Heinz-Jürgen Kluge, known as Jürgen Kluge (born 25 April 1941), is a physicist probably best known for the development of ion-storage devices

Ion trap

An ion trap is a combination of electric or magnetic fields that captures ions in a region of a vacuum system or tube. Ion traps have a number of scientific uses such as mass spectrometery and trapping ions while the ion's quantum state is manipulated...

 and methods for accurate measurements of nuclear

Atomic nucleus

The nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The...

 masses.

University of Mainz

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

Time-of-flight mass spectrometry

Time-of-flight mass spectrometry is a method of mass spectrometry in which an ion's mass-to-charge ratio is determined via a time measurement. Ions are accelerated by an electric field of known strength. This acceleration results in an ion having the same kinetic energy as any other ion that has...

 technique for the determination of the electron

Electron

The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

–proton

Proton

The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....

 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

Penning trap

Penning traps are devices for the storage of charged particles using a homogeneous static magnetic field and a spatially inhomogeneous static electric field. This kind of trap is particularly well suited to precision measurements of properties of ions and stable subatomic particles which have...

, for which Hans Dehmelt eventually won the Nobel Prize

Nobel Prize

The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...

 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.

CERN

A proposal to the scientific committee at CERN

CERN

The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...

/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

Gerald Gabrielse

Gerald Gabrielse is an American physicist and the George Vasmer Leverett Professor of Physics at Harvard University. In 2007, he was elected a member of the National Academy of Sciences.- Education :...

 proposed using a Penning trap

Penning trap

Penning traps are devices for the storage of charged particles using a homogeneous static magnetic field and a spatially inhomogeneous static electric field. This kind of trap is particularly well suited to precision measurements of properties of ions and stable subatomic particles which have...

 mass spectrometer at CERN for the investigation of antiproton

Antiproton

The antiproton is the antiparticle of the proton. Antiprotons are stable, but they are typically short-lived since any collision with a proton will cause both particles to be annihilated in a burst of energy....

s, 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

ISOLTRAP

ISOLTRAP is a tandem Penning trap mass spectrometer at the On-Line Isotope Mass Separator at CERN, very similar to SMILETRAP. The facility plays a leading role in the field of high precision mass spectrometry of radioactive ions...

. 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

ISOLTRAP

ISOLTRAP is a tandem Penning trap mass spectrometer at the On-Line Isotope Mass Separator at CERN, very similar to SMILETRAP. The facility plays a leading role in the field of high precision mass spectrometry of radioactive ions...

 used a stopping-reionization procedure in which the 60 keV ions, delivered from ISOLDE in a continuous beam, were implanted in a rhenium

Rhenium

Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an average concentration of 1 part per billion , rhenium is one of the rarest elements in the Earth's crust. The free element has...

 foil. This foil was then heated to release and surface-ionize the collected atoms. Thus, only surface-ionizable elements were accessible.

This major limitation was overcome by the introduction of a third ion trap designed to accumulate the ions directly without any implantation, to cool them with buffer gas

Buffer gas

A buffer gas is an inert or nonflammable gas. In the Earth's atmosphere, nitrogen acts as a buffer gas. A buffer gas adds pressure to a system and controls the speed of combustion with any oxygen present...

 and to release them as low-energy ion bunches. The first system of this kind was a large Paul trap, developed in collaboration with Bob Moore

Bob Moore

Bob Loyce Moore is an American session musician, orchestra leader, and bassist who was a member of the legendary Nashville A-Team during the 1950s and 60s.-Biography:...

 at Montreal. Short-lived mercury

Mercury (element)

Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

 isotope

Isotope

Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

s were the first nuclides of non-surface-ionizable elements studied with ISOLTRAP.

In the early years of ISOLTRAP the ring electrode of the trap was segmented into just two halves. However, it was soon realized that the ring was to be split into four segments for an efficient quadrupolar

Quadrupole

A quadrupole or quadrapole is one of a sequence of configurations of—for example—electric charge or current, or gravitational mass that can exist in ideal form, but it is usually just part of a multipole expansion of a more complex structure reflecting various orders of complexity.-Mathematical...

 excitation and conversion of the ion’s magnetron motion into the cyclotron

Cyclotron

In technology, a cyclotron is a type of particle accelerator. In physics, the cyclotron frequency or gyrofrequency is the frequency of a charged particle moving perpendicularly to the direction of a uniform magnetic field, i.e. a magnetic field of constant magnitude and direction...

 motion. This conversion is the basis of the direct determination of the ion’s “true” cyclotron frequency,
(for charge , mass and magnetic field ), i.e. the (angular) cyclotron frequency in the absence of an additional electric field. Today all Penning trap mass spectrometers for radioactive isotopes employ this technique.

