Login

FCC-FS EPOL group meeting 49

→ Europe/Zurich
354/1-016 (CERN)

354/1-016

CERN

20
Show room on map
Description

The FCC technical and financial feasibility study comprises a work package (EPOL) on precision determination of the centre of mass energy at FCCee. using resonant depolarisation of the beams, in conjunction with precise measurement of the energy spread and other parameters using physics events in the detectors, and other beam diagnostics in particular to control the collision parameters. Specific equipment involves polarimeters for both beams, polarisation wigglers, and depolarising RF kickers. The possible mono-chromatization of the beams in view of a measurement of the e+ e- —> H (125) process will also be studied and special requirements investigated. 

Short group meetings are foreseen at 15:00 on Friday.

FCC-FS EPOL group meeting
Zoom Meeting ID
63437787216
Host
Alain Blondel
Alternative host
Jacqueline Keintzel
Useful links
Join via phone
Zoom URL
Hide

News from the US: https://arxiv.org/abs/2601.00586

J. Keintzel presents that from now until end of 2027 the FCC is in the Reference Design Phase, followed by a Technical Design Phase.

R. Kieffer presents thoughts on the booster polarimeter.

Some suggestions:

  • Measuring also at discrete steps during the ramp
  • Polarized pilots not topped up, but re-injected
  • Detailed polarization measurements only during commissioning 
  • Simplified polarimeter compared to main rings (maybe only photons sufficient --> no long drift, no dipole)
  • Regular measurements at injection and extraction energy in booster need about 1s
  • Same laser room as for main rings, but other laser system
  • Precision requirements to be defined (~ few %)

F. Zimmermann comments that at BNL the RCS uses single photons, while EIC uses many photons.

J. Wenninger presents location of kickers in LCC106.2.2. 

J. Wenninger presents on off-energy injection of polarized pilots. With 1% offset the crossing between 103 and 104 spin tune happens roughly 60 times. The higher the equilibrium polarization, the higher tjhe transmission. LCC is using H and V correctors at quadrupoles and some seeds get negative polarization. 

J. Wenninger presents on snakes in the booster. 

W. Hofle reports on depolarization kickers. Polarization build up should be studied for colliding bunches and then duty cycle for kickers remains to be established, including cooling. What would be kick strength in DC mode without water cooling.

There are minutes attached to this event. Show them.