Dubna, June, 2005

98 th session of the JINR Scientific Council

Nuclear Physics PAC

Dubna, June, 2005

Road map: general considerations

The PAC appreciates the initiative of the JINR Directorate to define a road map of strategic goals for the Institute’s research programme. It is essential to include practical aspects of this programme, in particular financial and manpower resources in this road map. The vitality of the Institute’s activities demands a focusing of these resources, and this may involve some hard decisions concerning projects of lower scientific merit. It is necessary that the impact of the various themes and projects should be highlighted, including the relevance to the interests of the wider international community in general and of the JINR Member States in particular. In this context the provision, maintenance, operation and development of basic facilities is of course an essential element.

Dubna, June, 2005

Laboratory presentations

The laboratories presentations (BLTP, DLNP, FLNR, FLNP, LIT) reviewed traditionally their current activities and programmes for 2006. However it felt that in future presentations the strategic goals should be more clearly defined, in terms of the topical basic and applied physics questions to be

addressed. The PAC congratulates JINR physicists on their recent achievements and notes in particular the obtaining of a further two events in the Z=118 experiment at FLNR.

Dubna, June, 2005

Projects

Dubna, June, 2005

First experiments with 6He radioactive beams at DRIBs

The first experiments carried out at the DRIBs complex demonstrated a large potential for research with accelerated secondary beams. The presented results of the first experiments with 6He beams are of top quality. The investigation of the 6He break-up gave information on the momentum distributions of the 4He products at low energies. The fusion reaction with 6He showed first conclusive data on this process.

Dubna, June, 2005

RIB

U-400

Ве-target

catcher

Ion source

low energy beam line Li

35 AMeV

7

U-400M

decris-14

He6

10 AMeV

ECR-4M

RIB ACCELERATOR COMPLEX OF THE FLNR (JINR) - DRIBS-1RIB ACCELERATOR COMPLEX OF THE FLNR (JINR) - DRIBS-1

THE 6He BEAM PROFILE: X = 7 mm; Y = 8 mm

THE 7Li BEAM INTENSITY:600 pnA

THE 6He BEAM INTENSITY :5.106 pps

Dubna, June, 2005

Measurement of the energy and momentum of the 6He-beam

using the magnetic spectrometer MSP-144

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MOMENTUM DISTRIBUTIONS - CONCLUSIONS

The narrow width of the momentum distribution of 4He from the breakup of 6He ( = 28±1 MeV/c) gives evidence for the existence of

a halo in 6He.

The comparison of the data obtained at 10 MeV/A with data at high energies (50-100 MeV/A) shows that they are practically the same. This means that low energy experiments can be as informative.

The width of the momentum distribution of 4He from the breakup of 6He only weakly depends on the target Z.

The width of the momentum distribution of 4He from the breakup of 6Li

( = 54±3 MeV/c) is evidence that there is an “intermediate” pn-halo in 6Li (Phys. Rev. C51 (1995) 2488; Phys. Lett. B527 (2002) 50).

Dubna, June, 2005

EXPERIMENTAL SETUPEXPERIMENTAL SETUPfor measuring excitation functions of for measuring excitation functions of

fusion reactionsfusion reactions

66HeHe

60 MeV60 MeV

14 MeV14 MeV

Proportional gas chamberProportional gas chamber

197197Au-foilsAu-foils 206206Pb-foilsPb-foils

6He+197Au 203Tl*

Al-AbsorberAl-Absorber

6He+206Pb 212Po*

6He+197Au 196,198,199Au

Dubna, June, 2005

Sub-barrier Fusion Enhancement : 6He+206Pb

4He+208Pb (Q=+13MeV)

10 15 20 25 30

20

40

60

80

100

m

b

Elab, MeV exp neutron trasfer no neutron tranfer

Bc

6He+206Pb5He+207Pb (Q=+5MeV)

Zagrebaev. PRC 67 (2003)Zagrebaev. PRC 67 (2003)

Dubna, June, 2005

CONCLUSIONSconcerning fusion and transfer-reaction

excitation functions

Enhancement is observed for above-barrier fusion (the 2n-channel for the 206Pb+6He reaction) compared to predictions of the statistical model.

Good agreement is observed with the predictions of the sequential fusion model for reactions of 6He+heavy nuclei (Zagrebaev, Phys. Rev. C67 (2003)).

