Large Spike During Background

[Phouly]

Hello Everyone, Whilst I was taking a 24 hour background sample in my new lead castle as I just picked up 200 more pounds of lead giving me an almost complete 3.5" shielding around my detector on all sides, at ~5:30AM EST my standard rate of 1.5-2.0 Counts Per Second, Spike for about 500ms, now I dont know if 70 counts in 50ms is a true count or just the fastest the detector could keep up. you can see it instantly goes to max and then winds down to normal over 500ms each time step in the attached image is 50ms as when i made the time steps smaller there was a maximum bin count or something limiting me from going this far into the scan as it had already been running for around 5 hours.


If anyone knows how I can go back using PRA and Look at what energies these specific counts were, Please let me know I am hoping that will shed some light into the bizzare situation,

A couple theories I have are,
Gamma ray burst - I have no reason to believe this other than the complete randomness of the situation
Mass state police or US Government - I live close to Boston, Yesterday we had the Marathon here, and before the marathon they Fly the route with Very expensive detectors that I have no information on how they operate, But I do know they Scan the route for any signs of Dirty bombs, Radioactive material, so maybe it was just some new sensor they are using., but I did check flight aware and saw no aircraft near me.
Electronics bug - Always could be a case of electronics bugging out but Maybe someone else has had this happen
Statistical anomaly - I would definitely say no way on this because the sheer amount of counts

As always any useful information or ideas on what I am looking at, or How I can pull up the energies of the suspected region of time would be greatly appreciated.

Also I still have no idea what the spike around 1800kev on my background could be any help on that would be appreciated aswell.

[Sesselmann]

Patrick,

I can't help you with your speculation, but in Data acquisition & analysis you can define from and to time i.e. from 19775 to 19785 and the your spectrum will only display those counts.

Steven

[Phouly]

Thanks Steven,



Now that I can see the energies of the unknown rays, It seems they are all low energy X-rays, sub 10kev, From what I know either it would have to have been a very concentrated x-ray source to punch through my whole house, and ~4" of Lead, at such a low energy, I would assume it would be a fair assumption that this means the Rays came from inside the lead castle, which also doesn't mean much to me, I will continue searching I may setup for another 24 hour scan and see if it happens again. I am stumped.

[Sesselmann]

Patrick,

Counts right at the bottom of the spectrum, looks like electronic noise to me. Most likely an appliance or something in your house that switched on and sent a ripple through the line which exceeded the threshold.

LGM's are much less likely... 😉

Steven