SEM laboratory

Laboratory of scanning electron microscopy

Laboratory of scanning electron microscopy (SEM) at the Institute of Petrology and Structural Geology is equipped by scanning electron microscope TESCAN Vega with attached Back-Scattered Electron (BSE), Secondary Electron (SE) and cathodoluminescence (CL) detectors. The microscope is further equipped by the Energy Dispersive Spectroscope (EDS - detector X-Max 50 from Oxford Instruments) for qualitative and quantitative microanalysis and by the Electron Back-Scattered Diffraction (EBSD, detector NordlysNano, Oxford Instruments) for analysis of full crystallographic orientation.

Booking

The link "Booking" leads to an application allowing to book dates at the SEM laboratory. The system allows to book the whole day only. The analytical works take place from 9 AM to 5 PM, the time after 5 PM is supposed for analyses running in automatical mode. It is possible to book dates up to 4 weeks in advance. The nearest unblocked date is 5 days in advance. Bookings of earlier dates or specific requests (e.g. booking for a part of an day) should be arranged after contacting of an operator. After submitting of your booking, you will recieve an automatical confirmation. In the case of any changes, you will be contacted by an operator.

Price list

21% VAT is charged in case of works for other institutions

Laboratory equipment

Electron microscope: SE, BSE, CL detectors

The laboratory is equipped with a scanning electron microscope, the chamber of which comes from an old model of the CamScan S4 microscope. All electron optics, detectors, electronics and controls are from Tescan and are equivalent to the Tescan Vega scanning electron microscope. The microscope is equipped with new secondary electron (SE), backscattered electron (BSE) and cathodoluminescence (CL) detectors. The preservation of the original chamber size allows the study of objects even with relatively large dimensions.

EDS

Our laboratory is equipped with a new X-MAX 50 detector (silicon drift detector, SDD) with an active area of 50 mm² from Oxford Instruments, which is controlled by the INCA system. This system allows qualitative and, for major elements, quantitative chemical microanalysis in manual and automatic mode. The detection limit for quantitative analysis for most elements does not exceed 0.1 wt.%. The system also includes a semi-quantitative compositional mapping capability. The software allows export of analyses in clear tables, and when exporting maps, offers the possibility of assigning colour spectra for greater clarity of the result.

EBSD

Based on the diffraction of back-reflected electrons in crystalline materials, the EBSD method can be used to determine their preferred crystallographic orientation. This method is mainly used in geology to study deformation structures in rocks. The laboratory is equipped with an EBSD detector HKL NordlysNano (manufacturer Oxford Instruments) controlled by AZtec and Channel 5 software, installed in summer 2013. This system allows point analysis in manual mode and the creation of orientation maps in automatic mode.

The EBSD method is very demanding on the surface quality of the sample. In addition to the standard diamond paste polishing, it requires subsequent treatment by chemical polishing. This treatment can be ordered well in advance at an appropriate price in our laboratory.

Additional services

The study of samples by electron microscopy requires specific preparation of the samples to be studied, which is only partially provided by our laboratory, the prices of these services can be found in the price list.

Chemical polishing

Chemical polishing of the sample using acid or alkaline suspensions is necessary especially for the EBSD method, which has the highest demands on the surface quality of the sample. For this polishing, we use Struers products, OP-U, OP-S and OP-A suspensions are used depending on the nature of the material to be polished.As chemical polishing is the final finish of the sample, it is necessary that the sample has first undergone a standard polishing with diamond pastes. However, our laboratory does not provide this service, so we can only accept samples that have already undergone this treatment.

Carbon coating

In view of the necessity of conductivity of the surface of samples studied by electron microscopy, non-conductive samples must be coated with a conductive layer before being placed in the microscope. For studying samples in BSE, EDS or EBSD, we use carbon coating.

Contact

Laboratory address:

Institute of Petrology and Structural Geology
Faculty of Science, Charles University in Prague
Albertov 6, 128 43 Praha 2
1st floor, door number 114

Contact person:

Mgr. Martin Racek, Ph.D.
e-mail: racek@natur.cuni.cz, upsgscan@gmail.com
tel. +420 22195 1520 or 1535