Beam Instrumentation in the HL-LHC Insertion Regions

1. Beam Instrumentation in the HL-LHCInsertion Regions Rhodri Jones HL-LHC PLC - 18th Jan 2013

2. Current Equipment • Existing LHC Experimental Insertions • BPMs • Directional couplers in common beampipe regions (Q1, Q2, Q3) • Stripline Length 120mm • BPM length 256.4mm (cold - welded) – 285mm (warm - flanged) • Inter-electrode Diameter 61mm, 81mm (131mm also designed for Pt6) • Button pick-ups in separated beampipe regions (Q1, D2, Q4-Q7 + Trigger BPM for Expt) • BPM length 203mm (cold - welded) – 285mm (warm - flanged) • Diameter 49mm, 61mm, 80mm (injection) • Integrated BPMs in new TCT collimators • BLMs • External to cryostat ~50 per side covering TAS to Q7 • Luminosity monitors • Ionisation chambers inside TAN in 1 & 5 • CdTe detectors behind Y chamber in 2 & 8 • BTVs in injection regions

3. Current Equipment • Existing Equipment in Points 3,6 & 7 • BPMs • Striplines for large aperture in dump region (signal level) • including interlock BPMs • Button pick-ups • cold in all SSS & warm near collimators & warm quads • Integrated button pick-ups foreseen in new collimators • BLMs • BTVs • Existing equipment in Point 4 • Standard BPMs & BLMs • BCTs (2 DCCT & 2 Fast BCT per beam) • BSRT + undulator • BGI • Wirescanners • Special pick-ups • Tune, Schottky, Head-Tail • BTV - Injection Matching

4. Foreseen HL-LHC Equipment • HL-LHC Experimental Insertions- BPMs • Propose to maintain directional couplers in common beampipe regions • Position should be optimised to counter influence of 1 beam on other • Locate in between long range collisions • If not possible: • Can gate on pacman bunches • More complex to set-up & less operationally robust (needs precise timing) • Possibility to use alternative electronics • Diode orbit system will be tested after LS1 • Sensitivity to separation to be determined (still needs some separation) • Length of 220mm can be considered minimum for cold stripline BPM • Length of 285mm can be considered minimum for warm stripline BPM • The more we have the more robust the correction & feedback in this region • Button pick-ups for separated beampipe regions if aperture <= 80mm • Do we maintain button in front of Q1? • Originally installed to measure zero crossing angle for TOTEM & ALFA • Do not forget trigger BPM for experiments • If proved to be useful maintain integrated BPMs in all collimators

5. Foreseen HL-LHC Equipment • HL-LHC Experimental Insertions- BPMs Could think of Duplicating in these regions for more redundancy Proposed BPM locations Current BPM locations

6. Foreseen HL-LHC Equipment • HL-LHC Experimental Insertions– BPMs • Existing BPMSW

7. Foreseen HL-LHC Equipment • HL-LHC Experimental Insertions - Others • BLMs • Maintain BLMs external to cryostat • Add cryogenic BLMs in all new Quadrupoles (6 per magnet) • Proposed to distinguish between collision debris & beam loss • Integration to be foreseen at an early stage • Would welcome opportunity to qualify mechanical & electrical properties in prototypes as they are tested • Luminosity monitors • Do we maintain the need for monitors separate from experiments? • Useful if we cannot rely on data from experiment under all conditions • Do we maintain the need for 40MHz operation? • Considerably complicated current design • BTVs in injection regions • Maintain current number in the layout

8. Foreseen HL-LHC Equipment • New Instrumentation for HL-LHC Experimental Insertions • Long Range Beam-Beam Compensators • Optimal location will depend on optics (maintain 5m in Y chamber?) • Ideally require equal beta for H&V • Ideally require wire location at mean separation of long range collisions • Propose to maintain current idea of in-collimator design • Needs staggered B1 & B2 space reservation before D2 • Total of 2m per beam per side of each IR – combined with collimator? • Crab Cavity Diagnostics • Current proposal is for Head-Tail monitors • Either based on existing long striplines or higher bandwidth optical BPM currently being studied • Need to reserve 800mm space at suitable optics location • 90 degree phase advance to give maximum crab effect • Do we want 2 measurement points? • One as close as possible to IR? • One after crab cavities towards arcs to check compensation?

9. Foreseen HL-LHC Equipment • New Instrumentation for HL-LHC Experimental Insertions Investigate foreseen collisions optics at these locations to see if they are compatible with an effective long range beam-beam compensator ACTION: ABP

10. Foreseen HL-LHC Equipment • Instrumentation for HL-LHC Point 4 • Maintain currently installed hardware • Upgrades to be foreseen for some instruments • BSRT will already be partially redesigned during LS1 • BGI design to be adapted for higher beam intensity • BCTs may also need to be modified • New fast wire scanners to be installed during LS2 • Influence of optics • Optics at emittance measurement devices • Needs to be maximised in measurement plane if possible • Needs to be stable (or accurately measureable) • Some BPM locations may need to be modified to match optics • Tune measurement BPLX currently placed at equal H & V beta location

11. Foreseen HL-LHC Equipment • New Instrumentation for HL-LHC Point 4 • Beam Gas Vertex Imager (BGV) • In development as possible alternative emittance monitor • Based on LHC velo concept • Gas injection required • Study underway to look at feasibility (HL-LHC funded fellow) • Requires total space of ~7m per monitor (possibly between Q6 & Q7) • Beta functions should be equal and as high as possible • Additional Synchrotron Light Beam Line? • Currently already have 4 diagnostics on one line • Abort gap, longitudinal density monitor, fast & slow cameras • Additional items that could be added for HL-LHC • Halo diagnostics • Streak camera for study of crabbing • Proposal to study feasibility of second optical line • New undulator near D4 on incoming beam • Light extraction between D4 and D3 • Re-investigate option of coupling out light from D2

12. Foreseen HL-LHC Equipment • New Instrumentation for HL-LHC Point 4 • Beam Gas Vertex Imager (BGV)