Topic:

Ion Cyclotron Resonance

Assigned By: Prof. Dr. Shahabudin Memon

Presented By: Ghulam Mustafa Channa ( M.Phil Scholar )

University of Sindh, Jamshoro, Pakistan.

Contents:

• Introduction to Mass Spectrometry• Mass Spectrometer • Mass Analyzer• Introdction to ICR • History of Cyclotron• Working Principle, Instrumentation and Construction of Cyclotron

• Limitation• Application• Advantages• ICR V/S other Mass Analyzers • Conclusion• References• Acknowledgement

Mass Spectrometry:

•Mass spectrometry is the art of measuring atoms and molecules to determine their mass.

• Such mass or weight information is always useful in determining and identifying different species through mass spectra.

Mass Spectrometer:

• It is an instrument that produces ions, separates them according to their m/z values, detects them, and plots the mass spectra.

• There are four basic components standard in all mass spectrometers. a sample inlet, an ionization source,

a mass analyzer and an ion detector.

Mass Analyzer:• Mass analyzer is the Heart of the mass spectrometer that separates ions. It is

also called ion separator and subsequently records their intensities.

1. Quadrupole mass analyzer2. Time of flight analyzer (TOF)3. Magnetic sector mass analyzer4. Single focusing5. Double focusing6. Quadrupole ion trap mass analyzer

7. Ion Cyclotron Resonance

• Basic types of mass analyzers are listed below:

INTRODUCTION

Introduction to ICR

• Ion cyclotron resonance is the phenomenon related to the movement of ions in a magnetic field. It is used for accelerating ions in a cyclotron for measuring the mass/es of ionized analyte/s in mass spectrometry.

• Cyclotron uses a magnet and voltage to accelerate charged particles.

HISTORY

History:• Cyclotron was invented by Ernest Orlando Lawrence in

1932, in which charged particles accelerated in spiral path.

• Lawrence was awarded the Nobel prize in 1939 for this invention.

• The largest cyclotron was the 4.67m (184-inch) built between 1940-1946 by Lawrence at the University of California at Berkeley, which could accelerate protons to 100 - 730 MeV.

• In 1930

• Size of first cyclotron was only 4

inch (Diameter)

1st Cyclotron:

• In 1932

• Acquire Energy 1.2 MeV

• Can accelerate the proton

11 inch Cyclotron:

• In 1932

•Acquire Energy 4.8 MeV

27 inch Cyclotron:

37 inch Cyclotron:

• In 1937•Acquire Energy 8.0 MeV

60 inch Cyclotron

• In 1939

•Acquire Energy 16 MeV

184 inch Cyclotron

• In 1946

•Acquire Energy > 100 MeV

• The largest cyclotron.

Cyclotron Location Years of Operation

Accelerated Particle

Kinetic Energy Notes and Discovery made

4 inch University of California ,Berkeley 1930 Proton - Proof of Concept

11 inch University of California ,Berkeley 1932 Proton 1.2 MeV ---

27 inchUniversity of

California ,Berkeley 1932-36 Deuteron 4.8 MeV Investigate deuteron –nucleus interaction

37 inch University of California ,Berkeley 1938 Deuteron 8 MeV Discover many isotopes

60 inch University of California ,Berkeley 1939 Deuteron 16 MeV Discovered Many isotopes

95 inch Harvard Cyclotron Laboratory 1940 Protron 160 MeV Used for Nuclear Physics 1949-1961

Development of clinical proton therapy until 2002

184 inch Berkeley Radlab 1942 Various >100 MeV Research on Uranium isotopes separation

Modern Cyclotron

INSTRUMENTATION

DEESAC SOURCE

MAGNET POLE N/S

ION SOURCE

DEFLECTOR

CYCLOTRON TANK

TARGET ASSEMBLY

4 DP

MECHANIAL PUMP

WORKING PRINCIPLE

Working principle of ICR is based on these steps:

• Production of charge particles• Acceleration of charge particles • Extraction of particles• Bombardment of ions to target

Working Principle of ICR ?

