grids.
The PSB injection worst failure scenario can be simulated by hitting the foil with a 400 µs pulse and minimum beam size.
Many mechanical cycles and movement of the foil, with and without beam to test rigidity of different types of foils.
The BTV system will be tested, including correct filters selection for beam measurements over a large range of beam intensities as well as the Foil – BTV screen interference interlock.
01/09/2014
W. Weterings

6. Foil Handling Mechanism
Radiation Hard
Camera
Mirrors and
Optical Filters
Stepping motor
1 mm thick Chromox (Al2O3 doped with CrO2) scintillating screen, engraved with calibration marks.
The BTV has a position accuracy of ±0.2 mm and for a large range of beam intensities remotely controlled optical filters are included.
Magnetic coupling
Foil Changer
Beam Observation System (BTV) with
Screen in Beam
Rear View
Showing mirror
01/09/2014
W. Weterings

7. Foil Handling Mechanism
Radiation Hard
Camera
Mirrors and
Optical Filters
Stepping motor
A stripping foil current measurement will be made by means of taking the electrical signal from the foil holder
Beam
Magnetic coupling
Foil Changer
Beam Observation System (BTV) with
Screen Retracted
Rear View
Showing mirror
01/09/2014
W. Weterings

8. Foil Handling Mechanism
Radiation Hard
Camera
Mirrors and
Optical Filters
Stepping motor
Magnetic coupling
Foil Changer
Beam Observation System (BTV) with
Screen retracted
Vacuum Chamber
01/09/2014
W. Weterings

9. Foil Handling Mechanism
Final configuration to be
installed in Linac4
transfer line (L4T) sector 1.1
01/09/2014
W. Weterings

10. Configuration L4T sector 1.1
Beam Current Transformer (BCT)
Beam
Vacuum Valve
Vacuum
Valve
To optimise intervention time and avoid foil damage due to differential pressure, the system is installed in a dedicated vacuum sector.
Stripping Foil Test Stand
01/09/2014
W. Weterings

11. Tunnel Location
01/09/2014
W. Weterings

12. Tunnel Location
01/09/2014
W. Weterings

13. Blanc assembly – Required Space
Create the restricted environment with concrete blocks and/or wood panels
~ 4 meter
‘Mock-up’ dipoles in case BHZ are not available
~ 7 meter

14. Blanc assembly – Minimum Space
~ 5 meter
Create the restricted environment with concrete blocks and/or wood panels
‘Mock-up’ dipoles ends
~ 4 meter

15. Mock-Up building 355
01/09/2014
W. Weterings

16. Mock-Up building 355
01/09/2014
W. Weterings

17. Mock-Up building 355
01/09/2014
W. Weterings

18. Mock-Up building 355
01/09/2014
W. Weterings

19. Mock-Up building 355
01/09/2014
W. Weterings

20. Mock-Up building 355
01/09/2014
W. Weterings

21. STR mechanism prototype status
1104 mm Prototype progression
541.5 mm Foil Loader progression
Courtesy of Remi GUEYDAN
- All parts manufactured and modified - Ready for 2nd assembly and tests
Most of parts manufactured
Ready for assembly and tests January 2015
Prototype 1104mm has been completely dismantled
Modifications have been done after tests
Assembly has started for new tests in January 2015
16/12/2014
R. Noulibos

22. Study of Magnetic coupling replacement
Goal: overcome lack of precision due to magnetic drive
Drive Study
(in progress)
LHC BTV
Mechanism
LHC BTV
Mechanism
Present
Drive
Magnetic
coupling
Length : 80mm
Outside diameter : 35mm
Length : 80mm
Outside diameter : 35mm
16/12/2014
R. Noulibos

23. L4 STR test stand & HST Status
STR for HST
STR
for
Test Stand
_ All manufacturing drawings are all produced
_ A few drawings to control
16/12/2014
R. Noulibos

24. STR test stand & HST Tanks
_ Deadline : Dec. 2014
but…. dedicated
milling machine
breakdown 4 weeks
_ Machining finished
_ Electron beam welding
1st week of January
With new shape for
Inconel Chambers
16/12/2014
R. Noulibos

25. STR test stand & HST tanks
Flanges still
to be machined
16/12/2014
R. Noulibos

26. STR test stand & HST Loaders
_ Delivery of loader parts: 2nd week of January
_ Assembly ready for tests: 1st week of February
_ BI Mechanisms Delivery ?
16/12/2014
R. Noulibos

27. Linac 4 Planning Commissioning phases contain Installation
Ready for 50 MeV protons
YETS
Installation
Commissioning
50 MeV
Commissioning
100 MeV
Commissioning
160 MeV
Reliability Run
Half Sector Test
5 months
4 weeks
5 weeks
3 months
3 months
Commissioning phases contain
RF Conditioning
Connection of the beam line (vacuum , survey)
Hardware Tests (power converters, magnets)
LLRF calibrating
Beam Commissioning
EDMS
J. Coupard EN-MEF

28. STR Planning
Jan 2015 :
Tests of 1104mm band prototype improvements for precision
Assembly of Test stand & HST short loaders (541mm band)
Feb - Mar 2015 :
Lab tests with short loaders in L4 Test Stand vacuum tank
Apr 2015 :
Lab tests with BI instrumentation mechanism in L4 Test Stand
May 2015 :
Installation of STR Test Stand in Linac 4
Jun-Jul 2015 :
Lab tests with short loaders in L4 HST vacuum tank
Aug-Sep 2015 :
Installation of STR HST in Linac 4
Jan-Feb 2016 :
Tests of STR HST in Linac 4
16/12/2014
R. Noulibos