Transfer reactions – the transfer of 2 neutrons from 6He to 197Au is about 3 orders of magnitude less than the transfer of 1 neutron.

Dubna, June, 2005

Recommendation. The research programme with 6He beams should be continued with first priority.

Dubna, June, 2005

MUON project

“Investigation of the Muon Properties and the Muon Interactions with Matter” The PAC noted with interest the new results obtained in the MUON project during the last three years.

Dubna, June, 2005

1. Status of the project

Scientific collaboration with:

Paul Scherrer Institute(Switzerland)

Moscow Institute of Physics and Technology (MFTI,

Dolgoprudny)

St.-Petersburg Institute of Nuclear Physics (Gatchina)

RNC "Kurchatov Institute" (Moscow)

Institute of theoretical and experimental physics (Moscow)

Max-Plank Institut fur Metallforschung(Germany)

Institute of Solid State and Semiconductor Physics of NASB,

Minsk

Dubna, June, 2005

2. Resent results

2.1 Experiments with negative muons (Dr. T. Mamedov)

2.1.1 Semiconductors

2.1.2 g-factor of μ- in the bound state

2.1.3 Capture of μ- by the noble gases isotopes

Dubna, June, 2005

2.2 Experiments with positive muons

2.2.1 Magnetism in Holmium

Dubna, June, 2005

2.2 Experiments with positive muons

2.2.2 Heavy fermions Ce3Pd20Ge(Si)6

“… CePdSi compound is one of the heaviest-electron system with gamma reaching 8 J/

mol Ce K2 at 0.2 K …“

Dubna, June, 2005

3. Status of the set-up

Dubna, June, 2005

4. Plans and perspectives

We suppose: 4.1 - to continue experiments at PSI

(Si, SiC, diamonds, g-factor, …)

4.2 - to renew in Dubna the study of metals and oxides with big samples

( Bi2CuO4 Bi2O3 …)

4.3 - to start the study of ferroliquids (Rumania)

4.4 – to continue the activity with polarized targets

(Dr. E.I.Bunyatova)

Dubna, June, 2005

Recommendation. The PAC recommends continuation of this project.

Dubna, June, 2005

SAD project (written report)

The PAC welcomes the completion of the design stage of the project “Subcritical Assembly at Dubna” (project SAD), targeted on creating a facility for addressing important problems of modern nuclear energy production and waste transmutation.

Dubna, June, 2005

Dubna, June, 2005

Dubna, June, 2005

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Recommendation. The PAC encourages collaboration between the SAD project and running European and other transmutation projects aimed at establishing closer connection of JINR with the world scientific transmutation community and making it more attractive for Member States.

Dubna, June, 2005

New Projects

Dubna, June, 2005

PALM project PALM project proposes a first experiment with positronium

beams. In LEPTA the lifetime of the circulating electron beam was significantly increased, and reasonable parameters like UHV requirements for successful future operation were defined. The next step of LEPTA development will be construction of a positronium source, improvement of the vacuum and development of a positronium beam of adequate intensity for the proposed experiment.

The PALM experiment aims at an improved lifetime measurement of para-positronium by a factor of two compared with previous experiments. Although the PAC does not consider PALM to be a significant QED test, it welcomes this experiment as an important first educational step to train the young scientists who have made a major contribution in creating the LEPTA facility. The PAC expects, however, new physics proposals to be formulated in due time.

Dubna, June, 2005

Electron gun

Progress on LEPTA: Test of The Lepta Ring with Circulating Electron Beam

Dubna, June, 2005

Proposal of The Experiment PALM

(PArapositronium Lifetime Measurement)

Dubna, June, 2005

Experiment PALM (continued)

The proposed experiment is of a special interest due to two reasons:

1) The theory: QED calculations of para have been performed by several authors. The most advanced result

(para / para)theor = 210-6

was obtained by a single group (see [1] PRL 83 (1999) 1135) and have NOT been confirmed by any others.

Corrections of the para theoretical value have two originations. The first one

relates to the relativistic modification of Bethe-Salpeter equation including correction of Coulomb potential. The effect on para value is expected to be

of the order of (v/c)2 ~ 2 and 3 correspondingly (see Yad. Fiz. v.61, 1990). These effects are not investigated yet properly.

