P. Barton - The. MAJORANA. Collaboration

P. Barton
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Name
P. Barton
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The. MAJORANA. Collaboration
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Physics - Materials Science (8)
 
Physics - Instrumentation and Detectors (5)
 
Nuclear Experiment (5)
 
Quantum Physics (3)
 
High Energy Physics - Experiment (3)
 
Physics - Atomic Physics (2)
 
Mathematics - Dynamical Systems (1)
 
High Energy Physics - Phenomenology (1)
 
Physics - Strongly Correlated Electrons (1)

Publications Authored By P. Barton

An optimal control strategy is developed to construct nanostructures of desired geometry along line segments by means of directed self-assembly of charged particles. Such a control strategy determines the electric potentials of a set of electrodes located at fixed points in the line segment. The particles move under the electric forces generated by these electrodes and by the interactions between the particles themselves to form a desired pattern eventually. Read More

Low capacitance, large volume, high purity germanium (HPGe) radiation detectors have been successfully employed in low-background physics experiments. However, some physical processes may not be detectable with existing detectors whose energy thresholds are limited by electronic noise. In this paper, methods are presented which can lower the electronic noise of these detectors. Read More

The COHERENT collaboration's primary objective is to measure coherent elastic neutrino-nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. Read More

Temperature sensors fabricated from ultra-low radioactivity materials have been developed for low-background experiments searching for neutrinoless double-beta decay and the interactions of WIMP dark matter. The sensors consist of electrical traces photolithographically-patterned onto substrates of vapor-deposited parylene. They are demonstrated to function as expected, to do so reliably and robustly, and to be highly radio-pure. Read More

A structural phase transition from cubic $Fd\bar{3}m$ to tetragonal $I$4$_1$/$amd$ symmetry with $c/a >$ 1 is observed at $T_{\rm{S}}$ = 16 K in spinel GeCo$_2$O$_4$ below the N\'eel temperature $T_N$ = 21 K. Structural and magnetic ordering appear to be decoupled with the structural distortion occurring at 16 K while magnetic order occurs at 21 K as determined by magnetic susceptibility and heat capacity measurements. An elongation of CoO$_6$ octahedra is observed in the tetragonal phase of GeCo$_2$O$_4$. Read More

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Tennessee, provides an intense flux of neutrinos in the few tens-of-MeV range, with a sharply-pulsed timing structure that is beneficial for background rejection. In this white paper, we describe how the SNS source can be used for a measurement of coherent elastic neutrino-nucleus scattering (CENNS), and the physics reach of different phases of such an experimental program (CSI: Coherent Scattering Investigations at the SNS). Read More

The electronic structures of four semiconductor compounds BaCu2S2, BaCu2Se2, BaAg2S2, and BaAg2Se2 are studied by density functional theory using both semi-local and hybrid functionals. The ionization energies and electron affinities were determined by aligning the electronic states with the vacuum level by calculating the electrostatic profile within a supercell slab model. The ionization energy and electron affinity of the compounds were calculated using the Heyd-Scuseria-Ernzerhof (HSE) functionals and range from 4. Read More

The spinel NiCr$_2$O$_4$ is characterized using dielectric and high magnetic field measurements. The trends in the magnetodielectric response fall into three clear temperature regimes corresponding to known magnetic and structural transitions. Above 65\,K, weak magnetic field dependence of the dielectric constant is observed with no hysteresis. Read More

Co10Ge3O16 crystallizes in an intergrowth structure featuring alternating layers of spinel and rock salt. Variable-temperature powder synchrotron X-ray and neutron diffraction, magnetometry, and heat capacity experiments reveal a magnetostructural transition at T_N = 203 K. This rhombohedral-to-monoclinic transition involves a slight elongation of the CoO6 octahedra along the apical axis. Read More

Magnetic ordering in the geometrically frustrated magnetic oxide spinels MgCr_2O_4 and ZnCr_2O_4 is accompanied by a structural change that helps relieve the frustration. Analysis of high-resolution synchrotron X-ray scattering reveals that the low-temperature structures are well described by a two-phase model of tetragonal I4_1/amd and orthorhombic Fddd symmetries. The Cr_4 tetrahedra of the pyrochlore lattice are distorted at these low-temperatures, with the Fddd phase displaying larger distortions than the I4_1/amd phase. Read More

Polycrystalline Nd2Ru2O7 samples have been prepared and examined using a combination of structural, magnetic, and electrical and thermal transport studies. Analysis of synchrotron X-ray and neutron diffraction patterns suggests some site disorder on the A-site in the pyrochlore sublattice: Ru substitutes on the Nd-site up to 7.0(3)%, regardless of the different preparative conditions explored. Read More

