Noise temperature measurements for axion haloscope experiments at IBS/CAPP

Axion Haloscopes with Toroidal Geometry at CAPP/IBS

The present state of the art axion haloscope employs a cylindrical resonant cavity in a solenoidal field. We, the Center for Axion and Precision Physics Research (CAPP) of the Institute for Basic Science (IBS) in Korea, are also pursuing halo axion discovery using this cylindrical geometry. However, the presence of end caps of cavities increases challenges as we explore higher frequency regions for the axion at above 2 GHz. To overcome these challenges we exploit a toroidal design of cavity and magnetic field. A toroidal geometry offers several advantages, two of which are a larger volume for …

CAPP用于高质量搜索的轴子晕镜的开发

Development of axion haloscopes for high-mass search at CAPP

CAPP提出了多种基于新腔体概念的高质量轴子搜索晕镜设计，通过分割腔体、利用高阶模式及介电光子晶体结构实现高频下的大体积和高品质因子，并改进抛物面天线方案以适用于太赫兹区域的宽带搜索。

Axion Dark Matter Research with IBS/CAPP

The axion, a consequence of the PQ mechanism, has been considered as the most elegant solution to the strong-CP problem and a compelling candidate for cold dark matter. The Center for Axion and Precision Physics Research (CAPP) of the Institute for Basic Science (IBS) was established on 16 October 2013 with a main objective to launch state of the art axion experiments in South Korea. Relying on the haloscope technique, our strategy is to run several experiments in parallel to explore a wide range of axion masses with sensitivities better than the QCD axion models. We utilize not only the advan…

Haloscope searches for dark matter axions at the Center for Axion and Precision Physics Research

The Center for Axion and Precision Physics Research (CAPP) was founded in 2013, with the ambition of shedding light on the strong CP problem and the proposed existence of axions. Much of CAPP's effort focuses on the direct detection of dark matter candidate axions with a series of local haloscope experiments, which endeavour to expand dramatically the coverage on the "invisible axion" mass range. The first two of them plan experimental runs during this year, tapping into ultra-low cryogenics and toroidal cavity geometries. The overall programme builds on cutting-edge technology, including deve…

Search for Dark Matter Axions with CAST-CAPP

The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74 $μ$eV to 22.47 $μ$eV mass range. The detection concept follows the Sikivie haloscope principle, where Dark Matter axions convert into photons within a resonator immersed in a magnetic field. The CAST-CAPP resonator is an array of four individual rectangular cavities inserted in a strong dipole magnet, phase-matched to maximize the detection sensitivity. Here we report on the data acquired for 4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning mechanis…

CAPP-8TB: Search for Axion Dark Matter in a Mass Range of 6.62 to 7.04 $μ$eV

The axion is a hypothetical particle proposed to solve the strong $CP$ problem, and also a candidate for dark matter. This non-relativistic particle in the galactic halo can be converted into a photon under a strong magnetic field and detected with a microwave resonant cavity. Relying on this detection method, many experiments have excluded some mass regions with certain sensitivities in terms of axion-photon coupling ($g_{aγγ}$) for decades, but no axion dark matter has been discovered to date. CAPP-8TB is an axion haloscope experiment at IBS/CAPP designed to search for the axion in a mass ra…