f. Region of Limited Proportionality Objective B.4 (1) Region IV on the gas amplification curve. (2) In this region the voltage is increased above the proportional region and the output is no longer proportional to the input. (3) The strong field causes increased electron velocity, which results in excited states of higher energies capable of releasing more ion pairs. The positive ions remain near where they were originated and reduce the electric field to a point where further avalanche is impossible. (4) The small individual avalanches which occur start to interfere with each other. (5) is no direct proportionality between the incident radiation and the response. (6) This region cannot be used for radiation detection. g. Geiger-Mueller Region Objective B.4 (1) The Geiger-Mueller Region is Region V on the gas amplification curve. (2) The initial energy deposited by the Objective B.5.c radiation causes an avalanche, just as with the proportional counter; however, when the avalanche reaches the collecting anode, the energy density is so high that light photons are emitted from the electrode. (3) These, in turn, interact with the fill gas or the tube walls to produce photoelectrons. The photoelectrons start another avalanche at some other location on the electrode. This process repeats until the anode is completed enveloped by ions. (4) The voltage has been increased to a point where a single ion pair is enough to cause complete discharge. (5) In the GM region, any radiation event Objective B.5.c with sufficient energy to create the first ion pair can cause a large pulse. This explains the high sensitivity of detectors.
f. Region of Limited Proportionality (1) Region IV on the gas amplification curve. (2) In this region the voltage is increased above the proportional region and the output is no longer proportional to the input. Objective B.4 (3) The strong field causes increased electron velocity, which results in excited states of higher energies capable of releasing more ion pairs. The positive ions remain near where they were originated and reduce the electric field to a point where further avalanche is impossible. (4) The small individual avalanches which occur start to interfere with each other. (5) is no direct proportionality between the incident radiation and the response. (6) This region cannot be used for radiation detection. g. Geiger-Mueller Region (1) The Geiger-Mueller Region is Region V on the gas amplification curve. Objective B.4 (2) The initial energy deposited by the radiation causes an avalanche, just as with the proportional counter; however, when the avalanche reaches the collecting anode, the energy density is so high that light photons are emitted from the electrode. Objective B.5.c (3) These, in turn, interact with the fill gas or the tube walls to produce photoelectrons. The photoelectrons start another avalanche at some other location on the electrode. This process repeats until the anode is completed enveloped by ions. (4) The voltage has been increased to a point where a single ion pair is enough to cause complete discharge. (5) In the GM region, any radiation event with sufficient energy to create the first ion pair can cause a large pulse. This explains the high sensitivity of detectors. Objective B.5.c
RadMeasurementInstrumentLessonPlan.docx