Unit 9 Quiz

Question 1

At what temperature does an alloy of niobium and titanium become superconductive?

Answer 1

4 Kelvin

Question 2

This is a percentage of time during the TR period that the gradient is permitted to be at maximum amplitude, or “work”, during an imaging sequence

Answer 2

Duty cycle

Question 3

shielding accomplished by surrounding the magnet with steel plates

Answer 3

Passive shielding

Question 4

substance with a small but positive magnetic susceptibility

Answer 4

Paramagnetism

Question 5

uses metal discs/plates at installation to adjust for large changes in field homogeneity

Answer 5

Passive shimming

Question 6

solenoid electromagnet that uses super-cooled coils of wire so that there is no inherent resistance in the system through which the current flows & therefore the magnetism is generated without a driving voltage

Answer 6

Superconductive electromagnets

Question 7

magnets that retain their magnetism

Answer 7

Permanent magnets

Question 8

supplies power to the gradient coils

Answer 8

Gradient amplifier

Question 9

additional solenoid magnets to adjust field homogeneity

Answer 9

Active shimming

Question 10

process whereby the evenness of the magnetic field is optimized

Answer 10

Shimming

Question 11

Uses additional superconducting coils located at each end of the main magnet inside the cryostat to shield the system

Answer 11

Active shielding