@PhdThesis{diss_mods_00014516, author = {D{\"o}nsdorf, Esther Miriam}, title = {Development of a Phoswich Detector for Neutron Dose Rate Measurements in the Earth's Atmosphere}, year = {2014}, publisher = {Christian-Albrechts-Universit{\"a}t zu Kiel}, address = {Kiel}, keywords = {Phoswich Detector; Neutrons; Phoswich Detektor; Neutronen}, abstract = {The Earth is constantly exposed to a stream of energetic particles from outer space. Through the interaction of this radiation with the Earth's magnetosphere and atmosphere a complex radiation eld is formed which varies with the location inside the Earth's atmosphere. This radiation eld consists of charged and uncharged particles leading to the constant exposure of human beings to radiation. As this ionizing radiation can be harmful for humans, it is necessary to perform dose rate measurements in dierent altitudes in the Earth's atmosphere. Due to their higher biological eectiveness the exposure to neutrons is more harmful than the exposure to gamma-rays and charged particles, which is why the determination of neutron dose rates is the focus of this work. In this work the prototype of a Phoswich detector called PING (Phoswich Instrument for Neutrons and Gammas) is developed to determine dose rates caused by neutrons in the Earth's atmosphere and to distinguish these from gamma-rays. The instrument is composed of two dierent scintillators optically coupled to each other and read out by one common photomultiplier tube. The scintillator package consists of an inner plastic scintillator made of the material BC-412 and a surrounding anti-coincidence made of sodium doped caesium iodide (CsI(Na)). In this work the instrument is calibrated, tested and flown and a procedure for a pulse shape analysis for this instrument is developed. With this analysis it is possible to distinguish pulses from the plastic scintillator and pulses from the CsI(Na). The pulses from the plastic scintillator are mainly due to the interaction of neutrons but there is an energy-dependent contribution of gamma-rays to these events. Measurements performed on board an airplane show that the dose rates measured with the developed detector are in the same order of magnitude as results of other instruments. During measurements on board stratospheric balloons the altitude dependence of count rates and dose rates is determined. The count rates show a maximum which corresponds to the location of the Pfotzer maximum (Pfotzer, 1936). In the dose rates a maximum is found as well, which has been mentioned in Bartlett (2004).}, url = {https://macau.uni-kiel.de/receive/diss_mods_00014516}, file = {:https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00005426/diss_emdoensdorf.pdf:PDF}, language = {en} }