If one offset is supplied then the output energy of an event is given by:
PI_out = PI_in + off1
where PI_out is the output PI channel value, PI_IN is the input value and off1 is the supplied offset in the offset1 parameter.
If two offsets are supplied then the output energy of an event is given by:
PI_out = PI_in + off1 for PI_IN <= pi1
PI_out = PI_in + off1 + (off2-off1) * (PI_in-pi1)/(pi2-pi1) for PI_IN >pi1
where off2 is the second offset value in eV, pi1 is the PI channel in which the offset should be off1 and pi2 is the PI channel where the offset should be off2. For PI channels higher than pi2 the output value will be extrapolated. NB: This is prone to create large offsets at higher energies if two values are provided at energies with a small separation, e.g. 1.84 and 2.2 keV. If extrapolate is false then
PI_out = PI_in + off2 for PI_IN >pi2
If three offsets are supplied then the output energy of an event is given by:
PI_out = PI_in + off1 for PI_IN <= pi1
PI_out = PI_in + off1 + (off2-off1) * (PI_in-pi1)/(pi2-pi1) for pi1<PI_IN <=pi2
PI_out = PI_in + off2 + (off3-off2) * (PI_in-pi2)/(pi3-pi2) for PI_IN >pi2
If extrapolate is false then
PI_out = PI_in + off3 for PI_IN >pi3