INSTRUMENTATION Flashcards
(43 cards)
INSTRUMENTS ARE DESIGNED TO DETECT RADIATION OR TO MEASURE RADIATION, OR TO DO BOTH. THOSE DESIGNED FOR DETECTION USUALLY OPERATE IN THE _______ OR ____________ MODE AND ARE USED TO INDICATE THE PRESENCE OF RADIATION
Pulse, rate
THE PRESENCE OF RADIATION IS INDICATED BY A TICKING,
CHIRPING, OR BEEPING SOUND
pulse mode
THE INSTRUMENT RESPONE IS EXPRESSED IN
MILLIROENTGEN PER HOUR OR ROENTGEN PER HOUR
rate mode
USUALLY INSTRUMENTS ARE DESIGNED TO MEASURE THE INTENSITY OF RADIATION. THEY ACCUMULATE THE SIGNAL AND RESPOND WITH A TOTAL EXPOSURE. SUCH APPLICATION IS CALLED “DOSIMETRY”
integrate mode
are radiation measuring devices
dosimeters
3 types of gas-filled detectors:
- Ionization Chambers
- Proportional Counters
- Geiger-Muller Detectors
R in gas filled detectors is called as what
“Region of Recombination
It is the first stage when the voltage is very low, no electrons are attracted to the central cathode. The ion pairs produced in the chamber recombine
“Region of Recombination
I in gas-filled detectors is called as what?
“Ionization Region
- Most familiar type of ion chambers.
- This is used principally for area radiation surveys
PORTABLE ION CHAMBER SURVEY INSTRUMENT
the portable ion chamber survey instrument can measure a wide range of radiation intensities from __
10 µGy (1mR/hr) to several thousand Gy/hr (R/hr).
Used for accurate measurement of diagnostic x-ray beam
ION CHAMBER DOSIMETER
It is used in Nuclear Medicine to measure or assay accurately quantities of radioactive material
DOSE CALIBRATOR
unit used in the dose calibrator
MBq & mCi
P in gas-filled detectors is called as what?
Proportional Region
sensitive instruments that are used primarily as stationary laboratory instruments for the
assay of small quantities of radioactivity.
Proportional Counters
It is the ideal gas-filled chamber and this is the
region in which Geiger Counters operate
GM region
When did Geiger introduce the first successful detector of individual alpha particles
1908
What is CD in the gas-filled detectors?
Region of Continuous Discharge
It is the basis for the Gamma Camera in Nuclear Medicine , detector arrays of CT Imaging Systems, and Image Receptor of several types of Digital Imaging Systems
SCINTILLATION DETECTORS
Types of scintillation detectors
SOLID, LIQUID, and GAS
can be made to respond to radiation by
scintillation. This is rare because the detection efficiency is very low and the probability of interaction therefore is small.
noble gas
used frequently in the research laboratory to detect low-energy beta emissions from Carbon-14 (14C) and Tritium (3H). Nearly 100% detection efficiency for beta radiation
LIQUID SCINTILLATION
most widely used scintillation phosphors; have been incorporated into CT Imaging system detector arrays
INORGANIC CRYSTALS (Thallium-Activated Sodium Iodide (NaI:Tl) and Thallium-Activated
Cesium Iodide (CsI:Tl))
