This low minimum threshold permits experimenters to routinely reverse-terminate photomultiplier anodes and, coupled. Output durations are adjustable from 5 nsec to 1 usec in the Update Only mode and are independent of input amplitude, duration, and rate. The Model 621BL is also available with the option to permit remote control of both threshold and output width via DC levels applied to a rear panel 20-pin connector. This option, which makes it feasible to remotely adjust for PM high voltage drifts, is characteristic of the Model 621 BLP and is described in detail in the 621 BLP technical data sheet. C to 60Deg.
Output falltimes slightly longer on wide output durations.
Other characteristics same as for Fast Negative Timing Output. For input burst rates greater than the DPR of the unit, the output is equal to the duration of the burst or the preset width, whichever is greater. Less than 9 nsec at minimum output width setting.