FHI experimental opportunities? FHI meeting 17/9/14

Experiments at FCC injector complex? HEB will provide beams of around 3-4 TeV – Low duty cycle for filling FCC collider: spare p+ – Any requests from experimental community for experimental facilities? – Gather considerations which might affect the HEB design, or favour one HEB option – First informal discussion – WG meeting planned on 29 th

Experiments already mentioned i Very-High-luminosity IP in LHC collider – Tau -> 3 x mu experiment – “Simple” detector concept – No limit on pileup (being checked) – Reduction to 12 m L* (24 m between triplet edges at IP) – LHCb type spectrometer, but 2 arms – “Target” O 1000 fb-1 per year (3x HL-LHC)!

Experiments already mentioned ii Fixed target test beams – Highest energy for detector sub-assemblies – No information yet on spill rate – No information yet on annual PoT FT physics beams (kaons, …)? HiRadMat type material test facility? AWAKE-type plasma wakefield acceleration?

Dump Cleaning RF/Xing Injection B2 Injection B1 Extraction To FCC P1 P5 P3 P7 P8 P6 P2 P4 HEB-LHC option Empty? RF: need to keep ring 1 and ring2 same length! Min. of 2 crossings

Changes per IR (1-4) P1: extraction to collider: – removal of low-beta insertion, ATLAS, construction of floor through ATLAS cavern, civil engineering for junctions to new TLs to collider, installation of extraction system P2: injection of B1 (no crossing) – removal of low-beta and ALICE, modification of injection system to inject into INNER ring (presently outer!) P3: collimation – unchanged P4: RF and new crossing – Addition of D2 magnets, plus required matching quadrupoles for crossing (not at IP…)

Changes per IR (5-8) P5: FODO transport, no crossing – removal of low-beta and CMS, construction of floor through CMS cavern, installation of FODO quads – Possible location for FT extraction system P6: beam dump – unchanged P7: collimation – unchanged P8: Injection beam 2 (crossing) – removal/modification of low-beta and LHCb (2 options still open for crossing – medium beta, or with D2s only)

FT extraction insertion in LHC Depends on where transfer to FCC takes place, but would be either P1 or P5 Not yet looked at any details of extraction system requirements or possible layout Likely to be not particularly straightforward to design conceptually….

PoT estimates Simple methodology to compare options…. Limit peak power on targets to 2.0 MW – Maybe slightly pessimistic at this stage (or maybe not!) Stored energy in beam given by FCC filling constraints Adjust spill lengths to give 2.0 MW power Subtract FCC filling time 80% efficiency for FT physics Total cycle length and protons per spill then give maximum PoT per year (if no other limitations)

PoT from cycle length etc. e18-e19 p+/year at 4 TeV conceivable, in this respect at least….

Extraction of FT beams from HEB Slow extraction assumed essential – For experiments (digesting ~e14 p+ in ~100 us…?) – For targets ( MJ on target in ~100 us…?) Will be technologically “challenging” for a machine at 3-4 TeV! – Crystal extraction to take seriously as an option – Studies in SPS and LHC to follow-up

Possible limitations - i Slow extraction system for 3-4 TeV – SPS works at 450 GeV – Space in lattice is ~100 m – Beam losses will be kW in extraction region Equipment performance, activation, radiation damage – Limiting elements are Thin electrostatic septa (E field 100 kV/cm, 50 um diameter wires, 15 m active septum length) Thin magnetic septa (5 mm thick, 7.5 kA current)

Possible limitations - ii Distributed beam losses in SC magnet system – For re-use of present LHC, would appear *very* challenging to incorporate an insertion with 1% beamloss, while maintaining sufficient cleaning efficiency elsewhere – For tunnel, even if HEB is NC or SF, would be sharing a tunnel with 16-20T dipoles…. Maybe need separate parallel extraction straight for HEB for some 2-10 km, for extraction plus beam cleaning….cost, layout, … – For looks even more difficult to manage extraction losses, as the existing LSS are only 120 m long

Other challenges… 3-4 TeV beam transfer for slow-extracted beams – Losses may make SC magnets difficult, but huge bending radius with 2 T NC magnets! Targetry for 3-4 TeV, 2 MW beams – 3-4 TeV beam likely to pose different difficulties compared to typical ~GeV energy of spallation sources Shielding and experimental area design Secondary beamlines Very long spills… – Spill quality – Resonance and ripple control – POWER CONSUMPTION (HEB running most of time at top energy!) – Crystal extraction studies to look at

Future study directions e18-e19 PoT/year at 3-4 TeV ‘could be envisaged’ from time-sharing arguments, depending on which HEB option Gather firmer input from experimental community on requirements (29/9) Look at feasibility of 3-4 TeV slow extraction from these HEB machines – Extraction concept, layout, technology – Losses, collimation, quenches, collider cross-talk – Spill quality and control – Targets and Experimental area – Beam transport – Power consumption, operability Need to design “toy” very-high-lumi insertion for LHC (P8?) to check feasibility of >1e35 cm-2s-1 IP – Crossing schemes and beam beam – Max Luminosity – Burn off and beam lifetime – Pileup and pileup density – Integrated performance estimate – Triplet shielding

One more thing…. Mention by experiments of polarised p+ being interesting for FCC – Has this been discussed in FCC meetings? – Is it serious or not? – If so, major implications for injector complex: probably not compatible with the existing machines (to study) – Discuss in FCC accelerator/experiment meeting?