• A.Y. Murokh, M. Ruelas, R. Tikhoplav
  RadiaBeam, Santa Monica
• D.M. Gassner, E. Pozdeyev
  BNL, Upton, Long Island, New York

For high av­er­age cur­rent elec­tron ac­cel­er­a­tors, such as En­er­gy Re­cov­ery Linacs (ERL), the char­ac­ter­i­za­tion of basic elec­tron beam prop­er­ties re­quires non-in­ter­cep­tive di­ag­nos­tics. One promis­ing non-de­struc­tive ap­proach for a high av­er­age cur­rent beam di­ag­nos­tic is the laser wire scan­ner (LWS). Ra­di­a­Beam Tech­nolo­gies is de­vel­op­ing an in­ex­pen­sive, stand-alone laser wire scan­ner sys­tem specif­i­cal­ly adapt­ed to ERL pa­ram­e­ters. The pro­posed sys­tem uti­lizes dis­tinc­tive fea­tures of ERL beams, such as a rel­a­tive­ly long bunch length and ul­tra-high rep­e­ti­tion rate, to max­i­mize pho­ton count while using off the shelf laser tech­nol­o­gy. The Ra­di­a­Beam LWS pro­to­type present­ly under de­vel­op­ment will be in­stalled and com­mis­sioned at the Brookhaven Na­tion­al Lab­o­ra­to­ry (BNL) ERL fa­cil­i­ty. This sys­tem's de­sign and pro­ject­ed per­for­mance are dis­cussed here­in.

• Y. Hao, J. Kewisch, V. Litvinenko, E. Pozdeyev, V. Ptitsyn, D. Trbojevic, N. Tsoupas
  BNL, Upton, Long Island, New York

In this paper, we an­a­lyzed the linac op­tics de­sign re­quire­ment for a mul­ti-pass en­er­gy re­cov­ery linac (ERL) with one or more linacs. A set of gen­er­al for­mu­la of con­strains for the 2-D trans­verse ma­trix is de­rived to en­sure de­sign op­tics ac­cep­tance match­ing through­out the en­tire ac­cel­er­at­ing and de­cel­er­at­ing pro­cess. Mean­while, the rest free pa­ram­e­ters can be ad­just­ed for ful­fill­ing other re­quire­ments or op­ti­miza­tion pur­pose. As an ex­am­ple, we de­sign the linac op­tics for the fu­ture MeR­HIC (Medi­um En­er­gy eRHIC) pro­ject and the op­ti­miza­tion for en­larg­ing the BBU thresh­old.

• G. Wang, M. Blaskiewicz, A.V. Fedotov, Y. Hao, J. Kewisch, V. Litvinenko, E. Pozdeyev, V. Ptitsyn
  BNL, Upton, Long Island, New York

We pre­sent our stud­ies on var­i­ous as­pects of the beam dy­nam­ics in 'race­track' de­sign of the first stage elec­tron-ion col­lid­er at RHIC (eRHIC), in­clud­ing trans­verse beam break up in­sta­bil­i­ties, elec­tron beam emit­tance growth and en­er­gy loss due to syn­chrotron ra­di­a­tion, elec­tron beam loss­es due to Tou­schek ef­fects and residue gas scat­ter­ing, beam-beam ef­fects at the in­ter­ac­tion re­gion and emit­tance growth of ion beam due to elec­tron bunch to bunch nois­es. For all ef­fects con­sid­ered above, no show­stop­per has been found.

• C. Montag, L. Ahrens, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, A.V. Fedotov, W. Fischer, G. Ganetis, C.J. Gardner, J.W. Glenn, H. Hahn, M. Harvey, T. Hayes, H. Huang, P.F. Ingrassia, J.P. Jamilkowski, A. Kayran, J. Kewisch, R.C. Lee, D.I. Lowenstein, A.U. Luccio, Y. Luo, W.W. MacKay, Y. Makdisi, N. Malitsky, G.J. Marr, A. Marusic, M.P. Menga, R.J. Michnoff, M.G. Minty, J. Morris, B. Oerter, F.C. Pilat, P.H. Pile, E. Pozdeyev, V. Ptitsyn, G. Robert-Demolaize, T. Roser, T. Russo, T. Satogata, V. Schoefer, C. Schultheiss, F. Severino, M. Sivertz, K. Smith, S. Tepikian, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang
  BNL, Upton, Long Island, New York

Dur­ing the sec­ond half of Run-9, the Rel­a­tivis­tic Heavy Ion Col­lid­er (RHIC) pro­vid­ed po­lar­ized pro­ton col­li­sions at two in­ter­ac­tion points with both lon­gi­tu­di­nal and ver­ti­cal spin di­rec­tion. De­spite an in­crease in the peak lu­mi­nos­i­ty by up to 40%, the av­er­age store lu­mi­nos­i­ty did not in­crease com­pared to pre­vi­ous runs. We dis­cuss the lu­mi­nos­i­ty lim­i­ta­tions and po­lar­iza­tion per­for­mance dur­ing Run-9.

• D. Trbojevic, J. Beebe-Wang, X. Chang, Y. Hao, A. Kayran, V. Litvinenko, B. Parker, V. Ptitsyn, N. Tsoupas
  BNL, Upton, Long Island, New York
• E. Pozdeyev
  FRIB, East Lansing, Michigan

We pre­sent a medi­um-en­er­gy (4 GeV) elec­tron ion col­lid­er (MeR­HIC) lat­tice de­sign for the Rel­a­tivis­tic Heavy Ion Col­lid­er (RHIC). MeR­HIC rep­re­sents a staged ap­proach to­wards the high­er en­er­gy eRHIC, with MeR­HIC hard­ware being reused for eRHIC. The lat­tice de­sign in­cludes two En­er­gy Re­cov­ery Linacs (ERLs), mul­ti­ple isochronous arcs con­nect­ed to the ERLs, an in­ter­ac­tion re­gion de­sign, a low en­er­gy ERL with a po­lar­ized elec­tron source, and con­nect­ing beam lines.

* V. Litvinenko, proceedings from this conference.