Ageiger counter is used to measure: the mass of atoms radioactive intensity radioactive direction the speed of gamma rays

I believe Geiger counters are used to measure radioactive intensity. It can detect alpha particles, beta particles, and gamma rays.

RADIOACTIVE INTENSITY
EXAMPLE:
Geiger counter. A Geiger counter is an instrument used to determine the intensity of a radioactive sample. The major part of the Geiger counter is the Geiger tube. Each time radiation passes through the thin window, it causes the gas inside the tube to become charged, which completes an electrical circuit and records as a count on the Geiger counter. Some Geiger counters keep a running total of all counts and can be set to measure the counts per minute. A Geiger counter is most frequently used to check laboratory experiments and to prospect for radioactive ores.