| T O P I C R E V I E W |
| StevenL |
Posted - 04/18/2022 : 14:03:42
Dear GCM user base,
I recently bought a GGMC500+ Geiger counter and am thrilled with it. I have wanted a radiation measurement device for awhile.
I had not fully appreciated that a 'geiger counter' is actually a very specific kind of device, using a GM tube.
I am now wondering if there are solid state/semi-conductor devices that do the same thing as a geiger counter.
As in the sound industry, which moved away from vacuum tubes to semi-conductors, I wonder if radiation measurement is in the same place. Vacuum tubes are now only use by real audiophiles, and the tubes are typically from Russia or China, as the west no longer makes them.
Are 'geiger counters' still the best technology? Are there any GM tubes still made in the west?
Would love some informed comments from any experts. Thx. Steven Lightfoot
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| 5 L A T E S T R E P L I E S (Newest First) |
| StevenL |
Posted - 04/21/2022 : 06:28:34
quote:
Originally posted by Damien68
the LND company which manufactures the membrane tubes of the GMC-600+ (LND7317) is North American (NY), if you are at Montreal you just have to go down a bit to the south 
https://www.lndinc.com/products/geiger-mueller-tubes/7317/
they also manufacture the LND712 that can be founded on many Geiger counters.
The specifications referenced in the datasheet of the PIN diode + 8mm Sintilator (First sensor 3001447), defines a sensitivity of the assembly around 1000 CPM/uS/h with CS-137 as source. which is about 3 times higher than the sensitivity of M4011 or SBM-20 tube.
but a single pin diode is not very relevant
the solution may also have defects such as being sensitive to temperature, I don't know, I have no info on it.
Damien, thanks, that is very helpful. I am new to this area, but all this is helpingmy education,acquiring a little bit at a time.
Steve
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| Damien68 |
Posted - 04/21/2022 : 05:47:43
the LND company which manufactures the membrane tubes of the GMC-600+ (LND7317) is North American (NY), if you are at Montreal you just have to go down a bit to the south
https://www.lndinc.com/products/geiger-mueller-tubes/7317/
they also manufacture the LND712 that can be founded on many Geiger counters.
The specifications referenced in the datasheet of the PIN diode + 8mm Sintilator (First sensor 3001447/Made in Germany), defines a sensitivity of the assembly around 1000 CPM/uS/h with CS-137 as source. which is about 3 times higher than the sensitivity of M4011 or SBM-20 tube.
but a single pin diode is not very relevant
the solution may also have defects such as being sensitive to temperature, I don't know, I have no info on it. |
| StevenL |
Posted - 04/21/2022 : 05:04:47
quote:
Originally posted by ullix
Yes, such solid-state devices exist. Google for PIN diodes, or perhaps first read my "GeigerLog-Review Smart Geiger Pro (SGP-001)" in the Articles directory https://sourceforge.net/projects/geigerlog/files/Articles/
There was also a discussion in this forum https://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=5584
The principle is not new. Detectors of this kind are a staple in the Nuclear Physics labs since the 1970s.
In principle these "new" detectors are a solar cell, wrapped in a metal foil to protect from light. Compared to a M4011 they are 14 times less sensitive (i.e. still 5 times more sensitive than the 2nd tube in a 500+!).
The attractiveness of these devices is that the electric signal is proportional to the energy of the quanta. In other words, they could serve to generate spectra!
I tried the GDK-101 device hoping for a spectrum analyzer in GeigerLog, but that was a complete dud :-(
Thanks, very helpful info from Ullix and Damien.
Given that the M4011 is much more sensitive that the PIN diode and also catches more gamma, GM tubes still have a unique place is the sector. Even though they dont measure energy.
Thus I assume professional units still use high end GM tubes. Because they are a fairly specialized device, I would assume some are still made in the west, and maybe they are, at the high end of the market.
I am very keen to learn more about this, I want to get much closer to the nuclear sector.
Steve
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| Damien68 |
Posted - 04/21/2022 : 01:21:19
semiconductor sensors (PIN diode) only detect gamma radiation. these sensors alone are not very efficient, they do not detect the high energy gama radiation which passes through the sensor without being detected. it is better to add a small crystal scintillator in front of them which will also allow to intercept the high energy gamma.
for reference, I found a small sensor from "First Sensor" (a TE Connectivity company) the specs show the difference on the absorption spectrum (detection) with and without crystal scintillator, but they are not designed a priori to make spectrometry.
https://www.first-sensor.com/cms/upload/datasheets/X100-7_THD_3001447_3001448.pdf
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| ullix |
Posted - 04/20/2022 : 23:35:53
Yes, such solid-state devices exist. Google for PIN diodes, or perhaps first read my "GeigerLog-Review Smart Geiger Pro (SGP-001)" in the Articles directory https://sourceforge.net/projects/geigerlog/files/Articles/
There was also a discussion in this forum https://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=5584
The principle is not new. Detectors of this kind are a staple in the Nuclear Physics labs since the 1970s.
In principle these "new" detectors are a solar cell, wrapped in a metal foil to protect from light. Compared to a M4011 they are 14 times less sensitive (i.e. still 5 times more sensitive than the 2nd tube in a 500+!).
The attractiveness of these devices is that the electric signal is proportional to the energy of the quanta. In other words, they could serve to generate spectra!
I tried the GDK-101 device hoping for a spectrum analyzer in GeigerLog, but that was a complete dud :-(
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