Archive for May, 2008

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Scintillation Crystals and X-Rays

May 7, 2008

Here are a few photos of inorganic scintillators glowing from exposure to a ~ 300 R / hr x-ray field. These were all long digital exposures, 5-15 seconds, taken last year, and all had to be de-speckled extensively due to radiation noise on the camera CCD.

Bismuth germanate (BGO) crystals from a PET scanner. Lovely cyan glow, not particularly well-matched to photomultiplier tubes but gorgeous to the human eye. Dense, and a wicked photoabsorber of gamma rays, BGO is well-suited to portable homebrew scintillation detectors.

Barium fluoride, a material of choice for fast pulse-mode gamma detectors. Much of the light emission is in the ultraviolet, and to the eye the glow appears a deep purple color. Perhaps there’s a use for this in fast neutron detectors based on inelastic scattering on F-19?

Sodium iodide doped with thallium (NaI:Tl), the old standard for gamma spectrometry and high-class uranium prospecting. This 3″ x 1″ crystal is hermetically sealed because the NaI is hygroscopic. The rich blue glow resulting from exposure to a 60 microcurie radium source is literally bright enough to read by. Next to the x-ray machine, it shines like a spotlight!

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For Sale: Uranium Ore

May 5, 2008

I’m offering excess uranium ore from my early summer trips for sale. This includes an assortment of decent specimen pieces from Lisbon Valley, San Juan Co., Utah, and bulk carnotite-tyuyamunite ore from the Grants, NM region. Read below for details.

The Utah material, top, is a hard, coarse-grained red Chinle sandstone incorporated with veins and disseminated black uraninite. Fracture faces exhibit some colorful andersonite and other secondary uranium minerals. This comes from Big Indian Valley, San Juan Co., Utah. Piece descriptions and suggested pricing are provided after the jump.

The New Mexico material, bottom, comes from Poison Canyon near Grants, NM. It is a tough, gray Todilto limestone saturated with yellow carnotite and tyuyamunite and occasionally some dark-colored uraniferous humates. Unfortunately this collecting location has become inaccessible and this may be the last batch of this stuff for a while. Sold by weight at $12 / kg.

Read the rest of this entry ?

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Nuclear Collection (Part I)

May 5, 2008

Here are some relatively recent additions to my collection of radioactive and nuclear-related items. Some of them I don’t know nearly enough about! Take a look, and if you have some information to add, please contact me. I will post other galleries as I get the chance. Also: I collect this kind of stuff (obviously), so if you have something radioactive and you’re not a big fan of radioactive stuff, let’s make a deal: send it to me. You get rid of the hot stuff that’s gonna harelip your kids and give you leukemia and whatnot, and I’ll pay you money for it.

Click on a photo for large size. Descriptions are at bottom of post.

graphite from CP1Graphite from CP-1, the world’s first nuclear reactor, built under the stands of Stagg Field at the University of Chicago in 1942. This 25th Anniversary memento popped up on eBay not long ago and I paid dearly for it. However, there’s not much of this stuff left; all but a couple bars of this famously pure graphite went on to be incorporated in CP-2 and thereafter entombed in concrete under a nondescript field in Illinois. The eBay seller would only say “I do know that my grandfather worked on the building of the atomic bomb but other than that I don’t know much else.” I have a feeling that the human story could be interesting, but on account of the seller’s reluctance to share so much as her grandfather’s name and other “personal information,” there’s nothing more to say right now. Tips appreciated…

graphite from CP1More Graphite from CP-1. This example was also obtained on eBay, but bears slightly different markings (the additional Argonne National Laboratory label on the side of the graphite piece) and different dimensions. Also, no notecard or box came with this one.

worker\'s badge from ChernobylWorker’s badge from the Chernobyl Nuclear Power Plant, dating from 1987 (the year after the catastrophe at Unit 4). Anyone able to read Russian shorthand? The back of the badge contains addresses and perhaps a description of what this man did at the plant. This badge is not discernibly radioactive.

Uranium glassUranium glass memento from the “Conference Nucleaire Europeenne” of 1975, held in Paris. The box also came with a slip of paper informing the recipient that “Ce verre est colore par un sel d’uranium” (“This glass is colored by a salt of uranium”). A present from a good friend, James Thiel. Shown at right under light from a mercury vapor discharge.

ionium“Ionium thorium nitrate” from Marie Curie’s lab. At least that’s the provenance claimed by the previous curator of this fascinating and rather radioactive vial. Ionium was a name for Th-230, the naturally-occurring parent of radium (Ra-226). Today, the vial contains 8.6 +/- 10% microcuries of radium as determined by careful gamma radiation measurements. If it’s indeed as old as the Curie lab, then there should be a couple hundred microcuries of alpha-emitting Th-230 present, in addition to a rather inconsequential activity of Th-232 carrier. The vial is contained in a test tube that has some rather cryptic markings on it. Take a look at the full-size pic and let me know if this means anything to you…

Walkie recordallThis late-model Walkie-Recordall contains a 4.8 microcurie radium source. An expensive dictation recorder in its day (ca. 1950s and ’60s), the battery-operated apparatus came in a discreet suitcase with hidden microphone—perfect for industrial espionage. Radium was used to discharge static on the “sonoband” embossing medium. This specimen was found by scintillation detector in a flea market in Ohio. The included sonoband, containing a medical lecture, was heavily damaged by radiation in the place where it sat in front of the radium source for years. The band still plays (video coming shortly). I pay $50 per Walkie radium source; taking out this radioactive strip does not impact operability of the recorder.

back in the good ol\' daysBack in the good ol’ days of 2004, an average joe could still buy uranium oxide from MV Laboratories in New Jersey, with nary a question asked. Those days are history! This 30-gram quantity of greenish-black U3O8 remains sealed in its bottle, an emblem of American freedom that has been eroded by the drumbeat of irrational fear. Something about “islamofascists” I think.

alpha sourceThis is an interesting alpha check source kindly given to me by Taylor Wilson. On the backside is a bare surface deposit of black UO2, evidently reading 700 CPM on the Nuclear Chicago Model R6 survey meter. Perhaps the UO2 was electrodeposited?

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radium calibration sourceAnother interesting check source from Taylor, this one an “ionotron” type radium foil (probably about 0.1 microcurie) on a card that was last calibrated in 1955 at the height of the golden age of nuclear. It’s hard to see on the photo, but radiation damage has denatured and cracked the plastic right over the source strip in the lower right-hand corner.

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