Astrophysics and Astronomy Commons^™

Charm And Strange Quark Masses And FDS From Overlap Fermions, Yi-Bo Yang, Ying Chen, Andrei Alexandru, Shao-Jing Dong, Terrence Draper, Ming Gong, Frank X. Lee, Anyi Li, Keh-Fei Liu, Zhaofeng Liu, Michael Lujan

Physics and Astronomy Faculty Publications

We use overlap fermions as valence quarks to calculate meson masses in a wide quark mass range on the 2 + 1-flavor domain-wall fermion gauge configurations generated by the RBC and UKQCD Collaborations. . . .

For the remainder of the abstract, please download this article or visit https://doi.org/10.1103/PhysRevD.92.034517

The Lunar Exosphere: Spatial And Temporal Variations Of Sodium And Potassium Emissions From November 2013 To May 2014, Dona Chathuni P. Kuruppuaratchi

Doctoral Dissertations and Master's Theses

I apply high resolution spectroscopy to investigate the lunar exosphere by measuring sodium and potassium spectral line profiles to determine spatial and temporal variations in exospheric effective temperatures and velocities. Observations were made from the National Solar Observatory (MMP) at Kitt Peak, Arizona from November 2013 to May 2014, with the exception of March 2014. Data collection was centered of full moon and spanned several nights with lunar phase angle coverage ranging from 65.6° (waxing) to 78.7° (waning). Observations were concurrent with the NASA LADEE mission science and instrument testing phases. We used a dial etalon Fabry-Perot spectrometer with a …

Chemistry Of The Protolunar Disk And Volatile Depletion Of The Moon, Channon Visscher, Robin M. Canup, Julien Salmon, Bruce Fegley Jr.

Faculty Work Comprehensive List

In the giant impact theory for lunar origin, the Moon forms from a circumterrestrial disk of silicate debris produced by the collision of a planetary-sized impactor with the early Earth. Recent accretion models suggest that the final 10-60% of the lunar mass may be provided by the accretion of melt material spreading outward from the inner (Roche-interior) disk over the first ~102 years following the giant impact. The chemical and thermal evolution of the inner disk material is thus expected to strongly influence the bulk chemical composition of the Moon.

In a previous study we explored the chemistry of the …

Atomic Data And Spectral Model For Fe Ɪɪ, Manuel A. Bautista, Vanessa Fivet, Connor Ballance, Pascal Quinet, Gary J. Ferland, Claudio Mendoza, Timothy R. Kallman

Physics and Astronomy Faculty Publications

We present extensive calculations of radiative transition rates and electron impact collision strengths for Fe ii. The data sets involve 52 levels from the 3d⁷, 3d⁶4s, and 3d⁵4s² configurations. Computations of A-values are carried out with a combination of state-of-the-art multiconfiguration approaches, namely the relativistic Hartree–Fock, Thomas–Fermi–Dirac potential, and Dirac–Fock methods, while the R-matrix plus intermediate coupling frame transformation, Breit–Pauli R-matrix, and Dirac R-matrix packages are used to obtain collision strengths. We examine the advantages and shortcomings of each of these methods, and …

Long-Range Pseudorapidity Dihadron Correlations In D + Au Collisions At √SNn = 200 Gev, James K. Adkins, Renee H. Fatemi, Suvarna Ramachandran, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev

Physics and Astronomy Faculty Publications

Dihadron angular correlations in d + Au collisions at √^sNN = 200 GeV are reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity (Δη) on the near side (i.e. relative azimuth Δφ ~ 0). This correlated yield as a function of Δη appears to scale with the dominant, primarily jet-related, away-side (Δφ ~ π ) yield. The Fourier coefficients of the Δφ correlation, V_n = (cos nΔφ), have a strong Δη …

High Pressure Phase-Transformation Induced Texture Evolution And Strengthening In Zirconium Metal: Experiment And Modeling., Xiaohui Yu, Yusheng Zhao, Ruifeng Zhang, David Weldon, Sven C. Vogel, Jianzhong Zhang, Donald W. Brown, Yanbin Wang, Helmut M. Reiche, Shanmin Wang, Shiyu Du, Changqing Jin

