Department of Chemistry



site header

Electron Microscopy

  • Quanta 250 Instrument

    The Quanta 250 Instrument


Department of Chemistry
Chernoff Hall Room 105
Queen's University
90 Bader Lane
Kingston, Ontario, Canada K7L 3N6
Lab: 613-533-6000 ext.74653
Fax: 613-533-6669


Monday to Friday
8:30 a.m. to 4:30 p.m.

Electron microscopy illuminates the micro- and nano-worlds allowing us to see structures, textures, and elemental compositions in a variety of samples. Using electrons with much smaller wavelengths than visible light, we are able to resolve smaller features, down to atomic scales in the most powerful electron microscopes. There are two main types of electron microscopy, scanning (SEM) and transmission (TEM). In SEM a beam of electrons (~1-30 kV in energy) is scanned across the surface of the sample and information collected at each point (pixel) of the sample.

Our Quanta 250 environmental SEM is equipped with detectors for both secondary and backscattered electrons at a range of vacuum pressures, with an EDAX Element EDS detector for elemental X-ray characterization of samples. Samples should be conductive or can be coated with a conductive layer. However, the use of a variable pressure chamber allows for the imaging of non-conductive samples as well.

Contact Information

Photo: Kevin McEleney

Dr. Kevin McEleney
Instrumentation Manager



Thermo Fisher Quanta 250 eSEM with Everhart-Thornley, Concentric Backscattered Electron, Large Field, and Gaseous Secondary Electron detectors for variable pressure measurement of both secondary and backscattered electrons. An EDAX Element EDS detector is used for elemental characterization including mapping.

Sample Prep/Requirement

SEM can accommodate most materials for analysis.

  • Samples should be vacuum compatible (1 torr and below, typically 10-4 torr) and free of loose particles.
  • Conductive samples are easier to image but non-conductive samples can be run either by coating with a thin conductive layer or using one of the low vacuum modes to minimize sample charging.
  • Samples should be able to fit on a ¼” diameter stub, the stage can hold 7 stubs for multiple sample imaging.
  • Samples should be dry, preferably placed under vacuum prior to entering the SEM chamber.
  • Powder-type samples can be pressed into a pellet or deposited on double-sided conductive tape. Any loose particles should be removed using clean air prior to introduction into the vacuum chamber.

Users who wish to have samples run by a staff member should contact the Facility Manager directly and can submit a request form for SEM imaging.

SEM Request Form

Students/researchers can be trained on the Quanta 250 to run their samples independently of the instrument managers. Requests for training can be sent to Kevin McEleney. Groups of 2-3 can be trained simultaneously. Upon successful completion of the training program a user can request SEM time by e-mailing the Facility Manager directly and time will be assigned to the user.

Returning Samples

Samples will be disposed of 30 days after completion of the analyses, unless the return of the samples is requested on the Request Form. Sample return costs will be added to your invoice unless a courier account number (FedEx or DHL) is provided.