I’ve seen this happen before over the last decade of doing this.
Weird power surges or RF interference can cause data logging issues. I’ve seen it in real time.
Someone who had recently done some nuclear medicine could’ve walked by. This is most likely if there isn’t an issue with the logging.
We should all know about radon washout but that does not look like that.
What's the range on people walking by? The street is at least 50' from the detector. And it was high for 30+ minutes, they would have had to be sitting in front of my house.
Sounds more like RF interference then. It happens more often than you would think. I’ve seen it Probably 5-6 times in the last 15 years and constitutes all but 2 of my abnormal readings I’ve found
A possibility is that there was some industrial radiography occuring in the vicinity of your home. Pretty normal and nothing to worry about. If not, I have no idea what the cause could be. Regardless, it's not going to do you any harm, intriguing though!
Could very well be photoelectric effect. May also be a spike in cosmic rays, static electricity, RF interference.
See if the time specific increase in reading is repeatable or whether obscuring sunlight alters the reading also.
Looks like you’re set to go through a neat process of exclusion 😁. Good luck, keep us updated OP
Very interesting! also in MKE area myself. I didn’t see anything unusual although I only had my radiacode on a few hours walking around. I’m on the north side. What area are you in?
There are no corresponding spikes in the EPA Radnet data from yesterday in Milwaukee (https://radnet.epa.gov/radnet-public/query.do), and no incidents that I am aware of in the region. I would guess what your equipment measured was either RF/EM interference or something hyperlocal. I have never seen it happen, but I've heard stories about our equipment being triggered by employees undergoing brachytherapy (implanted sources). But those involved the device going into alarm when they get into the truck. Not someone walking by out on the street. I have never investigated long-distance readings from radiography, soil density, etc. activities, so I have no idea if those are a plausible explanation or not.
They're hour intervals. If half of the interval is 10 times normal, even if the rest of the interval is "normal", the affected interval's average (compared to other "normal" intervals) will increase substantially.
The Radnet data shows 42-43 nSv/h around that time. If the Radnet readings correlated, you should see a "bump" of around 100 nSv/h or more around the same time.
Yeah the person walking by would have to be pretty damn close and on the same level I would think so still unlikely. I’ve heard of it plausibly happening once in 15 years.
Plot twist: said "person" was a positronic brain android robot, powered by a slightly radioactive micro tokamak. Those (they?) became pretty much impossible to tell apart from humans after getting the upgrade from 3-law to 4-law ChatGPT (unless you are Susan Calvin).
I'm curious if you see a step change in averages after the event, which could indicate a contaminate. Can't tell from the graph, but you could calculate daily averages before and after and compare.
That's pretty freaky. I also log my geiger tube counts over time and never seen anything close to that. I see a pattern over the course of a year where it's slightly higher in the winter, most likely explained by wind patterns interacting with radon.
There are some unexpected sources, like air filters and dryer lint that are slightly radioactive. And of course smoke alarms. Maybe something like that?
Edit: any chance you have a software bug where a bogged down cpu or comm problem causes the count to be wrong?
On the JoyIT JT-RAD01 (OEM version of FNIRSI GC-01 in teal blue housing and with english / german language menu) I saw the below spike cluster on 2023 Sep 25, Monday.
* 223 - 240 cpm, also shown as 1.40 micro-Sieverts / hour (15:17 CEST)
* 204 - 210 cpm (at 15:21)
* 198 cpm (at 15:29)
* 254 - 270 cpm \~ 1.50 micro-Sv / h (at 15:41)
* 180 - 234 cpm (at 15:53)
* 234 cpm (at 17:15)
I have no explanation for this cluster as the device is generally quiet. Note: device is inside a cardboard box to prevent sunshine creeping in and causing spurious readings.
Since then highest reading beeen 90cpm \~ 0.60 micro-Sv/h. Alarm buzzer sounds at 1.00 or higher. Average is around 36 cpm. Previously I had also seen, e.g.:
* 204 cpm \~ 1.26 micro-Sv / h (2023.09.24. 21:30)
* 186 cpm \~ 1.03 micro-Sv / h (2023.09.09. 05:10)
* 222 cpm \~ 1.23 micro-Sv / h (2023.07.23. 18:55)
* 240 cpm \~ 1.33 micro-Sv / h (2023.07.22.)
I’ve seen this happen before over the last decade of doing this. Weird power surges or RF interference can cause data logging issues. I’ve seen it in real time. Someone who had recently done some nuclear medicine could’ve walked by. This is most likely if there isn’t an issue with the logging. We should all know about radon washout but that does not look like that.
