Radioisotope Identification

I have been messing with my spectrometer and this is my first spectrum for Am 241, its pretty amazing how it picks up all the x rays at low energy!
I still need to play with it and figure out why it wont capture higher energy (sensitivity issue I think)
but this is just a first test!

I changed the detector and plugged in a scintillation probe
and tried Co60 ...

this is what I obtained

made some improvement with the optical coupling between the photomultiplier and received a much bigger NaI(Tl) crystal

here is 10 minutes of acquisition with 2 pound of potassium hydroxide overlay with 10 minutes of blank background

if you look carefully there is a peak as expected in the 1460 Mev area ...
that's natural radioactivity !

here isa a much better photopeak at 1170 Mev with Cobalt 60...

sure . the detectors are a cadmium telluride semi conductor for the x rays from Amptek

http://www.amptek.com/xr100cdt.html

it may support pdf format I don't know I`ll check it out.
and an older model (though still very functional !) ADMCA multi channel analyzer 8000 channel

http://www.amptek.com/mcasoft.html

and a NaI(Tl) scintillation crystal from a Bicron 1.5M2.25/1.5L couple with a Hamamatsu photomultiplier running at 1500 Volts.
with a power supply Keithley 247 high voltage supply .




I am probably going to up grade to a 3inches crystal detector soon and maybe a cryogenic germanium detector later....




entire set up



semi conductor x rays detector

[Edited on 7-10-2013 by neptunium]

[Edited on 7-10-2013 by neptunium]

here is Ba133 .... pretty powerful stuff! and increadibly accurate!!

i set it up for x ray spectroscopy/diffraction...






I first did a naked spectrum of the x ray tube at 40 kV ...
its too bad I cant see the K shell electron typical peaks I was expected! but I only have a 40 000 Volt generator!






judging by the amount of x rays coming out of this thing I don't think I am going to do these analysis very often!
also , not too many people interested although I thought this was a great analytical way for unknown elements and even isotopes!

I`ll continue to post every so often we ll see...

[Edited on 16-10-2013 by neptunium]

Quote: Originally posted by neptunium

the charge would be minimal (like 15 bucks) and you would have to ship the sample to be measured

Regardless, I'm too poor for even the shipping, at the moment. When I find a job, I'll send a few specimens. I'm especially curious to see if my <a href="http://en.wikipedia.org/wiki/Trinitite" target="_blank">Trinitite</a> <img src="../scipics/_wiki.png" /> generates an interesting gamma spectrum (if any). It's only weakly radioactive (by <a href="viewthread.php?tid=25882">my Geiger counter</a>, so I'd suspect it would require a rather long sampling time and a decent amount of shielding from background. I'm a little surprised that nobody else has shown interest.

[Edited on 20.10.13 by bfesser]

Quote: Originally posted by vulture

What's the "range" of this thing? Could you detect x-rays from lightning?

Quote: Originally posted by vulture

I don't want images, it just would be cool to be able to detect those x-rays.

x rays from lightning sounds interesting but incredibly difficult to set up!
here is what I do with 40Kv !

radioactivity testing

no I do not own a neutron source , but I was considering building an alpha linear accelerator with a thin Be sheet I have..
the sensitivity ? let me put it this way, the sodium iodide crystals let me detect K40 in a pound of potassium hydroxide
the Cadmium Telluride diode lets me pick up the x rays from a cathode ray tube instantly, and the High purity Germanium detector I just order (if it works) would let me see through a complicated spectrum of multiple isotopes.
the sensitivity is not the problem. with enough time I could pick out a few thousand atoms (or less) given they are all radioactive.


here is an (old) source of Cobalt 60 with the NaI(Tl) crystal




the two peaks are clearly separated and visible

here is ba133 with the CdTe detector





and this is Americium 241...



I will post more when I get the HPGe detector and some liquid nitrogen


let me be clear, I cannot detect molecules or stable isotopes and a neutron activation would depend on the cross section of the element you are trying to activate .
also some isotope generated by neutron activation have a really short half life and cannot be shipped for analysis nothing would be left to detect!

only long lived isotopes (T/2>about 10 hours) can be successfully detected.

