Decay series, gamma spectra, nuclides data, etc.
NaI(Tl) gamma ray spectrum catalogue
Gamma ray spectrum catalog of isotope
Mass attenuation coefficients of elements
Mass attenuation coefficients of compounds/mixtures
Laboratory manuals
Experimental γ-Ray Spectroscopyand Investigations of Environmental Radioactivity
Gamma spectrometry software
Theremino - Still developed and improved with occasional updates.
PRA - Still developed and improved with occasional updates.
BeqMoni - The software is not updated anymore. Tutorials can be found here and here.
Fitzpeaks - Gamma spectrometry software for analysis of measured spectra
OpenGama - Gamma spectrometry software for analysis of measured spectra
Forums
Gammaspectacular - Discussions on gamma spectrometry related topics
Fusor.net - Some topics on gamma spectrometry and the radiation detection
Radiation safety and monitoring
MonRas - Radiation moinitoring map of the Czech Republic
uRADMonitor - Environment monitoring global network
National Radiation Protection Institute - Czech Republic institution
State Office for Nuclear Safety - Czech Republic institution
Gamma spectrometry systems for schools and hobbyists
Theremino - Hobby related open source gamma spectrometry system
Gammaspectacular - Hobby related commercial gamma spectrometry systems
RH - electronics - Hobby related commercial gamma spectrometry systems and geiger counters