Physics & Astronomy Faculty Research

We studied the phase-transition induced texture changes and strengthening mechanism for zirconium metal under quasi-hydrostatic compression and uni-axial deformation under confined high pressure using the deformation-DIA (D-DIA) apparatus. It is shown that the experimentally obtained texture for ω-phase Zr can be qualitatively described by combining a subset of orientation variants previously proposed in two different models. The determined flow stress for the high-pressure ω-phase is 0.5–1.2 GPa, more than three times higher than that of the α-phase. Using first-principles calculations, we investigated the mechanical and electronic properties of the two Zr polymorphs. We find that the observed strengthening can be …

Constraining The Redshift Evolution Of The Cosmic Microwave Background Blackbody Temperature With Plank Data, I. De Martino, R. Génova-Santos, F. Atrio-Barandela, H. Ebeling, A. Kashlinsky, Dale D. Kocevski, C. J. A. P. Martins

Physics and Astronomy Faculty Publications

We constrain the deviation of adiabatic evolution of the universe using the data on the cosmic microwave background (CMB) temperature anisotropies measured by the Planck satellite and a sample of 481 X-ray selected clusters with spectroscopically measured redshifts. To avoid antenna beam effects, we bring all of the maps to the same resolution. We use a CMB template to subtract the cosmological signal while preserving the Thermal Sunyaev–Zeldovich (TSZ) anisotropies; next, we remove galactic foreground emissions around each cluster and we mask out all known point sources. If the CMB blackbody temperature scales with redshift as T(z) …

High Precision Optical Cavity Length And Width Measurements Using Double Modulation, A. Staley, D. Hoak, A. Effler, K. Izumi, S. Dwyer, K. Kawabe, E. J. King, Malik Rakhmanov, R. L. Savage, D. Sigg

Physics & Astronomy Faculty Publications

We use doubly phase modulated light to measure both the length and the linewidth of an optical resonator with high precision. The first modulation is at RF frequencies and is set near a multiple of the free spectral range, whereas the second modulation is at audio frequencies to eliminate offset errors at DC. The light in transmission or in reflection of the optical resonator is demodulated while sweeping the RF frequency over the optical resonance. We derive expressions for the demodulated power in transmission, and show that the zero crossings of the demodulated signal in transmission serve as a precise …

A Remarkably Flat Relationship Between The Average Star Formation Rate And Agn Luminosity For Distant X-Ray Agn, F. Stanley, C. M. Harrison, D. M. Alexander, A. M. Swinbank, J. A. Aird, A. Del Moro, R. C. Hickox, J. R. Mullaney

Dartmouth Scholarship

In this study we investigate the relationship between the star formation rate, SFR, and AGN luminosity, L(AGN), for ~2000 X-ray detected AGN. The AGN span over three orders of magnitude in X-ray luminosity (10^(42) < L(2-8keV) < 10^(45.5) erg/s) and are in the redshift range z = 0.2 - 2.5. Using infrared (IR) photometry (8 - 500um), including deblended Spitzer and Herschel images and taking into account photometric upper limits, we decompose the IR spectral energy distributions into AGN and star formation components. Using the IR luminosities due to star formation, we investigate the average SFRs as a function of redshift and AGN luminosity. In agreement with previous studies, we find a strong evolution of the average SFR with redshift, tracking the observed evolution of the overall star forming galaxy population. However, we find that the relationship between the average SFR and AGN luminosity is flat at all redshifts and across all the AGN luminosities investigated; in comparison to previous studies, we find less scatter amongst the average SFRs across the wide range of AGN luminosities investigated. By comparing to empirical models, we argue that the observed flat relationship is due to short timescale variations in AGN luminosity, driven by changes in the mass accretion rate, which wash out any underlying correlations between SFR and L(AGN). Furthermore, we show that the exact form of the predicted relationship between SFR and AGN luminosity (and it's normalisation) is highly sensitive to the assumed intrinsic Eddington ratio distribution.

