X-ray detection device?

[Tim Brazelton]

Still stuggling with avoiding x-rays while traveling with my big suitcase of film (too big to carry-on to a plane). I've had my film fogged recently by an airline when the luggage was switched from one plane to another. Does anyone know of some sort of device or film that could be used to quantitate x-ray exposure and that wouldn't require a lab set-up to process (i.e., something that could be used after arriving on location). There is a film badge product but it requires development like normal film requiring me to travel with chemicals. If I could at least determine that my film is still unfogged prior to a shoot that would be very helpful.

Thanks, Tim

[Michael Mutmansky]

Tim,

Something like this might be useful, as it does keep a tabulation on the amount of radiation that is received...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2965676870&category=1469

Obviously, you would need to determine whether you could figure out what a safe doseage is depending on the film you have.

There are other products out there that may be suitable, but some research will be needed. Here's a listing for some indicator stickers:

http://www.gexcorporation.com/PI/100-124%20P8100%20Radiation%20Indicators_PI.pdf

If you figure this all out, please report back so the information can benefit others.

---Michael

[Pete Caluori]

How about a sheet of Polaroid film (type 54 or 55)? If you carried an unexposed, but developed print for comparison, it should be easy to visually see a density change.

Regards, Pete

[Alan Davenport]

Film in carry-on, get it hand inspected. This is per TSA recommendations. If you leave it in your checked baggage, expect it to be fogged.

[Ted Harris]

The dosages of the machines for checked luggage are very high and not publically available .. that is why the tell you NOT to put film in checked luggage. If you have too much to carry with you then send it ahead using FedEx or oen of the other commerical carriers.

[ronald lamarsh]

Like Alan said put your film in carry on, I repair x-ray equip and know that what they are using for baggage now is pretty well up there on the power scale. The bottom line being no film is safe in your baggage. What they use for carry-on si safe for any film and if you are really paranoid you can use a film shield bag in the carry on stuff. But if its in your checked bags the scanners they use will blast through it like wet toilet paper.

[Steve Hamley]

Tim,

Alan has it right. Any integrating dosimeter (radiation dose measuring device) gives after-the-fact information and your film is in the same shape it would be without knowing the dose. All the dosimeter will do is help you decide whether to throw it away without even trying to use it.

Now, there is a device called a high range direct reading dosimeter, also called "pencil meters" that used a charged quartz fiber to measure radiation. The civil defense used them and they are typically yellow and if you get one that measures to 500 or 1,000 rad, that should do it. You read them by looking through the device, but you need a charger to reset the device after use. Here's what they look like:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3638069301&category=208

You can still buy them new, but the charger and dosimeter would likely be about $500 or maybe a little more. You'd need the high range dosimeter that measures 100R or more full scale.

Here:

http://www.dosimeter.com/dosimeter1new.htm

Or Google "dosimter corporation".

The other (and better) options would seem to be buy film after you get off the plane or have FedEx or DHL ship it.

Thanks!

Steve

[Michael S. Briggs]

That must be a lot of film to be too much to carry on an airplane! It seems like you are risking a lot of money and time if your film is ruined by x-rays.





I think Pete's idea of including some Polaroid film is a good one. The high-speed Type 57 would probably give a sensitive check. You would also need a Polaroid Type 545/545i holder to process the film at your destination.





I am not sure that the dosimeters are sufficiently sensitive to detect doses that would cause some fogging of the film. X-ray scanners for luggage are limited by law to giving a dose of one milliroentgen -- above this dose a sign is required advising you to remove film from the luggage -- see
49 CFR - Chapter XII - Part 1544 of the Code of Federal Regulations.
The US Transportation Security Administration advises that film should not go through a carry-on x-ray machine more than 5 times -- see Transporting Film. This gives an approximate goal for the maximum dose for film -- 5 milliroentgens.





Dosimeters were mentioned with full scale readings of 100, 500 or 1000 rads. What is the smallest reading these are capable of? As a guess, if the more sensitive one could be read to 1% of its full scale reading, that would be 1 rad. Since a rad is essentially the same as a roentgen for x-rays, this guess for the sensitivity of the dosimeter is 200 times higher than a reasonable goal for the maximum exposure of film. The people who ran the Cold War Civil Defense effort thought that rather high radiation doses were acceptable.





