LINAC3 UPGRADE Strategy for the hardware modification of the GTS-LHC 18/3/2015 Ville Toivanen

Motivation for GTS-LHC modifications Strongly divergent beams is an inherent property of the current GTS-LHC extraction system when operated in afterglow mode – leads to significant initial beam losses Pb beam SOLENOID Pb 29+ simulated transmission ~ 38%

The proposed hardware modifications A new pumping chamber to allow the modifications Increased downstream branch bore Redesign of the upstream branch (einzel support) New port for einzel lens HV input A new beam pipe with increased bore size through the first beam line solenoid From 65 mm to 100 mm Solenoid bore is 110 mm Mitigates beam losses before the first solenoid Allows more flexible operation of the GTS-LHC extraction system A new focusing element in the extraction system An electrostatic einzel lens and support structures Downstream from the existing electrodes Mitigates beam losses by decreasing the beam divergence and size Normal beam delivery not critically dependent on modifications HIGH potential and LOW risk upgrade

Ions schedule

Proposed schedule Based on technical meeting held on 11/3/2015 Present: Didier Steyaert, Pierre Moyret, Alice Michet, Detlef Küchler, Ville Toivanen Time requirements set for mechanical design and manufacturing Adjusted to allow installation in the first quarter of 2016 First deadline: Optical design, end of May 2015 Einzel lens geometry definition with extraction simulations Simulation study to define LEBT transmission and beam matching to the RFQ with the modifications

ADDITIONAL SLIDES

GTS-LHC extraction system Intermediate electrode Plasma electrode Ground electrode Plasma chamber Ref.: LICNFIEA0001 Extraction pumping chamber

Extraction electrodes Beam Plasma Plasma electrode (+V) Intermediate electrode (-V) Ground electrode (GND)

Bigger beam pipes: pumping chamber Ref.: LICNFIEA0001 New pumping chamber with larger bore (100 mm instead of 65 mm) outlet branch for beam Modified for lens support

Bigger beam pipes: LEBT GTS-LHC (pumping chamber) 1 st diagnostics chamber Spectrometer Ref.: LICLM___ SOL1 Larger bore (100 mm) beam pipe through SOL1 100

New einzel lens inside pumping chamber Beam Plasma GTS extraction system An example: GTS extraction system with iThemba LABS einzel lens

New einzel lens inside pumping chamber Intermediate electrode Plasma electrode Ground electrode Plasma chamber Ref.: LICNFIEA0001 iThemba einzel

New einzel lens inside pumping chamber Intermediate electrode Plasma electrode Ground electrode Plasma chamber Ref.: LICNFIEA0001 New einzel lens design better optimized for GTS-LHC (ongoing)