Stable and radioactive beam studies @ ALTO Georgi Georgiev, CSNSM, - - PowerPoint PPT Presentation

▶
stable and radioactive beam studies alto
SMART_READER_LITE
LIVE PREVIEW

Stable and radioactive beam studies @ ALTO Georgi Georgiev, CSNSM, - - PowerPoint PPT Presentation

May 23, 2023 293 likes •474 views

Stable and radioactive beam studies @ ALTO Georgi Georgiev, CSNSM, Orsay, France The ALTO facility 15 MV 50 MeV 2013 2014 2015 Users 200 135 143 Beam-time 2983 h 2297 h 2736 h 373 UT 287 UT 342 UT 18 Sept. 2015, Krakw, Poland

slide-1
SLIDE 1

Stable and radioactive beam studies @ ALTO

Georgi Georgiev, CSNSM, Orsay, France

slide-2
SLIDE 2

18 Sept. 2015, Kraków, Poland

15 MV 50 MeV

2013 2014 2015 Users 200 135 143 Beam-time 2983 h 2297 h 2736 h 373 UT 287 UT 342 UT

The ALTO facility

slide-3
SLIDE 3

18 Sept. 2015, Kraków, Poland

Experimental areas

Split-Pole spectrometer Bacchus g-spectrometers ORGAM MINORCA PARIS Licorne ISOL mass separator experimental lines cluster, molecular & droplets beams Stable beam with spectrometer Stable beam w/o spectrometer Radioactive beam lines ISOL production cave

e LINAC

slide-4
SLIDE 4

18 Sept. 2015, Kraków, Poland

  • N. de Séréville & A. M. Laird N-SI-36

Credit: MPE Garching / R. Diehl

Astrophysical motivation:

  • Gamma-ray emission associated with 26Al observed in our

galaxy.

  • 26Mg coming from 26Al decay observed in presolar grains
  • 26Al yields depends strongly on reactions 26Al(n,p)26Mg and

26Al(n,a)23Na

  • Need for better

27Al spectroscopy (ER, Jp, Gp, Ga) above

neutron threshold (Sn = 13 MeV)

26Al(n,p)26Mg and 26Al(n,a)23Na in massive star

→ Populating resonances with the 27Al(p,p')27Al* reaction 30 new states above neutron threshold in 27Al

  • S. Benamara, N. de Séréville et al, PRC 89, 065805 (2014)

Split-Pole spectrometer (ALTO) + DSSSDs in reaction chamber

Adsley et al. to be submitted

26Al nucleosynthesis in massive stars

slide-5
SLIDE 5

18 Sept. 2015, Kraków, Poland

Hydrogen gas cells H2 pressure and flow control system

Development of a kinematically focused neutron source with the p(7Li,n)7Be inverse reaction M.Lebois, J.N. Wilson et al., Nucl. Instrum. Meth. A 735 145 (2014)

LICORNE II – fast-neutron source

slide-6
SLIDE 6

18 Sept. 2015, Kraków, Poland

24Mg 2+ state USD shell model: g(2+)=0.544

Our result: |g(2+)|= 0.538 (13)

Previous measurement: |g(2+)| = 0.51 (2)

R.F. Horstman et al., NPA 248, 291 (1975)

  • A. Kusoglu et al. PRL 114, 062501 (2015)

High-accuracy g-factor measurements are essential for constraining the theories!

beam: 24Mg @120 MeV (5 MeV/u) target: 2.4 mg/cm2 93Nb reset Foil: 1.7 mg/cm2 197Au

TDRIV on H-like ions: 24Mg

slide-7
SLIDE 7

18 Sept. 2015, Kraków, Poland

MINORCA in Orsay (June 2014 – March 2015) 12 ORGAM CS HPGe x 0.1% 8 Miniball TC at ~14 cm from target 7.3% efficiency @ 1.33 MeV ancillary detectors:

  • Orsay plunger (OUPS)
  • particle detector
  • DSSD
slide-8
SLIDE 8

18 Sept. 2015, Kraków, Poland

MINORCA – experiments performed

1. 1. Tim ime de dependent reco recoil in vac vacuum for for Na-like like 56

56Fe

Fe ion

  • ns
  • spo

spokespersons: s: A. . St Stuchbery, D. . Bala alabanski

2.

  • 2. Sh

Shape coe coexistence in 74

74Se

Se stu studied through com complete low

  • w-spin spe

spectroscopy af afte ter Cou Coulo lomb exc excitation

  • spo

spokespersons: s: M. . Zie Zielinska, , K.

  • K. Wrzosek-Lipska

3.

  • 3. Mea

easurement of

  • f octu
  • ctupole coll

collectivity in Nd Nd, , Sm Sm an and Gd Gd nu nuclei usin using Cou Coulo lomb exc excitation

  • spo

spokespersons: s: P.A. Butler, M. . Zie Zielinska

4.

