C7: RAD DETECTION & INTRUMENTS

area survey meters and personal dosimeters

Radiation monitoring instruments are distinguished into BLANK (or area monitors) & BLANK (or individual dosimeters)

Gas-filled detectors

this instrument are used to detect and measure radiation by sensing electrical signals created interacts with radiation inside the chamber

Solid state detectors

they measure radiation using a solid material usually silicon or germanium instead of gas

noble gas

Area survey meters uses BLANK in detectors

high charge-collection

Noble gases are generally used in these detectors.

Reason:

• The limit of the dose rate that can be monitored should be as high as possible: BLANK time is required!

non-electronegative gases

• Noble gases are BLANK in which negative ion by electron attachment is avoided.

pulse mode

BLANK detectors will saturate at high intensity radiation fields

ionization chambers

the number of primary ions of either sign collected is proportional to the energy deposited by the charged particle tracks in the detector volume

ionization chambers

Measure exposure rate

Build-up caps

IONIZATION CHAMBERS

BLANK are required to improve detection efficiency when measuring high-energy photon radiation, and they should be removed when measuring lower energy photons (10 - 100 keV) and beta particles.

Beta-gamma survey meters

IONIZATION CHAMBERS

BLANK have a thin end-window to register weakly penetrating radiation.

beta particles

IONIZATION CHAMBER

efficiency of ionization chamber detectors' response is near 100% for BLANK particles entering the detector

Proportional counters

are more sensitive than ionization chambers.

Proportional counters

are suitable for measurements in low intensity radiation fields.

Proportional counters

amount of charge collected from each interaction is proportional to the amount of energy deposited in the gas of the counter by the interaction.

GEIGER MULLER COUNTER

exhibit strong energy dependence at low photon energies and are not suitable for use in pulsed radiation fields.

GEIGER MULLER COUNTER

They are considered "indicators' of radiation, whereas ionization chambers are used for more precise measurements.

GEIGER MULLER COUNTER

Used to locate contaminations

GEIGER MULLER COUNTER

Because of negative charge amplification (9 to 10 orders of magnitude), BLANK survey meters are widely used at very low radiation.