Study of 58Ni excited states by (p, p’) inelastic scattering A primer course of experimental nuclear and particle physics Osaka University, 2009

Outline Introduction Experiment Data analysis Summary Acknowledgements RAIDEN spectrometer Detectors, electronics & DAQ Online tuning Data analysis State identification Differential cross section BG treatment Result Summary Acknowledgements Mar. 19, 2009 the Spectrometer Group

Introduction: inelastic scattering Inelastic scattering: (in a non-relativistic view) at a given angle … excitation states are measurable observable elastic term excitation term * Mar. 19, 2009 the Spectrometer Group

Introduction: spectrometer Spectrometer = prism Distinguishes particles with different momentum Well designed magnets are required to guarantee precise measurement g-1<<1 in a small range Mar. 19, 2009 the Spectrometer Group

inelastic perturbation Introduction: DWBA Distorted wave Born approximation 2-step scattering Cross section “DW”: elastic solution for as the zero order of final wave function “BA”: only the first order correction from is considered Refer to “Introduction to nuclear reactions”, G.R. Stachler, 1980 elastic term inelastic perturbation Mar. 19, 2009 the Spectrometer Group

Experiment: overview RAIDEN @ RCNP Proton beam at 53 MeV energy from AVF DW = 2.7 msr (slit), SWPC, plastic DE-E counters (CH2)m, 58Ni[0.92 mg/cm2] and nat.Mg[0.58 mg/cm2] ~ 20 hour beam time CAMAC + Tamii DAQ + PAW N.T. Huong, D.N. Thang, P.W. Zhao, Y. Lei, Y. Wang, and W. Guo Mar. 19, 2009 the Spectrometer Group

Experiment: RAIDEN @ RCNP RAIDEN spectrometer: NIM 175 (1980) 335 Incredible: 30 years old but still works well! Mar. 19, 2009 the Spectrometer Group

Experiment: detectors Single Wire Proportional Chamber NIM 196(1982)249; NIM 217(1983)441 Side view Signals: QL, QR  position DE1, DE2 DEL, DER, Time EL, ER, Time RF Time “Charge Division” Ar+CO2 5% Mar. 19, 2009 the Spectrometer Group

Experiment: detectors V Plastic Scintillater Mar. 19, 2009 the Spectrometer Group

Experiment: targets Mar. 19, 2009 the Spectrometer Group

Experiment: electronics Fast signals Slow signals Busy-resistant logic Mar. 19, 2009 Coincidence logic the Spectrometer Group

Experiment: online tuning Electronics: Gain of amplifiers: match the pulse heights CFD tuning: suppress major part of noise Delay tuning: establish coincidence / trigger logic Gate width tuning: match rising time of Int. Amp. Beam: Identify the elastic peak Adjust magnetic field to exclude the elastic peak Rotate RAIDEN (from 15o to 50o ) during measurement Mar. 19, 2009 the Spectrometer Group

Experiment: identification of state In our experiment, the outgoing particles (p) move in magnetic field of spectrometer like in fig: Bρ = pout /q pout ↑→ ρ ↑ & Eout+ Ex +Krecoil = Ein(const) pout↑→↓Ex(small region~linear) Mar. 19, 2009 the Spectrometer Group

On the other hand: ρcorresponding with x →Ex ~x From data analysis we get the position spectrum of proton (θ=150) Mar. 19, 2009 the Spectrometer Group

By using online analysis, we can identify g.s and 1st excited state. 2+(1454) 4+(2460) 2+(3038) 2+(3265) 4+(3621) 3-(4475) 4+(4755) By using online analysis, we can identify g.s and 1st excited state. Using table 1 refer [1] we can determine L=2+ , parity and Ex =1.454Mev of 1st Mar. 19, 2009 the Spectrometer Group

by using the assumption Ex~x (linear) And also, the L=3- (4475kev) state can be identify by using this table: For other states We can identify by using the assumption Ex~x (linear) Mar. 19, 2009 the Spectrometer Group

identify for other scattering angles. In face, the proportion between Ex and x is second-order linear like in fig Therefore, by using this simple way, we can identify for other scattering angles. Mar. 19, 2009 the Spectrometer Group

