Will Irradiated Mail hurt film?
DBaker9128
which will kill anthrax spores by irradiating big batches of mail all at once.
The Postal Official interviewed said it will be similar to the process that is
used to irradiate food. Does anyone know if this will hurt film sent in via
mailers to be processed?
Doug from Tumwater
Neurula [Sydney]
the film emulsion
"DBaker9128" <dbake...@aol.com> 撰寫於郵件
news:20011023001037...@mb-fx.aol.com...
Lassi Hippeläinen
>
> No, I think they use mainly Alpha & Beta particles, which have no effect on
> the film emulsion
Certainly not alpha-particles. A thin paper will stop them. Beta seems
unlikely, because they are just electrons.
I'd use gammarays for desinfection. The same stuff that is used for food
irradiation. I'm not sure about their effect on films, but probably
negligible. Detecting gammarays isn't that easy.
-- Lassi
Al Zeller
very likely make film completely black. Diagnostic x-ray levels are in
the range of a few millirad (thousandths of a rad) while doses needed to
kill viruses are thousands of rads. Figure a millions times higher dose.
They certainly won't use alpha particles because they won't penetrate
the envelope. Probably not betas either since that would be very
expensive. Both alphas and betas are quite capable of exposing film, as
that was the standard way of doing nuclear physics until about 30 years
ago. We still use film to do autoradiographs of activated parts with
betas doing the exposing.
Al Zeller
Neurula [Sydney]
structure + DNA are still susceptable to damage by Alpha, Beta particles.
"Lassi Hippeläinen" <lahi...@ieee.orgies.invalid> ?????
news:3BD54D10...@ieee.orgies.invalid...
> "Neurula [Sydney]" wrote:
> >
> > No, I think they use mainly Alpha & Beta particles, which have no effect
on
> > the film emulsion
>
> Certainly not alpha-particles. A thin paper will stop them. Beta seems
> unlikely, because they are just electrons.
>
> I'd use gammarays for desinfection. The same stuff that is used for food
> irradiation. I'm not sure about their effect on films, but probably
> negligible. Detecting gammarays isn't that easy.
>
> -- Lassi
>
> >
> > "DBaker9128" <dbake...@aol.com> źśźgŠóślĽó
Neurula [Sydney]
"Al Zeller" <Zel...@nscl.msu.edu> ?????
news:3BD54EE7...@nscl.msu.edu...
Al Zeller
"Neurula [Sydney]" wrote:
>
> but are those films comparable to the films we use in photography?
>
Sure. We just use regular Poloroid film. Like to use high speed, but
we've done it with ASA 1000 or so at source strengths of less than 100
millirad per hour for a few minutes.
Al Zeller
MZ
On Tue, 23 Oct 2001, Neurula [Sydney] wrote:
> No, I think they use mainly Alpha & Beta particles, which have no effect on
> the film emulsion
>
>
This is not quite right.
First of all, they may probably gonna have to use neutrons
instead of alpha & beta to get throgh the thick mailbags.
Second, any kind of energetic particle will hurt anything.
Since both alpha & beta are charged species, the "hurt"
will be particularly bad! Just that they lose their energy
much faster than neutrons, so the penetration is shallow.
Eugene A. Pallat
> "Neurula [Sydney]" wrote:
> >
> > No, I think they use mainly Alpha & Beta particles, which have no effect on
> > the film emulsion
>
> Certainly not alpha-particles. A thin paper will stop them. Beta seems
> unlikely, because they are just electrons.
>
> I'd use gammarays for desinfection. The same stuff that is used for food
> irradiation. I'm not sure about their effect on films, but probably
> negligible. Detecting gammarays isn't that easy.
It's quite easy. X-rays are gamma radiation. So is IR. It just depends upon
the wavelength. Radio and TV are *very* low frequency gamma rays. See any
physics text. If it's powerful enough to kill bacteria, it's powerful enough to
fog fast film.
Gene Pallat
eMeL
news:3BD54EE7...@nscl.msu.edu...
> If they use dose levels like those used to preserve food then this will
> very likely make film completely black. Diagnostic x-ray levels are in
> the range of a few millirad (thousandths of a rad) while doses needed to
> kill viruses are thousands of rads. Figure a millions times higher dose.
