Photoluminescent method detects explosives at a distance

EETimes ^ | October 18, 2004 | R. Colin Johnson

[raygun]

Those compounds are oxidizers not explosives.

[Drammach]

rendered device useless..

Wrong..
All that has been done is to add a "masking" signature..
The target would still flouresce in the 705 nm range..

The procedure might have some false positives, due to the masking, but there would not be any negatives..

It would still reduce the need to search every piece of luggage in an airport..
Only those with a signature would have to be searched..
Same with vehicles, persons..
Flourescence even on a broad bandwidth would be better than the technology (sniffers) that exist now..

[BobS]

"Those compounds are oxidizers not explosives."

I used them while making my own firecrackers while a little squirt. Graphite and sulfur, anhydrous sulfer makes a big bang. Until I woke up my sleeping dad, and all my chemicals went down the toilet after he used a belt on my ass. He was a WW2 vet and explosions wake him up fast. Chlorates are also in solid rocket fuels.

[TXnMA]

RDX is what the Soviets stole from us to use in their first nuclear weapons. Their other conventional explosives had a nasty habit of pre-detonating due to the exposure to radiation.

Ouch! That could be embarassing... ;-}

[AdamSelene235]

One of the cooler designs I've seen are antibodies designed to react with very low levels of explosives. Their optical index changes upon exposure. They are bonded on a prism and you look for the plasmon shift due to the index change. Very sensitive.

Bio-optical sensors....Tres chic!!

[raygun]

Yep, except for the belt thing. And the chemicals down the toilet. But other than that, yep. Oh, and except for the WWII sleeping dad thing too. I used to use those metal whip-its cartridges. And I used I used black powder (enhanced with a little potassium perchlorate). But other than that, we pretty much have the same story. Used to strap those things onto some 8" skyrockets. Had the green waterproof fuse length cut so they'd go off at about 500'. I'll never forget the sound of rain in the foliage all around us after one those things went off (about 10 seconds after they went off).

[Southack]

"Bio-optical sensors....Tres chic!!"

Weeee. Weeeee. Tres F'n Chic.

Yet one of *many* ways that bio-tech can and will protect us in the future.

Hey, what was that whole trans-Siberian trip of yours about, anyway?

[BobS]

Know what's funny about my story? I got 100' feet of fuse and all those other chemicals sent to my by US mail, one at a time. I made 6" firecrackers that sounded like a mortar round. Paper tubing and plaster end caps. I sure studied chemistry very early, also made nitro in the HS chem lab. And now I'm in microwave and creat the head-end of missiles that make an even bigger noise:)

[grey_whiskers]

We were attempting to do infrared fluorescence (the proper term for "photoluminescence")when I was in grad school back in the late seventies.

I kinda prefer 'triboluminescence'--chew up a wintergreen lifesaver in the dark while looking at a mirror. You can see the sparks in your mouth if you look close.

And less risk of detonation (grin).

[AdamSelene235]

Hey, what was that whole trans-Siberian trip of yours about, anyway?

I did Siberia back in 01.

The most recent trip was Russia, Kazahkstan and Kyrgyzstan on a Ural sidecar motorcycle.

Just blowing off a little steam. The purpose of long distance motorcycling is to make beer taste good.

I suspect sailing is similiar.

I'll tell you about over the beer you're going to buy me when FNM melts. The SEC just upgraded its investigation to "formal".

[grey_whiskers]

How about chlorates? Potassium perchlorate and chlorate are also explosive.

Yikes! Have you ever dealt with perchloric acid?

I've dealt with aqua regia and with 50-50 mixture of nitric-sulfuric acid, but perchloric bloody scares me.

[AdamSelene235]

Here ya go:

Tannerite Binary Explosive Targets

[raygun]

6" mortar rounds, erm, a little bigger than I usually made.

[Doctor Stochastic]

Wouldn't there be a problem with sensitivity. What is the background level? Are explosives as ubiquitous as cocaine and will show up on every dollar bill? Will Viagra trigger the detector? (I assume that therapeutic nitroglycerin would.)

[John O]

bump for later reading

[Wonder Warthog]

"Sensitive detection of 705nm may require some cooling, but not that much."

Depends on how sensitive you need to get. To get the max, even PMT's (photomultiplier tubes-for those not aquainted with spectroscopy jargon) are cooled.

[BobS]

"Yikes! Have you ever dealt with perchloric acid?"

No. Just anhydrous potassium perchlorate and anh. potassium chlorate. Acids had to be shipped by REA Express at that time, and by train. Too much bother at 15. I was a sneaky little squirt until my dad put an end to that hobby. Then I got into electronics for a different kind of mess. But it was a quiet mess:)

[VadeRetro]

Israel needs this ASAP for the checkpoints where the human bombs cross. We need it in Iraq to sweep for those roadside improvised booby traps.

[wattsmag2]

I liked to put the fuses of several crackers together. Make a little cone of Potassium permanganate on them. And put a drop of glycerin in a small indentation on top. Gives ya plenty of time to be long away from the scene chatting with someone for an alibi. No flame, no smoke while you are around.

[BobS]

"No flame, no smoke while you are around."

A time-delay fuse or a lit cigarette stuck on the end of the fuse would get you far away to observe your creation also:)

Didn't some news source call us FReeRepublic terrorists a few weeks ago? This was kid stuff from a long time ago because we were "bored" if anybody wants to know. We don't have time and are likely to spank kids that do this now.