| Zugriffsnummer | 35835 |
| Dokumenttyp | Dissertation |
| Peer Review | unbekannt |
| Sprache | Deutsch |
| Titel | Entwicklung eines Messsystems zur Charakterisierung magnetisch geschirmter Umgebungen |
| Autor(in); Institution |
Voigt, Jens; 8.2, Biosignale, PTB-Berlin
|
| Quelle/Jahr | (2015), IX, 190 S. |
| Dissertationsvermerk | Dissertation, Technische Universität Ilmenau, 2015 |
| Persistent Identifier | |
| Verlag | Ilmenau: |
| Freie Schlagworte | Charakterisierung MSR ; SQUID ; Absolutfeldmessung ; kompaktes SQUID System |
| Zusammenfassung | A number of experiments in fundaments in fundamental physics, such as the search of the electric dipole moments in atoms and particles, are limited by the uncertainty contributedfrom the magnetic properties of the environment. Hence, these magnetic properties have to be characterized carefully to allow further optimizations of the experiment. Sensors for such magnetic characterizations are typically limited by the magnetic noise, the frequency bandwidth, the absolute magnetic accuracy for flux densities below 1nT and the dimensions of the measurements system. This theses deals with the development, characterization and application of a new, compact and mobile multi-channel measurement system called Cube-II with performance suitable for characterizing the magnetic properties of magnetically shielded rooms. The Cube-II-system is based on 16 individual low temperature superconducting quantum interference devices (SQUIDs) inside a nonmagnetic cylindrical dewar with 30cm in diameter and 31cm in height. With this dewar, a measurement time of up to 20 hours is reached. During this time, a white noise level of less than 6fT/√Hz was achieved for all 16 SQUID magnetometers in a frequency range of 1Hz to ≥15kHz. Below 1Hz, the magnetic flux noise increases up to 5pT/√Hz below 1mHz. One special feature of the Cube-II-system,compared to typical multichannel SQUID-systems, is the possibility to estimate simultaneously the three vector and nine gradient components of the absolute magnetic fluxdensity inside magnetic shielded rooms. Due to the high accuracy of the mechanical parts of the measurement setup, the three vector components of the residual magnetic field inside the heavily magnetic shielded room BMSR-2 were estimated with an expanded uncertainty of ±8pT for Bx and By and ±23pT for Bz.. By using a new arrangement of the SQUIDs on the surface of a cube, two methods can be used to estimate the nine components of the magnetic field gradient. By using the first and well known method (shift method) to shift the Cube-II along the X-, Y- and the Z-axes of the magnetic shielded room, an expanded uncertainty for this method of below ±2pTcm were achieved. For the second method (intrinsic method) the new arrangements of at least 12 SQUIDs were used to estimate the nine components with an expanded uncertainty of less than ±11pTcm. |
