arXiv subjects

M. McCarthy

Publications and source records attributed to M. McCarthy.

4 recordsLinked to original sources

arXiv2024

Crossing the disciplines -- a starter toolkit for researchers who wish to explore early Irish literature

The inspiration behind this paper came from both authors' long-term collaboration with our friend and colleague, Professor Ralph Kenna. This connection emerged initially through his interest in Rathcroghan and in our paper, `Exploring the Nature of the Fr\'aoch Saga', which we concluded with the statement that we believed it `presents a case that will hopefully ignite conversation between disciplines'. This led us to consider the potential value for researchers of compiling a template list of useful and reliable sources and resources to consult, in other words a type of starter toolkit or guide for any individual from an alternative discipline or background, who might possess, or, in time, develop a personal or professional interest in Early Ireland and Early Irish literature. In doing this, we decided for ease of illustration, to take the example of the location name Rathcroghan/Cruachan A\'i, (the prehistoric Royal Site of Connacht in the west of Ireland and the place that we both work in and interact with on a daily basis), as a case study in order to demonstrate an initial methodological approach to not only the types of resources and information available, but also to highlight some potential pitfalls that may arise in the course of an investigation.

physics.soc-ph↗

arXiv2024

Towards the Discovery of New Elements: Production of Livermorium (Z=116) with 50Ti

The $^{244}$Pu($^{50}$Ti,$xn$)$^{294-x}$Lv reaction was investigated at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron facility. The experiment was aimed at the production of a superheavy element with $Z\ge 114$ by irradiating an actinide target with a beam heavier than $^{48}$Ca. Produced Lv ions were separated from the unwanted beam and nuclear reaction products using the Berkeley Gas-filled Separator and implanted into a newly commissioned focal plane detector system. Two decay chains were observed and assigned to the decay of $^{290}$Lv. The production cross section was measured to be $\sigma_{\rm prod}=0.44(^{+58}_{-28})$~pb at a center-of-target center-of-mass energy of 220(3)~MeV. This represents the first published measurement of the production of a superheavy element near the `Island-of-Stability', with a beam of $^{50}$Ti and is an essential precursor in the pursuit of searching for new elements beyond $Z=118$.

nucl-ex↗

arXiv2019

Search for RR Lyrae stars in DES ultra-faint systems: Grus I, Kim 2, Phoenix II, and Grus II

This work presents the first search for RR Lyrae stars (RRLs) in four of the ultra-faint systems imaged by the Dark Energy Survey (DES) using SOAR/Goodman and Blanco/DECam imagers. We have detected two RRLs in the field of Grus I, none in Kim 2, one in Phoenix II, and four in Grus II. With the detection of these stars, we accurately determine the distance moduli for these ultra-faint dwarf satellite galaxies; $\mu_0$=20.51$\pm$0.10 mag (D$_{\odot}$=127$\pm$6 kpc) for Grus I and $\mu_0$=20.01$\pm$0.10 mag (D$_{\odot}$=100$\pm$5 kpc) for Phoenix II. These measurements are larger than previous estimations by Koposov et al. 2015 and Bechtol et al. 2015, implying larger physical sizes; 5\% for Grus I and 33\% for Phoenix II. For Grus II, out of the four RRLs detected, one is consistent with being a member of the galactic halo (D$_\odot$=24$\pm$1 kpc, $\mu_0$=16.86$\pm$0.10 mag), another is at D$_\odot$=55$\pm$2 kpc ($\mu_0$=18.71$\pm$0.10 mag), which we associate with Grus II, and the two remaining at D$_\odot$=43$\pm$2 kpc ($\mu_0$=18.17$\pm$0.10 mag). Moreover, the appearance of a subtle red horizontal branch in the color-magnitude diagram of Grus II at the same brightness level of the latter two RRLs, which are at the same distance and in the same region, suggests that a more metal-rich system may be located in front of Grus II. The most plausible scenario is the association of these stars with the Chenab/Orphan Stream. Finally, we performed a comprehensive and updated analysis of the number of RRLs in dwarf galaxies. This allows us to predict that the method of finding new ultra-faint dwarf galaxies by using two or more clumped RRLs will work only for systems brighter than M$_V\sim-6$ mag.

astro-ph.GA↗

arXiv2000

Overview of the APT Accelerator Design

The accelerator for the APT Project is a 100 mA CW proton linac with an output energy of 1030 MeV. A High Energy Beam Transport (HEBT) conveys the beam to a raster expander, that provides a large rectangular distribution at a target/blanket (T/B) assembly. Spallation neutrons generated by the proton beam in the T/B reacts with Helium-3 to produce tritium. The design of the APT linac is an integrated normal-conducting (NC)/superconducting (SC) proton linac; the machine architecture has been discussed elsewhere [1]. The NC linac consists of a 75 keV injector, a 6.7-MeV 350-MHz RFQ (radio frequency quadrupole), a 96-MeV 700-MHz CCDTL (coupled-cavity drift-tube linac), and a 700-MHz CCL (coupled-cavity linac), with an output energy of 211 MeV. This is followed by a SC linac, that employs 700-MHz elliptical niobium 5-cell cavities to accelerate the beam to the final energy. The SC linac has two sections, optimized for beam velocities of b =0.64 and b =0.82. Each section is made up of cryomodules containing two, three, or four 5-cell cavities, driven by 1-MW 700-MHz klystrons. The singlet FODO lattice in the NC linac transitions to a doublet focusing lattice in the SC linac, with conventional quadrupole magnets in the warm inter-module spaces. This doublet lattice is continued in the HEBT. An overview of the current linac design will be presented.

physics.acc-ph↗