Progress at LAMPF PDF
Preview Progress at LAMPF
ThisworkwasfundedbytheUSDepartmentoiEnergy.01riceotEnergyResearch. TheLaboratory'sequalopporlunitypolicyrequires,inaccordancewithapplicablestateandlederallaws, DepartmentolEnergypolicy,and UniversityolCaliforniapolicy,ooncertedefforttoensurethattt_eLaboratory _- doesnotdiscriminate.Alipolicies,procedures, andpracticesareadministeredforaliemployeesandapplicants regardlessofrace,color,nationalorigin,religion,sex,sexualorientalion,handicap,age,veteranstalus,medical condition(asdefinedinSection12926ottheCaliforniaGovernmentCode), ancestry,maritalstatus,or citizenship,withthelimitsimposedbylawofUniversityofCalitorniapolicy.TheLaboratoryalsoundertakes aflirmatweaclionregardingwomen,minorities,individualswitllhandicaps,andcoveredveterans."Thispolicyof nondiscriminationappliestorecruting,employrnent,compensation,benehtsandservices,training,advancement, promotion,transfer,termination,andtheavailabilityofbothinformalandformalcornplaint-.resolutionprocedures. 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Neitherthe!,JnitedStatesGovernmentnoranyagencythereof,noranyoftheiremployees,makesanywarranty, expressedorm_phedo,rassumesanylegalliabdityorresponsibilityfortheaccuracy,completeness,or usefulnessofanyinformation,apparatus,product,orprocessdisclosed,orrepresenls that_tsusewouldnot infringeprivatelyownedrights.Referencehereintoanyspecificcommercialproduct,process,orservicebytrade - name.trademark,manufacturer,orotherwise,doesnotnecessarilyconstituteorimplyitsendorsemenl, recommendation,orfavoringbythe UndedStalesGovernment.oranyagencythereof.Theviewsandopinionsoi authorsexpressedhereindonotnecessarilystaleorreflectthoseoithe UnitedStatesGovernmentorany agencythereof LA--1197 0-PR DE91 006614 Pro,tlressatLAMPF January-Oecember 1989 z -i M STER t DISTRIBUTIONC_FrHIs,_'JL.._.U!_,:._NT,SUNL, M,TED_ • _ PROGRESASTLAMPF Foreword FOREWORD We should ali take a great deal of pride in how ,,,.'ellthe Los Alamos Meson Physics Facility (LAMPF) operated during 1989. A new mode of operation was incorporated during the year,multiplexed polarized and unpolarized beam to the external proton beam line (Line X).These two beams, together with the high- and low-intensity H- beam for the Proton Storage Ring (PSR) and Weapons Neutron Research (WNR), as well as the high-intensity H+ beam to Line A, had LAMPF simultaneously running five separate types of beams to a variety of experimental areas. Congratulations are in order to the accelerator operating staff! The optically pumped polarized ion source (OPPIS) was commissioned in 1989and should be incorporated into routine operation in 1990 at 60% polariza- tion and at least 15/JA peak current. Because of an effective effort throughout MP Division, the PSR has greatly increased both its reliability and peak current. The LAMPF/PSR combination delivered a time-average current of 60 irA at 20 Hz with an overall system re- liability of 75%. As the spill time of a PSR pulse is 0.25/ts, the instantaneous current is 12amperes, which corresponds to an instantaneous power of 10gi- gawatts. While the bulk of the neutrons generated by the PSR protons at the Manuel Lujan, Jr. Neutron Scattering Center (LANSCE) is used for research in materials science, a group of nuclear physicists from Triangle Universities Nu- clear Laboratory (TUNL), Los Alamos, Tri-University Meson Facility (TRIUMF), and Delft have carried out a set of pioneering experiments studying parity vi- olation using thermal-epithermal neutrons. The resulting data can be readily analyzed using well-established concepts from the statistical theory of spectra. This approach promises to be a very important development in nuclear physics. In the area of continuing developments in experimental capability, the use of polarized nuclear targets has become somewhat routine as two definitive mea. surements were carried out involving charge exchange and elastic scattering of pions from polarizc_ 1aC.The results from these new measurements are presently being