Two detectors are available for primary measurements by the coincidence method. Above is shown the proportional counter (pill-box type) working at atmospheric pressure, and on the right, the proportional counter working at pressures up to 2 MPa. Both are gas-flow counters. The , and - coincidence counts are either transferred from scalers to a computer through an RS-232 connection or directly obtained using scalers on a PC-card driven under LabVIEW.

Proportional counters can also be used to make measurements of alpha emitters such as ²³⁸Pu.