• R. M. Brodhage, H. Podlech, U. Ratzinger
  IAP, Frankfurt am Main
• G. Clemente, L. Groening
  GSI, Darmstadt

For the re­search pro­gram with cooled an­tipro­tons at FAIR a ded­i­cat­ed 70 MeV, 70 mA pro­ton in­jec­tor is re­quired. The main ac­cel­er­a­tion of this room tem­per­a­ture linac will be pro­vid­ed by six cou­pled CH-cav­i­ties op­er­at­ed at 325 MHz. Each cav­i­ty will be pow­ered by a 3 MW klystron. For the sec­ond ac­cel­er­a­tion unit from 11.7 to 24.3 MeV a 1:2 scaled model has been built. Low level RF mea­sure­ments have been per­formed to de­ter­mine the main pa­ram­e­ters and to prove the con­cept of cou­pled CH-cav­i­ties. For this sec­ond tank tech­ni­cal and me­chan­i­cal in­ves­ti­ga­tions have been done in 2009 to pre­pare a com­plete tech­ni­cal con­cept for man­u­fac­tur­ing. Re­cent­ly, the con­struc­tion of the pro­to­type has start­ed. The main com­po­nents of this sec­ond cav­i­ty will be ready for mea­sure­ments in spring 2010. At that time the cav­i­ty will be test­ed with dummy stems (made from alu­minum) wich will allow pre­cise fre­quen­cy and field tun­ing. This paper re­ports on the tech­ni­cal de­vel­op­ment and achieve­ments dur­ing the last year. It will out­line the main fab­ri­ca­tion steps to­wards that novel type of pro­ton DTL.

• M. Busch, M. Amberg, F.D. Dziuba, H. Podlech, U. Ratzinger
  IAP, Frankfurt am Main
• W.A. Barth
  GSI, Darmstadt

At the In­sti­tute for Ap­plied Physics a su­per­con­duct­ing CH-Cav­i­ty (Cross­bar H-Mode) has been de­vel­oped. It is the first mul­ti-cell drift tube cav­i­ty for the low and medi­um en­er­gy range of pro­ton and ion linacs. A 19 cell, β = 0.1 pro­to­type cav­i­ty has been fab­ri­cat­ed and test­ed suc­cess­ful­ly with a volt­age of 5.6 MV cor­re­spond­ing to gra­di­ents of 7 MV/m. The con­struc­tion of a new su­per­con­duct­ing 325 MHz 7-gap CH-cav­i­ty has start­ed. This cav­i­ty has an op­ti­mized ge­om­e­try with re­spect to tun­ing pos­si­bil­i­ties, high power RF cou­pling, min­i­mized end cell lengths and op­tions for sur­face prepa­ra­tion. Stat­ic tun­ing is car­ried out by small nio­bi­um cylin­ders on the gird­ers. Dy­nam­ic tun­ing is per­formed by a slow bel­low tuner driv­en by a step motor and a fast bel­low tuner driv­en by a piezo. Ad­di­tion­al ther­mal and me­chan­i­cal sim­u­la­tions have been per­formed. It is planned to test the cav­i­ty with a 10 mA, 11.4 AMeV (β = 0.158) beam de­liv­ered by the Uni­lac at GSI. An­oth­er cav­i­ty (f = 217 MHz, β = 0.059) is cur­rent­ly under de­vel­op­ment for the cw Heavy Ion Linac at GSI. It is the first of nine sc CH-Cav­i­ties planned for this pro­ject cov­er­ing an en­er­gy range from 1.4 to 7.3 AMeV.

• C. Zhang, M. Busch, F.D. Dziuba, H. Klein, H. Podlech, U. Ratzinger
  IAP, Frankfurt am Main

EU­RO­TRANS is a EU­RO­pean Re­search Pro­gramme for the TRANS­mu­ta­tion of High Level Nu­cle­ar Waste in an Ac­cel­er­a­tor-Driv­en Sys­tem. Frank­furt Uni­ver­si­ty is re­spon­si­ble for the de­vel­op­ment of the 352MHz in­jec­tor which main­ly con­sists of a 3MeV RFQ and a 3-17MeV CH-DTL. Based on the beam dy­nam­ics de­sign, the CH-cav­i­ties were de­signed with the con­cern to op­ti­mize the RF prop­er­ties. In the cav­i­ty de­sign, the tube-gap con­fig­u­ra­tions were mod­i­fied, so the beam dy­nam­ics has been ad­just­ed to fit the new ef­fec­tive gap volt­age pro­files ac­cord­ing­ly. A com­par­i­son of the beam dy­nam­ics re­sults be­fore and after the RF op­ti­miza­tion is pre­sent­ed.

• U. Ratzinger, L.P. Chau, H. Dinter, M. Droba, M. Heilmann, N.S. Joshi, O. Meusel, I. Müller, D. Mäder, Y.C. Nie, D. Noll, H. Podlech, H. Reichau, A. Schempp, S. Schmidt, K. Volk, C. Wagner, C. Wiesner
  IAP, Frankfurt am Main
• R. Reifarth
  IKF, Frankfurt-am-Main

An in­tense 2 MeV, 200 mA pro­ton beam will drive a neu­tron source by the re­ac­tion Li7(p,n)Be7 on solid as well as on liq­uid lithi­um tar­gets. Ac­tu­al­ly, the fa­cil­i­ty is under con­struc­tion at the physics fac­ul­ty new ex­per­i­men­tal hall in Frank­furt. To study in de­tail the burn­ing of el­e­ments in stars by the s-pro­cess, a pulsed beam op­er­a­tion with a bunch com­pres­sor at the linac exit will offer sev­er­al Am­pere beam cur­rent with­in 1 ns pulse length and with 250 kHz rep. rate at the n - pro­duc­tion tar­get. As the upper limit of gen­er­at­ed neu­trons and the total n- flux at this source are well de­fined the sam­ple for neu­tron cap­ture mea­sure­ments can be placed after a time of flight path as short as 0.8 m only. This will pro­vide high­est ac­ces­si­ble pulsed neu­tron flux rates for neu­tron en­er­gies in the 1 - 500 keV range. The high­ly space charge dom­i­nat­ed bunch form­ing pro­cess as well as the ion source, the rf cou­pled 175 MHz RFQ/DTL - res­onator and the tar­get de­vel­op­ment will be ex­plained.