A Critical Assessment Of Stellar Mass Measurement Methods, Bahram Mobasher, Tomas Dahlen, Henry C. Ferguson, Viviana Acquaviva, Guillermo Barro, Steven L. Finkelstein, Adriano Fontana, Ruth Gruetzbauch, Seth Johnson, Yu Lu, Casey Papovich, Janine Pforr, Mara Salvato, Rachel S. Somerville, Tommy Wiklind, Stijn Wuyts, Matthew L.N. Ashby, Eric Bell, Christopher J. Conselice, Mark E. Dickinson, Sandra M. Faber, Giovanni Fazio, Kristian Finlator, Audrey Galametz, Eric Gawiser, Mauro Giavalisco, Andrea Grazian, Norman A. Grogin, Yicheng Guo, Nimish Hathi, Dale Kocevski, Anton M. Koekemoer, David C. Koo, Jeffrey A. Newman, Naveen Reddy, Paola Santini, Risa H. Wechsler

Physics and Astronomy Faculty Publications

This is the second paper in a series aimed at investigating the main sources of uncertainty in measuring the observable parameters in galaxies from their spectral energy distributions (SEDs). In the first paper we presented a detailed account of the photometric redshift measurements and an error analysis of this process. In this paper we perform a comprehensive study of the main sources of random and systematic error in stellar mass estimates for galaxies, and their relative contributions to the associated error budget. Since there is no prior knowledge of the stellar mass of galaxies (unlike their photometric redshifts), we use …

Observational Properties Of Simulated Galaxies In Overdense And Average Regions At Redshifts Z ≃ 6–12, Hidenobu Yajima, Isaac Shlosman, Emilio Romano-Díaz, Kentaro Nagamine

Physics and Astronomy Faculty Publications

We use high-resolution zoom-in cosmological simulations of galaxies of Romano-Díaz et al., post-processing them with a panchromatic three-dimensional radiation transfer code to obtain the galaxy UV luminosity function (LF) at z ≃ 6–12. The galaxies are followed in a rare, heavily overdense region within a ∼5σ density peak, which can host high-z quasars, and in an average density region, down to the stellar mass of M_star ∼ 4 × 10⁷ M_⊙. We find that the overdense regions evolve at a substantially accelerated pace – the most massive galaxy has grown to M_star ∼ 8.4 …

Stellar Metallicity Gradients In Sdss Galaxies, Benjamin Roig, Michael R. Blanton, Renbin Yan

Physics and Astronomy Faculty Publications

We infer stellar metallicity and abundance ratio gradients for a sample of red galaxies in the Sloan Digital Sky Survey (SDSS) Main galaxy sample. Because this sample does not have multiple spectra at various radii in a single galaxy, we measure these gradients statistically. We separate galaxies into stellar mass bins, stack their spectra in redshift bins, and calculate the measured absorption-line indices in projected annuli by differencing spectra in neighboring redshift bins. After determining the line indices, we use stellar population modeling from the EZ_Ages software to calculate ages, metallicities, and abundance ratios within each annulus. Our data cover …

Measuring Infrared Surface Brightness Fluctuation Distances With Hst Wfc3: Calibration And Advice, Joseph B. Jensen, John P. Blakeslee, Zachary Gibson, Hyun Chul Lee, Michele Cantiello, Gabriella Raimondo, Nathan Boyer, Hyejeon Cho

Physics & Astronomy Faculty Publications

We present new calibrations of the near-infrared (near-IR) surface brightness fluctuation (SBF) distance method for the F110W (J110) and F160W (H160) bandpasses of the Wide Field Camera 3 Infrared Channel (WFC3/IR) on the Hubble Space Telescope. The calibrations are based on data for 16 early-type galaxies in the Virgo and Fornax clusters observed with WFC3/IR and are provided as functions of both the optical (g475-z850 ) and near-infrared (J110-H160) colors. The scatter about the linear calibration relations for the luminous red galaxies in the sample is approximately 0.10 mag, corresponding to a statistical error of 5% in distance. Our results …

A Numerical Simulation Of Cosmic-Ray Modulation Near The Heliopause, Xi Luo, Ming Zhang, Marius S. Potgieter, Xueshang Feng, Nikolai V. Pogorelov

Aerospace, Physics, and Space Science Faculty Publications

Based on a hybrid galactic cosmic-ray transport model, which incorporated MHD global heliospheric data into Parker's cosmic-ray transport equation, we studied the behavior of the transport of galactic cosmic rays and the corresponding gradients in their flux near the heliopause (HP). We found that, (1) by increasing the ratio of the parallel diffusion coefficient to the perpendicular diffusion coefficient in the interstellar magnetic field of the outer heliosheath, the simulated radial flux near the HP increases as well. As the ratio multiplying factor reached 10^10, the radial flux experienced a sudden jump near the HP, similar to what Voyager 1 …

