WALTER GREINER

RECOMMENDATIONS

Programme Advisory Committeefor Nuclear Physics

31st Meeting

25–26 January 2010

Preamble

JINR Vice-Director M. Itkis informed the PAC about the Resolution of the 106th session of the Scientific Council (September 2009) and the decisions of the Committee of Plenipotentiaries (November 2009).The PAC is pleased to note the decision of the Committee of Plenipotentiaries (CP) to increase the JINR budget by 20.7% in 2010.

The CP also emphasized the importance of the annual increase of the budget in 2010–2016, planned according to the budget forecast approved by the CP, for achieving the milestones of the development strategy for the next seven-year period.

 Results of the implementation of the “Programme of the Scientific Research and Development of JINR (2003–2009)” and the JINR Programme of Nuclear Physics Research proposed for 2010–2012

The PAC congratulates the Directorate and the international staff of JINR on the complete and successful realization of the previous seven-year scientific programme and highly appreciates the valuable contributions to the advancement of science and technology at the world level that have been achieved as part of this programme.

The PAC takes note of the report presented by JINR Chief Scientific Secretary N. Russakovich and endorses the proposed main lines of the JINR Programme of Nuclear Physics Research for the period 2010–2012 in accordance with the new seven-year JINR development plan.

IREN (Источник Резонансных Нейтронов)

First ExperimentsFirst Experiments• Radiation resistance of the Radiation resistance of the

materialsmaterials• Extracted neutron beam Extracted neutron beam

parameters testingparameters testing• Neutron Resonance Capture Neutron Resonance Capture

Analysis (NRCA) of Analysis (NRCA) of elemental/isotopic elemental/isotopic compositioncomposition

• 117mSn production with 117mSn production with photonuclear reactionsphotonuclear reactions

Accelerated electrons average energyAccelerated electrons average energy – 30– 30 MeV MeV

• Peak currentPeak current – 2 – 2.8.8 AA;;

• Pulse durationPulse duration – 100 – 100 nsns;;

• Repetition rateRepetition rate – – 5050 HzHz;;

• Neutron yieldNeutron yield – – 88101010 10 nn//ss

IREN-1 parameters by the end of 2009

Neutron flux density at 10 m flight path

IREN vs IBR-30 (Ta (n,))

The PAC heard with interest the report on the first test measurements performed at the improved IREN-1 neutron source. The achieved energy resolution of the facility is good and permits reaching the new higher level of neutron resonance identification.

IREN 1-st stage outlook for 2010-2016

• 2010 - Upgrade of the RF power system with new klystron. This will result in RF power increase and duplicate electron energy with neutron yield 1012 n/s;

• 2011–2012: further upgrade of the RF power system and starting operation with the second accelerating section. This will provide the designed 200 MeV electron energy and beam power about 5.5 kW with neutron yield about 5 1012 n/s;

• 2012–2016: upgrade of the klystron modulators in order to reach the designed value of the repetition rate –– 150 Hz. Design and construction of a uranium non-multiplying target. Reaching of the beam power at the level of 10–15 kW and neutron yield at the level of several units of 1013 n/s, which will position IREN facility in line with the most intense resonance neutron sources of such type.

Recommendation

The PAC recommends the acceleration of the upgrade of IREN-1 to rapidly reach the higher intensity of the source and to make it really comparable with powerful neutron sources in Europe. It also recommends that additional funding be provided for supplying the necessary equipment for the next phase of IREN and its full completion as well as for modernization of the experimental instruments.

Experiments on the synthesis of element 117

Experiments on the synthesis of element 117

The PAC heard with interest the report on the results of the experiment dedicated to the synthesis of element 117 in the 48Ca+249Bk reaction. The PAC congratulates the staff of the Flerov Laboratory on the discovery of element 117 and new isotopes of elements 115, 113, 111, 109, 107, and 105. The discovery of chains of two neighboring isotopes emphasizes the importance of the odd-even and odd-odd effect for such heavy nuclei. It is in fact especially interesting that the odd-odd chain (3n channel) neighboring to the odd-even chain (4n channel) is twice longer (6 α particles).

odd-odd

odd-even

Production of neutron-rich SHE in low-energy collisions of heavy actinide nuclei

Zagrebaev & Greiner, PRC, 2008

• The PAC suggests considering, during the modernization phase of the U400 cyclotron complex, the possibility to develop a uranium beam of large intensity (~1012 p/s). This will allow the exploration, in further perspective, of alternative pathways to extend the nuclear chart towards even heavier and longer living nuclei.

• The PAC looks forward to further discussions of the status of the operating basic facilities and of projects of new experimental physics instruments of FLNR at its future meetings.

Recommendation

MAss Separator of Heavy

Atoms

The proposed setup is a combination of the so-called ISOL method of synthesis and separation of radioactive nuclei with the classical method of mass analysis, allowing mass identification of the synthesized nuclides in the wide mass range.

