PRESENT STATUS OF THE MICHIGAN-MIT ULTRA-COLD POLARIZED HYDROGEN JET†

Progress is reported on t l~e p~uiluction of an intense polarized atolnic hydrogen beam using microtx,nre rli iven cs t rac t io~~ of stal)ilizrd a ttsnlic 1lgdlr)gcn. Electrc.)n ~ ~ i n ~ ~ o l i ~ r i z e t l a.t.olnic ytlrog~n call 1,s stored at 11igl1 drilsit,ies over rela.t,ivelg lol~g taillie 1)eriods in a higll nlz1.gpet.i~ field (2 5 T ) nntl a.t 1t)tv tcmpera.tmes (2 0.8 Ii). D. Iileppner and T. 0. ~iinikoskil proposed t,ll;l.t. R hiall tl(msit,y a.to~llic h~-drogen beam could I,e prod~~cetl I,y using clect,rol~ spill rcsona.~lce (ESR.) plulllping to est,r:~.ct 11)-dmge~i atollls froill a. nlagiletic storage l>ottlc. Such a ~~~ic ro~vave dri~ien est~mction process cvulrl l,rovitle a.11 i~ltc,lisc lonv velocity sl>in-pola.rized atomic bcaln with il, na.rrom relocit,y tlist,ribut.ion; it should be llossil,le t,o at,t,;l.in a, d(,i~sit,y of about 1014 atoms/cln2 l>>? using ll~aglletic focusil~g. We to use such a. sl,i~l-l)olarizetl jet t.o st ,~~tly l ) ~ elast,ic sca.tt.eriilg at 400 GcV and 3 TeV in t,lle NEPTUN-A experilnellt at, U N I ~ " 011r al,llaratus'~ was designetl specifically t,o develop the t,ecll~~iql~e of proclucillg a high density aton~ic l1ydrogffn 11eam by nlicrr)xvas-e tlriven estractio~l. Tlle vertical sectioll cont,a,inetl a, conti~l~~ous flow dilution refrigerat,or xt-ibh R, cooling poxxler of 27 ~ I F V at 0.35 I<. \Ve rece~lt,lp illstallet1 a. net%storage ccll, sllo~vn in Fig. 1, tvl1ic11 collsists of double-walled copper t,ubing xvith an iilterllal diameter of 26 nlm, allout half t,he diameter of our earlier stori.g.e cell. Tile spa,ce bet*een the two walls fornled the ~liixing chalnl~er of the dilution refrigerator. Tlle storage cell 11act a 1