I figured that the protons would have to be accelerated in several stages, but I am amazed that you can get them up to 12 Mev in two stages. That means you have to have a potential of 6 Mev between the anode and the cathode, how far apart do these need to be?
Steven
Proton Activation of Fe55
-
Steven Sesselmann
- Posts: 2128
- Joined: Wed Aug 10, 2005 9:50 pm
- Real name: Steven Sesselmann
- Location: Sydney - Australia
- Contact:
Re: Proton Activation of Fe55
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG
-
Carl Willis
- Posts: 2841
- Joined: Thu Jul 26, 2001 7:33 pm
- Real name: Carl Willis
- Location: Albuquerque, New Mexico, USA
- Contact:
Re: Proton Activation of Fe55
Steven,
The entirety of the pelletron machine is probably immersed in high-pressure SF6, since air would be unable to stand off 6 MV.
Among accelerator installations, this is nothing groundbreaking, and it's been possible to buy powerful van de Graaffs off-the-shelf for decades (http://www.pelletron.com/pellet.htm) with terminal voltages in excess of 25 MV. All you need in the US is a state radiation license and a couple million bucks. For all the folks out there with private pilots' licenses and twin-engine planes, I'm actually surprised we don't have a couple guys with rad licenses and van de Graaffs.
-Carl
The entirety of the pelletron machine is probably immersed in high-pressure SF6, since air would be unable to stand off 6 MV.
Among accelerator installations, this is nothing groundbreaking, and it's been possible to buy powerful van de Graaffs off-the-shelf for decades (http://www.pelletron.com/pellet.htm) with terminal voltages in excess of 25 MV. All you need in the US is a state radiation license and a couple million bucks. For all the folks out there with private pilots' licenses and twin-engine planes, I'm actually surprised we don't have a couple guys with rad licenses and van de Graaffs.
-Carl
-
John Futter
- Posts: 1850
- Joined: Wed Apr 21, 2004 10:29 pm
- Real name: John Futter
- Contact:
Re: Proton Activation of Fe55
Steven / Carl
The EN tandem is about 15 metres long ie the two accelerating sections with the Terminal in the middle. Diameter of the beast is around 2.4 metres inside and the insulating gas is a mix of nitrogen and carbon dioxide at 15 Bar.
As per Carl's earlier post the terminal houses the carbon foil strippers (stripping the electrons)that change the ions from negative to positive while passing through the terminal.
Steven the flight tubes are many sections of glass / metal with the metal sections connected together with high value resistors to give the required voltage gradient /focusing of the beam. Total current down each resistor chain is around 40 microamps (I think)(Ie Low energy to terminal and terminal to high energy end). The outer ends of each acceleration section are earthed so neg ions in > to +6MeV electrons stripped now positive ion so gets second 6MeV push towards earth at the high energy end so total ion energy is now 12MeV
Machine was originally van der Graff 5MeV but now changed to pelletron where we push the machine to over 6MeV for certain uses.
Normal use is for C14 dating at a 4+ charge state that requires the machine to run at 5.251 MeV for many hours on end on a 40 sample run.
conditioning of the beast is usually done 0.5 to 1.0 MeV above the run requirements to remove discharge debris from the flight tube and within the insulating gas. Tank sparks 5MeV and over are like canon shots with a huge burst of xrays attendant.
Total beam tube length is around 50 metres from the neg ion source to the detector array with the tandem about a third the way from the low energy end.
Normal c14 detector is temporarily on the cable rack above the beam tube in the photo at the start of this post.
Will post more pictures soon.
The EN tandem is about 15 metres long ie the two accelerating sections with the Terminal in the middle. Diameter of the beast is around 2.4 metres inside and the insulating gas is a mix of nitrogen and carbon dioxide at 15 Bar.
As per Carl's earlier post the terminal houses the carbon foil strippers (stripping the electrons)that change the ions from negative to positive while passing through the terminal.
Steven the flight tubes are many sections of glass / metal with the metal sections connected together with high value resistors to give the required voltage gradient /focusing of the beam. Total current down each resistor chain is around 40 microamps (I think)(Ie Low energy to terminal and terminal to high energy end). The outer ends of each acceleration section are earthed so neg ions in > to +6MeV electrons stripped now positive ion so gets second 6MeV push towards earth at the high energy end so total ion energy is now 12MeV
Machine was originally van der Graff 5MeV but now changed to pelletron where we push the machine to over 6MeV for certain uses.
Normal use is for C14 dating at a 4+ charge state that requires the machine to run at 5.251 MeV for many hours on end on a 40 sample run.
conditioning of the beast is usually done 0.5 to 1.0 MeV above the run requirements to remove discharge debris from the flight tube and within the insulating gas. Tank sparks 5MeV and over are like canon shots with a huge burst of xrays attendant.
Total beam tube length is around 50 metres from the neg ion source to the detector array with the tandem about a third the way from the low energy end.
Normal c14 detector is temporarily on the cable rack above the beam tube in the photo at the start of this post.
Will post more pictures soon.
Re: Proton Activation of Fe55
I would like to make an offer to you and anyone else on the group that has a use.
We just finished decommissioning a HVEC Van De Graaff accelerator and are tossing out literally tons of "Dependex" High Vacuum fittings. It is not much use to anyone that doesn't have a similar accelerator as that's just about the only place it is still used. If your accelerator uses it and you need some just ask. We also have a lot other spare components including fittings, targets, and the whole Van De Graaff generator if there is an interest.
It is an older device that was becoming a hassle to maintain; we have stripped out the control console so I can use it as a very cool new desk!
We just finished decommissioning a HVEC Van De Graaff accelerator and are tossing out literally tons of "Dependex" High Vacuum fittings. It is not much use to anyone that doesn't have a similar accelerator as that's just about the only place it is still used. If your accelerator uses it and you need some just ask. We also have a lot other spare components including fittings, targets, and the whole Van De Graaff generator if there is an interest.
It is an older device that was becoming a hassle to maintain; we have stripped out the control console so I can use it as a very cool new desk!