Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass...

12
Scanning Electron Microscope Jamie Goings

  • date post

    20-Dec-2015

  • Category

    Documents

  • view

    220

  • download

    0

TAGS:

Transcript of Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass...

Page 1: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.

Scanning Electron Microscope Jamie Goings

Page 2: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.

Theory• Conventional microscopes use light and glass lenses• SEM uses electrons and magnetic lenses to create magnification • Electron beam ‘traces’ over object, interacting with surface and dislodges surface electrons• Detector collects electrons, and registers different levels of brightness• Scanned onto monitor dot by dot, row by row

Page 3: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.
Page 4: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.
Page 5: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.
Page 6: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.

Instrumentation – Electron Gun

1. Thermionic Guns – most common voltage is applied that heats filament (usually tungsten)

2. Field Emission Guns Creates strong electrical field to pull e away from atoms

Anode attracts e causing them to accelerate down into a beam

Page 7: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.

II. Lenses Magnetic lenses direct electron beam into wanted path.

III. Scanning Coils-Additional magnetic field use voltage to move beam back and forth across sample. -Can adjust magnification here by adjusting scan area

IV. Sample Chamber-must be sturdy and isolated from vibration-adjustable position-vacuum chamber – keeps e beam clear of air particles and sample free of dust

Page 8: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.

V. Detectors1. Secondary Electron Detector- has a 300V positive charged metal cage to

attract e- collects e dislodged from surface - number of e collected per ‘dot scan’

determined brightness of spot- creates image2. Energy Dispersive X-Ray Detector (EDX)- elemental analysis- analyzes x-rays emitted from specimen - detects number of x-rays vs their energy-

energy of x-ray is specific to element it was emitted from

Page 9: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.

EDX Spectrogram

Page 10: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.

Sample / Sample PrepSample-must be conductive-must be able to withstand vacuum – no liquids-15/15 mm older machines-200/200 mm modern

Sample Prep-clean dust or debris-sputter coating-biological samples are dehydrated and dried

Page 11: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.

Benefits / Limitations

Benefits-High depth of field-High resolution – high magnification-Can adjust focus, contrast, brightness-Computer controls-3D image-With EDX is both qualitative and quantitative

Limitations-Generates radiation-Needs to be clean!!!

Page 12: Scanning Electron Microscope Jamie Goings. Theory Conventional microscopes use light and glass lenses SEM uses electrons and magnetic lenses to create.

Work Cited:

Oatley, C. W. The Scanning Electron MicroscopeGabriel, Biological Scanning Electron MiscroscopySpringer-Verlag, Methods of Preparation for Electron Microscopyhttp://www.purdue.edu/rem/rs/graphics/sem2.gifhttp://www.herguth.com/technical/sem.pdfhttp://static.howstuffworks.com/gif/scanning-elecron-microscope-illustration.jpg (image)

http://www.purdue.edu/rem/rs/graphics/sem2.gif
http://www.herguth.com/technical/sem.pdf

Describing Images COPYRIGHTED MATERIAL€¦ · understanding of optical systems (human’s eye, glasses, magnifying glasses, binoculars, microscopes, camera lenses, and telescopes);

Describing Images COPYRIGHTED MATERIAL€¦ · understanding of optical systems (human’s eye, glasses, magnifying glasses, binoculars, microscopes, camera lenses, and telescopes);

GX Microscopes Biological Upright Compound Microscopes ...

GX Microscopes Biological Upright Compound Microscopes ...

Microscopes History, Parts, and Usage. History of Microscopes Microscopes were invented in late 1500s –Compound microscope (2 or more lenses) –Used natural.

Microscopes History, Parts, and Usage. History of Microscopes Microscopes were invented in late 1500s –Compound microscope (2 or more lenses) –Used natural.

History of the cell: The development and refinement of magnifying lenses and light microscopes made the observation and description of microscopic organisms.

History of the cell: The development and refinement of magnifying lenses and light microscopes made the observation and description of microscopic organisms.

