Charles Gruhn, a colleague and friend for many of us at CERN and elsewhere, passed away peacefully on 24 March.

Chuck was a true experimental physicist and throughout his professional life he worked on the development of particle detectors. After gaining a PhD from the University of Washington (1961), he started his scientific career at MIT. He moved on to Michigan State University (1964) and the Max-Planck-Institute for Physics in Munich (1970) before being offered an indefinite contract at CERN.

Chuck left CERN for three years to work at Los Alamos National Laboratory. While at Los Alamos, he registered a US patent for the development of laser beam alignment systems. In 1978, Chuck moved to Lawrence Berkeley Laboratory where he kept a position as professor until his retirement in 1992. LBL was deeply involved in the CERN experiments, allowing Chuck to spend most of his time at CERN.

After his retirement, Chuck became a consultant for the ATLAS experiment. He was the first to study the characteristics of single proportional drift tubes, later to be produced in their hundreds of thousands to form the ATLAS muon spectrometer.

Chuck’s main scientific interest during his later years was astronomy and the study of binary stars. He developed methods for their observation and analysis with his own telescope and recorded real data at the international amateur observatory in Namibia.

Although suffering from heart problems, Chuck stayed active. His main remedy against his health problems was hiking in the Jura mountains.

Besides the many achievements in his brilliant scientific career, we would like to recall his large store of fine human qualities. Above all however, his greatest quality was perhaps that he was simply a nice person.

Our deepest sympathy goes to his wife Ute, their children and families.

His friends and colleagues