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

2. 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

3. 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

4. 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

5. 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

6. 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

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

8. 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

9. Experiment: detectorsV
Plastic Scintillater
Mar. 19, 2009
the Spectrometer Group

10. Experiment: targets
Mar. 19, 2009
the Spectrometer Group

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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

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

19. 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

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

21. 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

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

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

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

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

26. 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

27. 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

28. 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

29. Mar. 19, 2009
the Spectrometer Group

30. Mar. 19, 2009
the Spectrometer Group

31. Mar. 19, 2009
the Spectrometer Group

32. Mar. 19, 2009
the Spectrometer Group

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

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

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

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

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

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

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

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

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

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