Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
7 Cards in this Set
- Front
- Back
|
importance of AGUGUST 1 1946?
|
congress passed the ATOMIC ENERGY ACT, AFTER WWII creating the ATOMIC ENERGY COMMISSION. which was begining of modern day nuc med as a ways of getting a cheap supply of medical radioisotopes in the OAK RIDGE REACTOR in peacetime
|
|
|
who is HAL ANGER
|
granddaddy of the GAMMA CAMERA and made the WELL COUNTER used in labs today for testing radioactive materials
|
|
|
what kinds of interactions can protons have with matter?
|
1) photelectric
2) compton effect 3) pair production |
|
|
detector: scintillation material (crystal)
|
made of NaI(Tl)soaium iodide and thallium that converts photon energy to a light. crystals are sealed on 3 sides to keep moisture & light out. 4th side is seald w/transparent material so light impulses cna be deteced by PMT. light flashes are proportional to energy of gamma ray
|
|
|
purpose of the PMT
PHOTO MULTIPLIER TUBE |
lite sensitve coupled to crystal via lite-pipes or silicone like material. convert light from crystal to electric energy and amplifiy the resultant pulses of electricity. made of photocathode, focus grid, dynode series and anodes, runs on hi-volt power supply.
|
|
|
what happens in PMT
|
photocathode gets scintillaion from crystal:. electron release, electron release is proportional to light intensity from crystal. hi-volt draws electrons between dynodes and cathodes from first 10-14 dynodes. when dynode struck, F causes a 2nd emission. w/each strike more electrons released. # of E released @ cathode is magified by millions called voltage pulse. # of E at last dynode is proportionall to enrgy of gamma ray
|
|
|
importance of hi-volt supply
|
changes in line volt or temp will cause drift/instabilities.
|
