Well I started trying to do an ac aproach to the trusty linac but
when Dave Cooper posted the idea of a solid state cascading voltage multiplier.... well it was all over but the shouting.
I was against any voltage drop scheme due to the losses and the resistors get hairy near the output!
Telsa coils are mean to tune and make nasty xrays when diodes are used.
Van de Graff linear sets don't crank out enough amps.
The beauty of his suggestion was to tie at each point on the voltage multiplier circuit where the voltage doubles and run the dees at those voltages.
I didn't even think this way because I knew the history and had a mental picture of the massive set that disintegrated lithium. The 1932 cascading voltage multiplier filled a building. The Walton Crockcroft accelerator with modern parts will fit on a desk!
His idea (Dave's) is such a neat solution.
No longer do you calculate the dee length or sychronise anything.
No arc over due to very high potential....stages at a relatively low voltage. No xrays generated during acceleration. But you are on your own bub after that!
The only critical factor is to gap the dees so not to arc to it's neighbor but the dee could be a ring or very small length of pipe.
The particle could take it's own sweet time to move.
Uses availible parts that are still being manufactered.
Here's my interpretation of his thought ( I think!).
The design is pretty standard pi doubler but it is set up to accelerate positively charged particles.
This is a standard design that could be arranged as you need it.
Ferexample 10kv in 7 stages 400kv out. Do as many stages as you need. ( up to 15 but realize the cost escallates rapidily after the tenth section) But remember the higher you go the better insulation must be ...space out the final stages to include more dielectric between the hot wires.
But it will droop after a while tho. (Won't full charge the caps to the desired base voltage)
Build a plastic box and pot the heck out of it.
Just run the wires straight out don't even solder them onto feed tru if you want.
Be creative.
It's quiet and light as sin!
Thank you Dave!
Fusion is fun!
Larry Leins
Fusion Tech
DC Linac 1 power supply
DC Linac 1 power supply
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- linac dc1.ppt
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Re: DC Linac 1 power supply> insulators and structure
under construction
Insulators at these voltages don't exist in the Amateur price range...Aw don't look like that!
Let's build some.
Looking at high vacuum feedthru ,you will notice they all
use high grade alunmina in them with a flange and a cap with wire.
Looking in the Lesker catalog a 100kv standoff insulator cost about 2500 dollars. A bit pricey eh?
All the feed thru insulators can be built with a little sweat at low cost. Humm?
The trick is to joint the flange and the end cap in such a way that
it will work at 10^-7 torr.
High grade Alumina can be bought in tubes of .375" for $10.45 each at McMaster-Carr.
A rough guide to insulative collumn length is 2" for every 100kv.
Here's a small table of voltage verse insulator length for alumina
KV > Insulator length + Safety margin = Final length
15 > .5” + 2” = 2.5”
30 > .85” + 2” = 2.87”
60 > 1.75 + 2” = 3.75”
120 > 2.5 + 2” = 4.5”
240 > 5” + 2” = 7”
480 > 10” + 2” = 12”
920 > 20” + 2” = 22”
1500 > 32” + 2” = 34”
1840 > 40” + 2” = 42”
2000 > 43” + 2” = 45”
All figures were computed from the ASM Handbook Vol. 20. Material Guide
All these dimensions were rounded higher in case you wonder.
Most pro units use oxigen free copper but one can use nickel plated stuff.
I was going to indium solder it but found for earth bound lab type stuff that is not ruggedised high vaccuum epoxy works just fine.
Kurt J Lesker or Dunniways carries it.
Get the non conductive type only ,it is rated to 10^-7 torr.
In fact the whole accelerator system can be made out of glass stirr rods with vacuum epoxy or solid alumina rods.
My first demo linear collider fusor will use deuterium @ 10 ma
It will use 4 alumina rods as stands inside a large pyrex cookie jar from Walmart. The max voltage will be 60 kv for a collisional energy of 120 kv.. Even this tiny unit will require good lead shielding.
Fusion is fun!
Larry Leins
Fusion Tech
Insulators at these voltages don't exist in the Amateur price range...Aw don't look like that!
Let's build some.
Looking at high vacuum feedthru ,you will notice they all
use high grade alunmina in them with a flange and a cap with wire.
Looking in the Lesker catalog a 100kv standoff insulator cost about 2500 dollars. A bit pricey eh?
All the feed thru insulators can be built with a little sweat at low cost. Humm?
The trick is to joint the flange and the end cap in such a way that
it will work at 10^-7 torr.
High grade Alumina can be bought in tubes of .375" for $10.45 each at McMaster-Carr.
A rough guide to insulative collumn length is 2" for every 100kv.
