SpectrumBackground: Background estimation.

Description

This function calculates background spectrum from source spectrum and separates useful information (peaks) from useless information (background).

Usage

SpectrumBackground(y,iterations=100,decreasing=FALSE,order=c("2","4","6","8"),
        smoothing=FALSE,window=c("3","5","7","9","11","13","15"),compton=FALSE)

Arguments

the vector of source spectrum

iterations

maximal width of clipping window

decreasing

direction of change of clipping window. If TRUE the window is decreasing, otherwise the window is increasing.

order

order of clipping filter

smoothing

logical variable whether the smoothing operation in the estimation of background will be included

window

width of smoothing window

compton

logical variable whether the estimation of Compton edge (step-like feature at the peaks positions) will be included

Value

Numeric vector with background profile.

encoding

latin1

Details

Method is based on Sensitive Nonlinear Iterative Peak (SNIP) clipping algorithm.

New value in the channel $i$ is calculated (in the case of second-order clipping filter) with formula:

$$v_p(i)=min{v_{p-1}(i),(v_{p-1}(i+p)+v_{p-1}(i-p))/2}$$

References

C. G Ryan et al.: SNIP, a statistics-sensitive background treatment for the quantitative analysis of PIXE spectra in geoscience applications. NIM, B34 (1988), 396-402.

M. Morh�c, J. Kliman, V. Matoucek, M. Veselsk�, I. Turzo.: Background elimination methods for multidimensional gamma-ray spectra. NIM, A401 (1997) 113-132.

D. D. Burgess, R. J. Tervo: Background estimation for gamma-ray spectroscopy. NIM 214 (1983), 431-434.