>
> They certainly won't use alpha particles because they won't penetrate
> the envelope. Probably not betas either since that would be very
> expensive. Both alphas and betas are quite capable of exposing film, as
> that was the standard way of doing nuclear physics until about 30 years
> ago. We still use film to do autoradiographs of activated parts with
> betas doing the exposing.
Actually they (gov people) are talking about two different things: using UV
light to disinfect surfaces of mailings (UV light would not penetrate paper)
and/or irradiation (just like used for food) to do the rest. The content
would not be fully disinfected, though. There was/is/will be (depending on
the time zone, "was" on the East Coast) a story about it on NPR today.
Michael
Leonard Evens
<dbake...@aol.com> wrote:
Presumably they will come up with some alternative for material which
would be affected by radiation. But perhaps some sort of identification
or means of tracing will be required to use it.
--
Leonard Evens l...@math.northwestern.edu 847-491-5537
Dept. of Mathematics, Northwestern Univ., Evanston, IL 60208
Lassi Hippeläinen
Radio waves don't fog film ;-)
I know about the physics. I have a major on the item. Gamma rays are a
type of photons. Radio waves and visible light are photons too, but they
aren't gamma rays.
Gamma is so high-energy that usually it is associated with nuclear
processes. Its impact on electron shells isn't trivial to analyse. IIRC,
killing bacteria is based on the ionising effect that may break organic
molecules. Ionisation fogs film only if the returning electrons release
photons in the visible energy range, where the film emulsion is
sensitive. Not RF, not X-ray, not most of IR.
Anyway, usually physics laboratories use special gamma detectors rather
than film. The detectors work in real time, can detect single events,
and analyse the energy, too. That won't work with film.
-- Lassi
Al Zeller
Lassi Hippeläinen wrote:
>
> "Eugene A. Pallat" wrote:
>>> >
>>> > Lassi Hippeläinen wrote:
>>> >
>>>> >
>>> > It's quite easy. X-rays are gamma radiation. So is IR. It just depends upon
>>> > the wavelength. Radio and TV are *very* low frequency gamma rays. See any
>>> > physics text. If it's powerful enough to kill bacteria, it's powerful enough to
>>> > fog fast film.
>>> >
>>> > Gene Pallat
>
> Radio waves don't fog film ;-)
>
> I know about the physics. I have a major on the item. Gamma rays are a
> type of photons. Radio waves and visible light are photons too, but they
> aren't gamma rays.
>
> Gamma is so high-energy that usually it is associated with nuclear
> processes. Its impact on electron shells isn't trivial to analyse. IIRC,
> killing bacteria is based on the ionising effect that may break organic
> molecules. Ionisation fogs film only if the returning electrons release
> photons in the visible energy range, where the film emulsion is
> sensitive. Not RF, not X-ray, not most of IR.
>
Only by definition do gamma rays differ from x-rays. Gammas energies
overlap x-rays, but we define gammas as originating in the nucleus. Now
usually gammas are higher energy, but not always. All photons with
sufficiently high energy to break chemical bonds are classified as
ionizing radiation, regardless of the source (nuclear or atomic). When
ionizing radiation passes through the emulsion it creates a path of
electrons and positively charges ions (hence the name "ionizing
radiation"). The length and density of the track depends on the energy
and particle type. This gives rise to quality factors for determining
damage to humans. Photons have a quality factor of 1 and high energy
neutrons a quality factor of 10, tho the neutrons do not give rise
directly to the production of a ionization trail. Film is fogged not by
the release photons of optical wavelength (fluorescence), but by direct
ionization of the silver halides. If film were not sensitive to x-rays,
then we would never get chest x-rays, would we?
> Anyway, usually physics laboratories use special gamma detectors rather
> than film. The detectors work in real time, can detect single events,
> and analyse the energy, too. That won't work with film.
>
> -- Lassi
Now days we don't use film for photon detection, but that was the
standard for more than 50 years.
Al Zeller
Neurula [Sydney]
"Lassi Hippeläinen" <lahi...@ieee.orgies.invalid> ?????
news:3BD66B9B...@ieee.orgies.invalid...
Neurula [Sydney]
> photons in the visible energy range, where the film emulsion is
> sensitive. Not RF, not X-ray, not most of IR.
