Term
|
Definition
|
|
Term
| What Causes the single very large pulse that comes from a GM Detector? |
|
Definition
| An Avalanche of secondary and tertiary ionization formed from smaller avalanches that interfere with each other which is very unpredictable. |
|
|
Term
| GM Amplification Ranges upwards of.... |
|
Definition
|
|
Term
| Pulse size of a GM detector is independent of? |
|
Definition
| Radiation energy or specific ionization |
|
|
Term
| What is a disadvantage of a GM detector? |
|
Definition
| GM tubes cannot discriminate against different radiation types or energies. |
|
|
Term
| Which is more sensitive a GM detector or an ion chamber or a proportional counter and why? |
|
Definition
| The GM detector because any radiation event with sufficient energy to create the first ion pair can create a large pulse. |
|
|
Term
| GM detectors are not only a counting gas but they also have a quenching gas in the detector, what is the purpose of the quenching gas? |
|
Definition
| It is to stop the avalanches cause by positive ions which is undesirable. |
|
|
Term
|
Definition
| The time from the initial measured pulse until another pulse can be measured by the electronics. |
|
|
Term
|
Definition
| The time from the initial pulse until another pulse can be produced by the detector. |
|
|
Term
|
Definition
| The time from the initial full size pulse to the next full size pulse produced by the detector. It also encompasses dead time. |
|
|
Term
| In the Gm detector process this happens first? |
|
Definition
| An incident radiation causes ionization resulting in an ion pair. |
|
|
Term
| In the Gm detector process this happens second? |
|
Definition
| The Ion pairs accelerate toward the center electrode. |
|
|
Term
| In the Gm detector process this happens thirdly? |
|
Definition
| The primary ion pairs cause secondary ionization. |
|
|
Term
| In the Gm detector process this happens fourthly? |
|
Definition
| The secondary ion pairs cause additional ionization continuing as an "Avalanche" |
|
|
Term
| In the Gm detector process this happens at the end? |
|
Definition
| The negative ions are collected by the center electrode and form a pulse. |
|
|
Term
| What is the General idea of Dead Time? |
|
Definition
| is the time it takes for the postive ion cloud to drift towards the shell of the detector and neutralize to where a pulse may happen. |
|
|
Term
| What are the advantages of a GM detector? |
|
Definition
| Independent of pressure and temperature affects, Require less highly regulated power supplies, and they are more sensitive to low energy and low intensity radiations. |
|
|
Term
| What are the dis advantages of a GM detector? |
|
Definition
| The response is not related to the energy deposited, they have a large recovery time, and they cannot discriminate between different types of radiation. |
|
|
Term
| What are the two main Physical discrimination factors? |
|
Definition
| Shielding and the detector gas fill. |
|
|
Term
| What is an example of a shielding physical discrimination? |
|
Definition
| The hot dog Ion champer detector with its turning shield to block out alpha particles |
|
|
Term
| Knowing that each type of radiation has a specific ionization factor in a particular gas we can create what type of Physical discrimination? |
|
Definition
|
|
Term
| Analyzing pulse heights to discriminate the type of radiation is an example of? |
|
Definition
| Electronic discrimination |
|
|
Term
| How does electronic discrimination work? |
|
Definition
| It sets a discrimination level which makes it so the detector will only record pulses above the discrimination level that is set. |
|
|
