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Making your own "X-ray Photographs"
The discovery of invisible, penetrating rays in the 1890's ushered in a new era of scientific discovery and exploration. It opened the doors to nuclear medicine, non-invasive medical scanning, nuclear weapons, and much more.
It began in 1895 with Wilhelm Roentgen's discovery of the x-ray ('x' for unknown) and Henri Becquerel's accidental discovery of radioactivity one year later. The first x-ray photograph was of Roentgen's wife's hand.
Mrs. Roentgen held her hand between an electrically powered x-ray tube and a photographic plate. The result not only reveals her bone structure but also her wedding ring. A year later, while performing experiments on polarized light, Becquerel stumbled upon natural radioactivity. He had stored an unexposed photographic plate in a drawer near some Uranium salt samples. Later when the plate was exposed and developed, he discovered that the film had been fogged by the salts even though they emitted no light and the plate had never come into actual physical contact with the Uranium.
Table of Contents
- Project Idea
- Initial Results
- The Technical Challenges and the Legality of using Radioactive Material
- Safety Issues Regarding the use of Radon-Generating Materials
- Seeing Through Things
- Exposing Film Using Patients of Nuclear Medicine
- Appendix
Figure 2 - Becquerel discovers an invisible radiation emanating from Uranium. Note the Maltese cross placed between the lower sample and the film.
For some time I've been fascinated with the idea of reproducing these types of images in my home lab without great cost and with relative safety. As a collector of radioactive minerals and other ephemera, I decided that I wanted to use naturally radioactive materials as the source for my 'penetrating rays' rather than an amateur electrical x-ray machine setup. Secondly, as a participant in the digital revolution, the whole concept of a darkroom with the necessary equipment and development chemicals seemed unwieldy. I knew a digital setup wouldn't provide any results but I didn't want to invest in a darkroom.
Then it occurred to me: Polaroid! Polaroid film is readily
available and it develops itself. However, a workable technique needed to be developed. How to expose the film for hours or days
without the need for absolute darkness? How
would I develop the film reliably after an exposure was made?
Items you'll need:
- A
Polaroid SX-70, Type 600, or Spectra camera
- A package
of unexposed Type 600 or Spectra Polaroid film
- One
metal cookie tin at least six inches in diameter
- A few
sheets/roll of aluminum foil
- Radioactive material
Type 600 or Spectra Polaroid film is easy to find. SX-70 film is discontinued as of 2006 and it
is also much less sensitive than Type 600 or Spectra. Type 600 is the traditional 3 1/4"
square film area that everything thinks of when you say
"Polaroid". Spectra is a
slightly larger format which is used in dentistry and law enforcement. You can purchase either type of camera and
film in any drug store. Alternatively,
most thrift shops will have an old Polaroid SX-70, Type 600, or Spectra camera
lying around. If you prefer to shop from
your home, eBay always has a fine selection. An SX-70 camera can accept Type 600 film with a minor modification.
Figure 3 – On an SX-70 camera, remove the clips on either side (or sometimes in the center) using a screwdriver. When forced, they should simply pop out of the plastic mount without being damaged or damaging the film loading area. Do not damage the battery contacts (often copper colored). Once removed, the SX-70 will accept Polaroid Type 600 film. For photographic purposes, one must remember that Type 600 is 4 times as sensitive to light as SX-70. For this purpose, this difference is irrelevant.
By browsing the clearance rack in a photo store, you can
purchase recently expired Polaroid film on the cheap for between $0.25 - $0.40
per exposure. Very old Polaroid film is
a bad idea but film expired in the past twelve months is generally fine.
By the expensive route, you can spend $50 for a new camera and roll of film. The cheap route may take a little more time and effort, but you can get the job done for less than $5.
Setup:
1. Open the Polaroid film and insert it into the camera.
Making An Exposure
Now we can prove that certain materials have radioactive properties. Here are some objects you might want to try:
- Old,
unused lantern mantles
- Salt
substitute or certain rock salts (Potassium Chloride)
- Vaseline
glass (plates, cups, or marbles)
- Fiestaware
plates and dishes
- Welding rods
- Old
camera lens or vintage prescription eyeglasses
- Uranium
ores and minerals
- Exempt,
unlicensed radioactive calibration sources
- Radium
containing clocks, watch hands, compasses, dials, and gauges[1]
- Tritium
gunsights and keychain fobs
NOTE: All ionization type smoke detectors contain a tiny
plating of the radioisotope Americium-241. It is against federal law to tamper with a smoke detector in an attempt
to expose the radioactive source. No
usable amount of radioactivity can be detected on film without tampering so
cross this source off your list. The
penalties for tampering are severe not to mention the danger you pose to
yourself and others if you ‘tamper incorrectly’.