Ion source

Detectors

D1 Q1 Q2D2

Q3S1

D3aD3b

S2

Status on the MASHA set-up

General ion-optical parameters

Range of energy variation, kV 15-40Range of Br variation, Tm 0.08-

0.5Mass acceptance, % +/-2.8Angular acceptance, mrad +/-14Diameter the ion source exit hole, mm 5.0Horizontal magnification at F1/F2

0.39/0.68Mass dispersion at F1/F2, mm/%

1.5/39.0Linear mass resolution at F1 75Mass resolution at F2 1150

PAC for Nuclear Physics, 31st meeting, 25-25 January 2010

Mass-spectrometer MASHA at the beam line of the cyclotron U-400M

• New beam line with low energy of the U-400M was built• Mass-spectrometer mounted at the new beam line • Hot catcher is ready• Focal plane detector system is ready• Start of test and first experiments – April of 2010

Status of the mass-spectrometer MASHA

PAC for Nuclear Physics, 31st meeting, 25-25 January 2010

The PAC discussed in detail the current status and prospects of the MASHA spectrometer presented at this meeting. The PAC recognized with interest the plans for developing a gas ion-catcher in addition to the existing ISOL type ion source.

Status on the MASHA set-up

0 20 40 60 80 100 120 140 160 1800

8682 83

84

Strip num ber

0.10

A

0.15

0.05

2 .42 s trip sR = 14 00

K r

Mass spectrum of Kr isotopes:

Total efficiency – 47%

Mass resolution - 1400

Mass measurement accuracy – 1.3x10-5

First experiments: Start of test and first experiments – April of 2010

Mass identification of 112 и 114 elements synthesized at the reactions242Pu(48Ca,3n)287114(0.5 s, a) –> 283112(4 s, Ea= 9.95 MeV)244Pu(48Ca,3-4n)289114 (2.7 s, a 9.82 MeV) –> 283112(4 s,Ea= 9.95 MeV) Mass identification of 113 elements synthesized at the reaction 243Am(48Ca,3n)288115 (80 ms,E a= 10.5 MeV) ->284113(0.5 s,Ea= 10.0 MeV,

(analog of Tallium)

Recommendation

The PAC strongly supports the intention of the FLNR Directorate to start experiments with the MASHA mass spectrometer in 2010. The PAC recommends the installation of a gas ion-catcher and optimization of its properties for use at the MASHA set-up.

Status report on the GABRIELA set-up

• The PAC heard the current status and prospects of the VASSILISSA separator and the GABRIELA set-up (7 Ge detectors and a large number of Si strip detectors), based on the joint JINR-IN2P3 collaboration programme dedicated to the study of nuclear structure and nuclear reaction mechanism of heavy nuclei and superheavy elements. The scientific programme started in 2004, and 5 full-scale experimental campaigns (1 month of beam time per year) were completed with high-intensity beams of 48Ca, 22Ne, and 40Ar.

• The ongoing programme will benefit from the upgrade of the VASSILISSA separator started in 2008 from modified Ge detectors with higher multiplicity as well as from the use of actinide targets in asymmetric systems.

• The PAC appreciates the considerable progress achieved in the course of modernization of the VASSILISSA separator being performed in close collaboration with IN2P3.

Experimental set-up VASSILISSA + (α,)-detector array

Experimental hall of the U400 cyclotron

Experimental methods: Focal plane detector assembly

anticoincidence

tflight

= (T2-T

1)

T2

T1

TOF

(E + ECE

)

ER

'Backward - Detector'

'Backward - Detector'

'-Clover-Det.''Stop-Detector'

(E)

CE (ECE

)

(E + ER)

ER

(E) GABRIELA: Gamma Alpha Beta Recoil Investigation with the Electromagnetic Analyser

21

Published results

In progress

Future experiment

Failure from 210Pbtarget

22Ne + 242 Pu

U218

Lr255

Summary of results and on-going analysis

Th216

50Ti + 208Pb

Rf256Rf257

Velocity filter for asymmetric combinations(modernization of VASSILISSA)

High transmission for asymmetric combinations (beams of 12C, 14,15N,16,18O, 20,22Ne) movable plates of electrostatic deflectors

Availability for symmetric combinations (136Xe + 136Xe → 272Hs*) 50 cm long plates, high electrostatic field strength

0

1

2

3

4

5

6

7

8

9

10

11

12

Target W heel

Quadrupole Lenses I

Quadrupole Lenses II

Beam

Electric Deflector I

E lectric Deflector II

M agnetic Deflector II

M agnetic Deflector I

Beam Stop

Tim e of Flightdetector

Position-sensitivedetector array Magnetic

Deflector III

For asymmetric combinations – ♦ Increase of the electrostatic deflectors aperture

