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

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

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

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

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

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

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

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

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

Tunnel Location 01/09/2014 W. Weterings

Tunnel Location 01/09/2014 W. Weterings

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 2014-11-17 EDMS 1437718 J. Coupard EN-MEF

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