arXiv subjects

D. Moritz

Publications and source records attributed to D. Moritz.

4 recordsLinked to original sources

arXiv2026

Construction and Commissioning of a Compact Xenon Gas Recycling System for a High-Harmonic Generation VUV Frequency Comb

A compact, closed-loop xenon recycling system for application in a High-Harmonic Generation (HHG) Vacuum-UV (VUV) frequency comb laser systems is designed, constructed and commissioned. It consists of three main sections, a low-pressure section (LPS) pre-filtering the gas of particulates, water and hydrocarbons, then a compression station (CS), allowing for a variable pressure of up to 60 bar, and a high-pressure section (HPS) with more filtering, pressure control and monitoring. The system proves to meet all design criteria in gas quality (the sum off all hydrocarbon contaminations up to 120 amu and CO$_{2}$ being below 10$^{-8}$ mbar) and recovery efficiency (>99.8$\%$ for all expected operational cases, neglecting possible geometric gas catcher losses in the HHG laser itself). The operation and results are presented and discussed. Furthermore, the system is compared to the performance of a similar system from which it is derived.

physics.ins-det↗

arXiv2026

Exploring $α$- and $β$-decay-induced quenching of the $^{229}$Th nuclear-clock isomer in solid-state hosts

The radiative decay dynamics of an ensemble of $^{229\mathrm{m}}$Th nuclei embedded in CaF$_2$ and MgF$_2$ is investigated. The isomer is populated through $β$ decay of $^{229}$Ac following ion implantation, and its radiative decay is detected using vacuum-ultraviolet spectroscopy and measured as a function of time. This allows to identify and quantify the quenching of the radiative-decay signal induced by $α$ or $β$ radiation. The quenching probability density is determined in different CaF$_2$ crystals and in a MgF$_2$ crystal, revealing differences up to two orders of magnitude between the investigated samples and a strong dependence on the host material and defect densities. The results support a microscopic mechanism mediated by charge carriers in which electronic excitations created by the decay radiation are captured near Th defects, thereby favoring non-radiative decay channels.

nucl-ex↗

arXiv2024

Radiative Decay of the $^{229m}$Th Nuclear Clock Isomer in Different Host Materials

A comparative vacuum ultraviolet spectroscopy study conducted at ISOLDE-CERN of the radiative decay of the $^{229m}$Th nuclear clock isomer embedded in different host materials is reported. The ratio of the number of radiative decay photons and the number of $^{229m}$Th embedded are determined for single crystalline CaF$_2$, MgF$_2$, LiSrAlF$_6$, AlN, and amorphous SiO$_2$. For the latter two materials, no radiative decay signal was observed and an upper limit of the ratio is reported. The radiative decay wavelength was determined in LiSrAlF$_6$ and CaF$_2$, reducing its uncertainty by a factor of 2.5 relative to our previous measurement. This value is in agreement with the recently reported improved values from laser excitation.

nucl-ex↗

arXiv2021

'Phase Transition' in the 'Thorium-Isomer Story'

Given the drastic progress achieved during recent years in our knowledge on the decay and nuclear properties of the thorium isomer 229mTh, the focus of research on this potential nuclear clock transition will turn in the near future from the nuclear physics driven `search and characterization phase' towards a laser physics driven `consolidation and realization phase'. This prepares the path towards the ultimate goal of the realization of a nuclear frequency standard, the `Nuclear Clock'. This article briefly summarizes our present knowledge, focusing on recent achievements, and points to the next steps envisaged on the way towards the Nuclear Clock.

nucl-ex↗