• P.N. Ostroumov, J.D. Fuerst, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.W.T. MacDonald, R.C. Pardo, S.I. Sharamentov, K. Shepard, G.P. Zinkann
  ANL, Argonne

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

The on­go­ing en­er­gy up­grade of the heavy-ion linac ATLAS at ANL in­cludes a new cry­omod­ule con­tain­ing seven 109MHz β=0.15 quar­ter-wave su­per­con­duct­ing cav­i­ties to pro­vide an ad­di­tion­al 15 MV volt­age. Sev­er­al new fea­tures have been in­cor­po­rat­ed into both the cav­i­ty and cry­omod­ule de­sign. For ex­am­ple, the cry­omod­ule sep­a­rates the cav­i­ty vac­u­um space from the in­su­lat­ing vac­u­um, a first for TEM cav­i­ties. The cav­i­ties are de­signed in order to can­cel the beam steer­ing ef­fect due to the RF field. Clean tech­niques have been ap­plied to achieve low-par­tic­u­late rf sur­faces and are es­sen­tial for re­li­able long-term high-gra­di­ent op­er­a­tion. The sealed clean sub­assem­bly con­sist­ing of cav­i­ties, beam spools, beam valves, cou­plers, vac­u­um man­i­fold, and sup­port frame has been at­tached to the top plate of the cry­omod­ule out­side the clean room. Ini­tial com­mis­sion­ing re­sults are pre­sent­ed. The mod­ule was de­signed and built as a pro­to­type for the Fa­cil­i­ty for Rare Iso­tope Beams (FRIB) driv­er linac, how­ev­er, a sim­i­lar de­sign can be ef­fec­tive­ly used in the front-end of SC pro­ton linacs based on TEM-class SC cav­i­ties.

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