WALTER GREINER

RECOMMENDATIONS Programme Advisory Committee for 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 2009).

(November 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 strategy for the next seven-year period.

, planned according to the budget forecast approved by the CP, for achieving the milestones of the development

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 (И сточник Ре зонансных Н ейтронов)

• • • •

First Experiments Radiation resistance of the materials Extracted neutron beam parameters testing Neutron Resonance Capture Analysis (NRCA) of elemental/isotopic composition 117mSn production with photonuclear reactions

IREN-1 parameters by the end of 2009

Accelerated electrons average energy

– 30 MeV

• Peak current – 2.8 A; • Pulse duration – 100 ns; • Repetition rate – 50 Hz; • Neutron yield – 8  10 10 n/s

10 4 10 2 10 0 10 -2 10 -4 10 -3

neutron flux density Jan 23 2009 neutron flux density Mar 19 2009 neutron flux density May 21 2009 neutron flux density Dec 19 2009

10 -1 10 1

Energy, eV

10 3 10 5

4000

IREN vs IBR-30 (Ta (n,



))

IREN 325 min 2000 0 8000 6000 4000 IBR-30 10 min 2000 0 10 100 Energy, eV

The PAC heard measurements with interest the report on the first test 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

10 12 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 power about 5.5 kW with neutron yield about 5  and beam 10 12 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 10 13 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

48

effect

Ca+ 249 Bk 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 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

Recommendation

• The PAC suggests considering, during the modernization phase of the U400 cyclotron complex, the possibility to develop beam of large intensity (~10 12 p/s).

a uranium 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.



Status on the MASHA set-up

Detectors Ion source

MA

ss

S

eparator of

H

eavy

A

toms

D1 Q1 Q2 D2 S2

General ion-optical parameters

Range of energy variation, kV Range of Br variation, Tm Mass acceptance, % Angular acceptance, mrad 15-40 0.08-0.5

+/-2.8

+/-14 Diameter the ion source exit hole, mm 5.0

Horizontal magnification at F1/F2 0.39/0.68

Mass dispersion at F1/F2, mm/% 1.5/39.0

Linear mass resolution at F1 75 Mass resolution at F2 1150

Q3 S1 D3a D3b

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.

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

Status of the mass-spectrometer MASHA 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 PAC for Nuclear Physics, 31 st meeting, 25-25 January 2010

Status on the MASHA set-up

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.

0.15

Kr 0.10

0.05

82 83 84 2.42 strips R=1400 86 0 0 20 40 60 80 100 120 Strip number 140 160

Mass spectrum of Kr isotopes:

Total efficiency – 47%

Mass resolution - 1400

Mass measurement accuracy – 1.3x10-5 180

First experiments : Start of test and first experiments – April of 2010 Mass identification of 112 и 114 elements synthesized at the reactions 242 Pu( 48 Ca,3n) 287 114(0.5 s, a) –> 283 112(4 s, E a = 9.95 MeV) 244 Pu( 48 Ca,3-4n) 289 114 (2.7 s, a 9.82 MeV) –> 283 112(4 s,E a = 9.95 MeV) Mass identification of 113 elements synthesized at the reaction 243 Am( 48 Ca,3n) 288 115 (80 ms,E a = 10.5 MeV) -> 284 113(0.5 s,E a = 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 the joint JINR-IN2P3 collaboration with high-intensity beams of 48 Ca, 22 Ne, and 40 • The ongoing programme will benefit from the Ar. (7 Ge detectors and a large number of Si strip detectors), based on 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 upgrade of the VASSILISSA separator started in 2008 detectors with higher multiplicity as well as from the use of actinide targets in asymmetric systems.

from modified Ge • 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

,

b

)-detector array

Experimental hall of the U400 cyclotron

Experimental methods: Focal plane detector assembly 'Backward - Detector' TOF T 1 T 2 '  -Clover-Det.'  (  E  + E R ) 'Stop-Detector'  (E  ) t flight = (T 2 -T 1 ) ER 'Backward - Detector' ER CE (E CE ) (E  + E CE )  (E  )

GABRIELA

: G amma A lpha B eta R ecoil I nvestigation with the El ectromagnetic A nalyser anticoincidence

