LVEM 25E
The LVEM 25E (Low Voltage Electron Microscope) is a versatile and easy-to-use FEG-type transmission electron microscope (TEM) that combines several imaging modes: transmission mode, electron diffraction mode, scanning transmission mode, and SEM-like scanning mode (BSE detector only), providing the nanometer level resolution. The microscope is also equipped with energy dispersive X-ray spectrometer (EDS) for elemental analysis. It is designed to measure conventionally prepared TEM samples, especially those of low contrast and low atomic number materials (organic matter, polymers). Samples can be thin sections, thin foils, or fine particles dispersed on a standard supporting TEM grid with a diameter of 3.05 mm. High contrast of the light elements is achieved using significantly lower electron energy (25 kV) compared to standard TEM (60-300 kV). Considering this, the sample must be sufficiently thin to image objects containing heavy elements. The maximum thickness of the sample has to be up to 120 nm for low Z samples, ca 20 nm for metals for TEM mode, and up to 200 nm for low Z samples for STEM mode.
Specification
Basic Characteristics
| Electron gun | Schottky FEG |
| Objective lens | Magnetostatic (permanent magnet) |
| Projective lens | Electrostatic |
| Imaging modes | TEM, STEM, Electron diffraction, SEM |
| Specimen size | Standard ø 3.05 mm TEM grids |
| Specimen movement | X, Y: ± 1 mm; Z: ± 0.5 mm |
| Specimen (holder) tilt | ± 20° (manual) |
Imaging Modes
TEM Mode
| Nominal accelerating voltage | 25 kV |
| Resolution | 1.0 nm |
| Field of view | 100 – 0.25 µm |
| Field of view in Low mag regime | 225 µm |
Electron Diffraction Mode
| Nominal accelerating voltage | 25 kV |
| Probe size | 0.5 - 8 μm |
STEM Mode
| Nominal accelerating voltage | 10 kV | 15 kV |
| Resolution | 1.0 nm | 1.3 nm |
| Maximum field of view | 105 µm | 80 µm |
SEM Mode
| Nominal accelerating voltage | 15 kV | |
| Resolution | 4 nm | |
| Maximum field of view | 80 µm | |
Light Optics
| 10x | Objective Olympus M 40x | NA 0.95 |
| 5x | Objective Olympus M 20x | NA 0.75 |
| 1x | Objective Olympus M 4x | NA 0.13 |
NA ... numerical aperture
Image Acquisition
TEM Image Capture
| Camera | sCMOS |
| Sensor size | 2,048 x 2,048 pixels |
| Digitalization | 16-bits |
STEM/SEM Image Capture
| Max. image size | 2,048 x 2,048 pixels |
| Digitalization | 8-bits |
Analytical Detector Specifications (EDS)
| Detector type | Bruker SDD |
| Detector active area | 30 mm2 |
| X-Ray window | Windowless |
| Energy Resolution | Mn Kα ≤ 129 eV |
Publications
KRAL, J.; DECKA, K.; LIŠKA, P.; TORRES, S.; VALENTA, J.; BABIN, V.; MONZON, I.; CUBA, V.; MIHOKOVA, E.; AUFFRAY, E., 2026: Tailored thermally stable functionalization of CsPbBr3 nanocrystals for polymer nanocomposite scintillator fabrication. JOURNAL OF MATERIALS CHEMISTRY C, doi: 10.1039/d5tc03614c (HELIOS, LVEM)
BHARDWAJ, R.; DESHMUKH, S.; PUMERA, M., 2025: Laser-Assisted Mo2C-Derived Patterned Oxide for Highly Selective Room Temperature Ammonia Sensor for Food Spoilage Monitoring. SMALL METHODS 9 (11), p. 1 - 11, doi: 10.1002/smtd.202501246 (VERIOS, RIGAKU3, KRATOS-XPS, WITEC-RAMAN, LVEM)