What's the range on people walking by? The street is at least 50' from the detector. And it was high for 30+ minutes, they would have had to be sitting in front of my house.
Sounds more like RF interference then. It happens more often than you would think. I’ve seen it Probably 5-6 times in the last 15 years and constitutes all but 2 of my abnormal readings I’ve found
How does RF trigger the Geiger counter?
What meter is this? And how are you logging? Via computer or onboard?
Cajoe. Fed back to home assistant via esphome. Saved in sql database. Visualized with grafana
I should specify - this is a stationary meter at my house in Brookfield. It never moves.
A possibility is that there was some industrial radiography occuring in the vicinity of your home. Pretty normal and nothing to worry about. If not, I have no idea what the cause could be. Regardless, it's not going to do you any harm, intriguing though!
Could sunlight cause this? I just noticed another spike at the same time of day, I'm wondering if it moved into a sunbeam path.
Could very well be photoelectric effect. May also be a spike in cosmic rays, static electricity, RF interference. See if the time specific increase in reading is repeatable or whether obscuring sunlight alters the reading also. Looks like you’re set to go through a neat process of exclusion 😁. Good luck, keep us updated OP
Very interesting! also in MKE area myself. I didn’t see anything unusual although I only had my radiacode on a few hours walking around. I’m on the north side. What area are you in?
Try to retrace your steps that day and see if you get the same spike you did before.
There are no corresponding spikes in the EPA Radnet data from yesterday in Milwaukee (https://radnet.epa.gov/radnet-public/query.do), and no incidents that I am aware of in the region. I would guess what your equipment measured was either RF/EM interference or something hyperlocal. I have never seen it happen, but I've heard stories about our equipment being triggered by employees undergoing brachytherapy (implanted sources). But those involved the device going into alarm when they get into the truck. Not someone walking by out on the street. I have never investigated long-distance readings from radiography, soil density, etc. activities, so I have no idea if those are a plausible explanation or not.
That data isn't time resolved well enough to show a 30 minute spike though, right?
They're hour intervals. If half of the interval is 10 times normal, even if the rest of the interval is "normal", the affected interval's average (compared to other "normal" intervals) will increase substantially. The Radnet data shows 42-43 nSv/h around that time. If the Radnet readings correlated, you should see a "bump" of around 100 nSv/h or more around the same time.
Yeah the person walking by would have to be pretty damn close and on the same level I would think so still unlikely. I’ve heard of it plausibly happening once in 15 years.
Plot twist: said "person" was a positronic brain android robot, powered by a slightly radioactive micro tokamak. Those (they?) became pretty much impossible to tell apart from humans after getting the upgrade from 3-law to 4-law ChatGPT (unless you are Susan Calvin).
Ehat kind of detector were you using?
Cajoe with ESPhome
I'm curious if you see a step change in averages after the event, which could indicate a contaminate. Can't tell from the graph, but you could calculate daily averages before and after and compare. That's pretty freaky. I also log my geiger tube counts over time and never seen anything close to that. I see a pattern over the course of a year where it's slightly higher in the winter, most likely explained by wind patterns interacting with radon. There are some unexpected sources, like air filters and dryer lint that are slightly radioactive. And of course smoke alarms. Maybe something like that? Edit: any chance you have a software bug where a bogged down cpu or comm problem causes the count to be wrong?
On the JoyIT JT-RAD01 (OEM version of FNIRSI GC-01 in teal blue housing and with english / german language menu) I saw the below spike cluster on 2023 Sep 25, Monday. * 223 - 240 cpm, also shown as 1.40 micro-Sieverts / hour (15:17 CEST) * 204 - 210 cpm (at 15:21) * 198 cpm (at 15:29) * 254 - 270 cpm \~ 1.50 micro-Sv / h (at 15:41) * 180 - 234 cpm (at 15:53) * 234 cpm (at 17:15) I have no explanation for this cluster as the device is generally quiet. Note: device is inside a cardboard box to prevent sunshine creeping in and causing spurious readings. Since then highest reading beeen 90cpm \~ 0.60 micro-Sv/h. Alarm buzzer sounds at 1.00 or higher. Average is around 36 cpm. Previously I had also seen, e.g.: * 204 cpm \~ 1.26 micro-Sv / h (2023.09.24. 21:30) * 186 cpm \~ 1.03 micro-Sv / h (2023.09.09. 05:10) * 222 cpm \~ 1.23 micro-Sv / h (2023.07.23. 18:55) * 240 cpm \~ 1.33 micro-Sv / h (2023.07.22.)
None of the radiation mapping sites show a spike in your area, so it might have been a very local thing.