analyzed. There are plans formore experiments with polarized 1aCand _Li at the Energetic Pion Channel and Spectrometer (,EPICS).The Medium-Resolution Spectrometer (MRS) was commissioned near the end of the !ast cycle and imme- diately achieved a resolution of 1.2MeV at800 MeV,very near the design goal of 1.0MeV. lt was also successfully operated in the (n,p) mode in the neutron beam line. Thus, the Nucleon Physics Laboratory (NPL) is ready to go with Neutron Time-of-Flight (NTOF), MRS, and OPPIS. We can look forward to a great in- crease in the knowledge of the spin and isospin dependence ofnuclear structure and reactions from nucleon-nucleus _attering experiments over the next five or so years. Looking to the future, we plan to put into operation in 1990a superconduct- ; ing rf cavity termed the SCRUNCHER on the Low-Energy Pion (LEP) beam line. : The cavity is referred to as a SCRUNCHER because it compresses longitudinal : phase space of the pion beam in either energy or time to satisfy the require- ments of a given experiment. For example, at a fixed momentum resolution, by vi PROGRESS AT LAMPF Foreword compressing the beam in energy, it can increase the pion flux delivered to an experiment by a factor of S. In conjunction with LAMPF users and other leaders in the nuclear physics community, we are undertaking an examination of future direction for LAMPF in light of the most recent (1989) Nuclear Science Advisory Committee (NSAC) Long-Range Plan for U.S. nuclear physics. Although it appears that a large-scale upgrade to much higher energy at LAMPF is not possible for several years, there are a variety of enhancements that offer exciting new physics potential. Among those that draw a great deal of support from the LAMPF -user community is the development of a bright pion be.am at ,-,10'_pions/second at 1 GeV to al- low high-resolution studies in hypernucleus physics via the _-,K reaction. There is also strong support among users to further develop the intense, low-duty factor beams from the PSR for muon and neutrino physics. This would be a truly unique source that would alleviate the present requirement atthe Line A beam stop source for extensive and expensive active and passive shielding of cosmic rays. Such a developmen_ will make neutrino physics appreciably eas- ier and able to address a larger class of problems. There is also a community of nuclear physicists who find the possibility of doing world-class fundamental experiments with cold neutrons in the US. an exciting possibility. We are inves- tigating the degree to which LAMPF/PSR/LANSCE can meet this requirement. lt also emerged at the NSAC 1989 Long-Range Planning (LRP) meeting that a large segment of the community was interested in carrying out research with beams of exotic short-lived nuclei such as SHe, _1Li, etc. The most efficient way to produce these nuclei in sufficient quantity is by the use of a0.6-1 GeV proton beam to initiate spallation reactions on suitable heavy targets. The shor'-lived nuclei are then extracted from the target and ionized for acceleration in an ap- propriate post accelerator. LAMPF has in place the necessary proton beam and infrastructure to b,_a natural site for such a facility We are also actively looking into this possibility via a series of workshops and development plans. Thus, at the present moment, we see many possibilities forthe future. How- ever, they all require the necessary support to keep LAMPF a vital laboratory at the forefront of nuclear science. We believe that the Department of Energy wants us to continue in that role and expect that they will provide the resources required to do the job. Gerald T. Garvey Director of LAMPF vii PROGRESSATLAMPF Contents CONTENTS ExperimentaAlreas...................................................... xii LAMPFUsersGroup..................................................... 1 Twenty-Third Annual Meeting ........................................... 3 Committees ................................................................ 