Here's a small table of voltage verse insulator length for alumina
KV > Insulator length + Safety margin = Final length
15 > .5” + 2” = 2.5”
30 > .85” + 2” = 2.87”
60 > 1.75 + 2” = 3.75”
120 > 2.5 + 2” = 4.5”
240 > 5” + 2” = 7”
480 > 10” + 2” = 12”
920 > 20” + 2” = 22”
1500 > 32” + 2” = 34”
1840 > 40” + 2” = 42”
2000 > 43” + 2” = 45”
All figures were computed from the ASM Handbook Vol. 20. Material Guide
All these dimensions were rounded higher in case you wonder.
Most pro units use oxigen free copper but one can use nickel plated stuff.
I was going to indium solder it but found for earth bound lab type stuff that is not ruggedised high vaccuum epoxy works just fine.
Kurt J Lesker or Dunniways carries it.
Get the non conductive type only ,it is rated to 10^-7 torr.
In fact the whole accelerator system can be made out of glass stirr rods with vacuum epoxy or solid alumina rods.
My first demo linear collider fusor will use deuterium @ 10 ma
It will use 4 alumina rods as stands inside a large pyrex cookie jar from Walmart. The max voltage will be 60 kv for a collisional energy of 120 kv.. Even this tiny unit will require good lead shielding.
Fusion is fun!
Larry Leins
Fusion Tech
-
colinheath
- Posts: 78
- Joined: Sat Oct 19, 2002 2:48 pm
- Real name:
Re: DC Linac 1 power supply> insulators and structure
hi larry, im thinking of also building a linear accelerator but wanted to make sure i got the jist of this correct
is it a vac tube with say four pipes inside each at a higher dc voltage so that when an ion gun is used the particles get accelerated through the pipe until they hit the target?
or can you do away with the gun and just use deuterium a lower vac say 1x 10-3 torr ?
also could this unit be built in full demo mode using just air at a vacuum to show ion collision
please excuse my simple questions but i am still an amateur at this
many thanks
colin heath
is it a vac tube with say four pipes inside each at a higher dc voltage so that when an ion gun is used the particles get accelerated through the pipe until they hit the target?
or can you do away with the gun and just use deuterium a lower vac say 1x 10-3 torr ?
also could this unit be built in full demo mode using just air at a vacuum to show ion collision
please excuse my simple questions but i am still an amateur at this
many thanks
colin heath
Re: DC Linac 1 power supply> insulators and structure
For a single linac only one gun is needed.
The danger is a large xray flux from your target if high atomic number (z) is used for the target.
A target of low z would be best like frozen deuterium.
It is the age old neutron source.
To do fusion with the linac,two linacs are needed pointed at each other.
2 guns are needed to create a collumnised beam of deuterons that collide head to head with higher effeciency with regards to a solid target.
See this post for a picture
2003-02-18 10:41 Demo Linac Collider Fusor (larry leins) [Latest: ] (0)
A vacuum of 10^-6 to 10^-7 Torr is necessary.
I ran my power leads through the support legs.
Three wires.....three support legs.
The demo unit of the collider is really a low power version of a larger higher power unit...it is designed to make neutrons from the start. I was going to use it to work out problems of operation before going to higher amperages on the deuteron beams. An air unit would have to be at very low voltage to prevent xray generation at a large rate.
The small unit will need sheilding at the working voltages of:
electrode #1 15kv electrode #2 30 kv Electrode #3 45kv Electrode #4 60 kv
at 120kv collisional the output will meet or exceed Jon R's megaoutput run by a large factor maybe 2 times if all goes well. Jon used 1/2 thick lead sheild for the xray hazard. Don't be a victim of success...
be aware! A linac is tiny but mighty.
Fusion is fun!
Larry Leins
Fusion Tech
The danger is a large xray flux from your target if high atomic number (z) is used for the target.
A target of low z would be best like frozen deuterium.
It is the age old neutron source.
To do fusion with the linac,two linacs are needed pointed at each other.
2 guns are needed to create a collumnised beam of deuterons that collide head to head with higher effeciency with regards to a solid target.
See this post for a picture
2003-02-18 10:41 Demo Linac Collider Fusor (larry leins) [Latest: ] (0)
A vacuum of 10^-6 to 10^-7 Torr is necessary.
I ran my power leads through the support legs.
Three wires.....three support legs.
The demo unit of the collider is really a low power version of a larger higher power unit...it is designed to make neutrons from the start. I was going to use it to work out problems of operation before going to higher amperages on the deuteron beams. An air unit would have to be at very low voltage to prevent xray generation at a large rate.
The small unit will need sheilding at the working voltages of:
electrode #1 15kv electrode #2 30 kv Electrode #3 45kv Electrode #4 60 kv
at 120kv collisional the output will meet or exceed Jon R's megaoutput run by a large factor maybe 2 times if all goes well. Jon used 1/2 thick lead sheild for the xray hazard. Don't be a victim of success...
be aware! A linac is tiny but mighty.
Fusion is fun!
Larry Leins
Fusion Tech
Re: ppt as .gif
No problem!
Thanx
Larry Leins
Fusion Tech
Thanx
Larry Leins
Fusion Tech