• In electric field a charged particle is accelerated.

• In magnetic field a charged particle can be turned around.

• Where in magnetic field the magnetic force acts as a centripetal force.

• The magnetic force bend charges into a spiral path and applied electric field accelerates charged particle between the "Dees"

Working Principle of ICR ?

• We have an electromagnet which continuously generates a magnetic field.• The magnetic filed is directed vertically

upward.• Inside the magnetic field we have two

metallic plates D1 and D2 • Both these magnetic plates are connected

to an alternating electric source. • They are known as “dess” as they are in D

shape.

Working Principle of ICR ?

• These dees are enclosed in strong magnetic field produced by two pole of electromagnet.

• A charged particle “P” entering the cyclotron center will be attracted by the negative plate if it is positively charged and vice versa if negatively charged.

Working Principle of ICR ?

• Ion move with constant velocity in spiral path under the influence of magnetic field which is perpendicular the Dees.

• If the ions emerge from D1 or D2 , the polarity of the applied potential is reversed, the positive ions will again face the negative “Dee” and thus will be again accelerated by the electric field in the gap.

Working Principle of ICR ?

D1

D2

• The time passage to complete the semi-circle in the D1 remains the same as in D2.

• In this way the positive ions move faster and expanding circle until they reach the outer edge of the Dees, where they are deflected by deflector and strike the target.

Working Principle of ICR ?

5

C

FN

1

3

2

4

5

O

• Observations of such collisions yield information about the charged particles in form of spectra.

• It is expensive.

• It cannot accelerate neutron, because neutron do not have any charge.

• Capable of being used only with pulsed ionization sources, not continuous ion sources.

• Runs at very low pressure.

Limitation:

• Cyclotron is used to bombard nuclei with energetic particles and observe the nuclear reactions.• Ion beams from cyclotrons can be used, as in proton therapy, to penetrate

the body and kill tumors by radiation.

Application:

• Excellent accuracy and extremely high resolving power.

• The highest recorded mass resolution of all mass spectrometers.

• Non-destructive method, i-e ions at the end of this experiment can be used for another measurement.

Advantages:

ICR V/S other Mass Analyzers

Characteristics ICR Quadrupole Magnet Sector Time of Flight

Cost More Expensive - - Cheaper + + Expensive - Cheap +

Size Larger - - Smaller + + Large - Small +

Mass Resolution Highest

Resolution + + +

Less Resolution -

High Resolution +

High Resolution +

Efficiency of ion separation High ++ Moderate - Moderate - High ++

Operating Pressure (Torr) 10-9 (High) 10-3 (Less) 10-6 (Moderate) 10-6 (Moderate)

 • ICR-MS having highest resolution and separates ions more

efficiently using electric and magnetic field. •Non-destructiveness is its unique property.

• It is a most accurate technique but its compatibility with ion sources makes it of less demand.

Conclusion:

1. https://www.youtube.com/watch?v=cNnNM2ZqIsc2. http://www.research.uky.edu/core/massspec/jeolanalyzers.pdf3. An Introduction to Mass Spectrometry by Scott E. Van Bramer4. Mass Spectrometry Principles and Applications (Third Edition) Edmond de Hoffmann5. Fourier transform ion cyclotron resonance spectroscopy journal of pharmaceutical and

scientific innovation6. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: A Primer Alan

G.Marshall,*† Christopher L. Hendrickson, and George S. Jackson†Center for Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Dr.,Tallahassee, FL 32310

7. Ion Cyclotron Resonance By T. H. Stix and R. W. Palladino8. MASS ANALYZER BY:- VARUN GIRME

References:

Acknowledgment

•Thanks to Almighty ALLAH for everything in my life.

•Thanks to sir Shahbuddin Memon for his religious & motivational talks.

•Finally thanks to all my Classfellows for being patient during my presentation.

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