[Edited on 17-12-2013 by neptunium]

Quote: Originally posted by neptunium

can this be moved to a poll ? or no?

....gonna do some neutron activation soon though!

i got this 0.5mCi of Po210 on ebay so i made a poor man`s neutron source to see if i could activate this sample of mystery metal sent by hyfalco and this is what i got...




this is only about 30 minutes of exposure in a neutron oven... the 809Kev peak of the Po210 is clearly visible ,
however the area highlighted before that in the ROI (Region Of Interest) is particulary interesting...
arround 400 to 600 Kev is where the radio isotope of the mystery metal lay...
i am going to let it sit over night and see if anything else shows up on the gamma spectrum...

note
the red area is a background radiation without anything in front of the detector, the spectrum overlay on the background lets us appreciate the difference between the two spectrums and allows us to see minute amount of radiations..

i ran the analysis again with the x ray detector and i think the sample must contain Ta (tantalum)
the stable isotope is Ta181 and after neutron activation we should expect to find Ta182.
although the activity is barely above the background radiations, most of the expected gamma and X rays are present !
this is not to say that ta is the only element in the sample but rather the most neutron sensitive (higher cross section).
here is the x ray spectrum compare with the background.





i know it might not look like much but its pretty hard to mess up the calibration on this detector so i remain confident that Ta is present.
i dont know where the sample came from but Ta is often use in alloys because of its chemical stability 9corrosion resistant ) so it doesnt really suprise me .
what does suprise me is that i was able to detect it ! this is a very powerful and non destructive method of analysis and i find it mind blowing!

got a new bigger detector !!!!! this a a harshaw "well type" so 360 degrees detection for more accurate sample analysis !




I did a quick 15 minutes background ( black line ) followed by a 15 minutes of 2 lbs potassium hydroxide ...



don't let the size and resolution of the picture fool you this is natural radioactivity very visible! no doubt about the 1460Kev peak !

the number on the detector are 12SW12-w4 the hole is about 2 in deep and 3/4 in wide
these little glass bottle are a perfect fit.

been playing with this data analysis software fitzpeak to look at my spectrum and it seems like a powerful tool!
here is the report after calibration andanalysis


Attachment: Main Report.txt (3kB)
This file has been downloaded 1337 times
and here is the detail spectrum

Quote: Originally posted by neptunium

after collecting about a gallon of water i boilled it down to about 300 ml and pour 50ml in a small glass bottle that fit the dector...

i recently acquired some modest quantities of the mineral called monazite . A source of rare earth and Thorium...
The gamma spectrum with my new improved detector clearly shows the isotopes from the decay chain of Th232





after calibration the main peak is label as U235 or Ra226 wich doesnt really matter because if one is present we can deduce it either came from the other or the other must be there too .. also identified are isotopes of Pb, Bi, and Ac!
Also i have a small amoun of Euxenite ..



notice how the same peak appear on both spectrum indicating the presence of the same isotope..i beleive it to be Bismuth
i will redo the calibration with more care to be sure ...
but i find it quite interesting that U235 is clearly present in both rocks in much greater amont in Euxenite though
i have enough to seperate uranium ,Thorium and other element chemicaly but probably wont do it .
although it would be interesting to see how the spectrum changes...


[Edited on 20-8-2014 by neptunium]

the previous spectrum of Co60 was somehow erased..
this is what my new detector resolution is able to accomplish!



the two main peak at 1173.24Kev and 1332.5 kev are clearly seperated the small one over at 2.5Mev is just an addition peak.
The lower energy peak is the back scattering ( i need to built a shield)
and here is Barium 133 ...



i get a much better resolution with the semiconductor detector but the surface area window being so small, it barely see higher energy gamma...it is in fact an Xray sopectrometer.

here is the identification of a sample of euxenite...

here is monazite


interestingly enough, Ra223 is a daughter of U235 with a half life of 11 days whereas Pb212 come from Th232 wich is more likely since this is monazite...but with a half life of only 10 hours ... my calibration might need an update!

