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- เผยแพร่เมื่อ 22 ก.ย. 2024
- Three Geiger Counters Compared
Here I compare three common Geiger counters. This is not a scientific analysis, but merely a quick tour of each unit:
International Medcom -- CRM-100
medcom.com
Victoreen -- CD v-700 Model 6A
www.civildefens...
www.orau.org/pt...
SE International -- Inspector EXP+
Geigercounters.com
seintl.com/
@joelb79 I think I have read that somewhere so I suspect you are correct.
The unit I bought was calibrated with Cs137 gamma only. The person I bought it from had refurbished it and replaced many of the componants. He also calibrated it. I calibrate with Cs137 too.
I use a 1 uCi Cs137 source for all calibration needs. I am purchasing a calibrated source very soon as well.
Cheers!
Terrific video, very illuminating regarding the probes. Given their relative surface areas of the mica window on the CRM100 and the Inspector EXP, I would expect more reaction from the CRM100 than it showed indicating the Inspector EXP, even taking into account the greater surface area of the pancake probe is a more sensitive unit.
NOTES: Please watch in full HD!!!
Which unit do you like the best? Do you own any of these units? What do you think?
Well, you could get a CRM-100 from international Medcom for about 300 bucks... but I would recommend an Inspector from Geigercounters com for about 600.
If you are a do it yourself person, you could get an old CDV700 from eBay for $50 and up. Make sure it works and make sure it's a CDV 700... not a 715, 717, 720, etc.
you might also check out the Gamma Scout.
The 493 looks like a commercial CDV700, but I cannot tell you for sure. I have never used one before. The device looks just like a CDV and the tube looks similar. I aslo believe I read that the 493 was a commercial model.
If you really like the metal boxy units with dials (I love them!!!), than the Ludlum model 3 is probably the best unit.
My Ludlum model 12 is on the way, even now lol
Well, think it matters what you want to do with it in Japan. I would think that a Mazur PRM 9000 with it's large pancake tube and nice features. Another good unit is the Inspector. You should consider a pelican case to prevent changes in altitude during your trip damaging the tube.
I know you said 700, but you could get a really nice Ludlum 3 + pancake probe for about $835
Let me know if you have more questions.
The CDV-700 I have is a Lionel model 6b, and is completely analog except for a single small vacuum tube. It should be pretty much immune to EMP.
I am working on a how-to video for first time Geiger Counter users.
I am also working on a how-to for first time Gamma Spectroscopy users. =)
I'll post at least one of these videos tomorrow.
I am not sure how the unit would fare in an EMP. I am no expert, but I wouldn't think well. My old CDV 700 would probably do ok.
Are you talking about my CRM100 Geiger counter?
Hello,
SE Int. states that the efficiency for the Inspector for Cs137 is: "Cs137 - 0.605% @ 1cm (gamma/x-ray)" and "Cs137 - 20.78% (total)"
I tested a 37 kBq (1uCi) source of Cs137 against four detectors. The results:
Detector CPM Gamma+x-ray only (CPM total alpha/beta/photon)
Inspector EXP+: 8,940CPM(77,775CPM)
Ludlum 44-2: 140,000 CPM
Polimaster 1703MO-1B: 36,300 CPM
CDV700: 500CPM (9,000 CPM)
Thank you. That would be very helpful. Your content is QUALITY! The instructions provided are not as accessible to the novice. I will keep staring at them nevertheless. Cheers
CDV-700's are spec'd to be calibrated with CO-60 sources not CS-137, FYI.
You should do a come back tour.
@joelb79 The Inspector is probably the pick of the litter. I love my CDV, though.
Is it possible to get a big digital display to connect to Geiger counter in order to show the progress in a big audience?
What sold you on the Ludlum?
You can can hook up lots of different probes to those. Nice units.
The yellow GIEGER COUNTER looks very similar to a NAVY Gieger counter I used.It was called a ANPDR -27.Are these still available to civilians.
I was thinking about getting the inspector but without the wand.
So does your hair glow now?
Hello Antiprotons, after reviewing your comparison video I purchased the Inspector EXP. Can you suggest the best way on how to learn to use the the device for someone who is fairly new to the whole subject please? Thank you. PS - I am curious to know how you think this device would fair in a coronal mass ejection or an EMP event? Would it continue to work?
@antiprotons Entirely acceptable to calibrate the CDV-700 with CS-137. I'm sure as long as you can get to the middle of the 10x scale with gamma only anything at those levels is a reasonable calibration source.
What is the efficiency of the Inspector EXP detector for Cs-137? Or, alternately what is the average CPM when detecting your 1 uCi Cs-137 source?
AntiP:
On ebay there is a posting of a Victoreen Model CDV-700 6B that has been modified to detect Alpha radiation. Iittle information is given other than it has been converted to a "700M" type. Does this seem reasonable?
Thanks for your expertise,
RK
Sounds good to me. I wish to buy a Ludlum myself, soon enough. I blew a few too many thousands on lab equipment last year and this year I need to hold off more toys... but soon enough (6 months?) I will buy a Ludlum 12 + 44-2 2" NaI(Tl) scintillator. Until then, my CDV700 + RAP47 CsI(Tl) is doing it.