Optical Detection Of The Pictor A Jet And Tidal Tail: Evidence Against An Ic/Cmb Jet, Eric S. Gentry, Herman L. Marshall, Martin J. Hardcastle, Eric S. Perlman, Mark Birkinshaw, Diana M. Worrall, Emil Lenc, Aneta Siemiginowska, Claudia Megan Urry

Aerospace, Physics, and Space Science Faculty Publications

New images of the FR II radio galaxy Pictor A from the Hubble Space Telescope reveal a previously undiscovered tidal tail, as well as a number of jet knots coinciding with a known X-ray and radio jet. The tidal tail is approximately 5″ wide (3 kpc projected), starting 18″ (12 kpc) from the center of Pictor A, and extends more than 90″ (60 kpc). The knots are part of a jet observed to be about 4′ (160 kpc) long, extending to a bright hotspot. These images are the first optical detections of this jet, and by extracting knot flux densities …

High Precision Optical Cavity Length And Width Measurements Using Double Modulation, A. Staley, D. Hoak, A. Effler, K. Izumi, S. Dwyer, K. Kawabe, E. J. King, Malik Rakhmanov, R. L. Savage, D. Sigg

Physics & Astronomy Faculty Publications

We use doubly phase modulated light to measure both the length and the linewidth of an optical resonator with high precision. The first modulation is at RF frequencies and is set near a multiple of the free spectral range, whereas the second modulation is at audio frequencies to eliminate offset errors at DC. The light in transmission or in reflection of the optical resonator is demodulated while sweeping the RF frequency over the optical resonance. We derive expressions for the demodulated power in transmission, and show that the zero crossings of the demodulated signal in transmission serve as a precise …

Infrared Spectroscopy Of Symbiotic Stars. X. Orbits For Three S-Type Systems: V1044 Centauri, Hen 3-1213, And Ss 73-96, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood

Information Systems and Engineering Management Research Publications

Employing new infrared radial velocities, we have computed orbits of the cool giants in three southern S-type symbiotic systems. The orbit for V1044 Cen, an M5.5 giant, has a period of 985 days and a modest eccentricity of 0.16. Hen 3-1213 is a K4 giant, yellow symbiotic with an orbital period of 533 days and a similar eccentricity of 0.18. For the M2 giant SS 73-96 the orbital period is 828 days, and this system has a somewhat larger eccentricity of 0.26. Measurement of the H i Paschen δ emission lines, which may at least partially reflect the motion of …

Extreme Geomagnetic Disturbances Due To Shocks Within Cmes, Noe E. Lugaz, Charles J. Farrugia, Chia-Lin L. Huang, Harlan E. Spence

Physics & Astronomy

We report on features of solar wind-magnetosphere coupling elicited by shocks propagating through coronal mass ejections (CMEs) by analyzing the intense geomagnetic storm of 6 August 1998. During this event, the dynamic pressure enhancement at the shock combined with a simultaneous increase in the southward component of the magnetic field resulted in a large earthward retreat of Earth's magnetopause, which remained close to geosynchronous orbit for more than 4 h. This occurred despite the fact that both shock and CME were weak and relatively slow. Another similar example of a weak shock inside a slow CME resulting in an intense …

Three Candidate Clusters Around High Redshift Radio-Loud Sources: Mg1 J04426+0202, 3c 068.2, And Ms 1426.9+1052, J. R. Franck, Stacy S. Mcgaugh

Faculty Scholarship

We present near-infrared observations of the environments around three radio-loud sources (MG1 J0442+0202, 3C 068.2, and MS 1426.9+1052) at redshifts z = 1.10, 1.57, and 1.83 (respectively).,Qthat are surrounded by nearinfrared galaxy overdensities. Overdensities with respect to field counts were found to be significant up to 19£m, with 12 times the expected number of galaxies within the inner regions of the densest proto-cluster. Color¡V magnitude relations are constructed in Ks, J . Ks, with each candidate cluster exhibiting a feature consistent with the beginnings of a red sequence (RS). Galaxy models based on the redshift of the radio source are …

Simulating Correlated Disorder In Spin Glass, Jared D. Willard

Macalester Journal of Physics and Astronomy

Almost all materials undergo spontaneous symmetry breaking at sufficiently low

temperatures. For most magnetic materials, the spin rotational symmetry is broken

to form magnetic ordering. The discovery of metallic alloys which fail to form

conventional magnetic order has remained a puzzle for the last few decades.

