-LEB S3 Collaboration Workshop 27-30 March 2017, CEA Saclay - - PowerPoint PPT Presentation

S3 Collaboration Workshop 27-30 March 2017, CEA Saclay Pauline Ascher, CENBG

Mass measurements of neutron-deficient nuclei @ S3-LEB and @ S3-DESIR

• LEB

M(N,Z) = Z Mp + N Mn - BE(N,Z)

Use of « mass filters »

Mass spectrometry

Z=20 Z=20 Z=20 Z=20

Sn(N,Z) = BE(N,Z) - BE(N- 1,Z) S2n(N,Z) = BE(N,Z) - BE(N- 2,Z) D2n(N,Z) = S2n (N+2,Z) – S2n(N,Z)

deformation

ü First hint on nuclear structure effects but has to be combined with other observables (charge radii, beta decay studies, Coulomb excitation, …) ü Constrain models: nuclear models (shell model, mean- field models, …), local mass models as well as nuclear astrophysics models (nucleosynthesis processes)

ISOLTRAP (ISOLDE) SHIPTRAP (GSI) LEBIT (MSU) TITAN (TRIUMF) JYFLTRAP (IGISOL) CPT (ANL)

Mass market worldwide (short-lived nuclei)

TRIGATRAP (IKC/FAIR) RIKEN-Trap LANZHOU-Trap MLL-TRAP (ALTO/DESIR) Operational PT Planned PT PILGRIM (S3) Operational MR-TOF PIPERADE (DESIR) MR-TOF (GARIS)

7 operational Penning traps + 3 operational MR-TOF

MR-TOF (FRS- GSI) Planned MR-TOF MR-TOF#2 (SLOWRI) MR-TOF#3 (KISS)

l1,2 l1

towards DESIR

EVRs Neutralized EVRs Photoions

gas cell S-shape RFQ

• diff. pumping

RFQ QMF (m/Dm ~ 100) buncher

MR ToF MS

MCP bender 200 - 500 mbar Ar

from S3

towards Multi Purpose Room - Idenfification/detection

• R. Ferrer et al., Nuclear Instruments and Methods in Physics Research B 317 (2013) 570–581

S3 Low-Energy Branch (LEB)

Michael Bloch and Enrique Minaya talk This talk

Mass measurements @S3: motivations

N=50 Z=50 Z=40

q N=Z nuclei up to 100Sn

Neutrons and protons occupy the same orbitals Isospin symmetry breaking (Coulomb, strong force, …) Extra binding energy Understanding of the “Wigner effect” T=0 np pairing ? SU(4) spin-isospin symmetry ?

• P. Van Isacker, PRL 1995

Goriely & Pearson, PRL 2009

q Nuclear structure studies

Ø Evolution of shell effects Ø High-spin isomerism Ø Shape transition, coexistence Ø Isospin effects Ø IMME breakdown (isospin mixing, charge- dependent effects, …)

• D. Lunney et al., LOI DESIR
• M. Mc Cormick et al., LOI DESIR
• D. Lunney et al., LOI DESIR

q Masses of rp-process

Sequence of (p,γ) reactions and β+ decays

• K. Blaum, J. Dilling and W.

Nörtershäuser, Phys. Scr. T 152 (2013)

Exponential dep. of rates on Sp à need 10 keV mass precision (i.e. dm/m = 10-7)

• H. Schatz et al.

q Weak interaction

CVC hypothesis and unitarity of CKM matrix Tests of theoretical corrections 0+ -> 0+ transitions (Tz=0 and Tz=-1 nuclei)

Mass measurements @S3: motivations

Short half-lives à fast gas cell

à experiments at DESIR

• C. Weber et al., LOI DESIR
• D. Lunney et al., LOI DESIR

Complementary measurements of SPIRAL1 beams below Z=40

Neutron-rich nuclei around N=28 Quenching of the f7/2-p3/2 gap Neutron-rich nuclei at the dripline

• 2n radioactivity
• halo/clustering

Neutron-rich nuclei around island of inversion Quenching of N=20 gap/ birth of N=16 gap Neutron-rich nuclei to test the neutron-proton force

N=28 N=20

Mass measurements with SPIRAL1 beams @DESIR and @LIRAT(PILGRIM?)