Data analysis: run summary B [mT] Brho [Tm] q [deg] Tar I [nA] Trig Live Q [nC] LAB C.M. 001 711.602 1.0674 15 15.2　 58Ni 20 Tuning runs 002 690.613 1.0359 003 697.919 1.0469 2.25 004 697.93 30 177270 171667 51408.5 005 20.2　 45 79053 76555 26160.2 007 43 44468 43204 14723.0 008 25 25.3　 35 88817 86947 36346.0 010 30.4　 48-65 145175 141972 91920.8 011 35.5　 68 130913 129030 123316.7 012 697.92 40 40.6　 53 104762 103609 117726.8 013 nat.Mg 72 193259 175680 30672.3 014 47 196758 181074 29770.8 015 50 50.7　 65 84642 83994 162986.1 016 199188 186705 47744.0 Summary table Mar. 19, 2009 the Spectrometer Group

Data analysis: cross section calculation , C: the count of the state, Q: the total charge of incoming beam, r the reduced density of target, e the charge of proton, k the detecting efficiency, and DW the solid angle Mar. 19, 2009 the Spectrometer Group

Data analysis: background treatment ADC overflow of measured charge: which cause a pile- up at x = L/2 Mar. 19, 2009 the Spectrometer Group

Data analysis: background treatment QL, QR drifts caused by pre-amp resistance / ADC zero level: result in error on x calculation Mar. 19, 2009 the Spectrometer Group

Data analysis: background treatment Drift of PMTs of plastic E counter: 300 signal & BG not orthogonal 205 here Mar. 19, 2009 the Spectrometer Group

Data analysis: background treatment Drift of PMTs of plastic E counter: signal & BG orthogonal now Mar. 19, 2009 the Spectrometer Group

Data analysis: background treatment Mar. 19, 2009 the Spectrometer Group

Data analysis: ds/dW & DWBA cal. Fresco: http://www.fresco.org.uk/ After BG reduction Statistic error only. Mar. 19, 2009 the Spectrometer Group

We have learned The excitation states of 58Ni have been measured by inelastic proton scattering at Ep = 53 MeV; The excitation energy and angular momentum of these excitation state have been determined; The angular distributions of differential scattering cross section, which are well agreed with the DWBA calculations, have been obtained from the experimental data. Mar. 19, 2009 the Spectrometer Group

Summary Nuclear reaction theory with Born approximation Determination of the angular momentum of excited states Prepare of the target. Detection of charged particles with a single-wire proportional chamber and plastic scintillators and their operation. Electric circuits and a CAMAC based data acquistion system Data analysis, determination of differential cross section Mar. 19, 2009 the Spectrometer Group

Acknowledgements Osaka University, JSPS, JICA, Department of physics, RCNP, AVF operators Organizers: Prof. T. KISHIMOTO, Prof. M. NOMACHI, Prof. Y. KUNO, Prof. T. OGAWA, etal. Lectures: Prof. T. NAKANO, Prof. T.YAMANAKA, Prof. M. FUKUDA, etal. Experiment: Prof. Y. FUJITA, Prof. A.TAMII, Prof. H. OKAMURA, Prof. K. HIROTA, Prof. T. ITAHASHI, etal. All the secretaries, All the participants of this prime school Mar. 19, 2009 the Spectrometer Group

Mar. 19, 2009 the Spectrometer Group

Mar. 19, 2009 the Spectrometer Group

Mar. 19, 2009 the Spectrometer Group

Mar. 19, 2009 the Spectrometer Group

Thank you A primer course of experimental nuclear and particle physics Osaka University, 2009

Appendix: elastic term Mar. 19, 2009 the Spectrometer Group

Appendix: detector arrangement Mar. 19, 2009 the Spectrometer Group

Appendix: timing chart Trigger DAQ system GDG FIFO VETO CCNET BUSY Mar. 19, 2009 the Spectrometer Group

Appendix: excited states of 58Ni Mar. 19, 2009 the Spectrometer Group

Appendix: ds/dW & DWBA calculation Mar. 19, 2009 the Spectrometer Group

Appendix: ds/dW & DWBA calculation Mar. 19, 2009 the Spectrometer Group

Appendix: ds/dW & DWBA calculation Mar. 19, 2009 the Spectrometer Group

Appendix: ds/dW & DWBA calculation Mar. 19, 2009 the Spectrometer Group

Appendix: ds/dW & DWBA calculation Mar. 19, 2009 the Spectrometer Group