The X-ray Dosimeter sold by Dosimeter.com is more sensitive -- 200 mR full-scale (i.e., 0.2 rad) with 20 divisions, suggesting that the threshold might be about 5 or 10 mR. But the graph of energy response shows a rapid falloff for lower-energy x-rays, so the usefulness would depend on the x-ray energy used by the inspection machine.

[Tim Brazelton]

Thank you everyone for your replies.

Several options for detection were suggested but sensitivity remains an issue. My calculations are similar to Michael Briggs. I'm estimating that it takes about 5 mR to begin to see the loss of shadow contrast in ASA 200 film. The exact threshhold is difficult to determine but I did find several references that 100 mR (about 90 mRad) will result in substantial fogging. The new x-ray machines currently in use for checked baggage give an exposure of up to around 100-300 mR.

The x-ray monitoring stickers mentioned by Michael Mutmansky would be ideal (inexpensive, small) since I could put a sticker on each box of film to track each box's cumulative exposure over multiple trips. Howver, currently these stickers require 30,000 rads to change color. I was unable to find a more sensitive "sticker" type indicator. If anyone finds such a product please post it since it would be useful to many of us.

The idea of using Polaroid film seems like the best. I've emailed Polaroid to determine if they know the x-ray sensitivity of their different films. Has seen fogging of a Polaroid film after sending it through the carry-on or the checked baggage screening machine?

FYI: I don't what others experiences have been for moving their film around the country but we were recently notified by UPS that they have changed their policy and that our packages now can be x-rayed irregardless of how they are shipped. They also indicated that they don't track which packages are x-rayed and therefore were unable to inform us if a package had been x-rayed. (I believe that FedEx has had this policy for over a year now). So now when we get a delivery of film we test a few sheets to make sure it's performing as expected (as we should probably do anyway) and then we take the film with us when we travel.

For travelling, I've been having my crate(s) of film hand-inspected to avoid x-rays and then checked as normal luggage since there is no way we can fit enough film into our carry-ons. One of the reasons the film is so bulky is that we use only Quickloads since 1. it's handy, and 2. it's greatly preferred by the TSA (I've twice not been allowed through security when I refused to open a box of standard sheet film since that would have exposed it).

Another FYI and a clarification: There are new TSA regulations to allow film to travel in checked bags but the policy is only about 4 weeks old and many airports don't know about it yet. The policy exists since some checked pieces of luggage will be re-x-rayed when they are moved from one plane to another. As I understand the new policy, if a full-sized piece of luggage contains predominantly film (or better yet, only film) then it can be taken to the gate through the security gate that normally checks carrry-ons. In order to get a full sized piece of luggage through this gate the TSA indicates that you need an "Oversized carry-on waiver" from your airline. However, since I have yet to find an airline agent that's ever heard of an "Oversized carry-on waiver" you need to have the agent you're checking in with call the security gate to let them know you're coming. The luggage is then checked at the gate when you board and picked up when you leave the plane (like they do for strollers or wheelchairs). Make sure you specify that you want to get the luggage back at the gate when the plane lands otherwise it will get put into the normal luggage handling path. With the new policy, there is no chance that the suitcase will be x-rayed. The disadvantage is that when you change planes you need to drag not only your carry-ons but your full-sized suitcase to the next plane. Also, you need to confirm with your airline that they are willing to comply with the new policy since they are not required to do so by the TSA. Most of them seem willing to comply to my knowledge except for American Airlines which (at least according to one agent) is not going to provide this service.

All the best, Tim

[Pete Caluori]

Hi Tim,

Yes, I have seen x-ray exposure on Polaroid film. I had a few sheets in my carry on bag and they all picked up the same density pattern, which was a dark band running across the 4" dimension and some general fog. This occurred at Denver airport, which has some of the most unagreeable TSA personnel.

Regards, Pete