LhARA Weekly Meeting 2^nd June 2020; 14:00 BST

Notes

Present: KL, TG, CW, JPa, TSD, JH, JPar, WS, JM, OE, HTL, WGJ, RB

0. Introduction and news: KL
   • Last week KL met with G.Blair and N.Geddes of STFC to discuss LhARA and the way forward. The discussion went well and the tone was supportive.N.Geddes commented that the collaboration had achieved a lot with a little. This initial contact now needs to be moved forward.

1. Notes of previous meetings and actions:
   • KL: Create draft response to referees.
     • Stands.
   • JPa Draft reply to Y.Prezado's request.
     • Done.

2. Status of publication and pre-CDR:
   • Status of draft: KL
     • The paper is submitted to the journal and the arXiv.
   • Updates required to pre-CDR (e.g. Livingstone plot update): All
     • Livingstone and dose rate calculations need to be updated.
     • JPa noted that the bunch-length estimationm, the voltage in the FFA, and the energy spread needed to be updated too.
     • Agreed to address the details this week and to review changes needed tomorrow am.
   • News item for pre-CDR TN; preparation of news item for publication: AK, ALL
     • Still in preparation.

3. Preparation of response to referees: KL, ALL
   • Input will be needed on the laser (OE), the plasma lenses (CW), the FFA, size of the facility; beam loading (JPa), and aspects of the radiobiilogy programme (JPar).

4. Updates:
   • Capture section: CW
     • "Tooling up" with VSIM and SMILEI now done; both codes are being run by TSD and HT: respectively. CW is pursuing e-beam studies. RB has the dimensions of the lens and will calculate the instability onset. The calculations so far have neen useful as it has already been noted that a lack of charge on axis can lead to instability.
   • Simulation:
     • Particle production at laser target: HTL
       • Slides presented. Points noted:
         • The interpretation of the electric field evolution plot (slide 2) is unclear. Initial proton-energy distributions were presented. In this context, the issues discussed included the need to vary the cell size and cell occupancy. Details of simulation will be invesigated.
         • Excellent that details of simulation can now be investigated.
     • Transport through Gabor lenses and energy selection, Gabor lens simulation: TSD
       • TSD reported that since he is now able to run VSIM he has begun to solve for the electromagnetic fields within the lens in the absense of a plasma. done. Now simulating Gabor lens that CW has designed. Is now working out how to calculate teh field. Working through the guide to get the optimal situation. Then add plasma back. When these calculations have converged he will revisit the plasma-density calculations.
   • Any other simulation
     • WS proposes monthly experiment and simulation meetings. This will be done in the near future. Who will lead these meetings needs to be discussed.

4. Radiobiology meeting: JPar
   • The first radiobiology meeting took place last week. Turn out was good (about 20 people) and the meeting was an excellent starting point for the new thread. Presently invisage meeting every third week.

5. Next steps: All
   • CCAP plenary afternoon of 24Jun20:
     • Three sections: LhARA (topic leads should expect an invite to speak); radiobiology (JPar agreed to organise); and other aspects of the CCAP programme.

6. AOB
   • JM prpposed the simulation of the response of a BPM in the FFA? JPa supported strongly. JM has contact Kyoto group. JPa suggested also to discuss with ISIS Intense Beams Group personnel who have expertise in this area. JM to be added to updates section from next week.

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Agenda

0. Introduction and news: KL

1. Notes of previous meetings and actions:
   • KL: Create draft response to referees.
   • JPa Draft reply to Y.Prezado's request.
     • Done.

2. Status of publication and pre-CDR:
   • Status of draft: KL
   • Updates required to pre-CDR (e.g. Livingstone plot update): All
   • News item for pre-CDR TN; preparation of news item for publication: AK, ALL

3. Preparation of response to referees: KL, ALL

4. Updates:
   • Capture section: CW
   • Simulation:
     • Particle production at laser target: HTL
     • Transport through Gabor lenses and energy selection, Gabor lens simulatin: TSD
   • Any other simulation

5. Next steps: All

6. AOB

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