# Nuclear decay information

I'm looking at some gamma spectroscopy calibration data, produced by a known source (semi known... the source was last calibrated 2006...)

My question is, looking at for example http://www.nucleide.org/DDEP_WG/Nuclides/Co-57_tables.pdf or http://ie.lbl.gov/toi/nuclide.asp?iZA=270057

In the table for the gamma from Co-57, the KeV and #photons values have a number in a bracket beside their main number. What is the meaning of those numbers?

My guess is it's to make sure we only have whole numbers of photons (As required).

• Just a small nitpick: brackets = [,] while parenthesis = (,). On topic, you might want to see this related post – Kyle Kanos Oct 9 '13 at 16:23

## 1 Answer

I think the numbers in brackets are error bars. For example, 706,42(2) means $706.42\pm .02$.