Movable plates

Future plans: Advantage of Dubna

244Md

245Md

243Fm

244Fm

246Md

247Md

245Fm

246Fm

248Md

249Md

247Fm

248Fm

250Md

251Md

249Fm

250Fm

252Md

253Md

251Fm

252Fm

254Md

255Md

253Fm

254Fm

256Md

257Md

255Fm

256Fm

258Md

259Md

257Fm

258Fm

260Md

261Md

259Fm

260Fm

249Lr

250Lr

248No

249No

251Lr

252Lr

250No

251No

253Lr

254Lr

252No

253No

255Lr

256Lr

254No

255No

257Lr

258Lr

256No

257No

259Lr

260Lr

258No

259No

261Lr

262Lr

260No

261No

263Lr

264Lr

262No

263No

251Db

252Db

250Rf

251Rf

253Db

254Db

252Rf

253Rf

255Db

256Db

254Rf

255Rf

257Db

258Db

256Rf

257Rf

259Db

260Db

258Rf

259Rf

261Db

262Db

260Rf

261Rf

263Db

264Db

262Rf

263Rf

265Db

266Db

264Rf

265Rf

253Bh

254Bh

252Sg

253Sg

255Bh

256Bh

254Sg

255Sg

257Bh

258Bh

256Sg

257Sg

259Bh

260Bh

258Sg

259Sg

261Bh

262Bh

260Sg

261Sg

263Bh

264Bh

262Sg

263Sg

265Bh

266Bh

264Sg

265Sg

267Bh

268Bh

266Sg

267Sg

78Pt,79Au,80Hg,81Tl,82Pb,83Bi targets – « cold fusion »

90Th, 92U, 94Pu, 95Am, 96Cm targets – « hot fusion »

100

101

102

103

104

105

106

107

146 148 150 152 154 156 158 160

Present limits ≥ 3 -5 nb for decay≥ 50 - 100 nb for prompt

=> Acces to less neutron-deficient nuclei

263Sg

262Sg

Recommendation

 

The PAC strongly supports the approval of the proposed upgrade of the GABRIELA and VASSILISSA complex with high priority

Visit to FLNR

U400M U400 U200

IC-100 MT-25 DRIBs in Gallery

U400M U400 U200

IC-100 MT-25 DRIBs in Gallery

The PAC members are grateful to the Directorate of the Flerov Laboratory of Nuclear Reactions for the organization of a visit to the laboratory to see the experimental equipment, in particular the accelerator complexes. Great changes in the appearance were noted in many sections of this laboratory. The good status of the equipment and the good organization of the research at FLNR helped very much the members of the PAC to understand the excellent results produced in the laboratory, demonstrated very recently by the synthesis of the new element 117.

StandardStandard 3 3 GWGWthth reactor reactor ((ВВЭР-1000ВВЭР-1000))

Antineutrino yield Antineutrino yield 10102020 /s / /s / 44

New project DANSSDetector of the Reactor ANtineutrino based on Solid State Plastic Scintillators

The PAC heard the proposal on the project DANSS whose goal is to develop and build a solid scintillator-based antineutrino detector. The PAC was pleased with the comprehensive presentation and the quality of the proposal description provided well in advance.

Detection of the reactor neutrino would allow:

•Measure the actual reactor power

(Nν)

•Deduce the actual fuel composition

(Eν)

•Weak (ν-e) cross-section•On-line reactor monitoring (tomography?) – especially important in view of the future FBR (with longer life-time and less studied)

•Non-proliferation (prevent unauthorized extraction of 239Pu)

Detection idea: Inversed Beta-Decay

)

e+

(n,)

30-50μs

(from 2.6) to 8 MeV

Local burst

The burst spread in space

.

Segmental solid

plastic scintillator

(2500 cells)

Sensitivevolume=1

m3

Cu (carriage frames = -shield)

Pb (-shield)

CH2 + B(n-shield)

Plast. scnt.(µ-shield)

DANSSDANSS

Recommendation

The PAC strongly recommends the approval of the DANSS project with high priority to be implemented under the theme “Non-accelerator Neutrino Physics and Astrophysics”.

Scientific report “Study of the nuclear fusion reactions in a pt system with the muon

catalyzed fusion method”

The PAC heard a scientific report on the theory of muon catalyzed pt fusion. This process was studied extensively at PSI in the 1980s, but the e+e- channel was missed which would clarify the strength of the E0 transition and would shed light on the reaction mechanism of four-body systems.

Possible muon-catalyzed fusion processes in a triple mixture of protium, deuterium and tritium; Cp, Cd, Ct are the respective concentrations, multiplied by the density (relative to liquid hydrogen density, LHD).

Recommendation

The PAC recommends the development of an experimental project to study pt fusion by the Mu-CATALYSIS collaboration (JINR Dubna, VNIIEF Sarov, Delft University, INP Cracow, ITEP Moscow).

Poster session

The PAC was pleased with the presentations of new interesting results in intermediate energy physics obtained in the ANKE and EDELWEISS experiments and in the theoretical investigations of alpha-cluster and dinuclear models. The PAC congratulates the young physicists for their results, the demonstrated ability to work in top-teams of nuclear physics, and encourages them to continue their activities.

Next meeting of the PAC

The next meeting of the PAC for Nuclear Physics will be held on 17–19 June 2010. Its tentative agenda will include:

• Reports and recommendations on themes and projects to be completed in 2010

• Consideration of new projects• Poster presentations of new results and

proposals by young scientists in the field of nuclear physics research

• Reports dedicated to the 70th anniversary of the discovery of spontaneous fission

Thanks for your attention