4 Workshops ................................................................ 6 , Visitors Center ........................................................... 8 Research................................................................... 11 Nuclear and Particle Physics ................................... ........ 13 EXPERIMENT791-- BNLAGS A Study of Very Rare I__.Decays ................................... 13 EXPERIMENT960....BR Measurement of AaT and Ac,/, in Free Neutron-Proton Scattering Between 300 and SO0MeV ............................. 16 EXPERIMENT1035-- BR Three-Spin Measurements in pp _ pp at 730 MeV ................... 19 EXPERIMENT1161....EPICS Nuclear Structure Effects in DCX to the DIAS for 7_,7_,_°,a'2-Se....... 23 EXPERIMENTS581AND704-- Fermilab Polarized Proton and Antiproton Experiments at Fermilab .......... 26 EXPERIMENT772.....Fermilab Study of the Nuclear Antiquark Sea with the Drell-Yan Process at 800 GeV ................................................ 30 EXPERIMENT1075....HIRAB Interaction of Relativistic H- Ions with Matter ...................... 37 EXPERIMENT1121......HIRAB High Excitations and Double Escape in the Negative Hydrogen Ion ........................ ...... ....................... 41 EXPERIMENT1127--HIRAB Multiphoton Detachment of Electrons from the H- ._on............. 46 EXPERIMENT811 ......LEP Study of Unnatural Parity States in Nuclei Using Low-Energy Pions ................................................ 49 viii PROGRESS AT LAMPF Contents EXPERIMEN9T48-- LEP The Role of Quasi-Deuterons in Pion Absorption on aLi............. 57 EXPERIMEN9T75-- LEP Pion-Nucleus Single Charge Exchange at Threshold Energies ........ 59 EXPERIMEN1T023-- LEP Analyzing Power Measurements for the (Tr+,7r°) Reaction on a Polarized 13CTarget .............................................. 61 EXPERIMEN1T025---LEP Pion Elastic Scattering from Polarized 1aC........................... 63 EXPERIMEN1T085--- LEP Pion Absorption on Deuterium Below 20MeV ....................... 66 EXPERIMEN1T098-- LEP/Clamshell Energy Dependence of Low-Energy Pion Double Charge Exchange ......................................................... 67 EXPERIMEN2T25-- Neutrino-A Measurement of the Exclusive Cross Section 12C(ue,e-)l"N(g.s.) .... 71 EXPERIMEN2T25-- Neutrino-A ,, A Study of Neutrino-Electron Elastic Scattering ..................... 76 EXPERIMEN6T45-- Neutrino-A A Search for Neutrino Oscillations .................................. 81 EXPERIMEN1T173--Neutrino-A Search for Neutrino Oscillations with High Sensitivity in the Appearance Channels u, --, u,_and Ft, --,/;e ................... 82 EXPERIMEN1T123.-- NTOF The 160(p,n)16FReaction at 500 MeV ............................... 85 EXPERIMEN7T50....P:_-East Reaction Mechanism of Inclusive Pion Double Cha-ge Exchange in 4He .................................................. 90 EXPERIMEN1T103-- Pa-East Inelastic Pion Scattering on 1aOAbove the A Resonance ............ 96 ix PROGRESS AT LAMPF Contents EXPERIMEN1T107-- P3-East Studies of Pion Double Charge Exchange Scattering at Energies Above the A Resonance ................................ 100 EXPERIMENiT153- Pa-East Quasifree Pion Charge Exchange at 500MeV....................... 104 EXPERIMEN1T015--PSR A Large Cerenkov Detector for Neutrino Physics ................... 106 EXPERIMEN1T183-- PSR The Study of Time Reversal and Parity Symmetries Using Epithermal Neutrons ............................................ 109 EXPERIMEN9T69--SMC MEGA: Search for the Rare Decay iL+---+e+7... ................... 111 Astrophysics .117 CYGNUS Project .... ............................................... 117 Atomic and Molecular Physics ......................................... 119 EXPERIMEN9T63-- SMC First Direct Measurement of C_-l_Sticking in dt-ttCF ................ 119 EXPERIMEN1T151-- SMC ExperimentalInvestigation of Muon-Catalyzed Fusion............. 126 Materials Science...................................................... 