Changes to IR6 dump protection elements

B.Goddard, W.Weterings, C.Maglioni, R.Versaci, T.Antonakakis, R.Schmidt,

J.Borburgh, J.Blanco, plus many other colleagues

Contents

• TCDQ upgrade– Absorber material and length– Movement bellows– Controls

• Additional TCLA• Buttons in TCSG

TCDQ upgrade• Issue with robustness of present TCDQ design– Dynamic stresses exceed limit for damage at block corners– Graphite jaws, 1.8g/cc– Replace with graded Carbon Composite (1.4g/cc and 1.65

g/cc)

Absorber composition

1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12

1.8 g/cc 1.8 g/cc 10.8 g/cc.m

1.65 g/cc 1.4 g/cc 1.4 g/cc 1.65 g/cc 1.65 g/cc 13.9 g/cc.m

• Lower density and higher yield stress material – should be below damage limit for beyond ultimate beams– FLUKA and stress analyses ongoing to derive limits

• Total amount of material seen by beam increases from 10.8 kg/cm2 to 13.9 kg/cm2– Should be better for asynch dump protection

Beam

Absorber length 6m -> 9m

Location of extra module

• More difficult upstream, due to dump line interference, but would like to maintain location of TCSG and drift to Q4, so will extend upstream.

Layout

• Relocation of interlock BPMs by about 3m• No impact on functionality

TCDQ

BPMSA

TCSG

Schedule

• Install during LS1

Another benefit?

• Will have 9m of CC next to beam at location with largest H beta function– Could help reduce damage elsewhere in case of

major failure– Being investigated by J.Blanco & R.Schmidt

Improve present bellows (±20 mm)

• Presently large mechanical stress to displace• Distortion of RF fingers (away from beam!)

Will make double bellows system -> TE/VSC?

Controls

• Don’t expect any change in movement precision with 9m long absorber (10.4m)

• Are investigating an upgrade of controls to use collimation stepping motor system and low-level (although some other issues have been solved with existing DC motors)– Needs mechanical changes, and there is concern

about precision attainable in open-loop.

Additional TCLA?

• Space reserved in layout for TCLA, just before TCDQM

Reduction of heat load on Q4 with MQY

Factor 2 improvement

FLUKA studies of asynch dump

R.Versaci

Justification for TCLA

• “Not needed for beam cleaning” – Ralph• Two remaining justifications

– Reduce scale of quench if asynch dump• FLUKA studies in progress

– Help contain damage if “beyond design” failure• Energy tracking, retrigger failure

• Decision still to take – when is deadline for Coll project?– Would be good to do all IR6 work together in LS1 (TCSG

with buttons, new TCDQ plus motorisation, TCLA)

Buttons in TCSGs

• Requested by Ralph• Can only support this– Will need to investigate ‘servo’ of TCDQ position

with TCSG, beyond certain offset, if TCSGs are automatically adjusted

Conclusions• Some non-negligible upgrades for IR6 dump

protection– TCDQ upgrade for robustness (also adds more

material close to beam)– TCDQ controls – to be decided formally– New improved TCDQ bellows– TCSG with buttons– Additional TCLA – to be decided after FLUKA

studies