Patent ID: 8039787

Claim:
A method of adjusting a response of an energy measuring filter of a pulse processor based on a slope of a preamplifier signal having a plurality of step edges each corresponding to a respective photon, comprising: receiving a digital version of said preamplifier signal comprising a plurality of successive digital samples each having a digital value, said preamplifier signal having a portion defined by a first one of said step edges and a second one of said step edges immediately following said first one of said step edges; determining a first integral of the digital values of the digital samples associated with a first half of said portion; determining a second integral of the digital values of the digital samples associated with a second half of said portion following said first half; determining an integral difference equal to a difference between said second integral and said first integral; determining a slope value by normalizing said integral difference by a length of said portion; and using said slope value to correct the response of said energy measuring filter.