Physics reference
Physics calculators
Free calculators for radiation, particles and detectors. Each one runs on public reference data, shows its method and gives a result you can cite. The examples below are computed by the same code.
8 instruments, each with a worked example
Energy-loss calculator
Particle, material and thickness in; mean loss, most probable value and straggling out.
A 100 MeV proton in water
Stopping power 7.29 MeV cm²/g, CSDA range 7.71 g/cm²
Radioactive decay calculator
Calculate decay and daughter activity.
1 GBq of Mo-99 at time zero
Tc-99m activity peaks after 22.8 h
Materials library
Search and compare density, excitation energy and radiation properties for 17 materials.
Silicon
Density 2.329 g/cm³, radiation length 9.37 cm
Accelerator power and synchrotron loss calculator
Calculate dipole radiation for one beam in an isomagnetic ring.
LEP2: 104.5 GeV electrons on a 3,096 m bending radius
Energy lost per turn 3.41 GeV, critical photon energy 818 keV
Gamma dose rate calculator
Calculate air kerma from an isotropic point gamma source: K̇ = Γδ A / d², with optional shielding.
1 GBq of Co-60 at 1 m, no shielding
Air kerma rate 0.306 mGy/h
Radiation units converter
Convert activity, dose, exposure and energy units.
One curie in becquerels
1 Ci = 37 GBq
Photon attenuation calculator
Half-value layer and transmission for gamma and X-ray beams through common materials.
662 keV gammas (Cs-137) through 10 mm of lead
Transmission 28.6 %, half-value layer 5.54 mm
Detector signal calculator
Electron-hole pairs and fully collected charge in silicon and germanium.
A 3 GeV/c muon through 300 µm of silicon
Most probable signal 22,568 electron-hole pairs (3.62 fC)