[show abstract][hide abstract] ABSTRACT: The Cern Axion Solar Telescope (CAST) is in operation and taking data since 2003. The main objective of the CAST experiment is to search for a hypothetical pseudoscalar boson, the axion, which might be produced in the core of the sun. The basic physics process CAST is based on is the time inverted Primakoff effect, by which an axion can be converted into a detectable photon in an external electromagnetic field. The resulting X-ray photons are expected to be thermally distributed between 1 and 7 keV. The most sensitive detector system of CAST is a pn-CCD detector combined with a Wolter I type X-ray mirror system. With the X-ray telescope of CAST a background reduction of more than 2 orders off magnitude is achieved, such that for the first time the axion photon coupling constant g_agg can be probed beyond the best astrophysical constraints g_agg < 1 x 10^-10 GeV^-1. Comment: 19 pages, 25 figures and images, replaced by the revised version accepted for publication in New Journal of Physics
New Journal of Physics 02/2007; · 4.06 Impact Factor
[show abstract][hide abstract] ABSTRACT: The CERN Axion Solar Telescope (CAST), a 10 meter long LHC, 9 Tesla, test magnet is mounted on a moving platform that tracks the sun about 1.5 hours during sunrise, again during sunset. It moves ±80 vertically and ±400 horizontally. It has been taking data continuously since July 10, 2003. Data analyzed thus far yield an upper bound on the photon-axion coupling constant, gagammagamma
Nuclear Physics B - Proceedings Supplements, v.138, 41-44 (2005). 01/2005;
[show abstract][hide abstract] ABSTRACT: The LHC (Large Hadron Collider) project includes the construction of four large physics experiments, which will study particle collisions. The particle detectors that are made up of many parts need to be precisely positioned with respect to the accelerator beam line. The metrological networks to accomplish this task are in difficult configurations. Control and thus reliability degrade as detector installation progresses. Additionally, deformations of the structural parts of the experimental caverns are to be expected which will affect the networks and need to be monitored closely. As part of the installation process the network will be regularly measured in parts, including different types of measurements, but complete network measurements will be very rare. Good network configuration and reliability at early stages of the installation process need to be fully taken advantage of. This implies a good preliminary estimation of possible point movements. This knowledge could be utilized in later stages when network configuration and reliability will degrade. Another source of information about the network is empirical knowledge how the network points might deform depending on their location. This information could also be considered into the network calculations in order to support its solution. To treat these problems with classical deformation methods based on epoch-to-epoch congruency comparison poses several problems in application. A practical and easier to handle solution is the implementation of a kinematic model by an adaptive Kalman filter. In this paper we will present a special implementation of an adaptive Kalman Filter which is able to take full advantage of any measurement occurring in the cavern network context and to manage and maintain accuracy and reliability demands for the detector installation and operation.