Software Manual Section 11

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Setup 2 for Isotopic Measurements
	Introduction This is part two of the setup for an isotopic measurement. After the mass list has been entered in IsoSetup 1, the details of the measurement are set here.
	Blocks and Cycles Going through the list of entered masses and measuring each mass once is called one "cycle". Several "cycles" are combined to one "block", for which average ratios etc. are calculated. Several "blocks" together make up one "run". And finally, several "runs" with the same setup and the same sample together form one "measurement". At this point you can define the size of one "run" by selecting the numbers of "blocks" and "cycles". Select any of the default values from the pull-down menu or enter a different value ("other" in the pull-down menu). The only difference between a run with 10 blocks / 4 cycles and a run with 4 blocks / 10 cycles is how often the ratios get calculated (after each block). In both cases, the run consists of 40 cycles.
	Analysis Time The analysis time (in hours:minutes:seconds) for one cycle is defined primarily by the number of masses and the individual counting and waiting times. The total analysis time per run is updated according to the numbers of "blocks" and "cycles" entered above. At this point, the time/cycle is not very precise yet. I still have to work on this to also include an estimate for the peak centering time etc.
	Reference Peak for Secondary HV Offset This pull-down menu contains a list of all the masses that have been entered in IsoSetup 1. Select which peak you want to use for checking the HV offset.
	Offset from Edge (V) Select a value for the secondary HV offset from this pull-down menu. Several standard values are shown by default or enter a different value.
	Peaks to Track Select which peaks should be tracked during the measurement. A bullet in front of the name indicates that this peak gets tracked. Simply click on a name to select or de-select it. Alternatively, click "All" or "None" as shortcut.
	Cycles/Track Select here how often the peak positions should be checked. A value of "5" means that the peaks are checked during every 5th cycle.
	Status Several basic status settings are displayed here. This information is saved along with every data file. Please ensure that all this information is accurate. Note that this information is only displayed here; the values cannot directly be changed. This is because this kind of basic information was supposed to be entered and kept up-to-date with the "Intialize" program. Remember? In theory, this is supposed to save a lot of redundant data entering. Just in case something is wrong, click the "Change" button. That will take you directly to the "Initialize" program, which is described in Section 3.
	Directory for Data Files The directory where the data files are saved (on the NT workstation) is displayed here. The directory either comes from what was saved the setup file that was chosen or it is the default data directory that was set in the "Files and Folders" Program (see Section 50).
	Change Directory Click here to select a different directory for data files that are to be created.
	Measure Deadtime Based on Make sure to always choose the option 'none' here, unless you actually do want to measure the deadtime. For instructions on deadtime measurements see Section 27.
	Ratios and Signals to be Monitored All results of the measurements will be saved in the data files and you can do anything with the data after the measurement is completed. In many cases, however, it is desirable to follow certain signals or ratios already during a measurement. Which signal should be monitored can be selected here. There is no limit to the number of items that can be added to this list. How exactly these signals and ratios are supposed to be monitored (as a dynamic table or as a plot) will be decided later. The scroll arrows work in the same manner as those in IsoSetup 1.
	Mode The "Mode" defines what kind of signal or ratio is to be monitored. There are two different options: Ratio: Monitor the direct ratio between two signals, i.e. Signal1 / Signal2 Delta: Monitor the ratio between two signals and convert it to a delta-value in permil. In order to delete all values entered in the current row, select the empty line from this pull-down menu as shown in the figure on the left.
	Select Signals to be Monitored From these pull-down menus select the signals to be monitored. For modes "Ratio" and "Delta" both signals are needed.
	Standard Ratio For mode "Delta", we need to know the standard ratio in order to calculate a delta value. This value has to be entered here. In some cases, when two isotopes of the same element are used for the ratio (e.g. 12C and 13C), the computer 'knows' what the standard ratio of these isotopes is. In this case the computer enters this ratio here automatically, followed by an asterisk. You can manually change this value, if you really have to, but the asterisk then disappears.
	Instrumental Mass Fractionation If you know the instrumental mass fractionation for the given ratio, you can enter it here and all delta values will automatically be corrected for it. The default value here is "0". Note: Currently, this option is not yet available. It is possible to enter a value here, but it is not being used for delta-value calculations. The reason for this is backwards-compatibility with the old HP-format data files. Once we move away from using data processing software that uses the old data files, we will activate this option.
	Old File or Print These buttons let you choose which items should be included in different output formats. The 'Old File' column refers to isotope data files that are in the same format as those created by the vintage HP computer. A selection here is only relevant if the corresponding item is a delta value, since ratios cannot be included in HP-format data files. (For more information on the data file formats see Section 12: Setup 3 for Isotopic Measurements.) The 'Print' column allows the customization of the paper printout from isotopic measurements. The printout always includes the count rates of all masses measured. In addition, the ratios and delta values selected here can be included. A black square indicates that this type of output is used. Click on the squares to de-select them.
	Save Setup Click here to save this setup as a file under a new name. Note that there is no function to load a setup file in this window. To start over with a new setup, you need to go back to IsoSetup 1. This "Save Setup" button is disabled (grayed out as in the large picture at the top of this page) if essential information in the section "Ratios and Signals to be Monitored" is missing.
	File Name Display The name of the active setup file is displayed here. Note that the text displayed here changes from the file name to "-not saved-" the instant you make any changes to the setup.
	Abort ISO Stops IsoSetup and closes this window.
	Back to ISO Setup 1 Closes this window and goes back to IsoSetup 1.
	Go To Analysis This actually should have been called 'Go to IsoSetup 3'. I guess I will still have to change that. This button closes this window and goes to IsoSetup 3. This button is disabled (grayed out as in the large picture at the top of this page) if essential information in the section "Ratios and Signals to be Monitored" is missing.

FJ Stadermann	Back to Top	Next Section