Sector Test Meeting - MG 1

Possible beam measurements during 2014 sector tests

W. Bartmann, M. Giovannozzi, S. Redaelli, R. Tomas, J. Wenninger

•Aperture •Polarities•Optics•Collimation

Acknowledgements: B. Goddard

General comment: most of these measurements can be performed more efficiently with circulating beams. An early detection of possible issues is the justification for beam measurements during the sector tests.

22/05/2014

Aperture measurements• Regions:

– Injection– Arcs– IRs– Dump channel

• Arcs and IRs:– Create betatron oscillations along the sector(s)– Possibly fix amplitude to the expected required

aperture at injection.– Scan over the phase

22/05/2014 Sector Test Meeting - MG 2

Already covered by W. Bartmann on 8/5/2014

Polarity measurements - I• Elements to be probed (priority list):

1. BPM and orbit correctors

2. Circuits affected by LS1 activities• Skew correctors in sector 3-4: put back in operation

during LS1 -> not available for sector tests• RQTF.A81.B1: four magnets removed from circuit ->

not available for sector tests• RCOs: some magnets by-passed during LS1

– RCO.A78B2: 2 out of 77 magnets are bypassed -> available for sector test

– RCO.A81B2: 2 out of 77 magnets are bypassed -> not available for sector test

• Q5L8: new magnet installed during LS1 -> not available for sector tests

22/05/2014 Sector Test Meeting - MG 3

Polarity measurements - II• Elements to be probed:

3. Skew quadrupoles (usually have polarity issues)

4. Circuits not fully tested during Run I• …

5. Sample test of circuits, e.g.,• MQTs• MQTLs

22/05/2014 Sector Test Meeting - MG 4

Optics• Combined transfer line + LHC ring studies

(extension of tests proposed by W. Bartmann on 8/5/2014):– Kick response– Dispersion measurement

22/05/2014 Sector Test Meeting - MG 5

Remember TL and ring matching puzzles in 2008

Ring Collimation• See details in Belen’s talk on 08-05-2014 on

how to stop the beams • Envisage two dedicated measurements:

– Parasitic: check acquisition of BPM signal of new collimators, when applicable.

– Dedicated: BLM response with different collimator settings (“splash” events for different collimators in cleaning insertions – if reachable during the sector test) – BI request

– Note: no need of special controls setup in LSA, manual movements and adjustment of interlocks.

22/05/2014 Sector Test Meeting - MG 6

Possible plans: list of measurements/sector test

• Group measurements in four blocks:– 1 shift:

• arcs and IRs aperture• magnet polarities

– 2×1/4 shift (spare time):• BPMs and orbit correctors polarities• Collimation measurements (splashes)

– 1 shift: • Kick response measurements in TL and LHC ring.• Dispersion measurement in TL and LHC ring

22/05/2014 Sector Test Meeting - MG 7

Possible synergies between the two types f measurements: trajectory excursion can be used to probe non-linear magnets