Not entirely true, gamma rays will have enough energy (higher than the work
function required for the electron to escape from the silver atoms) to
reduce(or oxidise? i forgot how it goes with silver halid emulsions) the
silver atoms due to its high frequency.
Lassi Hippeläinen
[We are getting way OT... I'll comment only these details:]
> Film is fogged not by
> the release photons of optical wavelength (fluorescence), but by direct
> ionization of the silver halides.
I haven't been active in physics for several years. Of course I should
have remembered that metal halides are used in many kinds of detectors,
e.g. NaI...
> If film were not sensitive to x-rays, then we would never get chest x-rays, would we?
In basic X-ray machines the rays don't expose the film. A fluorescent
screen converts the X-ray shot to visible light. That is photographed in
the usual way. Besides, X-rays are at another wavelength than gamma.
BTW, when I was working with space electronics, the only protection
against gamma irradiation was "more lead". Film is a lot lighter.
Someone should have told us that it, too, catches gamma ;-)
-- Lassi
Al Zeller
so I'll try once more. If anyone is confused: try a good text book or
encyclopedia.
Lassi Hippeläinen wrote:
>
>
> In basic X-ray machines the rays don't expose the film. A fluorescent
> screen converts the X-ray shot to visible light. That is photographed in
> the usual way. Besides, X-rays are at another wavelength than gamma.
>
That may be the way some x-ray machines work, but that is not the way
most work. My undergraduate research involved x-raying sea sediment core
samples. I used standard x-ray film and standard developing techniques
which necessitated the removal of the paper on the film. It was nothing
more than regular paper with no fluorescent material on it.
> BTW, when I was working with space electronics, the only protection
> against gamma irradiation was "more lead". Film is a lot lighter.
> Someone should have told us that it, too, catches gamma ;-)
>
All matter absorbes electromagnetic radiation proportional to its
density. Depending on the material and the energy of the photons the
transmitted intensity of em radiation is proportional to e to the power
-mu x, where mu is the linear absorption coefficient and x is the
material thickness. So you need a lot of film to get the equivalent of a
sheet of lead.
Al Zeller
Eugene A. Pallat
> "Eugene A. Pallat" wrote:
> > It's quite easy. X-rays are gamma radiation. So is IR. It just depends upon
> > the wavelength. Radio and TV are *very* low frequency gamma rays. See any
> > physics text. If it's powerful enough to kill bacteria, it's powerful enough to
> > fog fast film.
> >
> > Gene Pallat
>
> Radio waves don't fog film ;-)
I never said that. Gamma rays are just *very* high frequency waves the same as radio
waves are very *low* frequencies. The higher the frequency, the higher the energy.
> I know about the physics. I have a major on the item. Gamma rays are a
> type of photons.
A *type* of photon? Photons are either particles or waves depending upon how you
measure them - the duality paradox. You measure for waves, you get waves. You
measure for particles, you get particles.
> Radio waves and visible light are photons too, but they
> aren't gamma rays.
Just very low frequency and energy versions of the same thing.
Re-read my point. If the energy, and therefore frequency, is high enough to kill
bacteria, it's high enough to fog film.
Gene Pallat
tos...@aol.com ab...@aol.com ab...@yahoo.com ab...@hotmail.com
ab...@msn.com ab...@sprintmail.com ab...@earthlink.net u...@ftc.gov
Neurula [Sydney]
using EB (electron beam) devices.
"Lassi Hippeläinen" <lahi...@ieee.orgies.invalid> ?????
news:3BD54D10...@ieee.orgies.invalid...
> "Neurula [Sydney]" wrote:
> >
> > No, I think they use mainly Alpha & Beta particles, which have no effect
on
> > the film emulsion
>
> Certainly not alpha-particles. A thin paper will stop them. Beta seems
> unlikely, because they are just electrons.
>
> I'd use gammarays for desinfection. The same stuff that is used for food
> irradiation. I'm not sure about their effect on films, but probably
> negligible. Detecting gammarays isn't that easy.
>
> -- Lassi
>
> >
> > "DBaker9128" <dbake...@aol.com> źśźgŠóślĽó
PSsquare
two potential sources as electron and x-ray. They interviewed manufacturers
and scientists, and as I heard it, both forms of radiation would fog film.