Unfortunately, analytical calculations cannot provide an unbiased answer for the

problem. Furthermore, on the numerical side, Monte Carlo simulations require

extremely long equilibration times. The parallel tempering method has proven a

powerful tool to alleviate the long equilibration time. With the extensive efforts of

numerical simulation research, some of the idealized models have been …

Supermassive Black Hole Formation At High Redshifts Via Direct Collapse In A Cosmological Context, Jun-Hwan Choi, Isaac Shlosman, Mitchell C. Begelman

Physics and Astronomy Faculty Publications

We study the early stage of the formation of seed supermassive black holes via direct collapse in dark matter (DM) haloes, in the cosmological context. We perform high-resolution zoom-in simulations of such collapse at high z. Using the adaptive mesh refinement code enzo, we resolve the formation and growth of a DM halo, until its virial temperature reaches ∼10⁴ K, atomic cooling turns on, and collapse ensues. We demonstrate that direct collapse proceeds in two stages, although they are not well separated. The first stage is triggered by the onset of atomic cooling, and leads to rapidly increasing …

Extragalactic Explorers: Professors Elizabeth Mcgrath And Dale Kocevski Divine The Mysteries Of The Universe, Gerry Boyle

Colby Magazine

From their offices on the fourth floor of the Mudd Science Building, Elizabeth McGrath and Dale Kocevski enjoy a view that takes in the terraced lawn of the academic quad, the rooftops of Lovejoy and Cotter Union- and distant galaxies as they appeared when the universe was young.

A Re-Interpretation Of The Triangulum-Andromeda Stellar Clouds: A Population Of Halo Stars Kicked Out Of The Galactic Disk, Adrian M. Price-Whelan, Kathryn V. Johnston, Allyson A. Sheffield, Chervin F. P. Laporte, Branimir Sesar

Publications and Research

The Triangulum–Andromeda stellar clouds (TriAnd1 and TriAnd2) are a pair of concentric ring- or shell-like overdensities at large R (≈30 kpc) and Z (≈−10 kpc) in the Galactic halo that are thought to have been formed from the accretion and disruption of a satellite galaxy. This paper critically reexamines this formation scenario by comparing the number ratio of RR Lyrae to M giant stars associated with the TriAnd clouds with other structures in the Galaxy. The current data suggest a stellar population for these overdensities (fRR: MG < 0.38 at 95 per cent confidence) quite unlike any of the known satellites of the Milky Way (fRR: MG ≈ 0.5 for the very largest and f …

Stout: Cloudy's Atomic And Molecular Database, Matt L. Lykins, Gary J. Ferland, R. Kisielius, Marios Chatzikos, R. L. Porter, P. A. M. Van Hoof, R. J. R. Williams, F. P. Keenan, P. C. Stancil

Physics and Astronomy Faculty Publications

We describe a new atomic and molecular database we developed for use in the spectral synthesis code Cloudy. The design of Stout is driven by the data needs of Cloudy, which simulates molecular, atomic, and ionized gas with kinetic temperatures 2.8 K < T <10¹⁰ K and densities spanning the low-to high-density limits. The radiation field between photon energies 10⁻⁸ Ry and 100 MeV is considered, along with all atoms and ions of the lightest 30 elements, and ~10² molecules. For ease of maintenance, the data are stored in a format as close as possible to the original data …

Probing Wolf–Rayet Winds: Chandra/Hetg X-Ray Spectra Of Wr 6, David P. Huenemoerder, K. G. Gayley, Wolf-Rainer Hamann, Richard Ignace, J. S. Nichols, Lidia M. Oskinova, A. M.T. Pollock, Nobert S. Schulz, Tomer Shenar

ETSU Faculty Works

With a deep Chandra/HETGS exposure of WR 6, we have resolved emission lines whose profiles show that the X-rays originate from a uniformly expanding spherical wind of high X-ray-continuum optical depth. The presence of strong helium-like forbidden lines places the source of X-ray emission at tens to hundreds of stellar radii from the photosphere. Variability was present in X-rays and simultaneous optical photometry, but neither were correlated with the known period of the system or with each other. An enhanced abundance of sodium revealed nuclear-processed material, a quantity related to the evolutionary state of the star. The characterization of …

