1 / 11

Particularities of normal conducting L-band deflecting cavities Valentin Paramonov ,

Particularities of normal conducting L-band deflecting cavities Valentin Paramonov , Institute for Nuclear Reseach of the RAS, 117312 Moscow, Russia. General remarks.

morley
Télécharger la présentation

Particularities of normal conducting L-band deflecting cavities Valentin Paramonov ,

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Particularities of normal conducting L-band deflecting cavities Valentin Paramonov, Institute for Nuclear Reseach of the RAS, 117312 Moscow, Russia

  2. General remarks 1. In S-band frequency range Normal Conducting (NC) structures operating both in Traveling Wave (TW) [SLAC, CERN] and in Standing Wave [SPARC] mode are known. Structure base is Disk Loaded Waveguide (DLW). 2. For NC structures the L-band frequency range is near the border between TW and SW mode of operation, (in the domain of SW influence). TW operation requires too much RF power. 2. SW operation – multi cell structure with operating p-mode for RF efficiency. ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

  3. SW operation, efficiency vs. stability (DLW) Efficiency Stability DLW practically has just one degree of freedom – aperture radius Ra. Both Rsh and kc are defined by Ra value, kc increases with Ra increasing , Rsh decreases. Deflection Coupling H E Even in S-band range only short deflecting cavities are known (N=5) [D. Alesini et al, PAC 07; P. Craievich et al., PAC 09] due to stability limitation. ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

  4. S-band SW operation. With lower frequency Rsh reduces, but Ra is already small .... Let us decouple functions. E-type Deflection Coupling H-type V. Paramonov et al., Linac 06 E field H field ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

  5. Field distributions along axis In the deflection participate transversal components both from electric and magnetic field. In E-type DLW transversal components work in phase, not so inH-type … Nevertheless… ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

  6. RF parameters E type H type Rsh ~ 1/Ra For L-band H type deflector has higher Rsh, higher coupling, but higher Esmax/E0. In last parameter it is not optimized finally. ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

  7. Aberrations Free from aberration is just DLW (b =1) in lower HEM passband. Any deterioration of rotational symmetry automatically leads to aberrations. Dependence of deflection in x-direction on the y position is dE0 ~ y2. Depending on Ra value, dE0/E0 <1% for y/Ra <0.4 is achievable by nose shape optimization. ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

  8. Dispersion properties Due to small transverse dimensions, Rc ~ 0.3 l, there is no HOM problem. TM01 Operating point ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

  9. Compensated RF structure (V. Paramonov,L.Krabchuk, Linac 2000) Operating point Branches due to waser+ stem Has no stability problem (compensated, bg=0.32, b=1). Efficiency ~ 0.9 from previous case. More complicated in design and dispersion properties. Field distribution for deflecting and coupling modes. ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

  10. Possible design Vacuum RF input, WR650 Beam pipe Tuning after brazing Cooling RF probes Possible parameters – Ra ~ 19 mm, Rsh ~ 38 MOhm/m, Ql ~ 7000, tt ~ 3 ms, L~ 1 m, P~30 kW, V~ 1 MV ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

  11. Summary • For application in L-band frequency range normal conducting standing wave deflectors are more effective. • As compared to Disk Loaded Waveguide structure, H-type structure has higher RF efficiency, essentially higher coupling and smaller transverse dimensions. • For H-type structure tolerable values both for aberrations and maximal surface fields can be obtained by appropriate shape optimization. • The high coupling value allows longer cavities without limitations for RF coupler position. ICFA BD Mini-Workshop on Deflecting/Crabbing Cavity

More Related