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Physics Seminar: Brian Baptisa |
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| Category: | College Of Engineering - Phy | |
| Date & Time: |
Friday , 12/21/2012 from 01:00 PM to 02:00 PM |
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| Location: | Seng 102 | |
| Admission: | Free! | |
| Contact: |
Jay Wang jwang@umassd.edu 508-999-9268 |
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| Description: | Seminar by Brian Baptista One of our recent alumni, Brian Baptista, better known as Tad, will be visiting us on Friday, Dec 21. He graduated from the Physics Department and is currently a PhD candidate in astrophysics at Indiana University. He will meet with all interested and give a talk at 1pm in SENG 102. Please join us to hear his experience and his talk. Speaker: Brian Baptista, Indiana University Date: Dec 21, 2012, 1pm, SENG 102 Title: Radiation hardness of InGaAs photodiodes as on-orbit calibration monitors for space-based dark energy experiments, and properties of high equivalent width Lyman-alpha galaxies at redshifts between 2.5 and 3.5. Abstract: I will discuss two of my dissertation projects: a study to determine the radiation hardness of InGaAs photodiodes for a space-based dark energy experiment, and work to determine the properties of high equivalent width Lyman-alpha galaxies(LAEs) at redshifts between 2.5 and 3.5. I will present results from a project to determine the radiation hardness of near-infrared InGaAs photodiodes. A space-based mission to measure dark energy parameters needs stable monitoring photodiodes to ensure that strict calibration requirements are met throughout the mission lifetime. I measured relative responsivity and dark currents in InGaAs photodiodes from five different manufacturers after irradiating them in the Indiana University Cyclotron Facility’s proton beam. I irradiated the photodiodes over a range of expected fluences during a ten-year mission lifetime at an L2 orbit from 1x10^8 -5x10^11 protons/cm^2. As LAEs have been discovered, they have been grouped into two main categories: normal equivalent widths (EWs) due to normal star formation and extreme EWs that exceed the modeled maximum EW due to star formation. I will present results from a spectroscopic follow-up of broadband-selected LAEs to search specifically for extreme EW LAEs. I used WIYN Hydra to confirm spectroscopically 63 new LAEs. I then analyzed the spectra in conjunction with the photometric data to determine the EW distribution for the population of LAEs that we have surveyed. | |
