ELENA EXTRACTION LINESW. Bartmann, D. Barna, M. Fraser, J. Jentzsch, R. Ostojic

ELENA Commissioning discussion, 23th November, 2015

ELENA transfer line sketch

Beam parameters at extraction

• Parameters for antiprotons from ELENA

• 100 keV protons or H- from ion source for commissioning• Pulsed• Bigger emittances, to be measured, LNS acceptance up to 50 um• Higher intensity, to be measured• Momentum spread – to be checked

Optics example LNE00

Instrumentation

M. Hori

Instrumentation

M. Hori

LNE50

• Beam size rms of 1-2 mm

First ideas on commissioning steps of extr. lines

• Objective:• Quantifiy sufficiently well equipment and beam parameters before standard operation

(transmission, beam size, trajectory stability)

• Prerequisites:• Machine + transfer lines installed and pumped to < 1e-6 (VSC to agree for NEG)• Zone interlocking (EIS) tested• Optics integrated into YASP• Commissioning algorithms prepared• HW commissioning completed (individual system tests like HV conditioning, power converter

stability run, SEM grid movement and acquisition, logging, data display)

HW check-out (ion switch, quadrupoles, static deflectors) - 1 • Before installation:• Elements protected after vacuum tests:

• pinch-off flanges mounted and elements purged with dry air• Feedthroughs grounded using protective (shorted) SHV connectors

• • After installation, before bake-out, cables not-connected:• Check assignment table (installation slot vs serial number of the unit) • Check labelling of the feedthroughs• Remove protective SHV connector

• Check for short circuit• Measure electrode capacitance• Use portative PS to power electrode to 0.5-1 kV (in air)• Reinstall protective SHV connector

• • After bake-out, connecting the cables• Remove protective SHV connector on the circuit to be used

• Check for short circuit• Measure electrode capacitance• Use portative PS to power electrode to ½ nominal voltage (in vacuum)• Install the corresponding cable, while checking for the polarity assignation• Check that protective SHV connectors remain on non-used feedthroughs

• • Vacuum sector ready for hardware commissioning – Phase-1

• Perform interlock checks •

HW check-out (ion switch, quadrupoles, static deflectors) - 2• Conditioning in vacuum - ZQNA• Use PS control system to raise voltage in steps to nominal, stay at nominal, and decrease voltage to

zero in steps, one circuit at a time; if discharge, repeat after a pause to stabilize vacuum• Discharge circuit - perform the same steps for all circuits used in a ZQNA unit• Discharge circuit – set nominal values from optics tables; leave on for several hours• Use PC control system to move the correctors from positive to negative kick, through zero setting;

perform on all correctors in a ZQNA unit• • Conditioning in vacuum – ZDSIA• Specific test depending on the final configuration of the powering system (should have been done

with the temporary system before closure of the sector)• After sector ready for HC, follow similar sequence but from PS control system.

• • Conditioning in vacuum – ZDS (Phase-2)• Use PS control system to raise voltage in steps to nominal, stay at nominal, and decrease voltage to

zero in steps, one circuit at a time; if discharge, repeat after a pause to stabilize vacuum• Perform the same for the two circuits in a ZDS unit• Discharge – set nominal values from optics tables; leave on for several hours

Beam commissioning steps of extr. lines

• Optics• Thread through extraction device – which beam, only H- first?• Establish trajectory until last valve - can we dump the beam there or do we have a dedicated beam

stopper?• SEM/corrector polarity check with kick response• Transfer function of correctors• Aperture check• Lower priority• Optics and dispersion measurement• Trajectory stability

• Before moving to antiprotons• Synchronisation checks

• Commissioning the TLs is part of the general ELENA commissioning – knowledge of both, ring and TLs, is useful and help is appreciated

• More detailed information on the lines: Layout of the ELENA transfer lines, EDMS 1388169