The second one is real radiation corrections including up to two-loop analysis. One can suspect that the contribution of the light-light scattering effect is underestimated in the paper [1].

(E. Kuraev, BLTP JINR, October 2005)

3.1. Motivation

Dubna, June, 2005

Experiment PALM (continued) 3.2. Experiment scheme

o-Ps

Fe

NbTi

150 mm Target

130 mm

PMTube BGO-crystal

o-Ps/p-Ps o-Ps

12

21)(TN

TNBg

One measures the function

N1(B) – number of detector counts during time interval T1 when solenoid field value is equal to B, N2 – the count number during T2 at B = 0.

NbTi

Fe

Superconductingsolenoid

1 m

Dubna, June, 2005

Experiment PALM: Statistics Requirements (continued)

Then the experiment duration is defined by the cycle parameters:

Cycle duration – 100 s, where45 s – B-field is ON ,

45 s – B-field is OFF ,10 s - transition (switching) time.

Besides, during every 45 s one half of time has to be spent for measurement of background (o-Ps is “closed”).

Thus, to obtain the necessary statistic precision p / p = 1·10-4

one requires to register

Nexp 41010 events number.

If the detector efficiency is ~ 0.7 and average o-Ps flux intensity is of

I = 6103 s-1

the full duration of the experiment will be of

.months9~I

N

45

100T exp

exp ~ 9

months.

Dubna, June, 2005

Recommendation. Further development of the LEPTA ring and the PALM proposal as an educational experiment are recommended for approval.

Dubna, June, 2005

GERDA–MAJORANA project

The PAC recognizes the fundamental importance of modern neutrino experiments and the internationally acknowledged expertise of DLNP staff in this domain. With this in mind, the PAC welcomed the new proposal on the GERDA–MAJORANA project on the search for neutrinoless double-beta-decay of 76Ge. After the latest discoveries of the oscillations in reactor, solar and atmospheric neutrino fluxes, this new type of experiment is an essential next step in neutrino physics, and DLNP’s participation is deemed to be very important.

Dubna, June, 2005

G&MExperimental Search for Neutrinoless

Double Beta Decay of 76Ge

(GERDA-MAJORANA)

Participants from Dubna:

V.Brudanin, M.V. Chirchenko I.Chirikov-Zorin, V.Egorov, K.Gusev, S.Katulina, A.Klimenko, O.Kochetov, I.Nemchenok, N.Rukhadze, V.Sandukovsky, A.Smolnikov, Yu.Shitov, V.Timkin, S.Vasiliev, Ts.Vylov, E.Yakushev,

J.Yurkowski.

Dubna, June, 2005

DDouble bouble beeta ta (0(0) ) decay : experimental observabledecay : experimental observable

Dubna, June, 2005

GERDAGermanium Detector

Array for the search of neutrinoless -

decays of 76Ge at LNGS

The Majorana Zero-Neutrino Double-Beta

Decay Experiment

Majorana

&

Dubna, June, 2005

Cost estimates & status of funding

Cap. Investment Phase I: 6490 kEuroPhase II: 3830 kEuro

(~70% of funding secured)

Dubna, June, 2005

JINR contributionJINR contribution:

• Muon veto (plastic scint.)

• Radon detectors

• Handling Ge detectors (we have a special group which can do it)

• 4 kg of 76Ge → SEGA (Majorana)

• Data analysis, simulation, etc.

• We’ll see…

Dubna, June, 2005

INFN LNGS, Assergi, ItalyA.Di Vacri, M. Junker, M. Laubenstein, C. Tomei, L. Pandola

JINR Dubna, RussiaV. Brudanin, V. Egorov, K. Gusev, S. Katulina, A. Klimenko,

O. Kochetov, I. Nemchenok, V. Sandukovsky, A. Smolnikov, J. Yurkowski, S. Vasiliev,

MPIK, Heidelberg, GermanyC. Bauer, O. Chkvorets, W. Hampel, G. Heusser, W.