I have order a steel shield inside of what i have melted some lead for the detector...
it cost me way more than i thought it would and left a bitter taste in my mouth.....untill



I am not finished with the lead melting process (over 200lbs is involve) the whole set up is looking a lot better than before .






and i had some interesting results with a substance i would never have suspected to contain any active material..
Zirconium dioxide
here is the gamma spectrum of about 2 lbs of ZrO2.





after careful calibration i was able to identify the natural element involve in the weak radio activity of this otherwise neutral substance...






click on the picture for better viewing.
I am running an X-ray spectrum right now but the detector being way more sensitive and much smaller this will take a while .Each peak will be a lot more defined but it only reads the spectrum untill about 330Kev ...so more results to come.


i beleive the chemical similarity of group 4 with the lanthanides (and actinides) allows some of those metals to be present in each other ore...
it would be interesting to see if they could be detected in Titanium and Hafnium salt as well...
we already know how Yttrium and some rare earth are often found with Thorium and vice versa..
maybe Zirconium is a big part of the impurities in Uranium processing..



[Edited on 8-8-2015 by neptunium]

Monazite is a Thorium rich ore but still contain small amount of Uranium, when Euxenite is clearly a Uranium rich mineral.
the gamma spectrum clearly confirmed the presense of both Th and U and the decay chain of each isotopes and also quantify
those metals ..
here is the 2 spectrums for comparaison

Quote: Originally posted by neptunium

there is (was?)a guy on ebay selling it for cheap... I acquire every pieces over the course of a year or 2 ... it was a long process but it paid off! some parts are cheaper than others thats true...

Quote: Originally posted by careysub

Quote: Originally posted by neptunium   there is (was?)a guy on ebay selling it for cheap... I acquire every pieces over the course of a year or 2 ... it was a long process but it paid off! some parts are cheaper than others thats true... I just bought 1 lb of monazite ore for $21 on eBay $15/lb plus $6 shipping), it was sourced to New Mexico. If any SM members live in North Carolina there is a river that is a good source of monazite sand, much easier than gold panning. Unlike the ore (perhaps), monazite sand is usually concentrated monazite. I am sure monazite sand would find willing buyers here.

Quote: Originally posted by annaandherdad

Hi, careysub, I just bought 1lb of that monazite, too. It was a good deal. A while back I spent a lot of time thinking about thorium, and I looked for monazite. There was none available, so now it's surprising to see it. I did find some thorium nitrate reagent, and bought a small amount. ... But something tells me it's going to get harder and harder to get things like this, so I decided to take it.

here is for your consideration Radium 226 (old Radium dial...)
some daughter of Ra226 are visible (nevermind the cursor on Tl)
giving Radium`s half life this should be interesting ...
the scale at the bottom has been calibrated.



[Edited on 1-10-2015 by neptunium]

Quote: Originally posted by neptunium

ahem I think you got the wrong page budd...

just received a sample of Coffinite U(SiO4) the Actinium is way up in this one ! but the 3 peaks for Uranium and Radium are clear.
Also, notice the Pb210 at 46Kev...

neptunium have you ever tried this software? If so how does it compare to software such as the program you are using.

http://sourceforge.net/projects/opengamma/

I find what you are experimenting with to be very interesting but I admit I have never accumulated the equipment and software to actually do it. So I am thinking about building such a device but I have a question. Do you have to look at the energy peaks and then compare to tables of various gamma emitters to identify the element or isotope or does your software have graphs which indicate this (built in tables)? I notice in the image you posted it merely shows the peaks and energy levels.

http://www.amptek.com/products/gamma-rad5-gamma-ray-detectio...



As example in this graph from their page one would not know merely by looking at the image what materials were shown without the inclusion to the graph stating UO2, 133 Ba, Th (lantern mantle). When you are operating your equipment is there a feature where identification is given or as I asked do you have to compare your energy readings to charts? I am seriously thinking it is time I had such capability but I need to learn more in order to build it and pick the right software. Buying a commercially made setup is beyond my budget for mere experimenting where no money return is anticipated, to me this is more of a fun addition to a life long hobby. I noticed the window in the image you posted showing Ac-228 but am unsure if this is called up automatically (auto ID function). I downloaded all their software just to install and study the program operation assuming it will run minus the specific model detectors they indicate. I noticed their page indicates the software only functions with their devices.

