The following letter to the ATLAS community reflects the sorrow in the Department of Physics over the untimely passing of Professor Rudolf Thun.

It is with deep regret that I report to you the passing of our dear colleague Rudi Thun. He died in Ann Arbor yesterday following a lifetime of key contributions to numerous physics endeavors. Over the past decade, as you know, his prime research involvement was in ATLAS.

Rudi’s work on ATLAS spanned  the design, prototyping, installation, commissioning and performance assessment for the endcap muon chambers, all the way to providing key insights into the analysis leading to the recently announced discovery of the Higgs.

A consummate physicist, Rudi was dedicated to our collective work in ATLAS with the singular, highly focused goal of advancing our boundaries of knowledge of the natural world. His intellect, vision and rigorous approach to the scientific method were matched by genuine modesty. His ideal was to follow the data and to push our analysis like explorers into the unknown, uninhibited by excessive allegiance to speculative hypotheses. He had a large influence on our group’s research direction and the motivation of our young researchers as they carried out their work. Rudi was in charge of ATLAS MDT tube production at the University of Michigan and the tube QAQC test rate exceeded 99% -- much higher than the ATLAS specification. He was the Muon detector production quality assurance officer at our university. He spent his last sabbatical at CERN in Building 180 for the big-wheel sector assembly and test. He was also in charge of all the related readout fiber tests. His graduate students worked on SM cross-section measurement on Z production, and on Higgs discovery employing the ZZ final state.

Rudi was  multidimensional in his interests, a proverbial renaissance man who penned novels, painted with a high level of  realism, precision, beauty and creativity. He had numerous scientific interests- including the nature of binocular vision, and the physical basis of consciousness.

His sudden death comes as a real shock to us at Michigan and to his many friends around the world. Rudi was in many ways the veritable heart and soul of the University of Michigan ATLAS group and he will be sorely missed.

Homer A. Neal, for the

University of Michigan ATLAS Group