Positron source discussion

Thursday 26 Mar 2020, 09:30 → 22:30 Europe/Zurich

Participants: 

Yongke, Hugo Bajas, Steffen, Andrea

Actions to be taken:

For Yongke:

1) Double check the implementation of magnetic field in Geant4.

2) Comparison between analytic and realistic field shapes (with the same peak field and length?)

3) Comparison between 2D field and 1D field extrapolation. If the difference is small, try to find a theoretical formula with flexible parameters to describe the 1D field. (The problem is, if all these are done, how to find the correlation between the theoretical parameters and the realistic parameters).

4) Introduce a distance between target and AMD (which is expected to reduce the effect of fringe field on PEDD)

5) If 4) does not work to neglect the effect of fringe field on PEDD, try to introduce a new solenoid surrounding (or before the target) the target to compensate the fringe field effect. (The problem is that injected electrons will be definitely affected by the peak or fringe field of new solenoid, before being injected, which we need to take into account in the simulation. Currently it's not simulated). So I put the priority of 5) after 4).

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For Hugo:

a) For the medium scenario, try to increase the current and entrance inner radius (for example 6.5 mm), but keep the peak field not changed (for example 4.5 T) or larger (for example 5 T). To keep that the field always ends at ~0.5 T at the AMD exit position, the length of AMD can be a bit longer (for example ~150 mm), but no longer than 200 mm, otherwise it's not realistic. 

b) ?

09:30 → 10:00 Positron source discussion

Speaker: Mr Yongke Zhao (CERN & Shandong University (CN))

Positron source discussion - 20200326-1.pdf