At the same time it was also realized, and experimentally confirmed, that the additional application of a buffer gas leads to cooling and mass selective centering of the ion motion. The method was studied in detail and the first Penning trap used in ISOLTRAP was reconstructed and optimized for efficient accumulation, cooling, and ion beam purification via isobar separation. Now implemented in many mass spectrometer systems for the study of exotic nuclei, this technique is also used in the first stage of a post-accelerator system at ISOLDE/CERN. The method was also rapidly adopted in analytical chemistry

Analytical chemistry

Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Qualitative analysis gives an indication of the identity of the chemical species in the sample and quantitative analysis determines the amount of...

. Not only the methods were spreading out, but also the instruments: when the use of ion traps for the study of unstable isotopes and antiprotons was originally proposed, Prof. em. Ingmar Bergström, former director of the Manne Siegbahn Institute at Stockholm, was a member of the Scientific Policy Committee at CERN

CERN

The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...

. He became very interested in the new technique and initiated his own trap project named SMILETRAP

SMILETRAP

SMILETRAP is a Penning trap mass spectrometer located in Stockholm, Sweden. The name is an acronym, which stands for Stockholm-Mainz-Ion-LEvitation-TRAP....

. The system was built and tested at Mainz and then transferred to Stockholm: The Stockholm-Mainz Ion LEvitation trap (SMILETRAP

SMILETRAP

SMILETRAP is a Penning trap mass spectrometer located in Stockholm, Sweden. The name is an acronym, which stands for Stockholm-Mainz-Ion-LEvitation-TRAP....

) has specialized in highly charged ions and thus achieves high resolving powers at the corresponding cyclotron frequencies. Thus, the ToF detection of ion cyclotron resonances joined other methods of highest accuracy as applied to stable species.

Guy Savard, who learnt the ion-trap business during a postdoctoral stay at ISOLTRAP, later went on and built the Canadian Penning Trap Mass Spectrometer

Canadian Penning Trap Mass Spectrometer

The Canadian Penning Trap Mass Spectrometer is one of the major pieces of experimental equipment that is installed on the ATLAS superconducting heavy-ion linac facility at the Physics Division of the Argonne National Laboratory...

 (CPT) now hosted at the Argonne National Laboratory

Argonne National Laboratory

Argonne National Laboratory is the first science and engineering research national laboratory in the United States, receiving this designation on July 1, 1946. It is the largest national laboratory by size and scope in the Midwest...

. Similarly, Georg Bollen, who had been in charge of ISOLTRAP

ISOLTRAP

ISOLTRAP is a tandem Penning trap mass spectrometer at the On-Line Isotope Mass Separator at CERN, very similar to SMILETRAP. The facility plays a leading role in the field of high precision mass spectrometry of radioactive ions...

 for more than a decade, has recently built up a new ion-trap system at the National Superconducting Cyclotron Laboratory

National Superconducting Cyclotron Laboratory

National Superconducting Cyclotron Laboratory is located on the campus of Michigan State University and is the leading rare isotope research facility in the United States...

 at Michigan State University

Michigan State University

Michigan State University is a public research university in East Lansing, Michigan, USA. Founded in 1855, it was the pioneer land-grant institution and served as a model for future land-grant colleges in the United States under the 1862 Morrill Act.MSU pioneered the studies of packaging,...

.

LEBIT, the Low-Energy Beam and Ion Trap Facility, is the first system of its kind allowing high-precision mass measurements to be performed on short-lived isotopes produced by fast-beam fragmentation and delivered at half the speed of light. Jürgen Kluge has always been open for any kind of collaboration. As coordinator of European networks he promoted the idea of trap-based nuclear-physics research. Further projects that took advantage of the know-how exchange are JYFLTRAP at Jyväskylä, WITCH at CERN, and TITAN

Titan

Titan most often refers to:*Titan , a class of deities who preceded the Olympians in Greek mythology*Titan , the largest moon of the planet Saturn-Music:*Titan, working title of Symphony No...

 at TRIUMF/Vancouver. Jürgen also included the theoretical aspects of the various nuclear and atomic physics research into the networks, bilateral collaborations, and close contacts.

Move to GSI at Darmstadt

Not being content with ISOLTRAP

ISOLTRAP

ISOLTRAP is a tandem Penning trap mass spectrometer at the On-Line Isotope Mass Separator at CERN, very similar to SMILETRAP. The facility plays a leading role in the field of high precision mass spectrometry of radioactive ions...

 and its on-going success, Jürgen himself started two new trap projects, SHIPTRAP and HITRAP

HITRAP

HITRAP is a research and technology development network of European research teams. It was founded on November 1, 2001. The goal of the network is the development of novel instrumentation for a broad spectrum of physics experiments with heavy Highly Charged Ions up to bare uranium at low...

 after his change from the University of Mainz to GSI at Darmstadt (Gesellschaft für Schwerionenforschung

Gesellschaft für Schwerionenforschung

The GSI Helmholtz Centre for Heavy Ion Research GmbH in the Wixhausen suburb of Darmstadt, Germany is a federally and state co-funded heavy ion research center. The current director of GSI is Horst Stöcker who succeeded Walter F...

