GravitationalRadiation Antenna In Leiden
Kamerlingh Onnes Laboratory, Leiden University, The Netherlands
Projects for students
MASTER PROJECT (6 months)
Vibration isolation systemIntroduction
|Schematic picture of a system of a mass (m) and a spring (spring constant k).||This graph shows the attenuation A (dB) of the system as a function of frequency. Amplification will occur around the resonant frequency of the system (A>0). At higher frequency there will be attenuation (A<0).|
|The attenuation system of MiniGRAIL consists of a stack of seven masses springs. In order to be able to start cryogenic experiments with MiniGRAIL as soon as possible, the initial attenuation system design was very simple. The springs consist of rods with a ring in the middle to increase the attenuation in the vertical direction. Measurements of the transfer function between two masses are shown in the graph. It is clear that the effect of the higher order modes of the rod decreases the attenuation of the system around 3 kHz. It could also be that the normal modes of the masses (at ~3500 Hz) are too close to the resonant frequency of the sphere.|
|This project implies optimizing the vibration isolation system for MiniGRAIL, so that the highest attenuation occurs at the resonant frequency of the sphere (~3 kHz). Designing a new spring using Finite Element Analyses (FEA) with ProMechanica and measure the results in a separate room temperature setup in vacuum. Once the mass-spring system is optimized, it can be installed in the MiniGRAIL setup.
Click here to read more about the attenuation system.