  • 4. Spe

Spectroscopy of

  • f the ne

neutron-ric ich fi fiss ssion frag fragments pro produced in n the 238

238U(

U(n,f) rea reactio ion

  • spo

spokespersons: s: J. . Wils ilson, M. . Le Lebois

5.

  • 5. Eva

Evalu luatio ion of

  • f the Ang

ngular Mom

  • mentum De

Dependence of

  • f the 96

96Mo γ Strength Fu

Functio ion

  • spokesperson: B.

. Gol

  • ldblum

6.

  • 6. Lif

Lifetim ime Measurement of

  • f 100

100Ru

Ru: A poss possible le can candid idate for for the E(5 E(5) cr crit itic ical po poin int sym symmetry

  • spokesperson: Th

Th. . Konstantinopoulos

7.

  • 7. Lif

Lifetim ime mea easurements in n 113

113Te

Te: De Dete termining Op Optim imal eff effectiv ive ch charges ap approaching the N=Z=50 do doubly-magic she shell l cl closure. .

  • spokesperson: D.M

.M. . Cul ullen

slide-9
SLIDE 9

18 Sept. 2015, Kraków, Poland

  • First in-beam experiments of Demonstrator
  • 2,048 Micromegas pads
  • 4 DSSDs + 12 Pad Si integrated
  • Newly-made GET electronics to take data
  • 2 successful runs (June to July ’15)
  • 12C @80 MeV + He gas
  • 6Li @11 to 23 MeV + He gas
  • 35 visitors (16 domestic, 19 international)

12C stable 10B stable 11B stable 8Be 5.6 eV 9Be stable 10Be 1.5 My 6Li stable 7Li stable

?

n p d α α

4+ ?

[MeV]

Hoyle like molecular like

DSSD Pad Si Micromegas

bacchus

Most-recent results

  • D. Suzuki et al.
slide-10
SLIDE 10

18 Sept. 2015, Kraków, Poland

Beam

ACTAR TPC: Demonstrator

  • Two experiments performed at ALTO:
  • a-clustering in light nuclei

bacchus

slide-11
SLIDE 11

18 Sept. 2015, Kraków, Poland

ALTO - RIB

First operational RIB facility based on photo-fission

populating the GDR of 238U

standard ISOLDE target ∅ = 14 mm; L = 140 mm ρ = 3.2 g/cm3; T ≤ 2100o C

 Estimated yields for 10 µA, 50 MeV e- beam

Y. . Oganess ssian et al. al., NPA A 70 701 1 (20 (2002 02) 87 87c

slide-12
SLIDE 12

18 Sept. 2015, Kraków, Poland

Rialto: Resonant laser ionisation at Alto

  • S. Franchoo et al.

Mezzanine of the mass separator/RIB zone

Nd:Yag pump laser (532 nm, 90 W) 2 dye lasers (540-850 nm, 8W @ 30W pump, 10 ns pulse width, 3 GHz line width) BBO doubling units (270-425 nm, >100 mW)

slide-13
SLIDE 13

18 Sept. 2015, Kraków, Poland

BEDO setup neutron detection TETRA fast timing LaBr3

up to 5 Ge detectors (ε = 5-6%) 4π β trigger 80 3He tubes ε(252Cf) = 53% borated polyethylene shielding Fast-timing studies using LaBr3 detectors

Nuclear structure in b-decay

slide-14
SLIDE 14

18 Sept. 2015, Kraków, Poland

[Heyde & Wood,

  • Rev. Mod. Phys. 83 (2011)]

shape coexistences: a general phenomenon?

50 ? 50

82Ge→82 33As49

(1) problem of the spectral distribution of 1+ states

in the N=50 region (→ responsible for the half-life of the mother nucleus, possible consequences on the r-process) interpreted by the theoretical work of Severyukhin… Giai et al. (influence of couplings to 2p-2h and tensor interaction)

(2) ubiquitous presence of intruder states of the type 1p-2h

→ signature of shape coexistence

νg9/2 50 νd5/2 1+ 1p-2h

conclusion: an «island of inversion» is « missed » at N=50 by 0.5 MeV only !

Though this phenomenon seems to concern all shell-closure regions: not a single study at N=50 for more than 3 decades! (Z=50 a textbook case)

  • A. Etilé et al., Phys. Rev. C 91, 064317 (2015)

Results from BEDO in b-delayed γ-spectroscopy mode

slide-15
SLIDE 15

18 Sept. 2015, Kraków, Poland BEDO/TETRA (existing) LINO (project) TAS (project) TETRA (existing) Identification station

Parrne mass separator

POLAREX (project)

MLL Trap (project) LTNO (3He/4He) Mass measurements Laser-Induced nuclear orientation (µ,Q, Jp)

Present setups and near-future projects

slide-16
SLIDE 16

► Stable and Radioactive beam facility ► R&D on ISOL & RIB ► low-energy physics program based on photo-fission ► R&D and physics at ALTO a step towards a next-generation ISOL RIB facility:

initiate physics program, train ISOL physicists, develop instruments and methodologies