Engineering topics
Publications and source records attributed to Esposito, M..
Describes the engineering approach used to convert existing 28 MHz RF cavities to operate at 24.6 MHz for use in the EIC Hadron Storage Ring, including modifications to cavity geometry and tuning range, along with RF performance validation.
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We present 3D calculations for dielectric haloscopes such as the currently envisioned MADMAX experiment. For ideal systems with perfectly flat, parallel and isotropic dielectric disks of finite diameter, we find that a geometrical form factor reduces the emitted power by up to 30% compared to earlier 1D calculations. We derive the emitted beam shape, which is important for antenna design. We show that realistic dark matter axion velocities of 10 -3 c and inhomogeneities of the external magnetic field at the scale of 10% have negligible impact on the sensitivity of MADMAX. We investigate design requirements for which the emitted power changes by less than 20% for a benchmark boost factor with a bandwidth of 50 MHz at 22 GHz, corresponding to an axion mass of 90 μeV. We find that the maximum allowed disk tilt is 100 μm divided by the disk diameter, the required disk planarity is 20 μm (min-to-max) or better, and the maximum allowed surface roughness is 100 μm (min-to-max). We show how using tiled dielectric disks glued together from multiple smaller patches can affect the beam shape and antenna coupling.
ABSTRACT In this paper, we report the discovery of TOI-220 b, a new sub-Neptune detected by the Transiting Exoplanet Survey Satellite (TESS) and confirmed by radial velocity follow-up observations with the HARPS spectrograph. Based on the combined analysis of TESS transit photometry and high precision radial velocity measurements, we estimate a planetary mass of 13.8 ± 1.0 M⊕ and radius of 3.03 ± 0.15 R⊕, implying a bulk density of 2.73 ± 0.47 $\rm {g\,cm}^{-3}$. TOI-220 b orbits a relative bright (V= 10.4) and old (10.1 ± 1.4 Gyr) K dwarf star with a period of ∼10.69 d. Thus, TOI-220 b is a new warm sub-Neptune with very precise mass and radius determinations. A Bayesian analysis of the TOI-220 b internal structure indicates that due to the strong irradiation it receives, the low density of this planet could be explained with a steam atmosphere in radiative–convective equilibrium and a supercritical water layer on top of a differentiated interior made of a silicate mantle and a small iron core.