Search found 28 matches

by Lukas Springer
Mon Jul 01, 2019 11:21 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Joe Gayo's lab tour
Replies: 69
Views: 20652

Re: Joe Gayo's lab tour

Damn statistics, ruin everything! :D

That sounds like signal pileup in your detector, have you tried just using a higher distance to your reactor?
faster shaping can do only so much and most gas proportional detectors are not made for high counting rate.
by Lukas Springer
Mon Jul 01, 2019 10:22 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Joe Gayo's lab tour
Replies: 69
Views: 20652

Re: Joe Gayo's lab tour

Your most recent graph shows some "oscillation" / quantized steps, any Idea as to where this comes from?
by Lukas Springer
Tue May 21, 2019 8:27 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: DIY Charge sensitive Amplifier
Replies: 5
Views: 3853

Re: DIY Charge sensitive Amplifier

The pin does not have to be lifted, with proper guard traces the capacitance can be held at a minimum. Also, this is a CSA, not a voltage amplifier, the input capacitance is not as important, since it only affects pulse shape, not the absolute output. The parasitic leakage and capacitance of the res...
by Lukas Springer
Mon May 20, 2019 10:04 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: DIY Charge sensitive Amplifier
Replies: 5
Views: 3853

Re: DIY Charge sensitive Amplifier

Did some noise measurements, noise is equivalent to 2.5 fC / 115 keV (Si).
Next revision will half that, a smaller feedback cap should also fix this.
by Lukas Springer
Sun May 19, 2019 8:25 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: DIY Charge sensitive Amplifier
Replies: 5
Views: 3853

DIY Charge sensitive Amplifier

Hello! Since my HP 5554A died I was in need of a proper charge sensitive amplifier for my detectors. They're not often on ebay, and if they are it's $100+... So I designed my own: The Operational amplifier is the heart of my design, that's why I choose a very fast one, with very low input current. T...
by Lukas Springer
Sun May 05, 2019 8:43 pm
Forum: Items For Sale
Topic: [REQUEST] Tungsten Wire 1.5 mm
Replies: 5
Views: 3719

Re: [REQUEST] Tungsten Wire 1.5 mm

Take a look at tig welding electrodes, they're sometimes aviable in that diameter.
Green tip should be pure tungsten!
by Lukas Springer
Wed Mar 20, 2019 9:12 pm
Forum: Images du Jour
Topic: Neutron detector build
Replies: 4
Views: 2061

Re: Neutron detector build

I don't see why you seem to dislike the russian SNM tubes and "my" circuit that much. The circuit with a 100 pF / 16 kOhm high pass filter is recommended by the manufacturer, what else can you wish for. The low impedance filters out pretty much everything of the high impedance corona noise, leaving ...
by Lukas Springer
Thu Feb 28, 2019 9:58 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Collection of information about russian SNM tubes
Replies: 13
Views: 7418

Re: Collection of information about russian SNM tubes

Which just goes to show how easy to use those tubes are :) No window comparator needed, no fine tuning, just a comparator with some hysteresis and done! I've got a question for you, steven: You spec your GS-NEUTRON-150 as 15% efficiency, is that with the moderator in a fast neutron field or just a s...
by Lukas Springer
Wed Feb 27, 2019 10:22 pm
Forum: Items For Sale
Topic: Old Oscilloscope for Sale
Replies: 2
Views: 1858

Re: Old Oscilloscope for Sale

http://w140.com/tekwiki/wiki/422
Here are its specs, 15 MHz.
by Lukas Springer
Wed Feb 27, 2019 10:21 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Collection of information about russian SNM tubes
Replies: 13
Views: 7418

Re: Collection of information about russian SNM tubes

I'm sorry, maybe I'm bad at explaining, but I wanted to make the point that people don't have to be "scared" by those russian detectors, but that they're instead pretty easy to use once one got the hang of it. They reject the 59 keV of Am-241, tested with a source giving off > 3mSv/h at point blank,...