Structure of Structure of Super-Heavy ElementsSuper-Heavy Elements

Andreas HeinzAndreas HeinzA. W. Wright Nuclear Structure LaboratoryA. W. Wright Nuclear Structure Laboratory

Yale UniversityYale University

ATLAS Workshop, August 8-9, 2009ATLAS Workshop, August 8-9, 2009

MotivationMotivation

Understanding the evolution of nuclear Understanding the evolution of nuclear structure of the heaviest nuclei.structure of the heaviest nuclei.The FMA measures A/q - an additional The FMA measures A/q - an additional parameter which is very useful for the parameter which is very useful for the interpretation of complicated decay spectra interpretation of complicated decay spectra and the measurement of weak branching and the measurement of weak branching ratios.ratios.Spectroscopy at the limits: decay of isomeric Spectroscopy at the limits: decay of isomeric states provides valuable information on states provides valuable information on nuclear structure.nuclear structure.

Measuring Weak Branching Measuring Weak Branching RatiosRatios

Two fission groups:

1) From 257Rf:

2) From 256Rf:

sT 4.19.02/1 2.3

msT 96.130.12/1 89.4

SF branch ratio of 257Rf:

Somerville et al., PRC 31, 1801 (1985): 0.14(9)

Mass of Mass of αα--correlated ERscorrelated ERs

Mass of Mass of SF-SF-correlated ERscorrelated ERs

)1(02.0SFRfb

random

(High-K) Isomers in (High-K) Isomers in 257257RfRf

ER

Daughter

Isomeric

γ or ICE

Alpha E (keV)ln

T(im

plan

t-IC

E)

Electron E (keV)

B

B

A

A

α

sB

sA4.23.1

4231

1.4:

160:

Ground

Isomeric

Ground/Isomeric

Electron E vs.lnT

Electron-alpha correlation

Decay of high-K isomers can provide valuable information of non-collective states near the Fermi energy.

High-K isomers might become more stable than the ground state.

J. Qian et al., PRC 79, 064319 (2009)

Possible Future Experiment: Possible Future Experiment: 5858Fe @ 264 MeV on Fe @ 264 MeV on 208208Pb Pb →→ 265265Hs + 1nHs + 1n

From: S. Hofmann, Rep. Prog. Phys. 61 (1998) 639

Production cross section: 63±10 pb

5 known alpha lines

1 known isomeric state

Wish ListWish List

Intensity, intensity, intensityIntensity, intensity, intensity

Long experimentsLong experiments

Complicated setup Complicated setup → campaigns→ campaigns

Dedicated detection system → Dedicated detection system →

complete spectroscopycomplete spectroscopy