H. Jürgen Kluge

Heinz-Jürgen Kluge, known as Jürgen Kluge (born 25 April 1941), is a physicist probably best known for the development of ion-storage devices and methods for accurate measurements of nuclear masses.

In the early eighties Jürgen Kluge at the University of Mainz considered mass measurements of trapped ions. Gernot Gräff, who worked at the same institute, had developed a time-of-flight technique for the determination of the electron–proton mass ratio from the respective cyclotron-resonance frequencies. During this period the determination of the fundamental properties of the electron was of the highest interest. This included the measurement of the g-factor of the free electron, again with a Penning trap, for which Hans Dehmelt eventually won the Nobel Prize in physics in 1989. Jürgen decided to apply Gräff’s method to the determination of masses of unstable nuclei. A setup was designed and built at Mainz, which comprised two Penning traps in a row. Following the idea of separation of functions, one trap served as the source of well-prepared ions for the actual mass measurement at the second trap. The operation of the setup thus included the ion transfer from one trap to the other. The first successful ion transfer was reported in 1986.

A proposal to the scientific committee at CERN/Geneva for starting such an experimental program at ISOLDE, the on-line separator for short-lived nuclei at the synchrocyclotron of CERN, was accepted in 1985.

Interestingly, at the same time Gerald Gabrielse proposed using a Penning trap mass spectrometer at CERN for the investigation of antiprotons, which turned out to become another very important and successful endeavor with ion traps.

At that time Jürgen acted as ISOLDE group leader. In the following years the tandem Penning trap setup was transferred from Mainz to ISOLDE and came to be known as ISOLTRAP. It started the measurements of short-lived nuclides in the late eighties and has been at the forefront of the field since then. In its early phase ISOLTRAP used a stopping-reionization procedure in which the 60 keV ions, delivered from ISOLDE in a continuous beam, were implanted in a rhenium foil. This foil was then heated to release and surface-ionize the collected atoms. Thus, only surface-ionizable elements were accessible.

...
Wikipedia