1. Jun 30, 2011

### skullcracker

Is there any way to economically produce positrons using particle accelerators or any other method?

2. Jun 30, 2011

### daveb

Sure. Just irradiate some material ina particle accelerator that would become a positron emitter. Look up the process for creating F-18.

3. Jun 30, 2011

### Bill_K

The accelerators typically produce positrons by letting a beam of gamma rays strike a target. This creates electron-positron pairs, which are then separated and thermalized.

4. Jul 2, 2011

### skullcracker

ok so is it possible to form positrons by bombarding electrons on a material (tungsten or lead - because of its high atomic no.)? because electrons on colliding with other electrons basically produce x rays which are basically low energy gamma raysso these gamma rays can produce positron electron pairs

5. Jul 2, 2011

### Bill_K

Here's a report on a positron source that does it that way:

"Positrons are generated via pair creation when energetic electrons are stopped in a high-Z target, the electron-positron converter. These positrons are then moderated, i.e. slowed to thermal energies, via interaction with a suitable material such as tungsten, and a slow positron beam produced."

http://arxiv.org/abs/1102.1220

6. Jul 5, 2011

### skullcracker

what would be the efficiency of this method?

7. Jul 5, 2011

Staff Emeritus
It's in the paper that Bill_K pointed you to. It's even in the abstract. We can point you to papers, but you have to read them yourself.

8. Jul 5, 2011

### jambaugh

So positrons come in different grades?

9. Jul 5, 2011

Staff Emeritus
Prime, choice, select, standard, commercial, cutter and canner. (Mmmm...utility grade positrons)

And nuclei come in sizes small, medium, large, extra large, jumbo, giant, colossal and super colossal.

10. Jul 5, 2011

### jambaugh

So that's the REAL reason for the "non commuting c-numbers"! It's a promotional gimmick!

SUPER-SIZE ME!

11. Jul 7, 2011

### skullcracker

can any one express the efficiency in billi_k's link in terms of percentage?

12. Jul 7, 2011

Staff Emeritus
I'm sure they can. Where are you getting stuck in the calculation?

13. Jul 7, 2011

### skullcracker

ummm.. at the beginning the calculation was a bit complicated

14. Jul 7, 2011

Staff Emeritus
Show us how far you got, please.

15. Jul 8, 2011

### skullcracker

ok so the abstract said "For an electron beam energy of 5 MeV (10 MeV) and current 240 $\mu$A (30 $\mu$A) production of a slow positron beam of intensity 5 $\times$ 10$^{6}$ s$^{-1}$ is predicted. The simulation also calculates the average energy deposited in the converter per electron, allowing an estimate of the beam heating at a given electron energy and current. For low energy, high-current operation the maximum obtainable positron beam intensity will be limited by this beam heating."

however i could not get the SI unit so can anyone tell me the SI unit as well as the formula for converting this unit into percentage

16. Jul 18, 2011

### skullcracker

Can any one tell me how many grams of positrons would be generated in one hour?

17. Jul 18, 2011

### xts

Skullcracker, if you know how many positrons are created in one second, then you know how many seconds are in one hour, and you know what is positron mass (if you don't - wiki it), then you should be able to answer your question yourself. If not, ask your 3rd grade primary school ma'am for help.

18. Jul 23, 2011

### skullcracker

xts u dint get the question i wanted to know what 'production of a slow positron beam of intensity 5 $\times$ 10$^{6}$ s$^{-1}$ is predicted.'meant and i dont think third grade teachers would be teaching particle physics

19. Jul 23, 2011

Staff Emeritus
We're done here.