2012Oct
Affiliations: 1The. MAJORANA. Collaboration, 2The. MAJORANA. Collaboration, 3The. MAJORANA. Collaboration, 4The. MAJORANA. Collaboration, 5The. MAJORANA. Collaboration, 6The. MAJORANA. Collaboration, 7The. MAJORANA. Collaboration, 8The. MAJORANA. Collaboration, 9The. MAJORANA. Collaboration, 10The. MAJORANA. Collaboration, 11The. MAJORANA. Collaboration, 12The. MAJORANA. Collaboration, 13The. MAJORANA. Collaboration, 14The. MAJORANA. Collaboration, 15The. MAJORANA. Collaboration, 16The. MAJORANA. Collaboration, 17The. MAJORANA. Collaboration, 18The. MAJORANA. Collaboration, 19The. MAJORANA. Collaboration, 20The. MAJORANA. Collaboration, 21The. MAJORANA. Collaboration, 22The. MAJORANA. Collaboration, 23The. MAJORANA. Collaboration, 24The. MAJORANA. Collaboration, 25The. MAJORANA. Collaboration, 26The. MAJORANA. Collaboration, 27The. MAJORANA. Collaboration, 28The. MAJORANA. Collaboration, 29The. MAJORANA. Collaboration, 30The. MAJORANA. Collaboration, 31The. MAJORANA. Collaboration, 32The. MAJORANA. Collaboration, 33The. MAJORANA. Collaboration, 34The. MAJORANA. Collaboration, 35The. MAJORANA. Collaboration, 36The. MAJORANA. Collaboration, 37The. MAJORANA. Collaboration, 38The. MAJORANA. Collaboration, 39The. MAJORANA. Collaboration, 40The. MAJORANA. Collaboration, 41The. MAJORANA. Collaboration, 42The. MAJORANA. Collaboration, 43The. MAJORANA. Collaboration, 44The. MAJORANA. Collaboration, 45The. MAJORANA. Collaboration, 46The. MAJORANA. Collaboration, 47The. MAJORANA. Collaboration, 48The. MAJORANA. Collaboration, 49The. MAJORANA. Collaboration, 50The. MAJORANA. Collaboration, 51The. MAJORANA. Collaboration, 52The. MAJORANA. Collaboration, 53The. MAJORANA. Collaboration, 54The. MAJORANA. Collaboration, 55The. MAJORANA. Collaboration, 56The. MAJORANA. Collaboration, 57The. MAJORANA. Collaboration, 58The. MAJORANA. Collaboration, 59The. MAJORANA. Collaboration, 60The. MAJORANA. Collaboration, 61The. MAJORANA. Collaboration, 62The. MAJORANA. Collaboration, 63The. MAJORANA. Collaboration, 64The. MAJORANA. Collaboration, 65The. MAJORANA. Collaboration, 66The. MAJORANA. Collaboration, 67The. MAJORANA. Collaboration, 68The. MAJORANA. Collaboration, 69The. MAJORANA. Collaboration, 70The. MAJORANA. Collaboration, 71The. MAJORANA. Collaboration, 72The. MAJORANA. Collaboration, 73The. MAJORANA. Collaboration, 74The. MAJORANA. Collaboration, 75The. MAJORANA. Collaboration, 76The. MAJORANA. Collaboration, 77The. MAJORANA. Collaboration, 78The. MAJORANA. Collaboration, 79The. MAJORANA. Collaboration, 80The. MAJORANA. Collaboration, 81The. MAJORANA. Collaboration, 82The. MAJORANA. Collaboration, 83The. MAJORANA. Collaboration

The MAJORANA DEMONSTRATOR will search for the neutrinoless double-beta decay of the 76Ge isotope with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate the neutrino is its own anti-particle, demonstrate that lepton number is not conserved, and provide information on the absolute mass-scale of the neutrino. The DEMONSTRATOR is being assembled at the 4850 foot level of the Sanford Underground Research Facility in Lead, South Dakota. Read More

A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. Read More

We have prepared the complete delafossite solid solution series between diamagnetic CuAlO2 and the t2g^3 frustrated antiferromagnet CuCrO2. The evolution with composition x in CuAl(1-x)Cr(x)O2 of the crystal structure and magnetic properties has been studied and is reported here. The room-temperature unit cell parameters follow the Vegard law and increase with x as expected. Read More

A complete solid solution series between the t2g^4 perovskite ferromagnet SrRuO3 and the diamagnetic t2g^6 perovskite LaRhO3 has been prepared. The evolution with composition x in (SrRuO3)(1-x)(LaRhO3)(x) of the crystal structure and electrical and magnetic properties has been studied and is reported here. As x increases, the octahedral tilt angle gradually increases, along with the pseudocubic lattice parameter and unit cell volume. Read More

Ground state cooling and coherent manipulation of ions in an rf-(Paul) trap is the prerequisite for quantum information experiments with trapped ions. With resolved sideband cooling on the optical S1/2 - D5/2 quadrupole transition we have cooled one and two 40Ca+ ions to the ground state of vibration with up to 99.9% probability. Read More

We have cooled a two-ion-crystal to the ground state of its collective modes of motion. Laser cooling, more specific resolved sideband cooling is performed sympathetically by illuminating only one of the two $^{40}$Ca$^+$ ions in the crystal. The heating rates of the motional modes of the crystal in our linear trap have been measured, and we found them considerably smaller than those previously reported by Q. Read More

We report a precise search for correlation effects in linear chains of 2 and 3 trapped Ca+ ions. Unexplained correlations in photon emission times within a linear chain of trapped ions have been reported, which, if genuine, cast doubt on the potential of an ion trap to realize quantum information processing. We observe quantum jumps from the metastable 3d 2D_{5/2} level for several hours, searching for correlations between the decay times of the different ions. Read More

We investigate single ions of $^{40}Ca^+$ in Paul traps for quantum information processing. Superpositions of the S$_{1/2}$ electronic ground state and the metastable D$_{5/2}$ state are used to implement a qubit. Laser light on the S$_{1/2} \leftrightarrow$ D$_{5/2}$ transition is used for the manipulation of the ion's quantum state. Read More

We report a measurement of the lifetime of the 3d 2D_{5/2} metastable level in 40Ca+, using quantum jumps of a single cold calcium ion in a linear Paul trap. The 4s S_{1/2} - 3d D_{5/2} transition is significant for single-ion optical frequency standards, astrophysical references, and tests of atomic structure calculations. We obtain tau = 1. Read More