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Ionizing Radiation

Prelude What’s the relevance of this class? Radiation: A History of Modern 1895: Wilhelm Conrad Roentgen: x-rays (1901: first Nobel Price, Physics) 1896: Henri Becquerel: salt radioactive (NP 03) 1897: Joseph John Thomson: Cathode rays are particles, nature independent of materials! (NP 06) 1898: Marie+: and radioactive (NP 03, NC11), 1/2 : α,β rays (NC 08) 1912: Victor Hess: Cosmic Radiation (NP 36) J.J. Thomson: Neon 20/22 Dec. 22, 1895 Radiation: A History of

Modern Physics (cont.) Cloud Chamber 1932: : (NP 35) Aug. 2, 1932 : deuteron (NC 34) Carl D. Anderson: positron (NP 36) John D. Cockcroft, Ernest T.S. Sinton: Accelerator induced fission (NP 51) Ernest O. Lawrence: (NP 39) 1933: : β decay (NP 38) 1934: Irene Curie+Frederic Joliot: induced radioactivity (NC 35) plate 1937: J. C. Street+M. L. Stevenson:2 µ 1938: +: Why is the trajectory bent? fission (NC 44) Which way did the particle go? (And how do you know?) The Nuclear Age

A 1946 test of an atomic bomb in the lagoon at Bikini atoll. The Nuclear Age (cont.)

Found on http://www.aip.org/history/einstein/index.html "Because of the danger that Hitler might be the first to have the bomb, I signed a letter to the President which had been drafted by Szilard. Had I known that the fear was not justified, I would not have participated in opening this Pandora's box, nor would Szilard. For my distrust of governments was not limited to ." The photograph shows a postwar reconstruction of the signing. Discovery of Radiation led to useful application in other fields

Example: Elementary Discovery of Radiation led to useful application in other fields (cont.) Example: Astrophysics

Photomultiplier

Whipple/VERITAS: Detection of gamma rays

HiRes: Detection of Cosmic rays Discovery of Radiation led to useful application in other fields (cont.)

Example: Medical Physics -> MeV electrons or gamma rays are used to destroy tumors

planned carbon ion and early cancer treatment therapy unit, siemens with radium Discovery of Radiation led to useful application in other fields (cont.)

Example: Biology

Carry out research in molecular structural biology by using the special properties of the synchrotron radiation

Study of proteins (crystal structure of cellulosomal endoglucanase CelA in complex with substrate at 0.94 Å resolution (Guerin et al, 2002)) Material to be covered, outline

• Basics on nuclear processes, radiation, units, biological effects etc. • Interaction of radiation with matter • various radiation detector concepts (PMTs, gaseous detectors, scintillators …) • Applications in various fields (see before)