In a dark, dim or extremely poorly lit room, unwrap the film
holder and place it, film side up in the cookie tin. Place your radioactive material directly onto
the Polaroid film backing and carefully close the tin. Because the inside of the tin is sealed to
all light, you can allow the film to accumulate a very long exposure without
fear of fogging.
Use the photos in the rest of this article to guide you on
proper exposure times as they may vary between five minutes, five days, or five
months. After you’ve made your exposure,
return to a dark or very dim place, open the cookie tin, remove the radioactive
material and insert the film holder into the camera. Once the film door closes, the camera should
feed your photo, upside-down through the development rollers. The camera thinks it is ejecting the
protective cardboard sheet on a new roll of film when in fact it is ejecting
and developing your upside-down Polaradiograph.
Initial
Results
Clark and I tested various items. The photographs below also give you a good
idea of the exposure times you’ll need to get results. In my photos, I was purposefully sloppy in
shielding my film from fogging. This
should give you an idea of the useable but imperfect results you’ll get if you
have limited access to a truly dark space. Many of
Figure 4 - Die with radioluminescent
painted spots / Kevin Clark
Figure 5 - 1 uCi Americium-241 source
/ Kevin Clark
Figure 6 - Dice with radioluminescent
paint on spots / Kevin Clark
Figure 7 - GE brand alarm clock with
radium hands and face / Kevin Clark
Figure 8 - Apollo brand alarm clock
with radium hands. Glass removed / Kevin
Clark
Figure 9 - Thorium-doped gas lantern
mantle. 7-day exposure / Kevin Clark
Figure 10 - Meter with radium-doped
radioluminescent paint. Legend says
"Setting" / Kevin Clark
Figure 11 – Two strips of depleted
uranium metal, a single radium watch hand, a Traser (tritium encased in a
quartz ampule), and Thorium nitrate. Yellow is fogging from ambient light. Brown/white is from radiation exposure. The outline of the baggie containing the thorium nitrate has been
traced. The baggie is not full and you
can see the concentration of the nitrate at the bottom of the baggie. The Traser generates extremely weak beta rays
which are unable to escape the quartz ampule. However, they interact with the quartz to generate more penetrating
Bremsstrahllung (x-ray) radiation which exposes the film.
Figure 12 - Polaroid 57 sheet
film. Exposure time 48hr. From top to bottom, left to right: Tritium
ampule (older), tritium ampule (newer), Vaseline glass marble, Radium tipped
watch hand,
square of Thorium metal,
depleted Uranium strips.
Figure 13 - Large piece of massive
Autunite was placed on the surface of the Polaroid 57 film pouch. Exposure time was 48hr. Uranium concentrations not visible from the
surface of the rock were clearly shown here.
Figure 14 - Torbernite sample. 24hr exposure time.
The Technical Challenges and the Legality of using Radioactive Material
While the photos in the previous section show us the power
of radioactive material to expose film with their invisible rays, the next step
is to use the radioactive material to penetrate regular objects and reveal
their innards.
There are many materials in our daily environment which
exhibit natural radioactivity and many examples can be found at the excellent
ORAU website and online museum.
However, only these materials listed below have enough
natural radioactivity to penetrate objects:
- Unprocessed
Uranium ore (autunite, uranitite, tobernite, carnotite and others)
- Thorium
Nitrate, Uranyl Nitrate or other radioactive salts used in lab work
- Radium containing
luminous materials (i.e. watch hands)
- A medical patient who has recently received a nuclear medicine procedure (i.e. a cardiac stress test).
