Iterative unfolding of two‐dimensional data by Siska's method

According to Siska (1973), we ®nd the (n + 1)th approximation fn+1(x, y) of the `ideal' unbroadened intensity pro®le f(x, y) from the nth approximation fn. In the nth iteration step, fn(x, y) is corrected by an expression formed with the instrumental function g(x, y) and the broadened (measured) pro®le h(x, y). Several correction schemes are possible, in particular the difference method (DM) and the ratio method (RM). For n = 0, one sets f0(x, y) = h(x, y). The coordinates x, y are given by the detector coordinate system D. Then the RM may be written as