<i>Spider</i>Optimization: Probing the Systematics of a Large‐Scale<i>B</i>‐Mode Experiment

Spider is a long-duration, balloon-borne polarimeter designed to measure large-scale cosmic microwave background&#13;\n(CMB) polarization with very high sensitivity and control of systematics. The instrument will map over half the sky&#13;\nwith degree angular resolution in the I, Q, and U Stokes parameters in four frequency bands from 96 to 275 GHz.&#13;\nSpider’s ultimate goal is to detect the primordial gravity-wave signal imprinted on the CMB B-mode polarization.&#13;\nOne of the challenges in achieving this goal is the minimization of the contamination of B-modes by systematic effects.&#13;\nThis paper explores a number of instrument systematics and observing strategies in order to optimize B-mode sensitivity.&#13;\nThis is done by injecting realistic-amplitude, time-varying systematics into a set of simulated time streams.&#13;\nTests of the impact of detector noise characteristics, pointing jitter, payload pendulations, polarization angle offsets,&#13;\nbeam systematics, and receiver gain drifts are shown. Spider’s default observing strategy is to spin continuously in&#13;\nazimuth, with polarization modulation achieved by either a rapidly spinning half-wave plate or a rapidly spinning gondola&#13;\nand a slowly stepped half-wave plate. Although the latter is more susceptible to systematics, the results shown&#13;\nhere indicate that either mode of operation can be used by Spider.