Rules of use for TEM
- Only researchers with TEM experience are allowed to use electron microscopes of the centre.
- Other persons may be trained by members of the staff to operate the microscope themselves.
- When damage occurs as the result of improper use of the microscope or sample holders, the user will be held responsible for the costs to repair the damage. When in doubt about the condition of the microscope, the staff of the centre must be consulted.
- When leaving the TEM unattended the access door must be locked.
Materials to be studied
- Before TEM investigations are started, the plans for TEM investigations are to be discussed with the staff of the centre.
- When magnetic material is to be studied the staff of the centre must be consulted first.
- When loss of magnetic material in the microscope occurs, the microscope must be opened to remove this material. The costs, between 2500 and 5000 Euro must be paid by the user.
- If specimens can be contaminating in the TEM, this must be discussed with the staff of the centre before insertion into the microscope.
Selection of the sample holder
there are six different types of sample holders available. The selection of the sample holder must be adopted to the planned experiment. Following sample holders are available:
- single tilt holder (cannot be used in combination with EDX, not for magnetic materials)
- analytical double tilt holder with clamp system (not for magnetic material)
- analytical double tilt holder with hexring system (only for magnetic material or if the other double tilt holder is used at the other TEM, it must not be used for standard investigations)
- double tilt rotation holder (cannot be used in combination with EDX)
- analytical cryo transfer double tilt holder (only for cryo experiments, temperature range: 100°C to -184°C)
- double tilt heating holder (cannot be used in combination with EDX, temperature range: 25°C to 1000°C)
TEM session, reservations
morning session: 8 am - 12 am
afternoon session: 12 am - 4 pm
evening session: 4 pm - 8 pm
morning session: 9 am - 1 pm
afternoon session: 1 pm - 5 pm
Sessions can be extended without overlap with other sessions and in mutual arrangement with other users if necessary. At least 4 hours should be used when a reservation is made. Suitable specimens in sufficient numbers must be prepared beforehand to guarantee full use of the microscope.
In principle each user can make a reservation for one session a week. More reservations are allowed if possible. No rights can be claimed by way of reservations. The staff can always change reservations for emergency cases like maintenance of the microscope and other cases.
Starting a TEM session at the TECNAI G20 (LaB6)
- The high tension should be on before you start, if not consult the a member of the staff.
- The sample holder must be checked before use: all components should be OK, if not, alert a member of the staff.
- Before inserting a specimen holder into the TEM, the vacuum must show IGP=6, and usually the liquid nitrogen cold finger must be cooled for at least 10 minutes.
- When inserting the holder into the TEM, take care not to let go of the holder.
- When the vacuum is better than IGP=11 and the specimen holder is inserted, the filament can be switched on and the column valves can be opened.
Starting a TEM session at the TECNAI F20 (FEG)
- The sample holder must be checked before use. When inserting a double tilt holder into the TEM the wire must be connected to the microscope, the correct holder must be chosen on the menu, and the vacuum must show IGP=6, respectively. If a single tilt holder is used, do not attach any cable.
- Before opening the FEG valve, the specimen holder must be moved to extreme positions (at least 500 μm) and back until leakage occurs.
- The high tension should be on before you start, if not consult a member of the staff. The FEG extraction voltage must not be changed. It is actual 4200V.
- The FEG valve can be opened when the vacuum is better than IGP=11.
Operation of the TEM
- A TEM is a subtle instrument which must be operated with care. Never apply extra force during an operation if an unusual mechanical resistance is experienced.
- When in doubt before a specific TEM operation is performed, a member of the staff should be consulted. Never try actions of which the result is uncertain.
- Never leave the TEM without closing the gun-valve.
- Always warn a staff member when unusual things happen or are found at the microscope.
Ending a TEM session
- The microscopist must leave the microscope in a good condition for the next user:
- When nobody will use the TEM the same day after your session, the cold finger of the TEM must be warmed up. The microscope is to be left aligned at 200 kV.
- The magnification must be left at a value higher than 6200 in order to leave the objective lens activated and stabilized.
- The logbook must be filled in. The specimen holder must be checked before and after use. If OK, the appropriate boxes in the logbook must be checked, if not, the staff of the centre must be alerted.
- The holder must be removed from the microscope gently: if too much force is applied, the vacuum system will fail.
- The holders must be stored in the appropriate place with the closing ring and anti-twist ring placed nearby the holder.
Reservations for a TEM session
- Reservations for a TEM can be made on the internet.
- In principle only one session a week can be reserved during day time. If more than one session is reserved, the staff can change reservations (after consultation if possible).
- No rights can be claimed by way of reservations. The staff can always change reservations for emergency cases like maintenance of the microscope and other cases.
Contact persons in cases of problems with the microscope
In case of doubt about the operation of the microscope: never do things you don't know, ask some one who does. In the following you findthe most relevant phone numbers.
Michael Stoeger-Pollach 45204 (person of responsibility for TEM)
Johannes Bernardi 45210
Sabine Schwarz 45202