Physical Sciences and Mathematics Commons^™

Measuring Polarized Emission In Clusters In The Cmb S4 Era, Louis Thibaut, Emory F. Bunn, Benjamin Wandelt, Joseph Silk

Physics Faculty Publications

The next generation of CMB experiments (CMB Stage-4) will produce a Sunyaev-Zel’dovich (SZ) cluster catalog containing ∼105 objects, two orders of magnitudes more than currently available. In this paper, we discuss the detectability of the polarized signal generated by scattering of the CMB quadrupole on the cluster electron gas using this catalog. We discuss the possibility of using this signal to measure the relationship between cluster optical depth and mass. We find that the area of observation of S4 maximizes the signal-to-noise (S/N) on the polarized signal but that this S/N is extremely small for an individual cluster, of order …

Pure E And B Polarization Maps Via Wiener Filtering, Emory F. Bunn, Benjamin Wandelt

Physics Faculty Publications

In order to draw scientific conclusions from observations of cosmic microwave background (CMB) polarization,it is necessary to separate the contributions of the E and B components of the data. For data with incomplete sky coverage, there are ambiguous modes, which can be sourced by either E or B signals. Techniques exist for producing “pure” E and B maps, which are guaranteed to be free of cross-contamination, although the standard method, which involves constructing an eigenbasis, has a high computational cost. We show that such pure maps can be thought of as resulting from the application of a Wiener filter to …

Analysis Of A Custom Support Vector Machine For Photometric Redshift Estimation And The Inclusion Of Galaxy Shape Information, Jack Singal, Evan Jones

Physics Faculty Publications

Aims. We present a custom support vector machine classification package for photometric redshift estimation, including comparisons with other methods. We also explore the efficacy of including galaxy shape information in redshift estimation. Support vector machines, a type of machine learning, utilize optimization theory and supervised learning algorithms to construct predictive models based on the information content of data in a way that can treat different input features symmetrically, which can be a useful estimator of the information contained in additional features beyond photometry, such as those describing the morphology of galaxies.

Methods. The custom support vector machine package we have …

Temperature Tuning From Direct To Inverted Bistable Electroluminescence In Resonant Tunneling Diodes, F. Hartmann, A. Pfenning, Mariama Rebello Sousa Dias, F. Langer, S. Höfling, M. Kamp, L. Worschech, L. K. Castelano, G. E. Marques, V. Lopez-Richard

Physics Faculty Publications

We study the electroluminescence (EL) emission of purely n-doped resonant tunneling diodes in a wide temperature range. The paper demonstrates that the EL originates from impact ionization and radiative recombination in the extended collector region of the tunneling device. Bistable currentvoltage response and EL are detected and their respective high and low states are tuned under varying temperature. The bistability of the EL intensity can be switched from direct to inverted with respect to the tunneling current and the optical on/off ratio can be enhanced with increasing temperature. One order of magnitude amplification of the optical on/off ratio can be …

Study Of The Neutron Detection Efficiency Of The Clas12 Detector, Keegan Sherman

Honors Theses

One of the central physics goals of Jefferson Lab is to understand how quarks and gluons form nuclei. The 12 GeV upgrade is nearing completion and a new detector, CLAS12, is being built in Hall B. One of the approved experiments will measure the magnetic form factor of the neutron (Gn ). To make this measurement, the ratio of electron-neutron (e-n) to electron-proton (e-p) scattering events will be extracted from deuterium in quasi-elastic kinematics. A major source of systematic uncertainty is the neutron detection efficiency (NDE) of CLAS12. To better understand the NDE I used the Monte Carlo …