arXiv subjects

Theodoros Vafeiadis

Publications and source records attributed to Theodoros Vafeiadis.

6 recordsLinked to original sources

arXiv2024

CIRCUS: an autonomous control system for antimatter, atomic and quantum physics experiments

A powerful and robust control system is a crucial, often neglected, pillar of any modern, complex physics experiment that requires the management of a multitude of different devices and their precise time synchronisation. The AEgIS collaboration presents CIRCUS, a novel, autonomous control system optimised for time-critical experiments such as those at CERN's Antiproton Decelerator and, more broadly, in atomic and quantum physics research. Its setup is based on Sinara/ARTIQ and TALOS, integrating the ALPACA analysis pipeline, the last two developed entirely in AEgIS. It is suitable for strict synchronicity requirements and repeatable, automated operation of experiments, culminating in autonomous parameter optimisation via feedback from real-time data analysis. CIRCUS has been successfully deployed and tested in AEgIS; being experiment-agnostic and released open-source, other experiments can leverage its capabilities.

quant-ph↗

arXiv2018

Axion Searches with Microwave Filters: the RADES project

We propose, design and construct a variant of the conventional axion haloscope concept that could be competitive in the search for dark matter axions of masses in the decade 10-100 $μ$eV. Theses masses are located somewhat above the mass range in which existing experiments have reached sensitivity to benchmark QCD axion models. Our haloscope consists of an array of small microwave cavities connected by rectangular irises, in an arrangement commonly used in radio-frequency filters. The size of the unit cavity determines the main resonant frequency, while the possibility to connect a {large} number of cavities allows to reach large detection volumes. We develop the theoretical framework of the detection concept, and present design prescriptions to optimize detection capabilities. We describe the design and realization of a first small-scale prototype of this concept, called Relic Axion Detector Exploratory Setup (RADES). It consists of a copper-coated stainless steel five-cavities microwave filter with the detecting mode operating at around 8.4 GHz. This structure has been electromagnetically characterized at 2 K and 298 K, and it is now placed in ultra-high vacuum in one of the twin-bores of the 9 T CAST dipole magnet at CERN. We describe the data acquisition system developed for relic axion detection, and present preliminary results of the electromagnetic properties of the microwave filter, which show the potential of filters to reach QCD axion window sensitivity at X-band frequencies.

hep-ex↗

arXiv2017

Testing the validity of the Lorentz factor

Our proposed experiment aimed to test the validity of the Lorentz factor with two methods: The time of flight (TOF) of various particles at different momenta and the decay rate of pions at different momenta. Due to the high sensitivity required for the second method the results were inconclusive, therefore we report only on the results of the first method.

physics.pop-ph↗

arXiv2017

Energy Dependent Features of X-ray Signals in a GridPix Detector

We report on the calibration of an argon/isobutane (97.7 %/2.3 %)-filled GridPix detector with soft X-rays (277 eV to 8 keV) using the variable energy X-ray source of the CAST Detector Lab at CERN. We study the linearity and energy resolution of the detector using both the number of hit pixels and the total measured charge as energy measures. For the latter, the energy resolution σ_E/E is better than 10 % (20 %) for energies above 2 keV (0.5 keV). Several characteristics of the recorded events are studied.

physics.ins-det↗

arXiv2014

An InGrid based Low Energy X-ray Detector

An X-ray detector based on the combination of an integrated Micromegas stage with a pixel chip has been built in order to be installed at the CERN Axion Solar Telescope. Due to its high granularity and spatial resolution this detector allows for a topological background suppression along with a detection threshold below $1\,\text{keV}$. Tests at the CAST Detector Lab show the detector's ability to detect X-ray photons down to an energy as low as $277\,\text{eV}$. The first background data taken after the installation at the CAST experiment underline the detector's performance with an average background rate of $5\times10^{-5}\,/\text{keV}/\text{cm}^2/\text{s}$ between 2 and $10\,\text{keV}$ when using a lead shielding.

physics.ins-det↗

arXiv2010

Signatures for Solar Axions/WISPs

Standard solar physics cannot account for the X-ray emission and other puzzles, the most striking example being the solar corona mystery. The corona temperature rise above the non-flaring magnetized sunspots, while the photosphere just underneath becomes cooler, makes this mystery more intriguing. The paradoxical Sun is suggestive of some sort of exotic solution, axions being the (only?) choice for the missing ingredient. We present atypical axion signatures, which depict solar axions with a rest mass max ~17 meV/c2. Then, the Sun has been for decades the overlooked harbinger of new particle physics.

astro-ph.SR↗