Jørn Dines Hansen

Jørn Dines Hansen

Professor emeritus

Current research

I worked first in ATLAS with the trigger studies. But later when my group joined the TRT, Transition Radiation Tracker, which is part of the inner detector of ATLAS I switched to it. I am currently taking shifts with it and working on improving its resolution.

At the same time I am part of a group who studies the properties of B-mesons again testing the theory of weak interaction.

Primary fields of research

My field of research is and has always been experimental particle physics.

What has occupied me has varied dependent on the experimental possibilities and the advances in my field. Experimentally I started already during my study with bubble chambers followed by a streamer chamber which is a sort of triggered bubble chamber. From the middle of the seventies it became purely electronic experiments.

In the first years at CERN and in the USA it was the properties of meson resonances that interested me using the particle wave analalysis formalism. After a short intermezzo measuring elastic scattering of elementary particles on protons i became interested in the weak interaction which still has my interest. My group joined the UA2 experiment at the antiproton-proton colider at CERN. We built half of the drift chambers. UA2 found the W- and Z-bosons at the same time as UA1.

To study these bosons with much higher precisions we joined the ALEPH experiment at LEP, CERN. We built the luminosity calorimeter which had a precision of a factor 2.5 better than believed possible by others. The first publication from ALEPH was the measurement of the number of different kinds of neutrinoes. It is my most cited publication. Our calorimeter was instrumental for this.

ALEPH stopped taking data in 2000. But already in 1994 we joined what later became the ATLAS experiment at the LHC.  ATLAS started taking data in December 2009.

To test our ideas for the trigger for ATLAS and to give our students a chance to get experience from a real experiment rather than simulations my group joined in 1996 the HERA-B experiment at HERA in DESY, Hamburg. The aim of the experiment was to study the CP-violation in the decay of the B-meson. A precise measurement of this is the test of the difference between matter and anti-matter and also of the theory of weak interaction. Problems with HERA  prevented us from competing with other experiments in the USA and Japan. So we stopped taking data in 2002. But we showed that our trigger ideas would work for ATLAS.

Teaching

I have given lectures, held problem solving sessions and given laboratory courses at all levels. In addition I have supervised bachelor student projects and thesis works of master and bachelor students.

I was from February 1st 1999 to March 31st 2007 Head of the physics study program. In 2002 I created the new study program of nanotechnology which I also became head of.

In addition to the contact with the students an important part of this work was the creation of the new curriculum structure. 

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