While I intend to build my equipment I find it helpful to first study what others have done, have you looked at the following:

http://beeresearch.com.au/

https://www.youtube.com/watch?v=xPeKkzhf2TU



[Edited on 12-12-2015 by IrC]

Thanks I will look into that software you linked. I have had a detector in my storage for years that I never toyed with due to no access to LN2. In my small town UFO's would be easier to locate and no doubt any source is a few hundred miles away. However it looks like your setup does not need it so I am wondering how well my detector would function without the cooling. It states 3KV for operating voltage on the tag but I cannot find specific listing of it on the Canberra site. It is a GC 520 Standard Electrode Coaxial Ge Detector (SEGe) with a 7935-2 portable cryostat. I have no other equipment originally designed for it so obviously some reverse engineering of the internal circuitry and building my own circuitry is needed. All I have is the detector itself seen in the pics. As you can see in the end view pic there is a fitting for LN2 in and another for a vent. The PDF I found on their site does not mention my specific detector as it is old and no doubt the company is little interested in it. I have yet to find a search function on the site.



Attachment: SEGe-detectors-C40021.pdf (179kB)
This file has been downloaded 821 times

What do you think of operating this detector removed from the cryostat, using it as part of a new design. How important is the cooling to LN2 temperatures for the kind of work as you are doing, is there any chance of harming the detector running it at room temperature. Possibly I can come up with some type of Peltier electrical cooling for it although cryonic temperatures would not be reached.

At the very least, looks cool and great
Would be cool to see it running if you had some LN.

as requested here is a break down of the equipment i use to produce the gamma spectrum of various radioactive compounds..
first the detector



this one is a sodium iodide thallium doped scintillation detector, its 3 inches by 3 inches it has two BNC connectors (not pictured)
one for the high voltage DC power supply



and one for the amplifier .
it doesnt matter what type of high voltage and amplifier you are using as long as its a DC HV and is very stable and the amplifier is rated for gamma or X rays spectroscopy.
I found that NIM BIN are very affordable ,easy to assemble ,very versatile and very rugged .



here you can see (above) a rate meter that produces a live display of the activity of the sample placed in the detector.



next is the most important and expansive part of the spectroscopy system.
the Multi Channel Analyzer or MCA.
it turns the signal out of the amplifier into a digital, readable signal for the computer to display a spectrum, it only reads voltage NOT energy, the calibration must be done to reflect on the energy scale.
for that i use a known source of Co60 (availlable to anybody without a license) for about $75 from spectrum techniques/
Cobalt 60 has 2 very visible peaks at 1172Kev and 1332 kev respectfully



knowing that , the software allows a calibration and by telling it where those two peaks are , the program readjust the scale to match the energy level corresponding to the energy of the known peaks.




now we are ready to place a sample of unknown origin and by knowing the energy at which each peaks will show up we can determine the radioisotope responsible for it.
this next sample is a concentrated of thorium ore.
the software has a bank of energy peak already uploaded in its database so we can move the cursor on the spectrum where the peaks are and it will automatically match it with a peak in its records.
if not, there is plenty of books, data sheets, software, the internet, etc.. to look for the energy level of any peaks found on the spectrum.



here the 63.3 Kev line matches the Thorium234 energy line.
there is always a certain level of uncertainty (as in science in general) and the detector is not precise enough to seperate very closed peaks (within about 15Kev) but it is good enough for a reasonable estimate of the radio nucleide involved.
it is precise and sensitive enough to detect potassium 40 in ashes or even bananas, the spectrums can be saved and compare to others which allows to determine with accuracy the presence (or absence ) of Radium228 in pottery and dirt.
but it only detect gamma rays with energy between 50Kev and 3000kev, which is where most radio gamma emitters are.