Room temperature CH resonator update and some plans

1. Room temperature CH resonatorupdate and some plans Technical Division PD Front End meeting July 21, 2005 Gennady Romanov

2. Outline • CH room temperature resonators (RTR) update • DSR with parallel spokes • Dynamic model of SC cavity (Lorentz+helium+mechanical vibrations) • RF model of chopper (for TRACK) • Interface for TRACK • Particle in field (toward multipacting simulation) Gennady Romanov

3. CH resonators optimization • = 0.0103 (2.5 MeV) • = 0.175 (15 MeV)  = 0.13 The drift tubes are the same (except length) for all cavities. The spoke shape is similar for all cavities. Gennady Romanov

4. CH RTR dimensions Dimensions are smooth functions of beta. So, it is easy to get analytical expression for every dimension. We don’t need to perform new optimization, if we choose cavity with another of beta Gennady Romanov

5. CH RTR RF parameters Gennady Romanov

6. CH RTR RF parameters +30% Ideal boundaries Gennady Romanov

7. CH RTR mechanical design Gennady Romanov

8. DSR, Parallel Spokes Problem The best orientation for electric coupler is 90 degrees to spoke – minimal losses. DSR does not have such area with zero magnetic field. • Alternatives • Magnetic coupler – it has losses, it is different coupler and • different everything. • 2) We put electric coupler somehow and try to leave with losses • 3) We replace DSR with SSR for beta = 0.4 – surface field limit • 4) We use DSR with parallel spokes. Gennady Romanov

9. DSR, Parallel Spokes F=325 MHz Beta=0.4 Simple flat end wall is OK for field distribution Gennady Romanov

10. Detuned end cell Two typesof errors – frequency errors and coupling errors: ~ N2/k. High k is very important for long structures with many cells Ring: dR=2 cm H=0.45 cm - does not depend on k Let’s consider frequency error of ~0.5 MHz 14% end-to-end Not a problem. Surface field enhancement (plus 5% to Ezmax) is a real concern Gennady Romanov

11. End cell tuned back We can tune end-cell frequency back Coupler here This area can be removed Gennady Romanov

12. Some comparison Stored energy 1 Joule So far I see only one problem with parallel spokes– we may need an individual tuning of end cells to make field distribution flat and avoid enhanced peak fields. Gennady Romanov

13. RF model of chopper Two reasons: we need to redesign chopper for 2.5 MeV and we need a lattice element for TRACK Input Pulse: Rise – 2 ns Hold – 5 ns Fall – 2 ns 192 mm model of HIPPI chopper (3 MeV) Gennady Romanov

14. Interface for TRACK Sergey Tsaregorodtsev, summer student 1) Graphic User Interface for TRACK. Optimizer TRack INterface Model TRACK output files Results PostProcessing of TRACK output files TRACK, TRACK files: Sclinac.dat Graph.cfg Fi-in.dat Track.dat *.*nn – real field elements Micro Wave Studio Output files MWSread.exe 2) “Particle in field” built in MWS -> multipacting Gennady Romanov

15. Beam halo experiment CHALLENGE OF BENCHMARKING SIMULATION CODES FOR THE LANL BEAM-HALO EXPERIMENT * W.P.Lysenko1, J.Qiang2, R.W.Garnett1, and T. P. Wangler1 1Los Alamos National Laboratory 2Lawrence Berkeley National Laboratory Figure 2 shows results for the matched case and the mismatched case for mismatch parameter µ=1.5, where µ is defined in Ref. [8]. Rms deviations for the matched case (difference between experimental and simulated profiles) are small, about 2%. However, using this beam to simulate the mismatched cases has not yet produced as good agreement between the simulated and measured profiles. Test for TRACK Gennady Romanov