Chapter 23Chapter 23 Mirrors and Lenses. Mirrors and Lenses •The development of mirrors and lenses aided the progress of science. •It led to the microscopes and telescopes. –Allowed

Chapter 23Chapter 23 Mirrors and Lenses. Mirrors and Lenses •The development of mirrors and lenses aided the progress of science. •It led to the microscopes and telescopes. –Allowed

Waves, Lenses, Microscopes Science Skills – Part 1 Safety & Mag.

Waves, Lenses, Microscopes Science Skills – Part 1 Safety & Mag.

Topic 4: Lenses and Vision. Essential Learning Outcome I can explain the use of concave and convex lenses in objects such as microscopes, eye glasses,

Topic 4: Lenses and Vision. Essential Learning Outcome I can explain the use of concave and convex lenses in objects such as microscopes, eye glasses,

Care Parts Focusing. Types of Microscopes Light Microscope - the models found in most schools, use compound lenses to magnify objects. The lenses bend.

Care Parts Focusing. Types of Microscopes Light Microscope - the models found in most schools, use compound lenses to magnify objects. The lenses bend.

Microscopes Biology Light Microscope (LM) [aka Compound Microscope] Visible light is projected through the specimen. Glass lenses enlarge the image &

Microscopes Biology Light Microscope (LM) [aka Compound Microscope] Visible light is projected through the specimen. Glass lenses enlarge the image &

Light Microscopes Use lenses to direct light in order to enlarge images.

Light Microscopes Use lenses to direct light in order to enlarge images.

Microscopes. Eyepiece Contains the ocular lens Nosepiece Holds the high and low-power objective lenses; can be rotated to change magnification. Objective.

Microscopes. Eyepiece Contains the ocular lens Nosepiece Holds the high and low-power objective lenses; can be rotated to change magnification. Objective.

Comings & Goings

Comings & Goings

(c) McGraw Hill Ryerson 2007 6.2 Extending Human Vision Microscopes A compound light microscope uses two convex lenses to magnify small, close objects.

(c) McGraw Hill Ryerson 2007 6.2 Extending Human Vision Microscopes A compound light microscope uses two convex lenses to magnify small, close objects.

MicroscopesSERIES 176 — Measuring Microscopes • An easy-to-operate standard measuring microscope using specially designed long working distance ML objective lenses. • Measuring

MicroscopesSERIES 176 — Measuring Microscopes • An easy-to-operate standard measuring microscope using specially designed long working distance ML objective lenses. • Measuring

Lenses. Applications of Light Refraction What are some common applications of the refraction of light? Cameras Microscopes Lenses Eyeglasses Human eye.

Lenses. Applications of Light Refraction What are some common applications of the refraction of light? Cameras Microscopes Lenses Eyeglasses Human eye.

Forensic Instrumentation PART ONE Microscopes. A microscope is an optical instrument that uses a lense or combination of lenses to magnify and resolve.

Forensic Instrumentation PART ONE Microscopes. A microscope is an optical instrument that uses a lense or combination of lenses to magnify and resolve.

The Microscope 6 th Grade. How a Microscope Works Convex Lenses are curved glass used to make microscopes (and glasses etc.) Convex Lenses bend light.

The Microscope 6 th Grade. How a Microscope Works Convex Lenses are curved glass used to make microscopes (and glasses etc.) Convex Lenses bend light.

Microscopes. Some Microscope Parts (lens to ‘see’ through; Magnifies 10x) (Carry microscope) (lenses close to object/specimen; Magnifies 10x, 20x, or.

Microscopes. Some Microscope Parts (lens to ‘see’ through; Magnifies 10x) (Carry microscope) (lenses close to object/specimen; Magnifies 10x, 20x, or.

Care Parts Focusing. Types of Microscopes Light Microscope - the models found in most schools, use compound lenses to magnify objects. The lenses.

Care Parts Focusing. Types of Microscopes Light Microscope - the models found in most schools, use compound lenses to magnify objects. The lenses.

Eukaryotic organism Premedical IV. The size range of organisms Light microscopes visible light is passed through the specimen and glass lenses the resolution.

Eukaryotic organism Premedical IV. The size range of organisms Light microscopes visible light is passed through the specimen and glass lenses the resolution.