Precision Velocity Measurements of Fission Fragments Using the SPIDER Detector

The SPectrometer for Ion DEtermination in fission Research (SPIDER) measures both position and time-of-flight (TOF) of charged particles using a system of thin carbon foils, electrostatic mirrors, microchannel plates, delay-line anodes, and a fast TDC. Tests have been conducted using 229Th and the alpha emitters in its decay chain. To date, timing resolution of 200 ps (FWHM) has been achieved corresponding to roughly 0.5% uncertainty in velocity measurements of fission fragments over a flight path of 52.1 cm. This velocity resolution, in combination with demonstrated fragment energy resolution is sufficient for 1 amu resolution of light mass fragments.