A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z  

Nassiri, R.

Paper Title Page
WEPEC079 Design and Prototype Progress toward a Superconducting Crab Cavity Cryomodule for the APS 3061
 
  • H. Wang, G. Cheng, G. Ciovati, J. Henry, P. Kneisel, R.A. Rimmer, G. Slack, L. Turlington
    JLAB, Newport News, Virginia
  • R. Nassiri, G.J. Waldschmidt
    ANL, Argonne
  
 

A squashed, el­lip­ti­cal su­per­cond­con­duct­ing (SC) cav­i­ty with waveg­uide dampers on the beam pipes has cur­rent­ly been cho­sen as the base­line de­sign [1] for the Short Pulse X-ray (SPX) pro­ject at the Ad­vanced Pho­ton Source (APS). An al­ter­nate cav­i­ty de­sign, with a waveg­uide damper lo­cat­ed di­rect­ly on the cav­i­ty cell for im­proved damp­ing char­ac­ter­is­tics, has also been de­signed and cold-test­ed with promis­ing re­sults. In ei­ther case, eight cav­i­ties would be op­er­at­ed CW in a sin­gle cry­omod­ule at 2K to pro­duce an elec­tron bunch chirp of 4MV at a fre­quen­cy of 2.815 GHz. De­tailed anal­y­sis of mul­ti­pactor­ing (MP), lorentz force de­tun­ing (LFD), and the ther­mal prop­er­ties of the base­line de­sign has led to an en­gi­neer­ing spec­i­fi­ca­tion of the basic pa­ram­e­ters of the cry­omod­ule.

  
THPEB059 Adjustable High Power Coax RF Coupler with No Moving Parts 4008
 
  • M.L. Neubauer, A. Dudas, R. Sah
    Muons, Inc, Batavia
  • M. Borland, R. Nassiri
    ANL, Argonne
  
 

An ex­treme­ly low emit­tance RF gun is being de­signed for the X-ray Free Elec­tron Laser Os­cil­la­tor (XFEL-O), which is now being pro­posed by ANL. An ad­justable cou­pling fac­tor for this gun is very de­sir­able for pro­vid­ing op­er­a­tional flex­i­bil­i­ty. What is re­quired is a fun­da­men­tal RF power cou­pler (FPC), ad­justable in situ, that can op­er­ate at 100 MHz and 200 kW CW. If ro­ta­tion­al mo­tion is used in the ad­justable cou­pler, it is usu­al­ly nec­es­sary to break the vac­u­um be­tween the cou­pler and the RF cav­i­ty, there­by risk­ing pro­longed down-times and the in­tro­duc­tion of con­tam­i­nants into the vac­u­um sys­tem. We pro­pose a novel sys­tem for ad­just­ing the cou­pling co­ef­fi­cient of coax­i­al cou­plers to allow for in­di­vid­u­al con­trol and ad­just­ments to the RF fields under dif­fer­ent beam load­ing sce­nar­ios. The RF cou­pler has no mov­able parts and re­lies on a fer­rite tuner as­sem­bly, coax TEE, and dou­ble win­dows to pro­vide a VSWR of bet­ter than 1.05:1 and a band­width of at least 8 MHz at 1.15:1. The fer­rite tuner as­sem­bly on the stub end of the coax TEE uses an ap­plied DC mag­net­ic field to change the Qext and the RF cou­pling co­ef­fi­cient, β, be­tween the RF input and the cav­i­ty.