miniature TEM sampler manual

Transcription

1 miniature TEM sampler manual Introduction The miniature TEM sampler is an instrument designed to collect nanoparticles on standard TEM grids. Particles are charged electrically, measured contactlessly by induction, and finally deposited on the TEM grid by an electrostatic field. Because the particle concentration is measured online, the sampler automatically determines how long it must sample for an optimal coverage of the TEM grid (~1% of the area covered with particles). The sampler can also be used to measure aerosol concentrations without sampling particles. The particles are measured in terms of alveolar lung-deposited surface area (A-LDSA), a metric which, according to latest results from toxicology studies, is likely more health relevant than the traditionally measured particulate mass. Packing list The TEM sampler carrying case contains the following items: TEM sampler (including one grid holder screwed into the bottom of the instrument) 5 spare grid holders, screwed into the grid holder transport plate. µsd-card to SD-card adapter (most computers are only equipped with an SD-card reader at most) USB cable Standalone USB charger

2 Basic Operation To use your TEM sampler, perform the following steps: Insert µsd-card with contacts facing upwards into the TEM sampler till it snaps in. You do not need the µsd- Card for measuring / sampling, but it is always better to have a record of your measurements. Turn on the sampler by pressing the power button. After displaying a short welcome message, the display changes to the main screen. The instrument writes data to the µsd-card automatically until it is turned off. A blinking red dot on the main screen indicates that data is being stored. Do not remove the µsd-card while the instrument is operating, as it will shut down if you do! The main screen Once the instrument is running, you can use it to measure lung-deposited surface area with a high time resolution (4s integration time). If/when you find a hotspot where you want to take a TEM sample, insert a fresh sample, and press the right button below the text deposit During deposition, the TEM sampler will display the percentage of the deposition time on its main screen. If you do nothing, it will sample until the value reaches 100%, then it will stop the deposition, and instead of the percent-display the sampler will display done. You can also stop the deposition manually by pressing the right button below the text stop. To power off the instrument measurement, press and hold power button for two seconds until a goodbye message appears on the screen. Main screen during deposition naneos particle solutions gmbh, Dorftrasse 69, CH-5210 Windisch (Switzerland),, info@naneos.ch 2 5

3 If you want to see what happened during the measurement, remove the µsd-card by pressing on it. Insert it into the µsd/sd-card adapter and then in your PC. Open the partector data analysis tool which you can find under Alternatively, you can view the data with any program that is capable of reading tab-delimited text files, e.g. Excel. Open the file on the µsd-card with the tool and view the data. File names encode the recording date, for example, if you start recording a file on 2 nd August at 12:35, the file will be in a folder called 08_02 (month_day), and the filename will be XXX_1235.txt where XXX is the serial number of the instrument, 1235 is the start time of the instrument. To charge the instrument, connect it via USB to a USBcharger or to a running PC or laptop. Charging is indicated by the blue LED on the lower left of the partector front. Remaining battery is displayed on the main screen. Handling the TEM grid Handling the small TEM grids is a bit tricky, but with some practice it is not hard. We suggest that you try loading and removing grids from the grid holder for a while until you feel comfortable with the procedure. The grid holder has a brass cap that you can unscrew Once the cap is unscrewed, you can place a TEM grid on the grid holder. Try to place it more or less in the center, it doesn t have to be perfectly centered naneos particle solutions gmbh, Dorftrasse 69, CH-5210 Windisch (Switzerland),, info@naneos.ch 3 5

4 Screw down the cap - slowly towards the end while observing the TEM grid. If it was reasonably centered, it will now align perfectly with the hole as you screw the cap down, as the cap matches the tapered end of the holder and thus automatically shifts the grid until it is nicely centered. To remove the grid after sampling, unscrew the cap and remove the grid with tweezers. Additional screens Press the left button labelled info in the main screen to switch to the info screen. In this screen, you will find: Serial: the instrument serial number Minutes: the number of minutes that the instrument has been turned on in its lifetime LDSAmin: the integrated value of the LDSA measurement over its lifetime (a measure of the The info screen amount of nanoparticles that have entered the instrument) Pulses: the number of HV pulses that the charger has generated in the instrument lifetime Calib: the calibration factor for the LDSA measurement Date: the calibration date Pressing exit will go back to the main screen, pressing status will move on to the status screen, and pressing config will move to the config screen In the status screen, you can see some of the signals that the sampler is measuring: TEM: the deposition voltage to the TEM grid RH,T: relative humidity (in%) and temperature (in C) in the instrument Batt: battery voltage ADC: signal on the sensing electrode The status screen HV: charger high voltage Idiff: charging current In the config screen, you can set an alarm level, above which the sampler will sound an audible alarm. In the low power mode, the LCD will dim and later turn off completely after short periods of inactivity. Pressing any button (preferably on/off so as not to activate any menu options) will turn the LCD on again. The LCD will also turn on if an error message appears The config screen The internal clock of the partector has an accuracy of about 1s/day. It does not change to daylight saving time naneos particle solutions gmbh, Dorftrasse 69, CH-5210 Windisch (Switzerland),, info@naneos.ch 4 5

5 and back automatically. Therefore, you may need to set the clock from time to time. Use the up and down buttons to change the highlighted field. In the statistics screen, you can view events detected in the past. By pressing + and you can change the time scale from minute to hour and day. Specifications Dimensions (body): 14.2x7.8x2.8 cm Weight: 440 g Flow rate: 0.45lpm Sampling efficiency: particle size dependent; approximately 3% at 50nm The statistics screen naneos particle solutions gmbh, Dorftrasse 69, CH-5210 Windisch (Switzerland),, info@naneos.ch 5 5