Hofmann, J. Kiko, K.T. Knöpfle, P. Peiffer, S. Schönert, J. Schreiner, B. Schwingenheuer, H. Simgen, G. Zuzel

Univ. Köln, GermanyJ. Eberth, D. Weisshaar

Jagiellonian University, Krakow, PolandM.Wojcik

Univ. di Milano Bicocca e INFN, Milano, ItalyE. Bellotti, C. Cattadori

INR, Moscow, RussiaI. Barabanov, L. Bezrukov, A. Gangapshev, V. Gurentsov, V. Kusminov, E. Yanovich

ITEP Physics, Moscow, RussiaV.P. Bolotsky, E. Demidova, I.V. Kirpichnikov, A.A. Vasenko, V.N. Kornoukhov

Kurchatov Institute, Moscow, RussiaA.M. Bakalyarov, S.T. Belyaev, M.V. Chirchenko, G.Y. Grigoriev, L.V. Inzhechik, V.I. Lebedev, A.V. Tikhomirov, S.V. Zhukov

MPP, München, GermanyI. Abt, M. Altmann, C. B\"uttner. A. Caldwell, R. Kotthaus, X. Liu, H.-G. Moser, R.H. Richter

Univ. di Padova e INFN, Padova, ItalyA. Bettini, E. Farnea, C. Rossi Alvarez, C.A. Ur

Univ. Tübingen, GermanyM. Bauer, H. Clement, J. Jochum, S. Scholl, K. Rottler

GERDA Collaboration

71 physicists listed; 30 full time equivalent staff + 5 PhD students9.5 FET engineer/technician

1.8 + 1

6 + 2

6 + 1

0.3

1.3

4

3

4

1.6

2+1

Dubna, June, 2005

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Summary

• Collaboration formed: expertise • Aggressive Schedule: start construction

summer 2005; first physics 2007• ~70% of funding secured• Manpower sufficient to get project going:

~30 FTE staff physicist + 9 FTE engineer • Competitive with relevant physics results

already in Phase I• Need approval to keep schedule

Dubna, June, 2005

Recommendation. The PAC considers the GERDA–MAJORANA project to be of the highest priority for DLNP and recommends its approval

Dubna, June, 2005

Development of the “Knowledge Base on Low-Energy Nuclear Physics”

The PAC welcomes the initiative of V. Zagrebayev’s team to create a network nuclear physics knowledge base. In particular, the provision of an on-line capability for performing nuclear reactions calculations is unique. The exercise is important to the wider international community and will bring great credit to FLNR. The PAC therefore urges the FLNR Directorate to assist in completing and continuously updating this base.

Dubna, June, 2005

Scientific reports

The PAC noted with interest the reports on the resonance states of heavy hydrogen and helium

nuclear systems, presented by G. Ter-Akopian, and appreciates the important new results in this field recently obtained at the ACCULINNA set-up.

"First results on fission, obtained at the n_TOF facility" presented by W. Furman. The impressive amount of top-quality nuclear data has been obtained by the collaboration CERN–JINR–IPPE (Obninsk). The PAC supports this activity and looks forward to the complete analysis of the measured data that will confirm their important practical and scientific input.

“Light nucleus clustering in fragmentation above 1 A·GeV” presented by P. Zarubin. Fragmentation of light nuclei has been observed at the Nuclotron beams using emulsion techniques. Inverse information on clustering features of nuclei is deduced.

Dubna, June, 2005

First Priority Experimental Tasks Scheduled for IREN with Budget and ManpowerFirst Priority Experimental Tasks Scheduled for IREN with Budget and Manpower

Dubna, June, 2005

Members of the PAC for Nuclear Physics Independent members Hans Börner * - ILL, Grenoble, France Rafal Broda* - INP, Cracow, Poland Jan Dobes - NPI, Řež, Czech Republic Yury Gaponov - RRC «Kurchatov Iinstitute», Moscow,Russia Andrei Goverdovski - IPPE, Obninsk, Russia Natalia Janeva - INRNE, Sofia, Bulgaria Gottfried Munzenberg - GSI, Darmstadt, Germany Сlaude Petitjean - PSI, Villigen, Switzerland Neil Rowley - IReS, Strasbourg, France Adam Sobiczewski - INS, Warsaw, Poland Ex officio members from JINR Michail Itkis - Director, FLNR Alojz Kovalik - Deputy Director, DLNP Valery Shvetsov* - Deputy Director, FLNP Victor Voronov - Deputy Director, BLTP Tsvetan Vylov - Vice-Director, JINR Pavel Zrelov - Deputy Director, LIT __________________________ *are not present at this meeting