Search for dissertations about: "gamma gamma"

Showing result 1 - 5 of 848 swedish dissertations containing the words gamma gamma.

2. 1. Photospheric emission in gamma ray bursts : Analysis and interpretation of observations made by the Fermi gamma ray space telescope

   Author : Shabnam Iyyani; Felix Ryde; David Burrows; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; gamma ray bursts; photosphere; radiation mechanism; Theoretical Physics; teoretisk fysik;

   Abstract : The large flashes of radiation that are observed in GRBs are generally believed to arise in a relativistic jetted outflow. This thesis addresses the question of how and where in the jet this radiation is produced. READ MORE

4. 2. Segmented HPGe detectors for post-irradiation examination of nuclear fuel : Design and demonstration in gamma emission tomography

   Author : Vikram Rathore; Peter Andersson; Erik Andersson Sundén; Ane Håkansson; Andrew Boston; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Segmented HPGe detector; Nuclear fuel; Post-irradiation examination; Nuclear fuel diagnostics; Gamma emission tomography; Gamma spectroscopy; Non-destructive fuel testing; Applied Nuclear Physics; Tillämpad kärnfysik;

   Abstract : Gamma emission tomography (GET) is a proven non-invasive technique for post-irradiation examination of nuclear fuel. In the past, collimated HPGe detectors were used for GET measurements due to their good energy resolution. READ MORE

5. 3. Gamma Spectroscopy and Gamma Emission Tomography for Fuel Performance Characterization of Irradiated Nuclear Fuel Assemblies

   Author : Scott Holcombe; Staffan Jacobsson Svärd; Hans-Urs Zwicky; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Nuclear fuel performance; Nuclear fuel assemblies; Gamma emission tomography; Gamma spectroscopy;

   Abstract : Gamma spectroscopy and gamma emission tomography are two non-destructive measurement techniques for assessing the performance of nuclear fuel which have been investigated in this thesis for existing and novel applications through theoretical studies and experimental demonstrations. For assessment of individual fuel rods using gamma spectroscopy, fuel assemblies are dismantled so that the fuel rods may be measured separately, which is time-consuming and may cause damage to the fuel. READ MORE

6. 4. Gamma-Ray Emission from Galaxy Clusters : DARK MATTER AND COSMIC-RAYS

   Author : Anders Pinzke; Lars Bergström; Olaf Reimer; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Galaxy clusters; gamma-rays; cosmic-rays; dark matter; High energy astrophysics; Högenergiastrofysik; teoretisk fysik; Theoretical Physics;

   Abstract : The quest for the first detection of a galaxy cluster in the high energy gamma-ray regime is ongoing, and even though clusters are observed in several other wave-bands, there is still no firm detection in gamma-rays. To complement the observational efforts we estimate the gamma-ray contributions from both annihilating dark matter and cosmic-ray (CR) proton as well as CR electron induced emission. READ MORE

7. 5. Gamma radiation techniques for non-destructive post-irradiation examination of nuclear fuel : Predicting performance and optimizing instrument design

   Author : Lorenzo Senis; Peter Andersson; Erik Andersson Sundén; Ane Håkansson; Fabiola Cappia; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Collimated gamma spectroscopy; Gamma emission tomography; Gamma transmission micro-densitometry; Pareto optimization; Post-irradiation examination; Applied Nuclear Physics; Tillämpad kärnfysik;

   Abstract : Collimated gamma-based techniques are widely used to study nuclear fuel, especially for non-destructive post-irradiation examination (PIE). Examples of such techniques include gamma emission tomography (GET) and gamma transmission densitometry (GTD). READ MORE