Software Manual Section 21

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Setup 1 for Trace Element Measurements
	Introduction This analysis type is used for measurements at low mass resolution and does not necessarily have to include trace elements. In this first setup step the masses that are to be measured are selected from an array of buttons, representing the masses 1 through 240. In addition, several other masses for calibration and tune-up are chosen here. It is also possible to save these set-ups in a file for later use.
	Clear All Selections Click here to erase all selected masses and to set all buttons to their 'off' position. Start over from scratch.
	Start Selection When nothing is selected (e.g. after clicking on 'Clear') the box in the top right part of the window looks like this. Four different groups of masses have to be selected in this setup window and the selection should be done in this order: Step 1: First select all the masses that you want to measure. Step 2: Then select several 'calibration' masses to be used for the mass calibration. Step 3: Choose one mass for determination of the 'energy edge' and the HV offset. Step 4: Finally set one mass for 'local calibration' and tune-up.
	Step 1: Select Masses for Measurement Make sure this slider is in its 'Measurement' position (yellow). Then click on all the masses you want to analyze in the large 240 button array. Each click on these buttons toggles between 'unselected' and 'selected' (yellow), so it is easy to undo any wrong selection.
	Step 2: Choose Calibration Masses Now the slider has to be in its 'calibration' position (red). Then select the masses you want to use for the automatic mass calibration from the button array. Note that all calibration masses have to be among the masses that were selected for the measurement. In other words, now you can only click on yellow buttons, which then toggle to red. For a valid trace measurement setup you have to select at least 3 calibration masses. These masses should span a large part of the mass range being measured.
	Step 3: Select a Mass for HV Offset One mass will be used to determine the 'energy edge' of the secondary ion energy distribution and to define the value for the HV offset. This mass has to be among the masses selected for measurement. Thus, the pull-down menu you reach by clicking on '??' only contains masses that have been selected from the large button array (in yellow or red). Non-integer masses (see below) are not available for this function.
	Step 4: Select a Local Calibration Mass In the same way as above, select a mass here that is to be used for tuning-up by the user. This should be a mass with sufficient secondary ion signal for the channel-plate detector. This mass does not have to be in the list of selected measurement masses. Non-integer masses (see below) are not allowed here.
	Verifying the Selection After the 4 selection steps, the box in the top right part of the window should look somewhat like this. It indicates that 63 masses have been selected for measurement of which 3 are being used for mass calibration. Mass 12 and 24 will be used for energy edge determination and local calibration, respectively. Only after a valid set of masses has been selected, the 'Continue' button will change from disabled to enabled: --->
	Special Case: Non-Integer Masses Although this analysis routine is mostly used for whole (integer) masses, it is possible to include non-integer masses (e.g. doubly charged Al++ at mass 13.5). Enter a non-integer mass by clicking on an unused (i.e. grayed-out '0.0') button. To delete a non-integer mass from the list, set its mass value to zero. These non-integer masses can also be used as calibration masses and the buttons behave just like the integer ones (selection in yellow or red).
	Save Setup To save an existing setup as a file, click here. It may be a good idea to save each 'good' setup as a file to establish a kind of setup library this way.
	Open Setup File A previously saved setup can be loaded into the setup window by clicking here. The new setup overrides all other selections.
	File Name If the current mass selections reflect the setup stored in a file, the name of this setup file (without the .txt extension) is shown here. A file name of '-previous setup-' indicates that the current mass selections are from a previous use of the trace setup program.
	Abort Trace Click here to exit the trace setup without starting a measurement.
	Continue with Trace Setup 2 Close this window and go to the next setup step. This button may be disabled if the current selection of masses is not valid (see above). The 'Enter' key on the computer keyboard can be used as a shortcut for this button.

FJ Stadermann	Back to Top	Next Section