I'm working a counting circuit for radiation detection. The input signal comes in as a 5V TTL signal, however the pulse width is an issue. According to the detection equipment datasheet, it should be a 500ns pulse, but it is very old and I'm guessing it is coming out less. I built a 4026 based counter which does work (tested clock input to positive 5V rail, it does indeed count). When A known radiation source is used, however, the counter doesn't get a single count (there are short bursts on my scope at the 5V line, however it isn't good enough to allow me to see the pulse length since it's an old non-storage scope).
I'm thinking that a monostable multivibrator (perhaps 555 based) would work between the radiation detection equipment and the counter. Any suggestions on this schematic? It seems that most multivibrators are designed to have high input with low pulses, whereas I have low input with high pulses. How should I go about building a multivibrator to lengthen this pulse?
Also any other ideas aside from a multivibrator?
I'm thinking that a monostable multivibrator (perhaps 555 based) would work between the radiation detection equipment and the counter. Any suggestions on this schematic? It seems that most multivibrators are designed to have high input with low pulses, whereas I have low input with high pulses. How should I go about building a multivibrator to lengthen this pulse?
Also any other ideas aside from a multivibrator?