This is the channel Rise Time Validation Window width register  0x1n70

The same value should be set for each channel involved in the coincidence. The width is expressed in sampling clock cycles - ie units of 10ns.
When 0, the RTD is disabled


Rise Time Validation Window (0x1n70 (channel n), 0x8070 (all channels, write only), 
R/W, )
‐
Bit Description
[9:0] Rise Time Validation Window width used by the rise time
     discriminator (RTD). The zero crossing of RC-CR2 signal must occur
    before the end of the Rise Time Validation Window. The width is
   expressed in sampling clock unit. When 0, the RTD is disabled.
[31:10] Reserved