EURISOL_DS – Task 11 Subtask 5 Neutron- and proton-induced reactions up to Fermi energy J. Äystö / V. Rubchenya JYFL, Jyväskylä (P9) / KhRI, St.Petersburg.

EURISOL_DS – Task 11

Subtask 5

Neutron- and proton-induced reactions up to Fermi energy

J. Äystö / V. Rubchenya

JYFL, Jyväskylä (P9) / KhRI, St.Petersburg (C4)

Deliverables

I. 232Th(p, fission) – Y(A), TKE, neutrons, gammas, experiment (March 2005) data processing (Oct. 2005)II 238U(p, fission) – Yprod(A,Z), JYFLTRAP (Dec. 2005)

III Code developing and calculations of the characteristics of p-induced reactions (Nov. 2005)

232Th(p, f)

1. Experiment was carried out during 10th week at JYFL at

Ep = 20, 40 and 55 MeV.

1. Experimental setup consisted of:

• Two arm ToF fission fragment spectrometer based on MCP detectors –CORSET

• One arm ToF-E fission fragment spectrometer – CORSET

• 8 DEMON neutron detectors

• 2 position sensitive neutron detectors (PSND)

• 12 BaF2 gamma detectors

The view of experimental setup and 2D-ToF1-ToF2 spectra are shown in the next slides.

232Th(p, fission)

Experiment was carried out during 10th week at Ep = 20, 40, 55 MeV

3500 4000 4500 5000 55003000

3500

4000

4500

5000

ToF1, channel

To

F2

, ch

an

ne

l3,000

8,270

22,80

62,83

173,2

477,4

1316

3628

10000

p(20MeV)+232Th233Pa

3500 4000 4500 5000 55003000

3500

4000

4500

5000

ToF1, channel

To

F2

, ch

an

ne

l3,000

8,270

22,80

62,83

173,2

477,4

1316

3628

10000

p(40MeV)+232Th233Pa

3500 4000 4500 5000 55003000

3500

4000

4500

5000

ToF1, channel

To

F2

, ch

an

ne

l3,000

8,369

23,34

65,12

181,7

506,7

1414

3943

1,100E4

p(55MeV)+232Th233Pa

JYFLTRAP

New method of fission fragment yield measurement

Combination of the IGISOL mass separator facility and

the JYFLTRAP facility

The proposal to JYFL PAC was submitted by March 15, 2005

238U(p, f) at Ep = 30 MeV

Y(A,Z) are planned to measure at A = 70 - 170

JYFLTRAP- a triple trap setupJYFLTRAP- a triple trap setup

Twin Penning trap7T superconducting solenoid1. Purification trap2. Precision trap

Spectroscopy station

beam from IGISOL

c =

(q/m)(B/2)A. Nieminen, et al., Phys. Rev. Lett. 88(2002)094801

S. Rinta-Antila et al., Phys. Rev. C 70(2004)011301

Laser beam

Interaction region

Penning trap

Cooler/buncher

Beam switchyard

55° dipole magnet

Ion guideBeam from K130 cyclotron

Ion Guide Isotope Separator On-Line (IGISOL) overviewIon Guide Isotope Separator On-Line (IGISOL) overview

Neutral atom

Ion

proton beam

U target

He inlet

500 V

250

10 kV 30 kV

5 10-4 10-6p [mbar]

Stopping volume

Fission ion guideFission ion guide

p + 238U, 232Th

• FWHM ~ 20 Hz• m/m = 145000 possible (above spectrum m/m ~ 53000) • sufficient for mass spectroscopy

Purification of isobars for A=101 fission productsPurification of isobars for A=101 fission products

0 50 100 150 200 250

0

200

400

600

800

1000

1200

1400

101Mo101Nb

101Zr

101Y

x10

Cou

nts

Frequency [+1064670 Hz]

ST3 Model of fission process

• Pre-equilibrium model in p- and n- reactions with heavy nuclei

• Systematics of fission modes from thermal-neutron-induced fission to high excitation energy

• Improving description of post scission neutrons