SearchHighRes() peak detection function - Consequence of sigma and number of decollation interration

Hi everyone,

I’m new to ROOT and this forum so please be indulgent.

I’ve been using ROOT for 3 days to analyse some particle physics spectrums. I’m having troubles with the function SearchHighRes() that I chose to use after seeing a few ROOT tutorials.

Int_t TSpectrum::SearchHighRes	(	Double_t * 	source,
Double_t * 	destVector,
Int_t 	ssize,
Double_t 	sigma,
Double_t 	threshold,
bool 	backgroundRemove,
Int_t 	deconIterations,
bool 	markov,
Int_t 	averWindow 

It seems to be an efficient and effective way to retrieve the position of a peak in a spectrum with quite a lot of background noise.

The issue is that, even with the help of the online documentation, I’m not quite sure to understand all the parameters of the function and especially how to choose them.

For instance, it is needed to provide a number of iterations for deconvolution but I have no idea how to chose it nor it is explained in the tutorials. Depending on this int, peaks position are sometimes good on a part of a spectrum and completely shifted on another. Amplitudes of the background-less spectrum varies a lot as well.

The other parameter with which I’m having an issue is sigma. I tried different values as well, but I’m not quite sure about the results.

Is anyone familiar with the function willing to help?

Thanks a lot.
ROOT Version: 6.12/06
Platform: macOS 10.3.4


regarding the sigma: check out this post, it says:

…The value in the center of the peak value[i] minus the average value in two symmetrically positioned channels (channels i-3*sigma, i+3*sigma) must be greater than threshold. Otherwise the peak is ignored…

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Thanks for the reply. I’ll have a look.

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