Summary of results and on-going analysis 50 Ti + 208 Pb 22 Ne + 242 Pu

Rf256 Rf257 Lr255 U218 Th216

Published results In progress Future experiment Failure from 210 Pb target

21

Velocity filter for asymmetric combinations (modernization of VASSILISSA) High transmission for asymmetric combinations (beams of 12 C, 14,15 N, 16,18 O, 20,22 Ne)  movable plates of electrostatic deflectors Availability for symmetric combinations ( 136 Xe + 136 Xe → 272 Hs*)  50 cm long plates, high electrostatic field strength

12 Time of Flight detector 11

For asymmetric combinations – ♦ Increase of the electrostatic deflectors aperture

Di sta 5 nc e i n M 6 ete rs 7

Movable plates

3 4 2 8 9 10 Quadrupole Lenses II Electric Deflector II Magnetic Deflector II 0 1 Magnetic Deflector I Beam Stop Electric Deflector I Beam Quadrupole Lenses I Target Wheel Magnetic Deflector III Position sensitive detector array

Future plans: Advantage of Dubna => Acces to less neutron-deficient nuclei 78 Pt, 79 Au, 80 Hg, 81 Tl, 82 Pb, 83 Bi targets – « cold fusion » Present limits  ≥ 3 -5 nb for decay  ≥ 50 - 100 nb for prompt 90 Th, 92 U, 94 Pu, 95 Am, 96 Cm targets – « hot fusion » 107 253 Bh 254 Bh 255 Bh 256 Bh 257 Bh 258 Bh 259 Bh 260 Bh 261 Bh 262 Bh 263 Bh 264 Bh 265 Bh 266 Bh 267 Bh 106 252 Sg 105 251 Db 104 250 Rf 253 Sg 252 Db 251 Rf 254 Sg 253 Db 252 Rf 255 Sg 254 Db 253 Rf 256 Sg 255 Db 254 Rf 257 Sg 256 Db 255 Rf 258 Sg 257 Db 256 Rf 259 Sg 258 Db 257 Rf 260 Sg 259 Db 258 Rf 261 Sg 260 Db 259 Rf 261 Db 260 Rf 262 Db 261 Rf 264 Sg 263 Db 262 Rf 265 Sg 264 Db 263 Rf 266 Sg 265 Db 264 Rf 101 244 Md 100 243 Fm 245 Md 103 249 Lr 102 248 No 246 Md 247 Md 244 Fm 245 Fm 246 Fm 146 250 Lr 249 No 248 Md 251 Lr 250 No 249 Md 252 Lr 251 No 250 Md 253 Lr 252 No 251 Md 254 Lr 253 No 252 Md 255 Lr 254 No 253 Md 256 Lr 255 No 254 Md 257 Lr 256 No 255 Md 258 Lr 257 No 256 Md 259 Lr 258 No 257 Md 260 Lr 259 No 258 Md 261 Lr 260 No 259 Md 247 Fm 248 Fm 148 249 Fm 250 Fm 150 251 Fm 252 Fm 152 253 Fm 254 Fm 154 255 Fm 256 Fm 156 257 Fm 258 Fm 158 262 Lr 261 No 260 Md 263 Lr 262 No 261 Md 259 Fm 260 Fm 160 265 Rf 264 Lr 263 No 268 Bh 267 Sg 266 Db

Recommendation

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

Visit to FLNR

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.

New project DANSS

D etector of the Reactor AN tineutrino based on S olid State Plastic S cintillators

Standard 3 GWth reactor (

ВВЭР-1000)

Antineutrino yield



10 20

 /s / 4  The PAC heard the proposal on the project DANSS advance.

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

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 239 Pu)

Detection idea: Inversed Beta-Decay



)

.

(from 2.6) to 8 MeV

e +

(n,



)

30-50 μs The burst spread in space Local burst

Segmental solid plastic scintillator (2500 cells) Sensitive volume=1 m

3

Plast. scnt.

(µ-shield)

CH 2

+ B (n-shield)

Pb

(  -shield) Cu (carriage frames =  -shield)

DANSS

Recommendation

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

to be

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



system with the muon catalyzed fusion method”

The PAC heard a

scientific

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

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 experimental project to study pt  of an 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