Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Rad Protection
Chap 4
| Question | Answer |
|---|---|
| Does an ionization chamber survey meter have a wide or narrow range? What is the range? | Wide ; 0-1000 mR/hr |
| Gas-filled radiation detectors are used? | As and integration type of ionization chamber |
| What is a crystal that is used in TLD? | lithium floride |
| What kind of dector can be used to identify an unknown gamma emitter? | Multichannel crystal spectrometer |
| What normally operates in the rate mode? | an ion chamber |
| operation in which region of a gas-filled chamber results in the lowest output? | recombination |
| The resolving time of a radiation dector is the time required: | to detect sequential ionizations |
| THe amt of light emitted by a scintillation phosphor is proportional to what feature of photon energy? | absorbed |
| In thermoluminescence dosimetry, a plot of output intensity versus temp is called a: | glow curve |
| When an accurate measurement of radiation exposure is made in the air, what should be used? | ionization chamber |
| What is a characteristic of a Geiger-Mueller counter? | measures counts per min |
| What is a characteristic of scintillation dectors that are used as survey instruments? | can detect individual photons |
| Sodium iodide is a good gammay ray detector bc: | it has a high Z |
| Compared with Geiger-Mueller counters, scintillation counters: | are more sensitive to gamma rays |
| The signal detector of a gas-filled radiation detector is the: | central electrode |
| -measuring and or detecting radiation | dosimetry |
| -devices that measure radiation | dosimeters |
| When are personnel monitoring devices required? | When the personnel might recieve 10% or more of the annual dose limit |
| What is the annual dose limit? | 50 mSv ( 5 rem) |
| Which area of the body is likely to receive 10-20 times more radiation that the waist? | head and neck |
| What are 5 common characteristics of personal monitoring instruments? | lightweight & easy to carry durable able to detect and record small and large exposure in reliable manner; mechanical shock shouldn't affect performance; low in cost |
| -recommended to wear as a second monitor device when the hands are required to be near the primary beam | extermity dosimeter |
| What are the 3 parts of the film badge? | durable & lightweight; assortment of metal filters; film packet |
| What should be made of a low atomic number to filter out the low energy x-ray and gamma ray? | plastic film cover |
| -allows the measurement of the approximate energy reaching the dosimeter | filters |
| What has a sensity range from 0.1 mSv (10 mRem) to 5000 mSv (500 rem) | film badge |
| What is the instrument used to measure the optical density on the film? | densitometer |
| What are the advandages of a film badge? | inexpensive; east to handle; reasonably accurate; provides a permanent record |
| What are the disadvantages of a film badge? | can't be used longer than a month; sensitive to heat and humidity; accuracy is limited to give or take 20% |
| - provides the best features of traditional film and TLD while elimination some of the disadvantages. | OSL |
| What is the chemical compound within an OSL? | aluminum oxide |
| How is a OSL read? | scannde by a laser light; will emit light porportional to the amt of radiation it receives; light is then measured and acheived |
| What is the readout that an OSL produces? | glow curve |
| What is the range of an OSL badge? | 5 keV - 40 Mev |
| What is the maximum sensitivity of an OSL? | 1000 Rem |
| How long can an OSL badge be worn? What is reccommended? | 1 yr ; 2 mths |
| What time of dosimeter looks like a fountain pen? | pocket dosimeters |
| -works on ionization chambers and the gold leaf electroscope | pocket dosimeters |
| What is the range for pocket dosimeters? | 0-200 mR |
| What are the advantages of a pocket dosimeter? | immediate reading, easy to carry, reasonably accurate and sensitive ( but not as accurate as film badge, OSL or TDL ) |
| What are the disadvantages of a pocket dosimeter? | expensive, very sensitive to mechanical shock, no permanent record |
| -uses crystals that can undergo changes in their physcial properties | TLD |
| What is one crystal that is used in TLD? | lithium floride |
| What are the advantages of the TLD? | crystals interact with radiation as tissue would; can measure radiation as low as 5 mR; not affected by heat or humidity; can be worn up to 3 mths; more sensitive and accurate than film badge |
| What are the disadvantages to TLD? | inital high cost; readouts must be carefully obtained or results will be lost |
| What are the two types of field survey instruments? | gas filled and scintillation |
| What type of dector are: ionization chambers, proportional counters, geiger-muller counters? | gas-filled detectors |
| High sensitivity means? | that an instrument can detect very low radiation intensities |
| The larger the chamber... | the more gas molecules, the more sensitive |
| Accuracy is controlled by? | the overall design |
| What are the 7 common requirements an area monitoring device should possess? | Lightweight; rugged; reliability & accuracy; simplicity; tissue equivalence; economic |
| -is used for contamination control in nuclear medicine and portable work | geiger-muller counter |
| - has an audio response | geiger-muller counter |
| What is the range of the Geiger-muller counter? | less than 100 mR/ hr |
| -very popular in clinical radiology | cutie pie |
| what is the range of a cutie pie? | 1 mR - 1R |
| - used to calibrate x-ray machines & is accurate withing + or - 20% | cutie pie |
| -have no realistic use in radiology & used in stationary labortory assay small quantities of radioactivity | proportional counters |
| more accuracy = | less sensitivity |
| How do ionization chambers work? | radiation passes through air & ionizes atoms; negative ions are measured & reading is est |
| - unusable region | region of recombination- first stage, very low voltage |
| - highest accuracy region, second stage, region the ion chamber operate in | ion chamber region |
| -more senstitive region but less accurate, third region, instruments using this range are in a lab setting | proportional region |
| -least accurate but most sensitive; avalanche of electrons are produced from a primary ion;quenching agent ; fourth region | geiger-muller region |
| -not useful, voltage too high; fifth region | region og continuous discharge |
| Out of the 5 regions, which are useful? | ion chamber, proportional, geiger-muller |
| -these devices are used in nuclear medicine and ct | scintillation dectors |
| What can scintillation phosphors be? | gases, liquids, solids |
Created by:
erikasmith28
Popular Radiology sets