Publications (11)
The Chemical Composition of an Extrasolar Minor Planet
B. Zuckerman, D. Koester, C. Melis +2
We report the relative abundances of 17 elements in the atmosphere of the white dwarf star GD 362, material that, very probably, was contained previously in a large asteroid or ast…
Cool Customers in the Stellar Graveyard IV: Spitzer Search for Mid-IR excesses Around Five DAs
J. H. Debes, S. Sigurdsson, B. Hansen
Hydrogen atmosphere white dwarfs with metal lines, so-called DAZs, require external accretion of material to explain the presence of weak metal line absorption in their photosphere…
LCLS-II-HE verification cryomodule high gradient performance and quench behavior
S. Posen, A. Cravatta, M. Checchin +43
An 8-cavity, 1.3 GHz, LCLS-II-HE cryomodule was assembled and tested at Fermilab to verify performance before the start of production. Its cavities were processed with a novel nitr…
Cold Test Results of Pre-Production PIP-II SSR2 Cavities with High-Power Couplers in the Fermilab Spoke Test Cryostat
A. Sukhanov, C. Contreras-Martinez, C. Grimm +13
As part of the PIP-II project at Fermilab, a pre-production cryomodule featuring 325 MHz Single Spoke Resonator type 2 (SSR2) superconducting RF cavities is under construction. The…
The phase-dependent Infrared brightness of the extrasolar planet upsilon Andromedae b
J. Harrington, B. Hansen, S. Luszcz +5
The star upsilon Andromeda is orbited by three known planets, the innermost of which has an orbital period of 4.617 days and a mass at least 0.69 that of Jupiter. This planet is cl…
The Galactic Center: A Laboratory for Fundamental Astrophysics and Galactic Nuclei
A. Ghez, M. Morris, J. Lu +24
As the closest example of a galactic nucleus, the Galactic center presents an exquisite laboratory for learning about supermassive black holes (SMBH) and their environs. Detailed s…
Commissioning And First Results From The Fermilab Cryomodule Test Stand
E. R. Harms, M. Awida, C. Baffes +34
A new test stand dedicated to Superconducting Radiofrequency (SRF) cryomodule testing, CMTS1, has been commissioned and is now in operation at Fermilab. The first device to be cool…
Nitrogen Precooling Heat Exchanger replacement and control system upgrade in Superfluid Cryoplant at CMTF
J. Subedi, B. Hansen, M. White +4
Liquid Nitrogen precooling is used in most Cryoplants to achieve cooldown to 80 K temperature range. In one such system at Fermilab's CMTF Superfluid Cryoplant, where the Helium su…
Integration and commissioning plan of Full Flow Purifier at Muon Campus
J. Subedi, T. Tope, B. Hansen +5
The Full Flow Purifier for Fermilab's Muon Campus uses a charcoal bed surrounded by a liquid nitrogen jacket to purify up to 240 g/s of helium gas. Fabrication by Ability Engineeri…
Stellar Pollution in the Solar Neighborhood
N. Murray, B. Chaboyer, B. Hansen +2
We study spectroscopically determined iron abundances of 642 solar-type stars to search for the signature of accreted iron-rich material. We find that the metallicity [Fe/H] of a s…
Design of Muon Campus full flow purifier for varying operational conditions and horizontal shipping
J. Subedi, T. Tope, B. Hansen +4
Constant ingress of impurities in Muon Campus g-2 experiment at Fermilab has resulted in reduction of efficiency of cryogenic expanders and occasional undesired downtime to flush t…