Kiyomi Sanders was born in Honolulu and grew up moving between Oahu, the continental US, and Scotland. She has recently earned the Associate in Science-Natural Science degree at Kapiolani Community College. She is currently participating in supermassive black hole research and is a physics and math peer mentor at KCC. In Fall 2019, she plans to transfer to UH Mnoa and pursue a Bachelor of Science in Physics with a minor in astrophysics. She is interested in many STEM-related fields, including particle physics, cosmology, sustainable engineering, and STEM outreach. After graduating from UHM, she would like to pursue a PhD in Physics and a career in research. In her free time, Kiyomi enjoys reading books and comics, playing music, and writing.

Home Island: Oahu

Institution when accepted: Kapi‘olani Community College

Akamai Project: Developing the WFOS Instrument Throughput Budget and Evaluating Optical Coatings and Materials

Project Site: Thirty Meter Telescope: WFOS – University of California, Santa Cruz

Mentor: Renate Kupke

Project Abstract:

The Wide Field Optical Spectrograph (WFOS) is the first optical spectrograph of the Thirty Meter Telescope. Its slit-mask design and large wavelength range (310-1000 nm) allows it to collect data from up to 100 objects simultaneously and observe large portions of the universe at a time. WFOS science cases include galaxy population studies, intergalactic medium tomography, and high-redshift studies. WFOS is currently in the conceptual design phase, in which the team is evaluating design options that will minimize loss of the light collected by TMT. This project focuses on determining the WFOS throughput budget, which quantifies the overall percentage of light gathered by the instrument at each wavelength. In order to pursue the expected science cases, the throughput should be >30% across the full WFOS wavelength range. I used Zemax optical design software to analyze each optical element of the design and the factors that affect the percent of light that they either reflect (for mirrors) or transmit (for lenses) across the wavelength range. Some elements had unknown transmission/reflectance curves, and required measuring witness samples with a spectrophotometer. I designed an Excel spreadsheet that includes reflectivity/transmissivity vs. wavelength data tables for every element of the optical design and the material/coating options for each element. I then calculated the total throughput by multiplying the percent of light reflected/transmitted by each individual element in the instrument. I linked the data tables to the throughput calculations so the design team can easily adjust aspects of the design and determine how the total throughput is affected by these changes. The throughput budget will allow us to make predictions about the throughput of WFOS vs. wavelength and determine which design maximizes throughput while still being technologically and logistically feasible. The instrument simulation team will use our results for the exposure time calculator, which will determine specific science objectives WFOS will be able to deliver.