• P. Ascher et al., LOI DESIR

• Typical trapping time: 10-30 ms
• Resolving power: up to few 105
• Mass measurement: dm/m~10-6-10-7
• Intensities down to fractions of pps

(single ion sensitivity) Such performances require

• Cooled and bunched beams, with Dt <100ns
• High vacuum (<10-8 mbar)
• High precision and stability of voltage supplies
• R. Wolf et al., IJMS

2012 ISOLTRAP MR ToF MS

• F. Wienholtz et al., Nature 498 (2013) 346-349

Mass separator and/or mass spectrometer !

MR-TOF technique

• Tests with stable beams at LPC Caen since July 2016
• Tests with radioactive beams at LIRAT (?): 2018
• Measurements at S3-LEB: 2019+

P<5×10-9 mbar!

Internal structure ~ 1m Design, simulation et tests (GANIL)

• P. Chauveau, P. Delahaye, Y Liu, A. Shornikov

Design and construction, electronics and slow control (LPC Caen)

• Y. Merrer, J. Lory, P. Desrues, J. F. com, C. Vandamme, J. Brégeault et F. Boumard

40K

Dt~150ns t=8.1ms

39K

Dt~100ns t =16ms

• R=Dt/(2t)~65,000 in 5 days (!)
• No trapping losses up to t~32ms
• Optimizations going on

Goals: R>100,000 and dm/m~10-6

Collaboration avec uni – Greifswald

• R. Wolf, M. Rosenbusch et L. Schweikhard

PILGRIM

• precision: ~10-7-10-8
• minimum yield: ~1-10 pps
• isomeric separation (DM/M>106)

Usual TOF-ICR technique

• K. Blaum, J. Dilling and W. Nörtershäuser, Phys. Scr. T 152 (2013)

Penning trap technique

Projection of the ion cloud on a position-sensitive detector

B B DAQ tacc

φ

!"#$""%&'"

%&("

!)#$)"%&')

%&()

* 𝜉, + 𝜉. = 𝜉0= 12

345. Courtesy: A.Welker

• S. Eliseev et al., PRL 110, 082501 (2013)

Phase Imaging – ICR (PI-ICR)

• Gain in precision of a factor ~ 5 (compared to TOF-ICR)
• High sensitivity

• R. Wolf et al. IJMS 349-350 (2013) 123-133
• S. Eliseev et al. Appl. Phys. B, 13 (2013)

20 50

[ms]

𝑤0 = 1 MHz, 𝑆> = 1 mm, Δ𝑠> = 50 𝜈m,

Courtesy: A.Welker

Resolving power

PI-ICR § Simultaneous mass measurements of gs/isomer states § Can also be used for delivering pure-isomeric beams (trap-assisted spectroscopy)

DETRAP

DESIR Experimental equipment

LUMIER E BESTIO L

S3/SP1 beams

Penning traps at DESIR: MLLTRAP and PIPERADE

§ MLLTRAP is being installed at ALTO § Dedicated to mass measurements and in- trap spectroscopy See talks of Enrique Minaya Ramirez and Araceli Lopez-Martens § PIPERADE is being developed at CENBG § Dedicated to purification purposes but can also be used for mass measurements

First trap (purification) Second trap (accumulation/selection/measurement)

Status § Traps delivery from MPIK HD: Feb 2017 § Magnet delivery from Cryogenic: May 2017 § First stable beam tests: Autumn 2017 Possibility to be installed at SPES before DESIR

5.9E2 6.6E 3 8.4E4 2.2E3 6.2E4 ? 2.5E2 ? 3.0E3 1.2E4 1.3E2 1.1E3 5.5E1 5.6E2 5.0E-1 6.6E 2 1.2E 3 6.0E 4 2.0E 4 2.8E0 2.8E2 4.4E-3 1.2E1 5.8E1 8.9E2 4.6E-1 1.3E1 6.2E1 2.0E3 ?

N=50 Z=50 Z=40

Estimated yields at N~Z and day-1 experiments

then… Higher precision à DESIR Shorter T1/2à fast gas cell (+ HRS cleaning) Isomers à PenningTrap cleaning possible day-1 cases (PILGRIM)

100-103Sn, 99-101In, 97Cd, 95-97Ag, 80-82Zr, …

(T1/2 > 700 ms, yields > 0.1pps)

? ?

Thank you for your attention !