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Search Publications by: Terrence J. Jach (Fed)

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Displaying 1 - 25 of 42

Near-edge x-ray absorption and emission of cyanates and thiocyanates

September 20, 2022
Karina Bzheumikhova, John Vinson, Yves Kayser, Rainer Unterumsberger, Terrence J. Jach, Burkhard Beckhoff
The comparability and reliability of the analysis of the electronic structure of selected cyanates and thio- cyanates at the nitrogen K edge based on BSE calculations have been investigated in this work. Using high-resolution x-ray spectroscopy with

The Effect of Transverse Wavefront Width on Specular Neutron Reflection

August 1, 2022
Charles Majkrzak, Norman F. Berk, Brian B. Maranville, Joseph Dura, Terrence J. Jach
In the analysis of neutron scattering measurements of condensed matter structure, it normally suffices to treat the incident and scattered neutron beams as if composed of incoherent distributions of plane waves with wavevectors of different magnitudes and

Controllable Catastrophe X-Ray Focusing

October 12, 2021
S M. Durbin, Terrence J. Jach, S. Kim, J. A. Aust
The interaction of waves with inhomogeneous media leads to the natural focusing of light, the channelling of waves into stable caustics such as the pattern of sunlight seen at the bottom of a rippled swimming pool. These effects are also found in surface

Processing Pulses from TES Microcalorimeter X-ray Detectors

August 6, 2021
Terrence J. Jach, Stephan M. Thurgate
Microcalorimeter x-ray detectors employing a transition-edge sensor are capable of very high energy resolution, but this depends on an understanding of the readout process. The combination of thermal cooling and thermoelectric feedback present in most

Resonant X-ray Emission and Valence-band Lifetime Broadening in LiNO3

August 28, 2019
John T. Vinson, Terrence J. Jach, Matthias Mueller, Rainer Unterumsberger, Burkhard Beckhoff
X-ray absorption and resonant inelastic x-ray scattering measurements are carried out on lithium nitrate LiNO3. Echoing previous studies on ammonium nitrate, the σ orbitals around the nitrogen atoms exhibit a large lifetime effect. Experimentally, this is

Intrinsic Orbital Angular Momentum States of Neutrons

March 2, 2018
Ronald L. Cappelletti, Terrence J Jach, John T. Vinson
A recent neutron interferometry experiment attempted to observe the orbital angular momentum (OAM) of neutron de Broglie waves of neutron de Broglie waves using a spiral phase (SPP) (Nature 525, 504 (2015) [1]). Based upon conventional neutron optical

Resonant X-ray Emission of Hexagonal Boron Nitride

November 9, 2017
John T. Vinson, Terrence J Jach, Matthias Mueller, Rainer Unterumsberger, Burkhard Beckhoff
The electronic structure of hexagonal boron nitride ({\it h}-BN) is explored using measurements of x-ray absorption and resonant inelastic x-ray scattering (RIXS) at the nitrogen K edge (1{\it s}) in tandem with calculations of the same using many-body

Quasiparticle Lifetime Broadening in Resonant X-ray Scattering of Ammonium Nitrate

July 28, 2016
John Vinson, Terrence J. Jach, Matthias Mueller, Rainer Unterumsberger, Burkhard Beckhoff
It has been previously shown that two effects cause dramatic changes in the x-ray absorption and emission spectrra from the N K edge of the insulating crystal ammonium nitate. First, vibrational disorder causes major changes in the absorption spectrum

The Multiple Origins of Broadening in Near-edge X-ray Spectra of Nitrogen Compounds

November 10, 2014
John T. Vinson, Terrence J Jach, W. T. Elam, J. D. Denlinger
A comparison of the N Kα emission spectrum of crystalline ammonium nitrate to molecular orbital calculations reveals a unique observation: the peak associated with the σNO recombination is broadened so extensively as to virtually disappear. We have

X-ray Emission Spectroscopy of Nitrogen-rich Compounds

March 31, 2011
Terrence J. Jach, Fernando D. Vila, W. T. Elam, J. D. Denlinger, John J. Rehr
Non-resonant x-ray emission spectroscopy was used to compare the nitrogen-rich compounds ammonium nitrate, trinitrotoluene, and cyclotrimethylene-trinitramine. They are representative of crystalline and molecular structures of special importance in

Multiplexed microcalorimeter arrays for precision measurements from microwave to gamma-ray wavelengths

August 21, 2007
Joel Ullom, W.Bertrand (Randy) Doriese, James A. Beall, William Duncan, S. L. Ferreira, Gene C. Hilton, Rob Horansky, Kent D. Irwin, Terrence J. Jach, John Mates, Nathan A. Tomlin, Galen O'Neil, Carl D. Reintsema, Nicholas Ritchie, Dan Schmidt, Leila R. Vale, Yizi Xu, Barry L. Zink, Andrew Hoover, Clifford R. Rudy, Derek Tournear, Duc Vo, Michael W. Rabin
Cryogenic microcalorimeters are a promising technology for ultrasensitive measurements of electromagnetic radiation from microwave to gamma-ray wavelengths. Cryogenic microcalorimeters derive their exquisite sensitivity from the minimal thermal noise at

Variable Magnification With Kirkpatrick-Baez Optics for Synchrotron X-Ray Microscopy

May 1, 2006
Terrence J. Jach, A S. Bakulin, S M. Durbin, J Pedulla, A T. Macrander
We describe the distinction between the operation of a short focal lengthx-ray microscope forming a real image with a laboratory source (convergentillumination) and with a highly collimated intense beam from a synchrotronlight source (K\{o}hler

Comparative Thickness Measurements of SiO 2 /Si Films for Thickness Less than 10 nm

January 1, 2004
Terrence J. Jach, Joseph A. Dura, Nhan V. Nguyen, J R. Swider, G Cappello, Curt A. Richter
We report on a comparative measurement of SiO 2 /Si dielectric film thickness (t < 10 nm) using grazing incidence x-ray photoelectron spectroscopy, neutron reflectometry, and spectroscopic ellipsometry. Samples with nominal thicknesses of 3 nm to 6 nm were

Real-Time Studies of Strains at Ferroelectric Domain Walls under an Applied Field

August 17, 2002
Terrence J. Jach, S. Kim, S M. Durbin, J. A. Aust, David S. Bright
We report on an improved method of visualizing domains in congruent ferroelectric crystals such as LiNbO^d3 with Bragg x-ray topography. Using monochromatic synchrotron undulator radiation and a magnifying x-ray camera, we are able to image domains created

Wide-Field X-Ray Microscopy with Kirkpatrick-Baez Optics

December 1, 2001
Terrence J. Jach, S M. Durbin, A S. Bakulin, David S. Bright, C B. Stagarescu, G Srajer, D. Haskel, J Pedulla
Modern technology permits us to fabricate Kirkpatrick-Baez (KB) multilayer optics with performance close to the theoretical limit. We have constructed a KB field-imaging microscope which operates in the x-ray energy range 6-10 keV with a field of view of