Suche nach solaren Axionen mit dem Röntgenteleskop des CAST Experiments (Phase II)

Mit dem CERN Solar Axion Telescope (CAST) Experiment wird unter Ausnutzung des inversen Primakoff-Prozesses, d.h. ein Axion konvertiert innerhalb eines transversalen Magnetfeldes in ein Photon, nach solaren Axionen gesucht. In CAST Phase II wurden die Magnetröhren mit einem Puffergas (He) gefüllt. Dadurch ist es erstmals möglich, in den durch theoretische Axionmodelle gegebenen Axionruhemassenbereich vorzudringen und eine obere Grenze für die Kopplungskonstante in einem Axionmassenbereich >0.02 eV anzugeben. Während der Datennahme in den Jahren 2005-2006 konnte so ein Axionmassenbereich von 0.02-0.39eV nach einem Axionsignal untersucht werden. In dieser Dissertation wird die Analyse der Daten von Phase II (4He),die mit dem CAST Röntgenteleskop genommen wurden, vorgestellt. Die Ergebnisse, die in dieser Arbeit berechnet wurden, liefern einen Wert für die obere Schranke der Kopplungsstärke von Axionen an Photonen: g<1.6-6.0 10^-10 GeV^-1 (95% C.L.) für m_a=0.02-0.4 eV. Dieses Ergebnis ist besser als alle anderen bisher angegeben Werte für diesen Axionmassenbereich

Suche nach solaren Axionen mit dem Röntgenteleskop des CAST Experiments (Phase II).

The CAST (CERN Solar Axion Telescope) experiment is searching for solar axions by their conversion into photons inside a transverse magnetic field. So far, no solar axionsignal has been detected, but a new upper limit could be given (CAST Phase I). Since 2005, CAST entered in its second phase where it operates with a buffer gas (4He) in the conversion region to extend the sensitivity of the experiment to higher axionmasses. For the first time it is possible to enter the theoretically favored axion massrange and to give an upper limit for this solar axion massrange (>0.02 eV). This thesis is about the analysis of the X-ray telescope data Phase II with 4He inside the magnet. The result for the coupling constant of axions to photons is: g<1.6-6.0 10^-10 GeV^-1 (95% C.L.) for m_a=0.02-0.4 eV. This result is better than any result that has been given before in this mass range for solar axions

Overview on the Design of the Machine Protection System for ESS

Scope of the Machine Protection System (MPS) for the European Spallation Source (ESS) is to protect equipment located in the accelerator, target station, neutron instruments and conventional facilities, from damage induced by beam losses or malfunctioning equipment. The MPS design function is to inhibit beam production within a few microseconds for the fastest failures at a safety integrity level of SIL2 according to the IEC61508 standard. These requirements result from a hazard and risk analysis being performed for the all systems at ESS. In a next step the architecture and topology of the distributed machine interlock system has been developed and will be presented. At the same time as MPS seeks to protect equipment it must protect the beam by avoiding triggering false stops of beam production, leading to unnecessary downtime of the ESS facility

Reliability and Availability Modeling for Accelerator Driven Facilities

Accelerator driven facilities are and will have to be designed to a very high level of reliability and beam availability to meet expectations of the users and experiments. In order to fulfil these demanding requirements on reliability and overall beam avai lability, statistical models have been developed. We compare different statistical reliability models as well as tools in terms of their performance, capacity and user - friendliness. In addition we also benchmarked some of the existing models. We will pres ent in detail a tool being used f or LHC and LINAC4, which is based on the commercially available software package Isograph, and a tool using Excel Visual Basics for Applications

Development and Realisation of the ESS Machine Protection Concept

ESS is facing extremely high beam availability requirements and is largely relying on custom made, very specialised, and expensive equipment for its operation. The proton beam power with an average of 5MW per pulse will be unprecedented and its uncontrolled release can lead to serious damage of the delicate equipment, causing long shutdown periods, inducing high financial losses and, as a main point, interfering drastically with international scientific research programs relying on ESS operation. Implementing a fit-for-purpose machine protection concept is one of the key challenges in order to mitigate these risks. The development and realisation of the measures needed to implement such concept to the correct level in case of a complex facility like the ESS, requires a systematic approach, and will be discussed in this paper

Injection Beam Loss and Beam Quality Checks for the LHC

The quality of the injection into the LHC is monitored by a dedicated software system which acquires and analyses the pulse waveforms from the injection kickers, and measures key beam parameters and compares them with the nominal ones. The beam losses at injection are monitored on many critical devices in the injection regions, together with the longitudinal filling pattern and maximum trajectory offset on the first 100 turns. The paper describes the injection quality check system and the results from LHC beam commissioning, in particular the beam losses measured during injection at the various aperture limits. The results are extrapolated to full intensity and the consequences are discusse

Beam Loss Monitoring for LHC Machine Protection

The energy stored in the nominal LHC beams is two times 362 MJ, 100 times the energy of the Tevatron. As little as 1 mJ/cm 3 deposited energy quenches a magnet at 7 TeV and 1 J/cm 3 causes magnet damage. The beam dumps are the only places to safely dispose of this beam. One of the key systems for machine protection is the beam loss monitoring (BLM) system. About 3600 ionization chambers are installed at likely or critical loss locations around the LHC ring. The losses are integrated in 12 time intervals ranging from 40 μs to 84 s and compared to threshold values defined in 32 energy ranges. A beam abort is requested when potentially dangerous losses are detected or when any of the numerous internal system validation tests fails. In addition, loss data are used for machine set-up and operational verifications. The collimation system for example uses the loss data for set-up and regular performance verification. Commissioning and operational experience of the BLM are presented: The machine protection functionality of the BLM system has been fully reliable; the LHC availability has not been compromised by false beam aborts