Higgs Shifts From Electron–Positron Annihilations Near Neutron Stars, Gary A. Wegner, Roberto Onofrio

Dartmouth Scholarship

We discuss the potential for using neutron stars to determine bounds on the Higgs-Kretschmann coupling by looking at peculiar shifts in gamma-ray spectroscopic features. In particular, we reanalyze multiple lines observed in GRB781119 detected by two gamma-ray spectrometers, and derive an upper bound on the Higgs-Kretschmann coupling that is much more constraining than the one recently obtained from white dwarfs. This calls for targeted analyses of spectra of gamma-ray bursts from more recent observatories, dedicated searches for differential shifts on electron–positron and proton–antiproton annihilation spectra in proximity of compact sources, and signals of electron and proton cyclotron lines from the …

The Sluggs Survey: Multipopulation Dynamical Modelling Of The Elliptical Galaxy Ngc 1407 From Stars And Globular Clusters, Vincenzo Pota, Aaron Romanowsky, Jean Brodie, Jorge Peñarrubia, Duncan Forbes, Nicola Napolitano, Caroline Foster, Matthew Walker, Jay Strader, Joel Roediger

Faculty Publications

No abstract provided.

Binary Central Stars Of Planetary Nebulae Discovered Through Photometric Variability. Iii. The Central Star Of Abell 65, Todd Hillwig, David J. Frew, Melissa Louie, Orsola De Marco, Sam Schaub

Physics and Astronomy Faculty Publications

A growing number of close binary stars are being discovered among central stars of planetary nebulae. Recent and ongoing surveys are finding new systems and contributing to our knowledge of the evolution of close binary systems. The push to find more systems was largely based on early discoveries which suggested that 10%–15% of all central stars are close binaries. One goal of this series of papers is confirmation and classification of these systems as close binaries and determination of binary system parameters. Here we provide time-resolved multi-wavelength photometry of the central star of Abell 65 as well as further analysis …

Kelt-7b: A Hot Jupiter Transiting A Bright V = 8.54 Rapidly Rotating F-Star, A. Bieryla, K. Collins, T. G. Beatty, J. Eastman, R. J. Siverd, J. Pepper, B. S. Gaudi, K. G. Stassun, C. Cañas, D. W. Latham, L. A. Buchhave, R. Sanchis-Ojeda, J. N. Winn, Eric L.N. Jensen, J. F. Kielkopf, K. K. Mcleod, J. Gregorio, K. D. Colón, R. Street, R. Ross, M. Penny, S. N. Mellon, T. E. Oberst, B. J. Fulton, J. Wang, P. Berlind, M. L. Calkins, G. A. Esquerdo, D. L. Depoy, A. Gould, J. Marshall, R. Pogge, M. Trueblood, P. Trueblood

Physics & Astronomy Faculty Works

We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of 1.28+/- 0.18 M_J, radius of {1.533}_-0.047^+0.046 R_J, and an orbital period of 2.7347749+/- 0.0000039 days. The bright host star (HD 33643; KELT-7) is an F-star with V = 8.54, T_eff = 6789{}_-49⁺⁵⁰ K, [Fe/H] = {0.139}_-0.081^+0.075, and {log}\{\text{}}g\=4.149+/- 0.019. It has a mass of {1.535}_-0.054^+0.066 M_☉, a radius of {1.732}_-0.045^+0.043 R_☉, and is the fifth most massive, fifth hottest, and the ninth brightest star known to …

Comparing Theory And Experiment For Analyte Transport In The First Vacuum Stage Of The Inductively Coupled Plasma Mass Spectrometer, Matthew R. Zachreson

Theses and Dissertations

The inductively coupled plasma mass spectrometer (ICP-MS) has been used in laboratories for many years. The majority of the improvements to the instrument have been done empirically through trial and error. A few fluid models have been made, which have given a general description of the flow through the mass spectrometer interface. However, due to long mean free path effects and other factors, it is very difficult to simulate the flow details well enough to predict how changing the interface design will change the formation of the ion beam. Towards this end, Spencer et al. developed FENIX, a direct simulation …