Would these tubes be suitable for Xray work?
Download, Sat Jan 31 2009, 07:36AMSo would these tubes be suitable for Xray work?
I plan to use my 15kv 30mA NST with a single stage multiplier on it
Re: Would these tubes be suitable for Xray work?
Proud Mary, Sat Jan 31 2009, 10:28AM
In a word, you must choose a valve with a very high impedance designed for EHT use, such as EHT rectifier diodes, or shunt stabiliser triodes like PD500.
Your voltage is not really high enough, either, so that very little of the X-rays produced will be able to escape the glass envelope.
Most amateur X-ray work with old EHT valves is done in the range 40 - 70kV, with currents between about 50uA and 1.5mA.
When using EHT rectifier diodes, the filament or cathode is not heated, in order to work in the very high impedance cold cathode mode when currents of the order of 50uA may be pulled through the valve.
Low energy X-rays are much the most dangerous, since they are readily absorbed by the body. Don't do these experiments if you haven't first spent your money on adequate shielding and apparatus for measuring low energy X-rays doses.
Proud Mary, Sat Jan 31 2009, 10:28AM
In a word, you must choose a valve with a very high impedance designed for EHT use, such as EHT rectifier diodes, or shunt stabiliser triodes like PD500.
Your voltage is not really high enough, either, so that very little of the X-rays produced will be able to escape the glass envelope.
Most amateur X-ray work with old EHT valves is done in the range 40 - 70kV, with currents between about 50uA and 1.5mA.
When using EHT rectifier diodes, the filament or cathode is not heated, in order to work in the very high impedance cold cathode mode when currents of the order of 50uA may be pulled through the valve.
Low energy X-rays are much the most dangerous, since they are readily absorbed by the body. Don't do these experiments if you haven't first spent your money on adequate shielding and apparatus for measuring low energy X-rays doses.
Re: Would these tubes be suitable for Xray work?
Download, Sat Jan 31 2009, 11:03AM
How about this?
I could double my multiplier to 60KV too.
Download, Sat Jan 31 2009, 11:03AM
Harry wrote ...
In a word, you must choose a valve with a very high impedance designed for EHT use, such as EHT rectifier diodes, or shunt stabiliser triodes like PD500.
Your voltage is not really high enough, either, so that very little of the X-rays produced will be able to escape the glass envelope.
Most amateur X-ray work with old EHT valves is done in the range 40 - 70kV, with currents between about 50uA and 1.5mA.
When using EHT rectifier diodes, the filament or cathode is not heated, in order to work in the very high impedance cold cathode mode when currents of the order of 50uA may be pulled through the valve.
Low energy X-rays are much the most dangerous, since they are readily absorbed by the body. Don't do these experiments if you haven't first spent your money on adequate shielding and apparatus for measuring low energy X-rays doses.
I plan to buy some of those rolls of lead they use on roofs and solder it together into a box, then put the tube etc inside itIn a word, you must choose a valve with a very high impedance designed for EHT use, such as EHT rectifier diodes, or shunt stabiliser triodes like PD500.
Your voltage is not really high enough, either, so that very little of the X-rays produced will be able to escape the glass envelope.
Most amateur X-ray work with old EHT valves is done in the range 40 - 70kV, with currents between about 50uA and 1.5mA.
When using EHT rectifier diodes, the filament or cathode is not heated, in order to work in the very high impedance cold cathode mode when currents of the order of 50uA may be pulled through the valve.
Low energy X-rays are much the most dangerous, since they are readily absorbed by the body. Don't do these experiments if you haven't first spent your money on adequate shielding and apparatus for measuring low energy X-rays doses.
How about this?
I could double my multiplier to 60KV too.
Re: Would these tubes be suitable for Xray work?
Download, Sat Jan 31 2009, 11:18AM
I'll get five of these, there EHT rated for 20kv at 500uA 50mA peak and this guy used one
Download, Sat Jan 31 2009, 11:18AM
I'll get five of these
, there EHT rated for 20kv at 500uA 50mA peak and this guy used one Re: Would these tubes be suitable for Xray work?
Proud Mary, Sun Feb 01 2009, 11:25AM
GY501 is a good one! The biggest problem at 60kV is flash over along the glass surface, so you'll get much the best results if you put the valve in a tube full of dielectric oil - remembering to include a pressure relief device, so the oil won't be forced out as it heats and expands. Oil will also cool the glass, which is a big issue at this voltage.
Proud Mary, Sun Feb 01 2009, 11:25AM
GY501 is a good one! The biggest problem at 60kV is flash over along the glass surface, so you'll get much the best results if you put the valve in a tube full of dielectric oil - remembering to include a pressure relief device, so the oil won't be forced out as it heats and expands. Oil will also cool the glass, which is a big issue at this voltage.
Re: Would these tubes be suitable for Xray work?
rp181, Sun Feb 01 2009, 03:01PM
how do these look?
rp181, Sun Feb 01 2009, 03:01PM
how do these look?
Re: Would these tubes be suitable for Xray work?
Download, Mon Feb 02 2009, 08:50AM
United Nuclear are over priced, plus they don't send to Australia
edit:
Now that I look at it the smaller xray valve looks like the one's I bought :)
Download, Mon Feb 02 2009, 08:50AM
United Nuclear are over priced, plus they don't send to Australia
edit:
Now that I look at it the smaller xray valve looks like the one's I bought :)
Re: Would these tubes be suitable for Xray work?
Proud Mary, Tue Feb 03 2009, 01:21AM
I'm sure you could get by with something much cheaper, and just as good.
EHT Shunt stabilizer triodes usually give very good results - TV valves such as the European PD500 or the American 6BK4B.
Don't go throwing your money away on things advertised on flashy looking websites with re-labeled valves to impress the gullible. Buy components from ordinary electronics trade suppliers.
Proud Mary, Tue Feb 03 2009, 01:21AM
I'm sure you could get by with something much cheaper, and just as good.
EHT Shunt stabilizer triodes usually give very good results - TV valves such as the European PD500 or the American 6BK4B.
Don't go throwing your money away on things advertised on flashy looking websites with re-labeled valves to impress the gullible. Buy components from ordinary electronics trade suppliers.
Re: Would these tubes be suitable for Xray work?
Download, Tue Feb 03 2009, 09:49AM
I'm not dumb enough to buy from UN
Download, Tue Feb 03 2009, 09:49AM
I'm not dumb enough to buy from UN
Re: Would these tubes be suitable for Xray work?
LutzH, Fri Feb 06 2009, 10:10PM
My advice is forget the radio tubes for x-ray use. The resolutuion you can get in making images is in direct proportion to the geometric size of the x-ray source, a radio tube if it works will give you a focal spot size measured in cm, in other words fuzzy pics. Just buy an x-ray tube off ebay, or from China via an "Alibaba" search and you will have lots of fun.
Just do not forget to buy a reliable method of radiation measurment from ebay or even build one. Then use plenty of lead and distance: Cancer, sterility, and a shortend life span just is not fun.
LutzH, Fri Feb 06 2009, 10:10PM
My advice is forget the radio tubes for x-ray use. The resolutuion you can get in making images is in direct proportion to the geometric size of the x-ray source, a radio tube if it works will give you a focal spot size measured in cm, in other words fuzzy pics. Just buy an x-ray tube off ebay, or from China via an "Alibaba" search and you will have lots of fun.
Just do not forget to buy a reliable method of radiation measurment from ebay or even build one. Then use plenty of lead and distance: Cancer, sterility, and a shortend life span just is not fun.
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