The first would penetrate up to 2 inches of paper and the latter would
penetrate up to 24 inches. After all, it takes a lot of radiation to
rapidly kill living organisms.
PSsquare
DBaker9128 wrote in message <20011023001037...@mb-fx.aol.com>...
Didier Adeline
Here is a link to the company that produces those devices.
Why not ask them ?
Cheers
Didier
Neurula [Sydney] <intelligence@!!!technologist.com> wrote in message
news:9r9hoa$t4r$1...@tomahawk.unsw.edu.au...
Chad Irby
"Didier Adeline" <dade...@cyberdude.com> wrote:
> Here is a link to the company that produces those devices.
> Why not ask them ?
What link?
Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.
Wilt W
on this thread, PPA's response is essentiall "We're not sure...stay tuned"!
Here is a cut and paste of an email I just received from the PPA:
***********************************************
New Postal Service Equipment May Destroy Film
Responding to the threat of additional anthrax attacks, the United States
Postal Service has announced that it is installing irradiation equipment to
sterilize mail. This security measure, which is reasonable in light of the
current situation, has prompted questions from several members regarding
the possibility of film being damaged or destroyed in the mail.
The Postal Service has cited security concerns and is refusing to give
specific details about the equipment. However, the Postal Service has said
that the irradiation equipment will be similar to that used for food
sterilization. Such food sterilization equipment either uses gamma rays or
electrons, generated by the radioactive isotope Cobalt-60 and electricity
respectively, to destroy bacteria. According to a NASA study obtained by
PPA, these types of so-called "soft radiation," are also very efficient in
transferring energy to photographic film. (NASA Contractor Report 188427,
Sept. 1995)
While the potential for film damage and fogging will likely depend on the
settings and types of equipment used, Professional Photographers of America
is urging caution on the part of all members who use the United States
Postal Service to ship film.
In the meantime, PPA is working diligently to obtain additional information
regarding the situation. When additional information becomes available, PPA
will notify its members immediately.
Photoshop Guy
Simply open up all mails and use a fan or a vacuum to suck/blow all the
spores.
Then get rid of the spores.
Joshua_Putnam
The outside of the mail can already be cleaned in the processing
equipment, but doing that to the contents may be a different
matter -- I buy my photo chemicals by mail, and some cooking
supplies, and tire talc, etc. If you open those up and vacuum
them, you'll be sucking up the contents, whether it has any
spores or not.
--
jo...@phred.org is Joshua Putnam
http://www.phred.org/~josh/
70mm Film Users: new Yahoo Club for 70mm, see
http://clubs.yahoo.com/clubs/using70mm
M. P. Brennan
"Photoshop Guy" <intelligence@!!!technologist.com> wrote in message
news:9rg7hk$m9v$1...@tomahawk.unsw.edu.au...
Q.G. de Bakker
> > If film were not sensitive to x-rays, then we would never get chest
x-rays, would we?
>
> In basic X-ray machines the rays don't expose the film. A fluorescent
> screen converts the X-ray shot to visible light. That is photographed in
> the usual way. Besides, X-rays are at another wavelength than gamma.
X-Rays, and gamma rays, release Compton electrons inside the emulsion. They
do cause "exposure". A lot of it, since they can travel quite a distance
through the emulsion. Fluorescent screens are not necessary to record an
image.
Eugene A. Pallat
> In basic X-ray machines the rays don't expose the film. A fluorescent
> screen converts the X-ray shot to visible light. That is photographed in
> the usual way. Besides, X-rays are at another wavelength than gamma.
That might have been done at one time, but not for at least 40 years that I know of. You
might be thinking of a fluoroscopes where the image is viewed visually. X-ray film is
sealed from light and exposed directly to X-rays.
Art Begun
mail drop box otherwise you are only protecting
half the process from contamination.
Joshua_Putnam
It's true, you're only protecting the sorting and delivery side
of the equation by irradiating at the sorting centers. But that
does localize the problem and prevent delivery of unsterilized
mail. If the contaminated mail can't reach its target, and the
whackos sending it know that it can't reach its target, they're
much less likely to send it through the mail to begin with.
--
jo...@phred.org is Joshua Putnam
http://www.phred.org/~josh/
Build your own bicycle frames. See
http://www.phred.org/~josh/build/build.html