Hello there!
I want to make this geiger project but i have some question.
1) Do i need a specific type of geiger tube?
2) Does the tube has polarity?
3) Will wrong wiring damage the tube?
4) What is a nmos?
5) I want to add an analog meter. where do i connect it and what kind of meter do i use? I mean is it a voltage meter or an amp meter? How can i transform a meter to do the job?
1) Do i need a specific type of geiger tube?
You want to find a tube that runs good at 300-400 volts, the SBM-20 does that
2) Does the tube has polarity?
Yes
3) Will wrong wiring damage the tube?
It can damage the tube, since it will erode the anode which is the center of the tube.
4) What is a nmos?
N-channel MOSFET transistor, not needed unless you are adding a micro-controller to count the pulses
5) I want to add an analog meter. where do i connect it and what kind of meter do i use? I mean is it a voltage meter or an amp meter? How can i transform a meter to do the job?
where the schematic says meter out, you will want to add a diode and capacitor to the meter out connection to use a meter. you will need a voltmeter
So i can remove the R8 and NMOS if i dont want to count the pulses.
A simple signal diode and any capacitor will work?
One last thing. What should the range of the volt meter be? (e.g. 0-100mV?) And how can i transform the volt scale into an equivalent radiation one? For example 10mV = 30 CPM or 10mV = 0.03 mR/h. I hope that you understand what I’m trying to say here
You will have to experiment with the capacitor value. Voltmeter could be around 2V full scale. Calibration would be up to you, easiest method would be to get a couple of known low level calibration sources. You can find some on e-bay every now and then.
The tubes (SI-3BG) that you are looking at are not very sensitive, like I said before the SBM-20 is a good tube. You should be able to find it on e-bay.
Thoriated welding rods are primarily Alpha emitters and will generally not be detected by a geiger tube unless it is sensitive to alpha, and if the tubes are Alpha sensitive then they are also pretty expensive tubes. There are some daughter products that are generated by the Thorium but it is not much, if the tube is designed to be sensitive to Beta it may pick up a large Thoriated welding rod.
And how insensitive are the SI-3BG tubes? Will they work for detecting radiation inside my house? Or are they made for detecting large amounts of radiation?
Hello there!
I want to make this geiger project but i have some question.
1) Do i need a specific type of geiger tube?
2) Does the tube has polarity?
3) Will wrong wiring damage the tube?
4) What is a nmos?
5) I want to add an analog meter. where do i connect it and what kind of meter do i use? I mean is it a voltage meter or an amp meter? How can i transform a meter to do the job?
Please answer me asap.
Here are some short answers to your questions:
1) Do i need a specific type of geiger tube?
You want to find a tube that runs good at 300-400 volts, the SBM-20 does that
2) Does the tube has polarity?
Yes
3) Will wrong wiring damage the tube?
It can damage the tube, since it will erode the anode which is the center of the tube.
4) What is a nmos?
N-channel MOSFET transistor, not needed unless you are adding a micro-controller to count the pulses
5) I want to add an analog meter. where do i connect it and what kind of meter do i use? I mean is it a voltage meter or an amp meter? How can i transform a meter to do the job?
where the schematic says meter out, you will want to add a diode and capacitor to the meter out connection to use a meter. you will need a voltmeter
First of all thank you for answering me!
So i can remove the R8 and NMOS if i dont want to count the pulses.
A simple signal diode and any capacitor will work?
One last thing. What should the range of the volt meter be? (e.g. 0-100mV?) And how can i transform the volt scale into an equivalent radiation one? For example 10mV = 30 CPM or 10mV = 0.03 mR/h. I hope that you understand what I’m trying to say here
You will have to experiment with the capacitor value. Voltmeter could be around 2V full scale. Calibration would be up to you, easiest method would be to get a couple of known low level calibration sources. You can find some on e-bay every now and then.
I found these geiger tubes. Will they work with this circuit?
1)http://www.ebay.com/itm/NEW-GEIGER-MULLER-TUBE-COUNTERS-SI3BG-/300792528116?pt=BI_Security_Fire_Protection&hash=item4608a1bcf4
2)http://www.ebay.com/itm/1-x-tube-SI-3BG-CI-3BG-GEIGER-Counter-/300833657520?pt=BI_Security_Fire_Protection&hash=item460b1552b0
And are these (3 and 4) good samples to test and calibrate my counter?
3)http://www.ebay.com/itm/Safe-check-test-for-geiger-counter-dosimeter-Thorium-rod-/251185449097?pt=BI_Security_Fire_Protection&hash=item3a7bd1c889
4)http://www.ebay.com/itm/Thorium-Rod-Geiger-Counter-Check-Test-Source-/260966288202?pt=BI_Security_Fire_Protection&hash=item3cc2cd8b4a
The tubes (SI-3BG) that you are looking at are not very sensitive, like I said before the SBM-20 is a good tube. You should be able to find it on e-bay.
Thoriated welding rods are primarily Alpha emitters and will generally not be detected by a geiger tube unless it is sensitive to alpha, and if the tubes are Alpha sensitive then they are also pretty expensive tubes. There are some daughter products that are generated by the Thorium but it is not much, if the tube is designed to be sensitive to Beta it may pick up a large Thoriated welding rod.
I have some Thoriated welding rods and uranium beads in my products section of the website.
http://www.madscientisthut.com/Shopping/agora.cgi?product=Radiation%20Detection&xm=on
The Uranium beads are picked up with the geiger, see my video here:
http://www.youtube.com/watch?v=qHvct2w6X5A
Will this tube work?
http://www.ebay.com/itm/1x-Russian-GEIGER-TUBE-COUNTER-SI-29BG-SBM-20-New-in-Box-/200857914068?pt=BI_Security_Fire_Protection&hash=item2ec4108ad4
And how insensitive are the SI-3BG tubes? Will they work for detecting radiation inside my house? Or are they made for detecting large amounts of radiation?