130 EXPERIMEN1T115 Magnetic Ordering in (YI_,.Pr,,Ba.2Cu:_O7as Evidenced by Muon Spin Relaxation ........................................... 130 Nuclear Chemisla'y ..................................................... 137 EXPERIMEN1T100-- TOFI Direct Mass Measurements Using the TOFI Spectrometer: The Neutron-Rich Isotopes of Chlorine through h'on ............. 137 Radiation Effects ....................................................... 142 EXPERIMEN1T014-- Radiation-EffecFtsacility Proton, Spallation-Neutron, and Fission Neutron Irradiation of Copper 142 EXPERIMEN1T139-- BeamStopirradiationFacility Testing of Radiation Resistance of Read-Out Chips for Use in _ High-Rate Nuclear and Particle Physics Applications ............ 144 X PROGRESS AT LAMPF Contents EXPERIMENT1165-- SpallationRadiationEffectsFacility Synergetic Load Effects on the Beam Entry Window of a High-Power Spallation Neutron Source .......................... 146 Radioisotope Production ................................................ 147 INC-11 Radioisotope Production Activities .......................... 147 Theory ................................................................. 150 Configuration Mixing as a Source of Three-Body Molecular Formation it. Muon Catalyzed d-I Fusion ......... ............... 150 Neutron Radius Analysis in the Trinucleon System from Pion Scattering ..................................................... 152 Report of the T-5 Theoretical Group ................................ 172 MP-Division Publications .............................................. 186 FacilityDevelopmen..t............................................... .. 211 OPPIS: The Optically Pumped Polarized Ion Source ................. 212 LAMPF and the Proton Storage Ring (PSR) Control Systems and Operations .............................................. 215 PSR and WNR Beam Delivery Systems ................................ 217 201-MHz RF System Problems ............................. ............. 221 Computing Directions and Opt:ms for Data Acquisition and Analysis at LAMPF ... .................................. ........ 223 Cost of the LAMPF Linac Extension ................................... 225 AcceleratorOperation.s.............................................. 227 Milestones 231 ...... Appendixe.s............................................................. 239 Appendix A: Experiments Run in 1989...................................... , .... 240 Appendix B:' New Proposals During 1989........................................ 243 Appendix C: L,AMPF Visitors During 1989....................................... 249 InformationforContributors ........................................... 259 xi PROGRESSATLAMPF ExperimentAalreas ' , _f-EXPERIMENTAL AREAS -'_ _ _i_.__.___j:_ ,_ BR MRS/_ n m r_ rq _ _ 800 Mev Linac = ,_' ,._'7---;-tk'- .- "% -'-"_'_,,"-A'--'''-'--'t::l_'' '.F.,;"m II/A\/kVl/I _1_" -------_m"tH,_Hf i LEP;',,_v,,., _ I I"--_/._IJk:./IJU- IJ m )_,, \ OTOFI ____L_I NEUTRINO _-_III ' DETECTOR H* HighIntonsil/Prolons \\ / _1_1 ........ .l, ....... H" Highlnlensi,yH" DD_TNIXIX,_"--.-._t/ \N L/_IXI_y..L., _1 U IU LU IU I_ PolarizeHd" " '" ..... _ i t I ."/ _ ..... BEAMCHANNELASNDPEFIMANEFNAI'CILITIES STORAGEGREINGRI_NLG\I, I ." " .._J YI m LEP Low-EnergyPionChannel -]_ I '" "_ p3 High-EnergyPionChannel FI_-J---.J' SMC Slopped-MuonChannel (-- i/_, ." • _ .... BR NeutronBeamChannel \ rT_/ IO: .... BEAMS EPICS EnergeeficPionChannelandSpectromeler _ L--'I 1/[ ' ' "' ............. HRS HighResolullonSpoclromoler fl.,_ t _ ' __ Dm,..... 1.+4 MRS Medium.l:_esolulionSpectrometer " " "_.,,) U _ ............ TOFI Time.oi.Flight IsochronousSpectrometer ". /",,./-; • r. ....... PolarizedProtonsorH- HIRAB HighReso!ulionAtomicBeamFacility '/, _ ' '. I " ,.... N!STOORFAD NIseoutotrpoenPTrimodeu.octfi-oFnligaNndFRaacdiliilayllonEllecls .. .f'.._'_u'T..J/ 'WvvNINRI ...... v_1,.o...n_s.i,o-,r...,M. uons LANSCE LosAlamosNeulronScalleringCenler . , _- .......... ,_,._uH,,u:., WNR WeaponsNeutronResearchFacilily ' • ........ Neurons xii
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