) as the atomic physics group leader. He also realized the great possibilities of storage-ring based mass spectrometry and supported the very successful efforts at GSI. As described, Jürgen is probably best known for the development of ion-storage devices and methods for accurate measurements of nuclear masses. However, in more general terms he has been a key player in pioneering the application of methods of atomic physics at accelerators. Starting with the work on his doctoral thesis at Heidelberg.

CV of Heinz-Jürgen Kluge

25 April 1941 Born in Sorau, Germany

1960–1963 Study at the University of Bonn

University of Bonn

The University of Bonn is a public research university located in Bonn, Germany. Founded in its present form in 1818, as the linear successor of earlier academic institutions, the University of Bonn is today one of the leading universities in Germany. The University of Bonn offers a large number...

1963 Pre-diploma examination at the University of Bonn

1963–1967 Study at the University of Heidelberg

1967 Diploma examination at the University of Heidelberg

1970 Dissertation at the University of Heidelberg on “Hyperfine structure

Hyperfine structure

The term hyperfine structure refers to a collection of different effects leading to small shifts and splittings in the energy levels of atoms, molecules and ions. The name is a reference to the fine structure which results from the interaction between the magnetic moments associated with electron...

 of the lowest P-states of alkaline earths

Alkaline earth metal

The alkaline earth metals are a group in the periodic table. In the modern IUPAC nomenclature, the alkaline earth metals are called the group 2 elements. Previously, they were called the Group IIA elements . The alkaline earth metals contain beryllium , magnesium , calcium , strontium , barium and...

isotopes” (Ph.D.)

1970–1972 Research stay at CERN, Geneva, Switzerland

1972 Assistant Professor for Experimental Physics at the University of Mainz
1974–1975 Paid Scientific Associate at CERN

1975 Habilitation for Experimental Physics at the University of Mainz

1978 Professor for Experimental Physics at the University of Mainz

1980–1981 Temporary replacement of Prof. G. zu Putlitz at the University of Heidelberg

1983–1984 Chairman of the ISOLDE Collaboration at CERN

1984–1987 Member of the PSCC-Committee at CERN (program advisory committee)

1985–1987 Research Scientist Staff Member and Leader of the ISOLDE Group at CERN
since 1985 Associate Editor of “Hyperfine Interactions”

1988 Fellowship of the Japan Society for Promotion of Science

1989–1992 Member and Vice Chairman of the Program Advisory Committee of GSI, Darmstadt

1990 Helmholtz-Prize for Physical Measuring Techniques in Medicine and Environmental Monitoring

1990–1996 Officer of the International Union of Pure and Applied Physics

International Union of Pure and Applied Physics

The International Union of Pure and Applied Physics is an international non-governmental organization devoted to the advancement of physics...

 (IUPAP), SUNAMCO (C2)

1991–1994 Member of the Executive Committee of the German Physical Society (DPG)

1991–1994 Member of the Executive Board of the Deutsche Gesellschaft für Massenspektrometrie
(DGMS)

1992 Call for a chair in physics at the University of Heidelberg and as a Leading Scientist at GSI
since 1994 Professor of Physics at the University of Heidelberg and Head of Atomic Physics Division/GSI

1995–1998 Associate Member of the International Union of Pure and Applied Chemistry

International Union of Pure and Applied Chemistry

The International Union of Pure and Applied Chemistry is an international federation of National Adhering Organizations that represents chemists in individual countries. It is a member of the International Council for Science . The international headquarters of IUPAC is located in Zürich,...

 (IUPAC)

1996–2003 Member of the Evaluation Committee “Hadrons and Nuclei” of the German Ministry for Research and Technology

1999–2005 Member of the Editorial Board of the European Physical Journal D

1999–2005 Research Director of GSI

2000–2004 Member of the evaluation committee (Fachgutachter) for atomic physics proposals of the Deutsche Forschungsgemeinschaft

Deutsche Forschungsgemeinschaft

The Deutsche Forschungsgemeinschaft is an important German research funding organization and the largest such organization in Europe.-Function:...

(DFG, German
science foundation)

2000–2004 Member of the ISOLDE Neutron Time of Flight Committee (INTC) at CERN

2001–2004 Member of the Emmy-Noether Selection Board of the DFG (German science foundation)

2002–2004 Member of the PALS User Selection Board (kJ laser at Prague)

since 2000 Member of the Committee of the PTB Braunschweig for the Helmholtz Prize

since 2000 Member of the Advisory Board for Danish CERN Physics

since 2004 Member of the International Program Committee of the LMJ/LIL Facility (Laser MegaJoule and Ligne
d'Intégration Laser) of CEA-CESTA Center, Bordeaux
since 2004 Member of the JYFL Program Advisory Committee (cyclotron at Jyväskylä, Finland)

2005 Fellow of the American Physical Society

since 2005 Editor of Hyperfine Interactions