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Porcellato, A.M.

Paper Title Page
FR-03 Improved on line performance of the installed ALPI Nb sputtered QWRs 203
 
  • A.M. Porcellato, L. Boscagli, F. Chiurlotto, M. De Lazzari, D. Giora, S. Stark, F. Stivanello
    INFN/LNL, Legnaro
 
 

The av­er­age ac­cel­er­at­ing field of the ALPI 160 MHz sput­tered QWRs has been im­prov­ing with time up to reach, after the last con­di­tion­ing cycle, the av­er­age ac­cel­er­at­ing field of 4.8 MV/m @ 7 W. Such value can be ef­fec­tive­ly sus­tained in op­er­a­tion due to the in­trin­sic me­chan­i­cal sta­bil­i­ty of the sput­tered cav­i­ty whose fre­quen­cy is prac­ti­cal­ly not in­flu­enced by fluc­tu­a­tions in the bath He pres­sure. The pre­sent av­er­age cav­i­ty per­for­mance ap­proach­es the max­i­mum av­er­age ac­cel­er­at­ing field ob­tain­able in the present­ly in­stalled cav­i­ties, most of which were pro­duced by re­place­ment of Pb with Nb in the pre­vi­ous­ly in­stalled sub­strates. A high­er av­er­age value can be ob­tained in ALPI re­plac­ing the less per­form­ing units; it is in­stead nec­es­sary to sput­ter on ap­pro­pri­ate­ly built sub­strates to pro­duce QWRs which can re­li­ably ex­ceed 6 MV/m @7W. The cav­i­ty Q-curves, which were re­cent­ly mea­sured in ALPI, show a wide range of Q0 and Q-drop, main­ly as­so­ci­at­ed with the sub­strate char­ac­ter­is­tics, but in some cases also in­flu­enced, as dis­cussed in the paper, by cryo­stat as­sem­bling pro­ce­dures and by cav­i­ty pro­duc­tion and con­di­tion­ing.

 

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C-08 Wide Bandwidth, Low Cost System for Cavity Measurements 274
 
  • S. Stark, A.M. Porcellato
    INFN/LNL, Legnaro
 
 

Re­cent­ly we de­vel­oped a novel mea­sure­ment ap­pa­ra­tus that sim­pli­fy the tests of su­per­con­duct­ing cav­i­ties. A few com­mer­cial elec­tron­ic boards, mount­ed in a de­vot­ed chas­sis and con­trolled by a PC, op­er­ate most of the func­tions usu­al­ly car­ried out by stan­dard RF in­stru­men­ta­tion. The set up al­lows the mea­sure­ments of res­onators in the 80-700 MHz fre­quen­cy range and we used it to char­ac­ter­ize res­onators both in the ALPI vault and in off-line tests. Up­grad­ed con­trol pro­gram car­ries out all the typ­i­cal pro­ce­dures, re­lat­ed to the cav­i­ty mea­sure­ments in clas­si­cal VCO-PLL sys­tem. It al­lows to ad­just and to mea­sure the RF for­ward power, to find and up­date the cav­i­ty res­o­nant fre­quen­cy, to cal­i­brate the pick-up sig­nal, to mon­i­tor the trans­mit­ted power, to ad­just the cou­pler po­si­tion. The im­ple­ment­ed au­to­mat­ic pro­ce­dures per­mit to mea­sure the cav­i­ty decay time, to trace the Q-curve, to per­form CW and pulse RF con­di­tion­ing, to cal­i­brate ca­bles and mea­sure­ment in­stru­ments. The same soft­ware ap­plies to the other two mea­sure­ment sys­tems rou­tine­ly used at Leg­naro to test res­onators up to 6 GHz fre­quen­cy.

 
FR-04 Operational Experience in PIAVE-ALPI Complex 208
 
  • E. Fagotti, G. Bassato, A. Battistella, G. Bisoffi, L. Boscagli, S. Canella, D. Carlucci, M. Cavenago, F. Chiurlotto, M. Comunian, A. Facco, M. De Lazzari, A. Galatà, A. Lombardi, P. Modanese, F. Moisio, A. Pisent, M. Poggi, A.M. Porcellato, P. A. Posocco, C. Roncolato, M. Sattin, F. Scarpa, S. Stark
    INFN/LNL, Legnaro
 
 

PI­AVE-ALPI is the INFN-LNL su­per­con­duct­ing heavy ion linac, com­posed by an SRFQ (su­per­con­duct­ing RFQ) sec­tion and three QWR sec­tions for a total of 80 cav­i­ties in­stalled and an equiv­a­lent volt­age ex­ceed­ing 70 MV. In the last years the SRFQ and the bulk nio­bi­um QWR came into rou­tine op­er­a­tion, the medi­um en­er­gy QWR sec­tion was up­grad­ed with a new Nb sput­tered coat­ing, ECR source was first­ly im­proved by using water cooled plas­ma cham­ber and then re­placed with a new one. The op­er­a­tion of the ac­cel­er­a­tor com­plex al­lowed ac­quir­ing a strong ex­pe­ri­ence on many op­er­a­tional is­sues re­lat­ed to ECRIS, su­per­con­duct­ing cav­i­ties and cryo­gen­ics, beam con­trol and ma­nip­u­la­tion (with the new and high­er ac­cel­er­at­ing gra­di­ent). The paper re­ports about op­er­a­tional ex­pe­ri­ence, the pre­sent lim­i­ta­tions and the fu­ture per­spec­tives of the fa­cil­i­ty in view of the ex­per­i­men­tal cam­paign with the EU de­tec­tor AGATA and of the use of PIAVE ALPI as RIB post-ac­cel­er­a­tor for SPES ra­dioac­tive ion beam fa­cil­i­ty.

 

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