Sandra Eldrum

Diplom Physikerin/MScR Physics

MA Archaeological Practice

homepage: http://se.anomic.de

Publications/Contributions

Talks:

Experimental/Nuclear Physics, Orange detector:
orange.pdf

Archaeological Geophysics, general investigations on artificial islands/Crannogs:
crannogs.pdf

Abstracts:

Diploma thesis in Experimental Nuclear Physics

The inner conversion is a process in competition with gamma emmission and therefore a useful alternative to low energetic transitions inside the Compton continuum of a gamma germanium detector, and when gamma decay is less probable then conversion. The Orange Spectrometer was rebuild and setup at the Cologne Institute for Nuclear Physics in 2004/5 after an overall technical obsolescence that took over 3 years with more than a dozen people involved.
The energy resolution that can be achieved after focusing the electrons into a scintillator crystal through a varying magnetic toroidal field is about 0.8 % at 180 keV which equals 1.5 keV.

Title: Conversion electron spectroscopy at the Cologne Tandem-accelerator: Setup und test of the big Orangen spectrometer and measurements on 180Ta and 195Au. Diploma thesis of the faculty of mathematical and natural sciences 10th August 2005, Institute for nuclear physics, University of Cologne, Germany Sandra Christen

Abstract
The content of this Diploma thesis generally was and is the coordination and documentation of the re-setup of the 'Orange' spectrometer, which had been designed by E. Moll and build by the company 'HAEREUS'. It is an electron-focusing magnetic spectrometer that, during the work for this thesis, has been setup at the R30 beam-line of the Cologne Tandem-van de Graaf accelerator. The spectrometer had formerly been in use at the GSI Darmstadt (before 1997) and at the Bonn cyclotron (between 1997 and 2001) with magnetic focusing strengths of up to 800 keV conversion energy. Therefore, part of my work related to the coordination of the works for the technical transformation of the geometry and its adjustment in relation to the beam-line, the extention of the field currents of up to 1200 keV, the renewal of the steering- and analysing software, the concept of a security automatisation1, issues of influences of magnetic disturbances by beam steering lenses, vacuum systems, avoidance of iron-containing parts, as well as the finalizing optimisation of the electronic parameters and the adjustment of the ideal source point, statically and 'in-beam' and the related elimination of problems during the focusing of the accelerator beam. The results of test measurements revealed a resolution of the apparatus to be 0.8 % at an electron energy of 181 keV, which equals an error of 1.5 keV. After the measurements, which lasted from January until April with an addition of July in 2005, the data was analysed to release some interesting knowledge about the pre-adjustment of the spectrometer and about the method of analysis, resulting in three new transitions in 195Au, two of which could already be related to known levels, while the term scheme could be enhanced and corrected. In the following, first chapter, the theory of conversion electron spectroscopy will be explained along the general explications of R. Reinhard, K. S. Krane, und J. L. Wood 2, while in the following, second chapter, the theory of the re-setup of the Bonn Orange spectrometer at the Cologne Tandem accelerator and a re-assessment of the method of measurement and the analysing software will be given. The theoretical calculations for the magnetic field generating coil system generally rely on the work of E. Moll, while the presentation of the energy calibration is based on the considerations of K. Siegbahn. In the third, and last chapter, the measurements will be presented and the results will be discussed, followed by a visitation of the theoretical formalism of the super-symmetric IB(FF)M model and the measurements of the super-symmetric nucleus of 195Au. Finally, an outlook on future fields of duty of the spectrometer, and a summary of the content of this diploma thesis will be given. 1 Observation and automated alarm system of temperature and vacuum, fast closing valves, barometer, current velocity guardian, etc. 2 uncited passaged should be taken as comments.
Thesis:

Master of Arts in Archaeological Practice

Title: Waterland–People: On Structure and Origin of Crannogs Geophysical and Environmental Evidence in Orkney
Dissertation Master of Arts in Archaeological Practice 12/09/2008, University of Highlands and Islands Orkney College Department of Archaeology
Sandra Christen

Abstract
Crannogs have been a target object of theoretical approaches, sourrounded by mysteries concerning their origin since their discovery in the 19th century. Investigations comprised from large scale excavations to random sampling with few geophysical surveys and a range of theories concerned with their structural identity. The Islands of Orkney provide an excellent environment in which a framework for local communities studies can be set up which helps finding patterns in the information of the site types crannog and other island settlements, of which there are more than 30 possible only on Mainland. An attempt is made in this work to find reasons for the patterns associated with crannogs and other island–type settlements by looking at their possible origins in the Mesolithic through detailed environmental and a critical historical research, their structural evidence using geophysical instrumentation on the exposed surface as a first step and by comparison with similar sites in the world wide record. Since the geophysical approach is relatively new, the practicability of such approaches is studied in detail and an evaluation of its application to different site types is given in order to estimate the value of a site fingerprint. The conclusion is that site patterns and structural evidence (although sparse at this stage) give hints to their origins which are manifest in beliefs that emerged from observations and perceptions of humanity in the late Holocene and that these origins can be projected into different phases of civilization, all related by some few variables such as water, continuity, supply and, perhaps, transformation. The first chapter introduces the approach, taken throughout the entire work and the second chapter unrolls the history of previous research generally, critically and in an european context, it also provides an insight in the main objectives of this work. Chapter 3 assesses the sites localized in Orkney and chapter 4 introduces the geophysical methods used during fieldwork. The succeeding chapter 5 gives and investigates the geophysical results in their context while chapter 6 discusses all results along the line of some related aspects. The conclusion extracts from the local Orkney scale and projects by including all findings, onto a general, spacially and chronologically independent, scale, which is the topic of the final chapter 7. An outlook that offers future objectives and a summary, that reassesses the preliminary aims and objectives follow. The appendices comprise of abbreviations, site lists and a photographic register.
Dissertation: