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Publications

Active-site protein dynamics and solvent accessibility in native Achromobacter cycloclastes copper nitrite reductase

Cornell Affiliated Author(s)
Author
K. Sen
S. Horrell
D. Kekilli
C.W. Yong
T.W. Keal
H. Atakisi
D.W. Moreau
R.E. Thorne
M.A. Hough
R.W. Strange
Abstract

Microbial nitrite reductases are denitrifying enzymes that are a major component of the global nitrogen cycle. Multiple structures measured from one crystal (MSOX data) of copper nitrite reductase at 240K, together with molecular-dynamics simulations, have revealed protein dynamics at the type 2 copper site that are significant for its catalytic properties and for the entry and exit of solvent or ligands to and from the active site.

Journal
IUCrJ
Date Published
Research Area
Group (Lab)
Robert Thorne Group

CBETA - Cornell university brookhaven national laboratory electron energy recovery test accelerator

Cornell Affiliated Author(s)
Author
D. Trbojevic
S. Bellavia
M. Blaskiewicz
S. Brooks
K. Brown
C. Liu
W. Fischer
Carl Franck
Y. Hao
G. Mahler
F. Meot
R. Michnoff
M. Minty
S. Peggs
V. Ptitsyn
T. Roser
S.J. Berg
P. Thieberger
N. Tsoupas
J. Tuozzolo
F. Willeke
H. Witte
N. Banerjee
J. Barley
A. Bartnik
I. Bazarov
D. Burke
J. Crittenden
L. Cultrera
J. Dobbins
B. Dunham
R. Eichhorn
S. Full
F. Furuta
R. Gallagher
M. Ge
C. Gulliford
B. Heltsley
G. Hoffstaetter
D. Jusic
R. Kaplan
V. Kostroun
Y. Li
M. Liepe
W. Lou
C. Mayes
R. Patterson
P. Quigley
E. Smith
K. Smolenski
D. Sabol
D. Sagan
J. Sears
C. Shore
V. Veshcherevich
D. Widger
D. Douglas
Abstract

Cornell's Lab of Accelerator-based Sciences and Education (CLASSE) and the Collider Accelerator Department (BNL-CAD) are developing the first Superconducting RF multi-turn energy recovery linac with Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) racetrack. The existing injector and superconducting linac at Cornell University are installed together with a single NS-FFAG arcs and straight section at the opposite side of the linac to form an Electron Energy Recovery (ERL) system.

Conference Name
Conference
Date Published
Group (Lab)
Carl Franck Group

Impact of trapped magnetic flux and thermal gradients on the performance of Nb3Sn cavities

Cornell Affiliated Author(s)
Author
D.L. Hall
D.B. Liarte
M. Liepe
J.P. Sethna
Abstract

Trapped magnetic flux is known to degrade the quality factor of superconducting cavities by increasing the surface losses ascribed to the residual resistance. In Nb3Sn cavities, which consist of a thin layer of Nb3Sn coated on a bulk niobium substrate, the bimetallic interface results in a thermal current being generated in the presence of a thermal gradient, which will in turn generate flux that can be trapped. In this paper we quantify the impact of trapped flux, from either ambient fields or thermal gradients, on the performance of the cavity.

Conference Name
Conference
Date Published
Funding Source
PHY-1549132
DE-SC0008431
Research Area
Group (Lab)
James Sethna Group

Quench studies in single-cell Nb3Sn cavities coated using vapour diffusion

Cornell Affiliated Author(s)
Author
D.L. Hall
P. Cueva
D.B. Liarte
M. Liepe
J.T. Maniscalco
D.A. Muller
R.D. Porter
J.P. Sethna
Abstract

The superconductor Nb3Sn is known to have a superheating field, Hsh, of approximately 400 mT. This critical field represents the ultimate achievable gradient in a superconducting cavity, and is equivalent to an accelerating gradient of 90 MV/m in an ILC single-cell cavity for this value of Hsh. However, the currently best performing Nb3Sn single-cell cavities remain limited to accelerating gradients of 17-18 MV/m, translating to a peak surface magnetic field of approx. 70 mT.

Conference Name
Conference
Date Published
Funding Source
PHY-1549132
DE-SC0008431
DMR-1120296
Research Area
Group (Lab)
James Sethna Group

Using sloppy models for constrained emittance minimization at the Cornell Electron Storage Ring (CESR)

Cornell Affiliated Author(s)
Author
W.F. Bergan
A.C. Bartnik
I.V. Bazarov
H. He
D.L. Rubin
J.P. Sethna
Abstract

In order to minimize the emittance at the Cornell Electron Storage Ring (CESR), we measure and correct the orbit, dispersion, and transverse coupling of the beam. However, this method is limited by finite measurement resolution of the dispersion, and so a new procedure must be used to further reduce the emittance due to dispersion. In order to achieve this, we use a method based upon the theory of sloppy models. We use a model of the accelerator to create the Hessian matrix which encodes the effects of various corrector magnets on the vertical emittance.

Conference Name
Conference
Date Published
Funding Source
DGE-1144153
DE-SC0013571
Group (Lab)
James Sethna Group

X-ray reflectivity measurement of interdiffusion in metallic multilayers during rapid heating

Cornell Affiliated Author(s)
Author
J.P. Liu
J. Kirchhoff
L. Zhou
M. Zhao
M.D. Grapes
D.S. Dale
M.D. Tate
H.T. Philipp
Sol Gruner
T.P. Weihs
T.C. Hufnagel
Abstract

A technique for measuring interdiffusion in multilayer materials during rapid heating using X-ray reflectivity is described. In this technique the sample is bent to achieve a range of incident angles simultaneously, and the scattered intensity is recorded on a fast high-dynamic-range mixed-mode pixel array detector. Heating of the multilayer is achieved by electrical resistive heating of the silicon substrate, monitored by an infrared pyrometer. As an example, reflectivity data from Al/Ni heated at rates up to 200Ks-1 are presented.

Journal
Journal of Synchrotron Radiation
Date Published
Funding Source
1332208
DE-AC52-07NA27344
DE-AC02-76SF00515
LLNL-JRNL-695561
Group (Lab)
Sol M. Gruner Group

Sub-microsecond x-ray imaging using hole-collecting Schottky type CdTe with charge-integrating pixel array detectors

Cornell Affiliated Author(s)
Author
J. Becker
M.W. Tate
K.S. Shanks
H.T. Philipp
J.T. Weiss
P. Purohit
Darol Chamberlain
Sol Gruner
Abstract

CdTe is increasingly being used as the x-ray sensing material in imaging pixel array detectors for x-rays, generally above 20 keV, where silicon sensors become unacceptably transparent. Unfortunately CdTe suffers from polarization, which can alter the response of the material over time and with accumulated dose. Most prior studies used long integration times or CdTe that was not of the hole-collecting Schottky type. We investigated the temporal response of hole-collecting Schottky type CdTe sensors on timescales ranging from tens of nanoseconds to several seconds.

Journal
Journal of Instrumentation
Date Published
Funding Source
DMR-1332208
DE-SC0016035
1332208
Group (Lab)
Sol M. Gruner Group

Collective Modes of a Soliton Train in a Fermi Superfluid

Cornell Affiliated Author(s)
Author
S. Dutta
E.J. Mueller
Abstract

We characterize the collective modes of a soliton train in a quasi-one-dimensional Fermi superfluid, using a mean-field formalism. In addition to the expected Goldstone and Higgs modes, we find novel long-lived gapped modes associated with oscillations of the soliton cores. The soliton train has an instability that depends strongly on the interaction strength and the spacing of solitons. It can be stabilized by filling each soliton with an unpaired fermion, thus forming a commensurate Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase.

Journal
Physical Review Letters
Date Published
Funding Source
1508300

Measuring the densities of aqueous glasses at cryogenic temperatures

Cornell Affiliated Author(s)
Author
C. Shen
E.F. Julius
T.J. Tyree
R. Dan
D.W. Moreau
R. Thorne
Abstract

We demonstrate a method for determining the vitreous phase cryogenic temperature densities of aqueous mixtures, and other samples that require rapid cooling, to prepare the desired cryogenic temperature phase. Microliter to picoliter size drops are cooled by projection into a liquid nitrogen-argon (N2-Ar) mixture. The cryogenic temperature phase of the drop is evaluated using a visual assay that correlates with X-ray diffraction measurements. The density of the liquid N2-Ar mixture is adjusted by adding N2 or Ar until the drop becomes neutrally buoyant.

Journal
Journal of Visualized Experiments
Date Published
Group (Lab)
Robert Thorne Group

Interface-induced phenomena in magnetism

Cornell Affiliated Author(s)
Author
Frances Hellman
Axel Hoffmann
Yaroslav Tserkovnyak
Geoffrey Beach
Eric Fullerton
Chris Leighton
Allan MacDonald
Daniel Ralph
Dario Arena
Hermann Dürr
Peter Fischer
Julie Grollier
Joseph Heremans
Tomas Jungwirth
Alexey Kimel
Bert Koopmans
Ilya Krivorotov
Steven May
Amanda Petford-Long
James Rondinelli
Nitin Samarth
Ivan Schuller
Andrei Slavin
Mark Stiles
Oleg Tchernyshyov
André Thiaville
Barry Zink
Abstract

This article reviews static and dynamic interfacial effects in magnetism, focusing on interfacially driven magnetic effects and phenomena associated with spin-orbit coupling and intrinsic symmetry breaking at interfaces. It provides a historical background and literature survey, but focuses on recent progress, identifying the most exciting new scientific results and pointing to promising future research directions.

Journal
American Physical Society (APS)
Date Published
Funding Source
DE-FG02-06ER46275
DMR-1420013
DMR-1507048
DMR-1406333
DMR-1410247
DMR-1420451
SC0012670
682955
268066
LM2011026
14-37427