✓ must provide enough resistance to e- flow so that heat produced will cause
thermionic emission (occurs @ 2200 degrees)
filament material and why
✓ tungsten because it has high melting point and difficult to vaporize. Can also be
rhenium and molybdenum.
Explain thermionic emission
✓ occurs when filament heated at 2200 degrees, causes electrons to be released from
filament. when high voltage released at exposure, e- are driven toward anode
what causes tube failure
✓ - tube arcing (vaporized tungsten collection on envelop)
✓ - filament breakage (often due to boost and hold)
what is the focusing cup made of
✓ nickel or molybdenum
does a focusing cup have a high/low, negative/postivite potential
✓ low negative
what is the mA for space charge effect
Examify | Smart Grades | Latest update
✓ portion of anode that electron stream contacts, point source of xray photons
✓ - target, focus, focal point, focal spot, focal track
is a large or small focal spot better for life of anode
✓ large focal spot is better for life of anode
what size focal spot is required for image quality
✓ small focal spot
What is the line focus principle?
✓ by using a small anode angle you can change the size of the effective focal spot (make
it smaller for better resolution) without increasing the heat and damaging the anode.
Examify | Smart Grades | Latest update
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Examify. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $13.49. You're not tied to anything after your purchase.