Term
| What affects the number of ion pairs collected in a gas-filled detector |
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Definition
| Ion pair production, Type of radiation, Energy of the radiation, quantity of radiation, Detector size, type of detector gas, detector gas pressure, Voltage potential across the electrodes, Effect of voltage potential on the detector process |
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Term
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Definition
| Factors such as the size and shape of the detector, the pressure and composition of the gas, the size of the voltage potential across the electrodes, the material of construction, the type of radiation, the quantity of radiation, and the energy of the radiation can all affect the response of the dectector |
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Term
| Voltage potential across the electrodes |
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Definition
| This process if known as secondary ionization. the secondary ion pairs are accelerated towards the electrode and collected, resulting in a stronger pulse than would have been created by the ions from primary ionization |
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Term
ON THE GRAPH FOR "GAS FILLED DETECTORS"
RECOMBINATION |
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Definition
| not enough voltage potential, ion pairs just recombined |
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Term
ON THE GRAPH FOR "GAS FILLED DETECTORS"
IONIZATION CHAMBER |
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Definition
| Good Dose rate, 1 to 1 saturation curve |
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Term
ON THE GRAPH FOR "GAS FILLED DETECTORS"
PROPORTIONAL |
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Definition
| Start to get gas amplification,every primary ion creates and proportional or constant number of ion pairs |
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Term
ON THE GRAPH FOR "GAS FILLED DETECTORS"
LIMITED PROPORTIONAL |
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Definition
| High voltage is not constant that why we can't use that region |
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Term
ON THE GRAPH FOR "GAS FILLED DETECTORS"
GEIGER-MUELLER |
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Definition
| Gas amplification, All of it ionizing and its good for low levels, Dead, Resolving, Recovery time. Avalanche |
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Term
ON THE GRAPH FOR "GAS FILLED DETECTORS"
CONTINUOUS DISCHARGE |
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Definition
| High energy voltage potential, creates ion pairs on its own |
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Term
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Definition
As the voltage to the detector is increased, a point is reached at which essentially all of the ions are collected before they can recombine. No secondary ionization or gas amplifications occurs. At this point, the output current of the detector will be at a Maximum for a given radiation intensity and will be proportional to that incident radiation intensity. Also, the output current will be relatively independent of small fluctuations in a the power supply
-- The output of a gas-filled detector when 100% of the primary ion pairs are collected is called saturation current |
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Term
| Advantages For Ion Chamber Detectors |
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Definition
| Battery operated, no gas amplicication |
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Term
| Disadvantages for Ion Chamber Detectors |
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Definition
| Output currents are small, Effected by humidity |
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Term
| Typical Applications for Ion Chamber Detectors |
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Definition
| Portable survey instruments used for measuring dose rates are typically ion chamber instruments. Ion chambers may also be used in several installed monitor systems such as(ARMS)- Area Radiation monitor systems and the various (PRMs) Process Radiation Monitors |
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Term
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Definition
| have a large electrical pulse, As the voltage on the detector is increased beyond the ion chamber region, the ions created by primary ionization are accelerated by the electric field towards the electrode. |
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Term
| What is gas amplification |
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Definition
| where there is constant voltage, the ratio between the primary ionizations and the total number of ions produced is a constant. |
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Term
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Definition
| The total amount of time from a measurable detector respone before another pulse can be measured. After the ion avalanche occurs, it takes a finite time for the ions to be collects and for the pulse to be generated |
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Term
| Advantages to a proportional counter |
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Definition
can be used to discriminate between the different types of radiation,
signal is larger and therefore a ingle ionizing even can be recorded,
useful for dose rates since the output signal is proportional to the energy deposited by ionization and therefore proportional to the dose rate |
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