Search for dissertations about: "cryogenic temperatures"

Showing result 16 - 20 of 48 swedish dissertations containing the words cryogenic temperatures.

2. 16. DESIREE: Instrumentation Developments and Hot Metal Cluster Decays

   Author : Emma K. Anderson; Henning Schmidt; Henrik Cederquist; Henning Zettergren; Oded Heber; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; DESIREE; microchannel plate; clusters; spontaneous decay; small metal cluster anions; silver; copper; gold; carbon dianions; fragmentation; vibrational autodetachment; DESIREE; mikrokanalplattor; kluster; spontana sönderfall; små metallklusteranjoner; silver; koppar; guld; kol di-anjoner; fragmentering; Physics; fysik;

   Abstract : This thesis presents instrumentation developments and measurements performed at the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. DESIREE operates at cryogenic temperatures ~13 K, with very low background pressures of ~10-14mbar, allowing the observation of stored ions to long times of tens of seconds and longer. READ MORE

4. 17. Improved components for 2SB THz receivers with enhanced sideband rejection performance

   Author : Hawal Marouf Rashid; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Thin-film Circuits; S-parameters Measurements; Sideband Separating Receivers; Superconducting Circuits; Millimetre Wave Mixers; Directional Coupler; Terahertz Technology; Waveguide Directional Coupler;

   Abstract : The thesis presents work done in improving the sideband rejection ratio for 2SB cryogenic radio astronomy receivers in general, but more specifically, for the future Onsala 20 m 3-mm receiver system and the ALMA Band 5. In order to attain better than 15 dB sideband rejection ratio over the entire bandwidth (approximately 26% RF fractional bandwidth and one octave the IF bandwidth), it is necessary to improve both RF and IF hybrid assembly to optimum performance, i. READ MORE

5. 18. Ions in cold electrostatic storage devices

   Author : Peter Reinhed; Henning Schmidt; Henrik Cederquist; Jason Greenwood; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Atomic and molecular physics; Atom- och molekylfysik; fysik; Physics;

   Abstract : We have constructed a compact purely electrostatic ion-beam trap, ConeTrap, which we have mounted inside a double-walled vacuum chamber. In the inner vacuum chamber, we can obtain ultra-high vacuum (UHV) conditions and reach thermal equilibrium at well controlled temperatures down to 10 K. READ MORE

6. 19. Experiments on mutual neutralization using storage rings with merged ion beams

   Author : Gustav Eklund; Henning T Schmidt; Henrik Cederquist; Ansgar Simonsson; Daniel W. Savin; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; mutual neutralization; storage rings; merged beams; fysik; Physics;

   Abstract : This thesis presents work on merged-beams experiments using the DESIREE facility, which consists of two electrostatic ion-storage rings operated at cryogenic temperatures of about 13 K. The two storage rings have a common straight section, where oppositely charged ions can interact at sub-eV collision energies. READ MORE

7. 20. Phosphor Thermometry on Surfaces - A Study of its Methodology and its Practical Applications

   Author : Christoph Knappe; Förbränningsfysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Coating Thickness; Temperature Calibration; Two-Colour Ratio; Lifetime Decay; Thermometry; Thermographic Phosphor; Laser Combustion Diagnostics; Laser-Induced Phosphorescence; Non-Linearity; ICCD; PMT; Signal Processing Algorithms; Fysicumarkivet A:2013:Knappe;

   Abstract : Phosphor Thermometry is a term describing an optical measurement technique for remote temperature sensing. Its working principle is based on the temperature-sensitive emission characteristics of certain ceramic substances termed thermographic phosphors. READ MORE