Energy levels of A = 21−44 nuclei (V)

Development and applications of the IGISOL technique

Laser spectroscopy for nuclear structure physics

The projectile fragment separator provides a wide variety of short-lived RI-ions with less restrictions on their chemical property or lifetime limit. The beam energy and quality is, however, not adequate for low-energy beam experiments, in particular for trapping experiments. Recently, one has proposed to obtain a low-energy beam from an energetic RI-beam leaving a projectile fragment separator by using a large gas-catcher and an rf ion-guide system. In off-line and in on-line test experiments, the principle of the rf ion-guide was proven. An overall efficiency of 0.2% for 70 MeV/u 8 Li from the RIKEN projectile fragment separator (RIPS) was obtained so far.

Slow RI-beams from projectile fragment separators

Some errors were found in this review after it was published. Page 642, line 1: gSchmidt(πd3/2)=0.083 Page 642, paragraph 2.1.3, line 7 and line 12: gSchmidt = -1.913 should read μSchmidt = -1.913 Page 663, expression (4.7) should read: Figure 13 was incorrectly labelled. The correct figure is given below. Figure 13. (a) Zeeman splitting of the nuclear m-quantum levels due to interaction of the nuclear dipole moment (μ = gIμN) with a static magnetic field B. In a classical picture this can be seen as a precession of the spin I around B with a Larmor frequency νL. (b) Non-equidistant quadrupole splitting of the nuclear m-quantum levels due to interaction of the nuclear spectroscopic quadrupole moment Qs with an EFG Vzz. Page 673, expression (5.8) should read:

https://iopscience.iop.org/article/10.1088/0034-4885/66/4/205/pdf

Nuclear magnetic and quadrupole moments for nuclear structure research on exotic nuclei

Transportation of thermalized primary recoil ions from nuclear reactions by helium flow has been investigated as a means of injecting short-lived radioactive nuclides into an on-line isotope separator. Several short-lived radioactive isotopes of highly nonvolatile elements such as B, Sc, Nb, and W have been separated. The efficiency for heavy nuclides with half-lives above 1 ms is between 1 and 10%. The shortest-lived activity identified in an on-line separation is the 182-\ensuremath{\mu}s isomeric state in $^{207}\mathrm{Bi}$.

Submillisecond on-line mass separation of nonvolatile radioactive elements: An application of charge exchange and thermalization processes of primary recoil ions in helium.

A new ISOL method, the IGISOL (Ion Guide Isotope Separator On-Line), permits thermalized primary recoil ions produced in nuclear reactions to be run directly through a mass separator without a conventional ion source. It allows a fast (≳ 100 μs) separation of various radioactive isotopes of both volatile and nonvolatile elements. The overall separation efficiencies measured for heavy nuclides produced in light ion induced reactions are up to 10%. The shortest-lived activity identified in an on-line separation is the 182 μs isomeric state of 207Bi.

The ion guide isotope separator on-line, IGISOL

Beta decay of Tz = −12 nuclides 51Fe and 55Ni: A new approach to on-line isotope separation

Experimental and Shell-Model Study of the Beta Decay of 43Ti

The decay properties of theJπ=1/2+,Eexc=1,098 keV state in203Bi were studied. The state was populated via the204Pb(p, 2n) reaction and the activity was studied with the ion guide isotope separator on-line system IGISOL. The half-life of the 1/2+ state was measured to beT1/2=303 ±5 ms. From this value the partial half-lives of the three depopulating branches 1/2+ →7/2− (E3), 1/2+→5/2− (E3 +M2) and 1/2+→9/2 g.s. − (M4) were deduced. Since all the transitions are configuration forbidden in first order, a detailed study of second-order shell-model configuration mixing could be performed.

H. Hyvönen

Papers

Submillisecond on-line mass separation of nonvolatile radioactive elements: An application of charge exchange and thermalization processes of primary recoil ions in helium.

The ion guide isotope separator on-line, IGISOL

Beta decay of Tz = −12 nuclides 51Fe and 55Ni: A new approach to on-line isotope separation

Experimental and Shell-Model Study of the Beta Decay of 43Ti

Half-life and configuration of the 1/2+ intruder state in203Bi