You should find lots of uranium in AZ. I lived there once (Ganado) and it was loaded with hot stuff lol
?
What an odd comment. I do usually remove my rings, but why do they bug you? What is a ting?
Personally, I prefer the analogue dial. My new Ludlum 12 is all dail :)
Typically, the tiny detectors are not sensitive enough. My Polimaster is a contrast to this, being tiny but having a powerful 4 cm^3 CsI(Tl) detector.
Have you looked at the (if you like that sort of detector) PoliSmart?
Tom Thanks For the info! Ron
What happens when you take a Geiger counter to the supermarket?
Thanks for the data, this is helpful for my understanding the calibration process. If the total detector efficiency for Cs-137 is 20.78% and a 37 kBq source gives 37,000 DPS, I would expect that you would measure about 461,316/2 = 230,658 CPM (I divide by 2 since the detector just measures one side of the source). But you detect 77,775 CPM. The Inspector EXP system is specified to operate up to 300,000 CPM. Did you hold the detector several cm from the source?
To me the inspector Geiger counter would be the perfect choice if it wasn't so darn expensive :(
I've just been loaned a 493 victoreen. What's the difference between that and the CDV-700?
Ok through the video. I'd rather have the EXP+ around because of the 100K cpm capability and sensitivity. However, I'd throw a CDV-700 with a CDV-700 Replacement Probe (model CDV-700RP from SEI, International) any day over that EXP. Especially in a dreaded atomic bomb detonation scenario where an EMP was in question.
Yes. GeigerCounters com sells such an external probe. As awesome as the CDV700 is, you could get an Inspector or PRM9000 with the same sensitivity for about 500 bucks. I have both and I think I love my CDV700 the most, but my Inspector is more useful. =)
You need a thin window (like a pancake probe) to detect alpha's.
The same disk was place directly upon the tube OR with about 4mm of plastic between it and the tube (for gamma readings).
I don't trust the SE efficiency readings much. I have found that companies come up with all sorts of goofy methods for determining these things.
Actual readings must include backscatter, Compton edge, Compton plateau, bremsstrahlung, XRF, and (of course) the source emissions.
Actual readings are VERY hard to determine.
if i boy a cbv-700 and add a panceked detector it will detect alpha? and it will decome more sensitive?
My sister lives on the coastal area of California is concerned about monitoring because of Fukushima. I don't want her to spend more than she needs to for a unit. What would be adequate for her to use for this purpose? Thank you.
@joelb79 I should change the word "are" to "were".
yes, you can. you need to get one of these:
Gamma Sapiens (threeW(dot)gamma-sapiens(dot)com) or TERRA MKS-05 with Bluetooth channel and connect to your PC or Android device.
Thanks Tom for the info - it was very helpful. I would appreciate your opinion on what product would work best for a problem I have. I had some construction done in a basement room and the radon levels has increased significantly (in anticipation of a potential problem I had been monitoring levels via 2 Siren Pro radon detectors). What I want is a relatively inexpensive handheld alpha detector that I can use to track down the source of the radiation. Can you offer a recommendation?
Thanks
Ah, as much as I would adore said samples, it is a bad idea.
I spoke with the NRC about contaminated samples in detail (I have emails, letters, etc). It is sort of illegal and legal at the same time. many in the USA have such samples and the NRC seems to be ignoring it, but in theory it is somewhat bad. They were vague. lol
But, if I were to actively start collecting them en masse, the NRC sleeping dragon would awaken lol
Sorry... I would love to, otherwise.
It's only going to test for cesium? We're about iodine and the thousands of other isotopes
thank you, i like your videos and let me tell, you have a new subcriber
Well done. Thank you.
i would go with a cdv-700 and a ludlum any day i have a cdv-700 from lionel its a little bit different from yours from victoreen i have a cdv-715 from them there not good with low level radiation but it was cheap so i am like why not.
I have a WWII compass that has Radium paint for the dial. Would the CD unit work for me? Am I looking for Gamma? If so, how much is unsafe? Many thanks!!
A CDV700 can detect radium. I'd recommend and Inspector USB or a PRM9000. These have large "pancake" style detectors which are more sensitive.
Radium is quite dangerous if it gets inside of you. The leaking oil can have radium in it. If you place it inside of a plastic bag or glass jar, it is pretty safe. Radium and it's decay daughters emit Alpha, Beta-, x-ray, and gammas... and even some random spontaneous fission's.
alpha...beta..gamma rays...what unit tests for all 3 ?
The 6b is a later design
so what is a harmful reading
What's the difference between exp and exp+ ?
Honestly, I do not recall. It has been a long time since I looked at the normal EXP specs. I do not recall the difference being that great. Sorry :(
Cannot reply to your message because TH-cam is stupid. lol Please repost and maybe I can then.
see i want to get one of these things just to have fun and see what is more radioactive. what would be a good one for begginers but not something that i would have to sell my kidney for.
I would love to have a CDV-700... Just a shame I'm from Europe...
I have Cdv