A Review BY:

Ahmed Mohamed Maghraby

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 3

1-EPR discovery and History:

Stern-Gerlach experiment (1921).

Walter Gerlach

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 4

Zavoisky, E., (1945).

Evgeny Konstantinovich Zavoisky

CuCl2.2H2O

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 5

Frankel, J., et al., (1945).

Microwave systems following World War II.

Gordy, W., et al., (1955).

Van Roggen, A., et al., (1956).

Miyagawa, I., and Gordy, W., (1959).

Bradshaw, W., et al., (1962).

Brady et al, (1968).

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 6

Theory:

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 7

Fundamental Principle of EPR:

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 8

Fundamental Principle of EPR:

E = g.B.H.M

∆E = h.υ= g.B.H g is Spectroscopic splitting factor: ge = 2.002319304386(20)

M : ½ or -½

B: Bohr magneton, (9.274x10-28 J G-1)

H is expressed in Tesla (T), mT, or gauss.

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 9

E

B = 0

B ≠ 0

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 10

Spectrometer Structure

1- Automatic frequency control.

2- Microwave source power supply.

3- Microwave source (Klystron or

Gunn diod. 4- Isolator. 5- Frequency

counter. 6- Attenuator. 7- Terminating

load. 8- Oscilloscope. 9- Detector

crystal. 10- 100 kHz signal amplifier.

11- 100 kHz signal detector. 12- Pen

recorder and data bank (or computer).

13- Circular or hybrid tee. 14- Cavity

system. 15- 100 kHz. Modulation coils.

16- 100 kHz. Power amplifier. 17-

100 khz. Oscillator. 18- Resonant

cavity. 19- Magnet power supply.

20- Field scan drive

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 11

Field-Frequency Combinations

Waveband L S C X P K Q U V E W F D — J —

λ / mm 300 100 75 30 20 12.5 8.5 6 4.6 4 3.2 2.7 2.1 1.6 1.1 0.83

ν / GHz 1 3 4 10 15 24 35 50 65 75 95 111 140 190 285 360

H / T .03 0.1 .14 .33 .54 .86 1.25 1.8 2.3 2.7 3.5 3.9 4.9 6.8 10.2 12.8

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 12

Field-Frequency Combinations

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 13

Some Advantages of Radiation

Dosimetry using EPR

Non-destructive technique, hence archivable.

Small Sample size.

Accurate and reproducible.

Wide dose range, hence wide applications.

Possibility of quantification.

Rapid results accessible.

Measurements in wide range of temperatures.

Varieties of spectrometer design fits different applications.

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 14

EPR Radiation Dosimetry

Industrial Applications Medical Applications Emergency

Alanine Food Irradiation Drug Irradiation Other Applications Other organics Human subjects Non-Human Subjects Environmental subjects

Teeth

Nails

Hair

Others

In-Vivo

In-Vitro

Meat

Vegetables

Fruits

Seeds

Oters (Tea, Spices, Herbs, …)

Alanine Dosimeters

Alanine derivatives

Structure

Shape

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 15

EPR Radiation Dosimetry

1- Industrial Applications:

I- Food Irradiation.

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 16

EPR Radiation

Dosimetry

1- Industrial Applications:

I- Food Irradiation.

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 17

EPR spectra of irradiated crab exoskeleton:

a- Cheliped, b- dactyl, c- walking legs, d- carapace,

e-apron, f- swimming legs.

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 18

1- Industrial Applications:

II- Drug Irradiation.

III- Other Applications.

EPR Radiation Dosimetry

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 19

EPR Radiation Dosimetry

2- Medical Applications:

I- Alanine Dosimeters

(C3H7O2N)

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 20

2- Medical Applications:

I- Alanine Dosimeters

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 21

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 22

2- Medical Applications:

I- Alanine Dosimeters

Shape and Size

Structure

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 23

2- Medical Applications:

I- Alanine Dosimeters

Standardization

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 24

2- Medical Applications:

I- Alanine Dosimeters

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 25

Advantages: 1. Nearly tissue equivalent over the radiation energy range above about 100

keV of photon energy.

2. Usefulness over a wide dose range 10-105 Gy.

3. Low fading in standard conditions.

4. Zero (or negligible) background.

5. Small sample size.

6. Reproducible.

7. Reasonable inter-batch uniformity.

Disadvantages: 1. Spectrum is attributed to not less than 3 radicals

2. Complex-time dependence.

3. Non-single peak spectrum.

4. Wide spectrum.

5. Limited sensitivity.

2- Medical Applications:

I- Alanine Dosimeters

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 26

Alanine Derivatives.

Other Organics.

Inorganics.

EPR Radiation Dosimetry

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 27

Retrospective and emergency dosimetry

Teeth Enamel Dosimetry

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 28

Retrospective and emergency

dosimetry Teeth Enamel Dosimetry

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 29

Retrospective and emergency

dosimetry

Teeth Enamel Dosimetry

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 30

Emergency Dosimetry

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 31

Emergency Dosimetry

Nails

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 32

Hair

Teeth Biopsies

Non-Human Subjects

Environmental

Dosimetry

Emergency Dosimetry

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 33

Hardware developments

Resonators

Bridges

Magnets

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 34

Imaging

16-Nov-14 Recent Techniques of Radiation Dosimetry Using EPR - A Review by: Ahmed Maghraby (Ph.D.) 35

Dating

Data Processing

Uncertainities

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T

H

A

N

K

Y

O

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