Instruments Flashcards
What units do you calculate lasers in?
J/cm or W/cm
It’s energy or power per length
What is 1 roentgen in electrostatic units? ESU
1R = 1 esu/cm^3
What is Ohm’s law
E=IR
Remember ohm is resistance
Which type of detector is best for energy resolution?
Semiconductor
In ion chambers what is the relationship between current and volume?
They are proportional
What are the gas filled detector regions
Recombination, ionization, proportional, Geiger
Gas amplification factors in ionization region are equal to what? As opposed to other instruments.
1 for ionization chambers and >1 for the others.
What is the range of mica?
1.5 - 2 mg/cm^2
What is the disadvantage of long counting time for counting statistics?
Background may change
Power density of radio frequency is in which units?
mW/cm^2
Where does the dose to tissue come from for 6 MeV neutrons
Recoil protons because tissue is mostly hydrogen. And proton interaction is more probable than neutron interaction.
Bragg-Gray leaves primary electrons unchanged in velocity. How do we do this in the chamber?
Very thin volume so that only a small fraction of energy is deposited while traversing the cavity
What is the +/- at the 95% confidence level (2sigma)
1.96 x sqrt (bk rate/bk time + samp rate/samp time)
Nobel gases pose mostly internal or external hazard?
External
What is optimal time ratio in stats
Time ration = sqrt (rate/rate)
