DeLong's novel Low Voltage Tabletop SEM STEM TEM Scanning Transmission Electron Microscope

This electron beam imaging instrument is of rather novel design - both economical and unique in being 3 mode - SEM, STEM and TEM and low voltage and extremely compact. The instrument is manufactured curiously in Brno Czechoslovakia by a firm that has been making electron optics imaging instruments for quite some time, albeit with little visibility in North America until recently.

links to the firm in North America

the main company back in Brno

a university research team in Czechoslovakia

an electron microscope museum at the university

another link describing the firm and the prior history

This picture shows the coupling between the inverted electron column and the optical microscope used for image data capture via a CCD camera on the optical microscope, followed by detail of the instrument in the region of the microscope objective and the YAG phosphor screen.

[ NOTE CLICK ON ANY IMAGE IN THE POST TO ENLARGE PICS - reduced image sizes are in post to improve page loading, my apologies ]



A salient performance feature of the DeLong LVEM (Low Voltage Electron Microscope), is that due to the unique low voltage beam for a TEM imaging setup, this feature provides unusually good contrast of thin biological specimens, dominated by low mass (carbon) and sensitive to excessive energy of typical fragile biological specimens.

Notably is that LVEM improves signal to noise in thin low atomic mass biological samples due to a reduced depth / volume from which the electron image sample signal is generated, from the low energy electron beam.

Picture showing the contrast advantages of LVEM in thin samples

and better yet, real image data for side by side comparison of SIGNIFICANTLY improved image contrast in thin biological samples using LVEM low voltage TEM, over conventional High Voltage TEM imaging. Who would have thought that such an inexpensive scientific microscope would best the conventional expensive HV TEM ?? Quite amazing really. (realize that conventional HV Tems are easily between $300k - easily 1m+ )

Despite the unusual design, the imaging obtained with the Field Emission electron source is very good even excellent for a $125k-150k instrument, that is simple enough to be quickly installed very conveniently on a desk. The image contrast is typically excellent, even impressively so, although maximum magnification / resolution might not be as good in SEM mode as a typical high end ~$500k conventional field emission sem. Nor will the TEM be in the least capable of atomic lattice type imaging as often done with conventional high voltage TEMs.

I think this is a wonderful electron microscope, with its unusual mix of simplicity and nicely designed features at very low cost. Notable is that despite the low price a sample vacuum load lock is included, which is critical for any Field Emission source electron beam imaging microscope. Really astounding for a $125k instrument.

Picture of the high vacuum system of the LVEM, showing pumps, electron column, sample load lock & holder among others.

Under certain conditions the imaging field has substantial imaging field curvature in the periphery of the imaging field, in part due to the low cost and simple electron optics design, but again even in high end SEMs one observes field curvature with very low magnifications.

But all in all, this hardly matters in typical use, as most of the time, one is keen on getting good images of high contrast in short time and at modest cost. The DeLong LVEM is a wondrous mix of features and capability, at an unprecedented low cost that is almost unbelievable for a decent Field Emission electron microscope.

I say this quite emphatically as I have used numerous SEMs that obviously are considerably more of a typical headache due to their complexity, at little benefit over this DeLong instrument, in workhorse day to day small sample work

But do not confuse oneself as the TEM images will never be near atomic resolution, yet there are many imaging applications which never need that in the least.

All in all, an excellent lab instrument, especially for the unique capabilities of low voltage TEM for biology, aside from superb high contrast work of more common samples using SEM and low voltage TEM.

[ NOTE - click on any of the pictures to see a higher resolution image ]

Here is the main microscope column on a desk, with imaging camera / visual optics + an overall cross section of the function of the unique design.



Close ups of the front of the electron column, a cross section of the electron optics showing the sample manipulator and load lock, detail of the microscope objective lens in proximity to the imaging phosphor screen, and another cross section of the electron column with some extra detail of the electron lenses ( or deflectors?)



The optical camera, system power supply electronics, the operator electron beam control panel, and a snap of the control software interface screen.





Below are TEM, SEM and STEM Pictures that DeLong kindly provided for me for this article. Click on any picture and a higher resolution version will open, with a scale bar visible in most images...

TEM Malaria


TEM Quantum Dots


TEM RAT Brain


TEM Amyloid


TEM Pollen


STEM stained lymphocyte


STEM polyethylene crystal


STEM MgO nanoparticles


STEM bacteria


SEM polymer Blend


SEM polystyrene Beads Low Voltage uncoated


SEM gold nanoparticles material relief


SEM gold nanoparticles


SEM Alloy


SEM Nanowires in Polymer Matrix


SEM Hydrogel


SEM polymer Foam


SEM magnetic nanoparticles on Cell Surface


Uncoated Red Blood Cells SEM


SEM Ant Bits


SEM Catalase Protein Crystal


FLY SEM DATA EYE and LEGS



AND for those interested in novel beam or probe based imaging advances here is an article on a most novel FIB ( Focused Ion Beam ) from Zeiss / ALIS
which uses a Helium Ion Beam, and has advanced largely on the key innovations in the ion source technology.

and another article describing the instrument technology and scientist behind the advance of AFM - Atomic Force (probe) Microscopy into the realm of subatomic resolution - the amazing previously unthinkable nanomechanical probes and microscope.

some trends in R&D of advanced Atomic Force Microscopy

and discussion of a method to advance fine scale AFM / nanoprobe based metrology

POSTSCRIPT June 5th 2007, crazy thought would be to take this instrument and couple a Nabity pattern generator and see how well it might write patterns in photoresist (albeit carefully $ properly prebaked). If testing showed some interesting results, it might prove fun to make a more serious cheap electron beam writer...so long as the FE electron source was a TFE (thermal field) rather than CFE (cold field ), since CFE sources tend to drift excessively in emission, and can be a bit of a pain to maintain steady dosing in writing larger longer writing patterns..


I hope you enjoy the reading, especially Deron from "nowhere" in santa barbara who is downloading ALL the pics from this page. Happy nano trails .....

wendman nanotechnology nano nanotech SEM Electron+Microscope Silicon+Micromachining MEMS IBM ETEC Applied Materials Electron+Beam+Lithography Maskless Lithography KLA Tencor Veeco Intel 65nm nanometrology ebeam lithography