Physic Homework Quizzes Flashcards
which of the following is indiretly ionizing radiations? A. protons B. neutrons C. positron D. electrons
B. neutrons
the fraction of photons absorbed or scattered per unit thickness of a material is called the
linear attenuation coefficient
Which type of photon interaction is proportional to the cube of the atomic number, Z^3?
photoelectric
what is annihalation radiation?
a positron interacts with a free negatron creating two photons
Which is true about Compton scatter? A. the photon is absorbed by the atom B. the scattering photon gains energy C. a characteristic x-ray is released D. the incident photon energy is much greater than the binding energy of the electron
D. the incident photon energy is much greater than the binding energy of the electron
Which is true about Pair Production?
A. the photon energy must be greater than 1.02 MeV
B. the phton interacts with the electromagnetic field of the nucleus
C. all the phton energy is given to the nucleus
D. all the answers are correct
D. all the answers are correct
which of the following is a possible product after photoelctron interactions?
A. auger electron
B. scattered phton
C. characteristic x-ray
D. characterisitic x-ray and auger electron only
D. characterisitic x-ray and auger electron only
which of the following would produe a Bragg Peak? A. 35 MeV electron beam B. 200 MeV proton beam C. 25 MV photon beam D. cobalt-60 beam
B. 200 MeV proton beam
which of the following is an example of ionization? A. alpha decay B. beta decay C. gain of an orbital electron D. nucleus absorbing an electron E. all of the answers are correct
C. gain of an orbital electron
which ionization chamber has an adjustable electrode seperation? A. free air ionization chamber B. parallel plate chamber C. thimble chamber D. farmer chamber E. extrapolation chamber
E. extrapolation chamber
the thimble wall of a thimble ionization type chmaber is designed to
be a solid air shell
in an ionization chamber the cumber of ions collected divided by the number of ions created is called the A. collection efficiency B. polarity collection ratio C. ionization potential D. total charge collection
A. collection efficiency
in the exposure measurement equation, NX is used to represent
A. the chamber reading
B. the stem leakage correction
C. the chamber calibration factor from NIST
D. the number of x-rays measured
C. the chamber calibration factor from NIST
what is meant by the stem effect?
A. voltage created by the insulator in the stem
B. extraneous collection of charges in the stem
C. current lost in the stem of the chamber
D. additional volume created by the stem being in the radiation bea
B. extraneous collection of charges in the stem
which of the following is an advantage of a thimble chamber ove a free air ionization chamber? A. measures dose directly B. smaller size C. dose not require high voltage D. all of the above
B. smaller size
which of the following corrections is made to an ionziation chamber to account for environmental conditions during the measurement? A. saturation B. polarity C. temperature and pressure D.collection efficiency
C. temperature and pressure
what is the temperature and pressure correction for the following?
T= 22.4 degrees celsius
P= 75.88 cm Hg
1.003
what is the temperature and pressure correction for the following?
T= 23.1 degrees celsius
P= 757.5 mm Hg
1.007
a program to control or maintain a standard of quality is called
Quality assurance
which of the following organizations prescribes mandatory requirements for a QA program in radaition therapy?
nuclear regulatory commission
the two important parameters for monitoring a QA progam are objectivity and ________
unambiguous measurements
which of the following is a component of the structure of a QA program? A. staffing B. facility features C. equipment capabilities D. all of the above
D. all of the above
which of the following is a compnent of the equipment component of a QA program? A. acceptance testing B. periodic quality control C. performance specifications D. commissioning E. all of the above
E. all of the above
the collection of the data necessary for calculating the dose delivery to patients is called
commissioning
the daily performance specification for the ODI of the linear accelerator is
2 mm
who is responsible for QA activities in radiation therapy? A. radiationi therapist B. nurses C. physicists D. physicians E. all the above
E. all the above
which of the following is an expected outcome for a QA program? A. improving outcomes B. meeting stated outcomes C. identifying variations D. all of the above
D. all of the above
quality control measurements to verify compliance with the vendor’s specifications is called
acceptance testing
which region of the current versus voltage curve is most accurate for determining exposure or dose levels?
ionization region
at higher voltages an ionization interaction can excite all the gas in the chamber at once. This region is called…..
geiger muller region
before using a survery meter it is important to first
A. check the condition of the battery
B. verify the chamber responds to a source of radiation
C. check the chamber has recently been calibrated
D. all of the above
D. all of the above
the type of survery meter which has a solid etector made from a crystalline material is called a
scintillation detector
the small signal from a scintillation detector must be amplified in a
photomultipler tube
the survey meter most suitable for measuring very low levels of radiaiton leakage around the linear accelerator room is a
geiger mueller chamber
a REM meter uses BF3 probe centered in polyethlene ball to measure neutrons. what is the purpose of the polyethylene ball?
to moderate the neutrons
the ionization chamber collection efficiency is defined as
the number of charges measured divided by the number of charges created
when the plotted graph of the current created relative to increasing voltage in the chamber first becomes approximately horizontal, this is called
the ionization chamber region
the typical voltage to operate the ionziation chamber region for clinical use is approximately
300 volts
whihc fo the following organzaitions has regulatory responsibilities for the use of radioactive materials in the united states?
nuclear regulatory commission
what is the function of the secondary barrier in radiation protection design?
attenuate the scatter and leakage radiation
in the shielding equation, what does the letter P represent?
max permissible dose
in radiation shielding design what is the max permissible dose typically used for a radiation worker ina controlled area?
0.1 mSv/week
what is the definition of the occupatncy factor in radiation protection design?
the fraction of time the area is occupied by an individual
at approximately what energy do photons begin to interact with nucli to release neutrons?
10 MV
which of the following sing s would be required for radiation lelvel which may exceed 50 Sv/hr at 30 cm from a radiation shielding wall?
radiation area
whcih of the following is not a primary source for determining the hazardous effects of radiation?
A. radiation workers involved in accidents during the 1940s
B. survivors of atomic bombs
C. studies of populations near high natural radiation areas
D. military personnel inovlved in radiation accidents
C. studies of populations near high natural radiation areas
which of the following is a function of the national council on radiation protection and measurement?
disseminate information and recommendations on radiation protection
which ALARA guideline requires the RSO to investigate the radiation exposure of an employee?
Level II
