Testing Crystals at FACET-II: discussion

Monday 10 Sept 2018, 15:00 → 16:00 Europe/Zurich

Participants: Thibaut Lefevre, Uli Wienands, Andrea Mazzolari, Laura Bandiera, Andrea Latina, Viktor Tikomirov

Thibaut: introduces his expertise as beam instrumentation for crystal collimators. 

Silicon is not ideal as it emits infrared radiation.

Silica and Diamond crystals are better because they produce radiation in the GHz regimes, which is suitable for bunch length measurements.

Andrea M:
* deflection : need photo of the beam
* radiation emission : we need to lower the background, then detect radiation

Uli W:
* the channeling radiation, MeV range - more difficult to detect, it has an energy resolution 10% at high energy but much less at low energy

ESTB should be the right test stand for checking channeling process simulations.

For a positron source we should test Tungsten crystal.

Laura B: the quality of Tungsten is crucial. They have crystal of Tungsten, 0.4 - 0.5 mm with not perfect Tungsten crystal.

There might be crystals with 1.4 mm to be tested. Check Indico page of the 16 August meeting. They presented results with a 2 mm thick crystal.

Uli W: points that we would need a short crystal (200 micron for Tungsten) to avoid multiple scattering. For testing the simulations a thin crystal will need to be used.