|
The Electron Microscope is an essential component
for scientific analysis of a variety of materials. The
centre has a well equipped
laboratory which houses both a Transmission Electron Microscope
(TEM) and Scanning Electron Microscope (SEM). Together, the
instruments comprise a powerful tool in studying (cell and molecular
biology, anatomy, microbiology, pathology and forensic science)
biological specimens, food stuffs and several other areas of
material sciences (electronics, metallurgy, polymer and surface
science).
Transmission Electron Microscope
(TEM)
TEM is analogous to the optical microscope. It
provides very high resolution which can reach approximately 0.1 nm
in the case of lattice images. Consequently very high
magnification (Close to 1 million times) can be obtained. TEM
is used to examine very thin sections (<60 nm in thickness)
through the cells and tissues or through materials as well as
replicas of the surfaces of the smples.
120 kV Transmission Electron Microscope
A Transmission Electron Microscope, Hitachi (H-7500)
120 kV is equiped with CCD Camera This instrument
has the resolution of 0.36 nm (point to point) with
40-120 kV operating voltage and can magnify object
up to 6 lakh times in High Resolution mode. It has
Electron Diffraction, Tungsten Filament, Low Dose
Function, High Contrast Mode with ergodynamic look.
The specific features of the instrument are: maximum
field of views at x700 with dual picture modes, Auto-navigation,
Largest possible field with mose contrast, auto pre-irradiation
mode (APIS). The equipment has provision for future
up-gradation for an analytical system by adding EELS,
EDS and STEM attachments.
Scanning Electron Microscope (SEM)
SEM
facilitates the observation of very fine details (high resolution)
of biological materials and good focus over a wide range of specimen
surface (large depth of field). It also produces clear image of
specimen ranging from object visible to the naked eye to a structure
spanning few nanometers. Besides its use in studying soils,
sedimentary particles and rock materials, it also helps to elucidate
the architecture and evolution of microfossiles.
Digital Scanning Electron Microscope - JSM 6100
(JEOL)
 This was the first
microscope of its kind in India when installed in 1991.
The JSM-6100 is equipped with a digital image processor. It
has a large specimen chamber that allows observation of the entire
surface of a specimen upto 150 mm and a tilt of -5 to
90o. A special feature of this SEM is a cryostage
attached to it to study the low melting point specimens.
The image processing function permits image
averaging and storage, filling of acquired still images and
comparison of two/four images displayed simultaneously on the 12
inch CRT. This function makes it possible to observe specimens
without causing damage to them.
Other features of this microscope are:
|
Resolution |
= |
4.0 nm at 8mm working
distance |
|
Working distance |
=
|
6 to 48 mm |
|
Accelerating Voltage |
= |
0.3 to 30 KV |
|
Magnification |
= |
x10 to x300,000 |
|
Image Recording |
= |
on 120 B&W Roll Film (100 ASA) or
35mm B&W roll (25 ASA) |
|
Instant Print |
=
|
an instant print is also possible on a
Thermal Video Printer
(8x10.5) |
Ancillary Equipments available
- Ultramicrotomes (LKB Nova) & RMC XL
- Glass Knife Maker (LKB Knife Maker) and RMC
- Sputter Coater (JEOL JFM 1100)
- Evaporation unit ('Ladd' Research Laboratory)
- Freeze-drying apparatus
- Critical point dryer
- Image analyser which will further enhance the utility and
versatility of this instrument
- Automatic tissue processory and a autostainer
Specimen Requirement for TEM
This
tissues/specimens are received for examination in the form of
stained grinds. The particulate samples are received in
suspension for negative staining. The grids are prepared in
the laboratory. Efforts are on to create the facility of
tissue processing in the centre in near future.
Specimen Requirement of SEM
The
biological samples stored in 0.1 M buffer at 4oC after
primary fixation are received for studies. The subsequent
treatment is undertaken by the technical personnel of the
centre.
For transmission electron microscopy, plate
films/35 mm films are made available, depending on the need of the
users. For scanning electron microscopy, 120 mm/35 mm film is
provided by the user. The films are developed and the
negatives are handed over o the users. The Centre also
provides photograph printing facility to users on demand.
Recently, the facility to prepare projection slides with an
attachment of 35 mm camera while doing routine recording on SEM of
results has been
started. |
