STE #1

Question 1

Which of the following is a required pre-operational check?

Answer 1

1. Physical condition of the instrument.
   2 . Calibration due date
   And 3. Battery check

Question 2

Scintillation detector operate in the G-M region of the gas amplification curve? True or False?

Answer 2

False

Question 3

Zinc-Sulfide detectors are good for detecting what type of radiation?

Answer 3

Alpha

Question 4

Sodium Iodine scintillation detector is used for detecting gamma radiation. True or False?

Answer 4

True

Question 5

You are using an RO-2 survey meter to measure the activity on a smear taken from the refueling canal. The closed window reading is 4 mR/hr and the open window reading is 22.4 mR/hr. Given a beta correction factor of 4.0 what is the dose rate in mrad/hr?

Answer 5

73.6

Question 6

How does N-16 gamma’s affect G-M type detectors?

Answer 6

Can cause them to over respond

Question 7

You took an air sample and count it for 10 minutes and it had a reading of 22000 counts. The 60 minute background count on the instrument was 1400 counts.
What is sample net counts per minute (round your answer)?

Answer 7

2177

Question 8

Entering a high gamma dose rate field with an extendable G-M detector on low range scale could result in which of the following…

Answer 8

Instrument could become saturated which would result in a low reading

Question 9

Ionizing radiation interacts with phosphor crystalline material to produce light is called scintillation. True or False?

Answer 9

True

Question 10

In a noble gas atmosphere a vented ion chamber could…

Answer 10

Become saturate giving a false reading

Question 11

When alpha frisking how close should the detector be to the surface of the object

Answer 11

¼ inch

Question 12

In a G-M detector, the amount of time from the initial pulse until the detector can produce another pulse is called

Answer 12

Dead time

Question 13

In a G-M detector, resolving time is the time from the initial measured pulse until another pulse can be measured. True or False?

Answer 13

True

Question 14

In a G-M detector, saturation is when a detector reads high in a high field of radiation. True or False?

Answer 14

False

Question 15

Neutron detector use some type of moderator to slow down the fast neutrons so they can measured. The moderator most often used is

Answer 15

Sodium

Question 16

A contact dose rate taken on a very small point source by a G-M detector, will it be __________ when compared to same dose rate taken by an Ion Chamber?

Answer 16

Higher

Question 17

Which of the following is not true with a contamination survey instrument

Answer 17

Normally detects neutron activity

Question 18

A frisker has the ability to detect both fixed and loose contamination at the same time. True or False?

Answer 18

True

Question 19

Scintillation detectors are used to detect very low levels of radioactivity. True or False?

Answer 19

True

Question 20

What would the contact beta dose rate be given the following information?
Open window reading 140
Closed window reading 20
Beta Correction Factor is 4

Answer 20

480 mrad/hr

Question 21

In which region of the Six Region Curve is enough voltage applied where all of the ions produced and be detected.

Answer 21

Ionization chamber

Question 22

The instrument that is used to determine stay times and assess dose rate is typically which of the following

Answer 22

Ion Chamber

Question 23

In a proportional counter, due to the amount of voltage being applied, many electrons reach the reach the anode for each primary ion pair produced in the
gas. These secondary ion pairs creates additional secondary ion pairs as it gets closer to the anode. This is called____________.

Answer 23

Townsend Avalanche

Question 24

In an ion detector, radiation interacts with an atom in the fill gas resulting in the development of an ion pair. The ions will be attracted to the positively charged (+) anode or the negatively charged (-) cathode where they are detected as current flow. The amount of dose is related to the amount of current detected. True or False?

Answer 24

True

Question 25

Due to the large gas amplification in the G-M region, it is a beneficial detector to use for detecting low levels of radiation. True or False?

Answer 25

True

Question 26

Which of the following factors should be considered when selecting an instrument to perform a radiation survey?

Answer 26

1. Expected radiation type to be measured (e.g beta, gamma, neutron).
2. Expected dose rates to be encountered
   and 3. Environmental conditions

Question 27

Which of the following instruments is normally used to measure contamination and reading our in counts-per-minute (CPM)?

Answer 27

Frisker

Question 28

Which instrument below typically has a removable shield which can be slide opening allowing the instrument to detect beta radiation?

Answer 28

Ion chamber

Question 29

Prior to use of a radiation survey instrument is should pass a “source check”. What is the criteria for passing a source check?

Answer 29

+/- 20%

Question 30

The effects that gravity can have on an instrument to measure radiation accurately is called_______________.

Answer 30

Geotropism