While United States law allows private individuals to possess NORM (Naturally Occurring Radioactive Material) and a variety of grandfathered items (radium clock faces and watch hands), it is important to remember that it is illegal to process radioactive material in the United States without a license. Inquiries to the NRC (Nuclear Regulatory Commission) have made clear that processing may mean alteration of the material. If you dissolve the paint on a radium watch hand to concentrate or reshape it, that is considered processing. If you burn old-style lantern mantles to concentrate the ash, that is considered processing. The penalties for processing nuclear materials without a license are, needless to say, non-trivial. Therefore, it is important to stay within the law if you chose to replicate these experiments. NRC regulations can been found here. The NRC is extremely conservative in their interpretation of these regulations. If there is a chance your activity is in violation, they will probably determine that it is. If you have a question, simply pick up the phone and give them a call. They can be quite helpful.
Safety Issues Regarding the use of Radon-Generating Materials
When working with radioactive material we want to take
precautions so that the material is not inhaled or ingested. Often this can be assured by sealing the
material behind a plastic or lacquer. However, Uranium, Thorium and Radium materials are Radon generating and
pose unique difficulties.
All Uranium mined from the Earth consists of three isotopes:
U-234, U-235, and U-238. Uranium-238 makes up 99.27%. Uranium-235 which is used for nuclear power
and weapons exists as only 0.72% of natural Uranium. This low percentage of fissile U-235 is why
Uranium much be enriched to be useful
for those purposes.
Figure 15 - Decay chain of Uranium-238
(includes Radium)
Radium is created as part of the Uranium decay chain shown in
Figure 15. What makes it unique is that Radium
decays to Radon which is a not a solid, but a gas. That gaseous form allows Uranium and Radium
to spread their radioactivity in a way that other materials can’t.
Thus, Radon creates a serious problem of radiation migration
and contamination. Anything near Uranium
ore (which contains radium) or Radium itself will become contaminated with a radioactive
dust that settles out of the air. You
can attempt to coat your Radium with plastic, lacquers, etc but it won't work. The Radon gas will, to some extent, find an escape.
Seeing Through Things
Visibly opaque material which would be transparent to an
airport x-ray machine are often still opaque to this method because of the
low-power of the radioactive source. However,
while materials like bone, rock, and metal will appear as opaque, other mostly
organic materials such as paper, cardboard, and flesh will appear fairly
transparent.
Figure 16 - Matchbook w/Staple (top
left), Paperclip (top right), and Lighter (bottom right). Yellow/orange splotches are fogging from ambient
light. Radium Source placed directly on top of subject matter. Exposure of 16 hours.
Figure 17 – Matchbook with an uneven
number of matches remaining. Spots are
from dust specks on the camera’s development rollers. Radium source was suspended 1” above subject
matter. 1” distance sacrifices sharpness
for improved even coverage of the entire film surface.
Figure 18 - Keychain flashlight. The radium source was unable to significantly
penetrate the plastic casing over a 90hr exposure. Source was suspended 1" above subject
matter. Shadow can be seen lengthening
away from center of image.
Figure 19 - First attempt. Three dried goldfish with radium source
1" over surface of subject matter. Eye socket and ribcage of center fish is clearly visible.
Figure 20 – Second attempt. Reduced exposure time as first image was
overexposed. Radium source was in place
1” over the film surface. Ribcage, eye
socket, and other internal features are clearly visible.
Figure 21 - Joseph
Maria Eder and Eduard Valenta, X-ray study of two goldfish and a saltwater
fish, 1896. This photo provides a useful
comparison of professional work using x-rays to the methods described herein.
Figure 22 - Mole killed and brought
home by my cat Q-Tip. Placed on sealed
film pouch with baggie of radium watch hands over top. Exposure time 48hr. The high water content of the mole prevented
the radiation from significantly penetrating the mole’s body. No internal structures were revealed. Film is Polaroid 57.
Exposing film using
patients of nuclear medicine
There are a wide variety of nuclear medicine procedures that
involve injecting patients with radioactive isotopes such that, after they
return home, they remain radioactive for some time. This provides an opportunity for normal citizens
to use patients of nuclear medicine as a radioactive source for exposing film
and creating Polaradiographs.
Figure 23 - Scan of Polaroid 57 from
my father with Photoshop enhanced contrast. The penny and paperclip shadow photographs are visible at the top left. The lower right shows the keychain
flashlight. The other various shapes and
images are a result of the film being bent and misshapen during normal body
movements.
