rad physics

Question 1

What part of the Atom is hardest to shield, why?

Answer 1

Neutrons - they have no charge

Question 2

Rest mass of a neutron

Answer 2

939.6 MeV

Question 3

Rest mass of a proton

Answer 3

939.6 MeV

Question 4

Rest mass of an electron

Answer 4

0.511 MeV

Question 5

Define AMU, and what is it normalized to?

Answer 5

Atomic Mass Unit, how atoms are weighed - normalized to C-12 (carbon-12)

Question 6

Mass Number symbol and define

Answer 6

(A) - # protons + # neutrons

Question 7

Atomic number symbol and define

Answer 7

(Z) - # protons

Question 8

What is an Isotope

Answer 8

Same # Protons (Z)

ex. C-12 and C-14

Question 9

What is an isotone

Answer 9

Same # Neutrons

ex. I-131 and Xe 132

Question 10

What is an isobar

Answer 10

same Mass Number (A)

ex. N-14 and C-14

Question 11

What is an isomer

Answer 11

same Z, A, and neutrons in a metastable state

Question 12

Stability of atom with > 20 protons

Answer 12

atom must have 1.5 to 1, neutrons to protons

neutrons > protons

Question 13

As Z number increases, binding energies ____?

Answer 13

Increase

Question 14

Where do gamma rays originate from?

Answer 14

the nucleus

Question 15

What do x-rays originate from?

Answer 15

Characteristic x-ray, and Bremsstrahlung x-ray

Question 16

Describe Characteristic X-Ray

Answer 16

1. orbital electron is ejected from atom
2. An outer orbital e’ “falls down” to fill the vacancy
3. E is radiated off in the form of electromagnetic radiation
4. E of x-ray is the difference between corresponding energy levels (subtract e’ shells to determine E of x-ray)

Question 17

Describe Bremsstrahlung X-Ray

Answer 17

• breaking radiation - can occur in any charged particle;
  1. e’ is accelerated and deflected from passing by the nucleus;
  2. e’ losses part of its E as electromagnetic radiation.

Question 18

Does Bremsstrahlung Increase or Decrease with Z of target?

Answer 18

Increasees

Question 19

Does Bremsstrahlung Increase or Decrease with e’ energy?

Answer 19

Increases

Question 20

What kind of spectrum in bremsstrahlung x-ray?

Answer 20

continuous spectrum

Question 21

Energy of scatted Neutron:

Answer 21

1/4 E of incoming neutron

Question 22

Energy of Neutron at LINAC Door:

Answer 22

100-200 kev

Question 23

On what side of the tx room door is borated poly for neutron shiedling?

Answer 23

LINAC side