Tree rings are one of the sensor effects that may affect precise measurements in the Large Synoptic Survey Telescope (LSST). The effect is caused by silicon wafer manufacturing process, resulting in formation of circular patterns due to variations of the silicon dopant concentration. We have analyzed flat-field images taken at Brookhaven National Laboratory and SLAC for all production sensors used to build the LSST camera in order to measure the amplitudes and periods of the tree ring patterns as a function of the radius, illumination wavelength, and sensor back bias voltage. With nominal back bias voltage settings, the tree ring amplitudes and periods for both ITL and e2v sensors are considered to have small impact on the galaxy shear measurement in LSST.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither SPIE nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the SPIE website.