The 16 hour exposure was obviously not enough as the film
was barely developed. I placed a number
of other items under his bed sheets and they received a full 8 hour exposure
but nothing at all was visible on the developed film.
a. Polaroid 612 Type film – Until recently Polaroid
manufactured an extremely fast B&W film for recording oscilloscope readings
and other types of data. Rated at ISO
20,000, this film has 32 times the sensitivity to light as Type 600. Theoretically, it would reduce and exposure
time of 16 hours to 30 minutes. As this
was a specialty film, it was always difficult to find. Even more so now that it has been
discontinued. I did purchase a few packs
that expired in May 1992 but they were dried up and did not work. It’s too bad as this would be the perfect
film for these experiments.
b. One can also use an x-ray machine and Polaroid film to
make Polaradiographs. X-ray usage has
its own safety procedures, special requirements, and even amateur setups may be
subject to state regulations. For
example photos and description of a different technique, see here.
c. Polaroid 4x5 sheet film is available in light-tight
paper pouches that contain a single sheet of film. The radioactive material can be placed
directly on the surface in bright daylight without a fear of light leaks or preparation
in dark space. Polaroid Type 57 film is
an ISO 3000 B&W film that provides a five times increased sensitivity to
radiation over the ISO 600 films. It is
expensive at around $3.00 per exposure and is only available for purchase in
packs of 20 sheets. It also requires a
Polaroid 545 film holder to process and develop the film. This holder can be purchased used on eBay for
around $50. The film can be purchased
from B&H Photo Video or other online camera retailer.
d. I have no professional training in this area so I’m
sure there are many improvements, ideas, and suggestions that I am
missing. I welcome your ideas and
input. Let me hear from you. Please email me at aaron@muderick.com and please use the word
Polaradiograph in the subject line. Thanks!
[1] As of
2007, all of these items are exempt from licensing in the
December 29, 2007 in Science | Permalink
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Comments
I'm sure you know that Tc-99m has only a 6.01 hr half-life. So, lengthening the exposure time on a recently dosed patient won't do a huge amount of good. Though it's less common, it'd be better would be to find someone who'd received a Iodine-131 whole body scan, or even thyroid ablation therapy, which uses even larger doses (tho typically when a patient's been given such a large dose, they have to remain in hospital isolation for a few days). I-131 has a 8.01 day half-life. Also, not mentioned on your list of unregulated radioactive stuff: old dentures, which used thorium (primarily) to give the porcelain some fluorescence, more like natural teeth. They can be highly radioactive! Also, some old "EXIT" signs contain huge (5 Ci, etc.) amounts of tritium (H3). But, aren't a good emitter source, being a beta emitter.
Posted by: Cat | Jan 2, 2008 11:26:22 AM
Collect radioactive material? "It seems like every couple years I only have half of what I remember collecting."
Posted by: Allen | Jan 10, 2008 9:07:02 AM
hello.are there video abouth Making your own X-ray Photographs?
Posted by: rıdvan | Feb 26, 2008 10:49:44 AM
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Posted by: opmqr eyvqmf | May 9, 2008 3:28:13 PM
Good post.
Posted by: Saffron | Oct 28, 2008 9:46:22 PM
Yeah very good post.One can make x-ray shadow photographs of common items which have natural radioactivity. With time, one can also make x-ray photographs of fish and other thin living things to reveal bones and other internal structures.
Posted by: alloy analyzer | Dec 7, 2008 9:55:51 PM
Yeah very good post.One can make x-ray shadow photographs of common items which have natural radioactivity. With time, one can also make x-ray photographs of fish and other thin living things to reveal bones and other internal structures.
Posted by: alloy analyzer | Dec 7, 2008 9:56:39 PM
That was fascinating, particularly with the attempts to image biological samples.you could probably safely experiment with a glow-in-the-dark wristwatch or compass; although that'd be pretty limited, it ought to be safe...
Posted by: x-ray fluorescence | Jan 19, 2009 10:11:48 PM
I've done some amateur experiments with real x-ray tube :) If that interests you check my website at http://c4r0.skrzynka.org/_hv/index.php?page=_xrays&lang=1
:D
Posted by: c4r0 | Feb 28, 2009 5:12:55 AM
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Great its very interesting subject thank you and we wait for more
Posted by: johnstevens | Jun 22, 2009 12:25:58 PM