photographic emulsion presentation

8/11/2019 Photographic Emulsion Presentation

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Photographic Emulsion


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What is Photographic Emulsion in Particle

and Nuclear Physics?

PhotographicEmulsionparticledetectorsfeature

thehighestpositionandangularresolutioninthe

measurementoftracksofionizingparticles.

PhotographicEmulsion,usedtorecordthetracks

ofchargedparticles,isaphotographicplate.

Aphotographicemulsionconsistsofalarge

numberofsmallcrystalsofsilverhalide,mostlybromide.

Thesensitivitytolighthasallowedsilverhalidesto

becomethebasisofmodernphotographic

materials.

Nuclear Disintegration


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Photographic Emulsion

It is the layer of the film or paper that contains

the light sensitive material necessary to it to

actually work.

For example an old camera film is a

photographic emulsion. That film is, very

simply, a light-sensitive emulsion on a plastic

base.

Example bread on butter


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Example

Old Camera film is an example of

photographic emulsion


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Cont.

A photographic emulsion consists of a large

number of small crystals of silver halide,

mostly bromide.

The sensitivity to light has allowed silver

halides to become the basis of modern

photographic materials.


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What is Nuclear Emulsion?(2)

Asilverhalideisoneofthecompoundsformedbetween

silverandoneofthehalogenssilverbromide(AgBr),

chloride(AgCl),iodide(AgI),andthreeformsofsilver

fluorides.

Themethodofrecordingtracksofchargedparticlesin

photographicplatesisbasedupontwoachievementsof

moderntechnology,thephotographicemulsionandthe

opticalmicroscopes. Pion Interaction


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Construction of Photographic emulsion

The light-sensitive part of a photographic

emulsion consists of a myriad of tiny (about a

micron) crystals of silver halide (mostly bromide).

These crystals are suspended in a mediumconsisting mainly of a very pure form of gelatin

The resulting emulsion is thinly spread on a

supporting substrate such as a glass plate orplastic film.


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Cont.

The atoms in a silver bromide crystal exist as

ions.

Each bromine is a negative ion with an extra

electron.

Each silver is a positive ion with one electron

missing.

The combination, of course, has no net

electrical charge.


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Latent Image

A latent image on photographic film is aninvisible image produced by the exposure of

the film to light.

During an exposure to light, a photon eventoccurs when an incoming photon knocks off

the extra electron from one of the bromine

ions. The former bromide ion is released from the

crystal as bromine and is absorbed by the

gelatin.


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Cont.

The electron form a negative charged speck.

This now negatively charged speck attractspositive silver ions which are neutralized to

form silver atoms. This process is continue to happen until a

clump of silver atom is formed.

This clump of silver atoms is now large enoughthat it has become a fully formed latentimage.


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Ag Br

Photon

Photon

Photon

Photon

Ag Br


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Ag+ Br-

Ag+ Br-

Ag+ Br + e-

Ag Br


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Development

This latent image is not visible yet.

We will further develop it to get the image.

Developable means that when an exposedplate or film is placed in a developing solution.

Starting around the clump of silver atoms, the

chemical action of the developer progressively

converts the whole crystal into a grain of

metallic silver.


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Cont.

Those silver halide crystals that are not

converted into silver metal during

development are removed from the emulsion

during the fixing process that follows.

The remaining part is now called the Negative.


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Summary


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Effect of Intensities of light

The Law of Reciprocity

it states that the photographic effect of an

exposure should be proportional to the

product of the light intensity (image irradiance

in photons/mm/second) multiplied times the

exposure duration (in seconds).

But there is failure of this law on high and low

intensities


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At high intensity

At high intensity the photons come in very

high speed and more photoelectrons produce

that require more silver ions. These silver ions

are not present at the time.

Photoelectrons repel each other and some

transfer to other place to neutralized.

This cause low efficiently in latent image.


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Multiple photographic emulsion

From single photographic emulsion we get on

black & white image.

For color image we use different layers of

emulsion.

Each emulsion recording different color.

Between the emulsions are protective

interlayers and all of these layers together

aren't as thick as a human hair.


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e

The PEP4/9-TPC

energy depositmeasurements

The Bethe-Bloch

Formula

Particle Identification.

In Emulsions, the grain density is proportional toenergy loss by ionization(Bethe-Bloch)

If the momentum known, dE/dx allows the particleidentification.

If the Momentum unknown, the combinedmeasurement of momentum(P by MCS) and

grain density allows particle identification.

2=p2/(p2+m2)


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References

http://www.camerabooks.com/Custom.aspx?i

d=5ed3b85d-9c65-429b-b561-b61b89902b72

http://www.silverlight.co.uk/tutorials/basicpf/

latent.html

http://en.wikipedia.org/wiki/Photographic_e

mulsion

www.kodak.com/bglobal/en/consumer/educa

tion/lessonplans/lessonplan152.shtml
http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.silverlight.co.uk/tutorials/basicpf/latent.htmlhttp://www.silverlight.co.uk/tutorials/basicpf/latent.htmlhttp://en.wikipedia.org/wiki/Photographic_emulsionhttp://en.wikipedia.org/wiki/Photographic_emulsionhttp://www.kodak.com/bglobal/en/consumer/education/lessonplans/lessonplan152.shtmlhttp://www.kodak.com/bglobal/en/consumer/education/lessonplans/lessonplan152.shtmlhttp://www.kodak.com/bglobal/en/consumer/education/lessonplans/lessonplan152.shtmlhttp://www.kodak.com/bglobal/en/consumer/education/lessonplans/lessonplan152.shtmlhttp://en.wikipedia.org/wiki/Photographic_emulsionhttp://en.wikipedia.org/wiki/Photographic_emulsionhttp://www.silverlight.co.uk/tutorials/basicpf/latent.htmlhttp://www.silverlight.co.uk/tutorials/basicpf/latent.htmlhttp://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72http://www.camerabooks.com/Custom.aspx?id=5ed3b85d-9c65-429b-b561-b61b89902b72

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