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is loaded and “Show ROIs” is checked under the “View” menu. If no ROI set is loaded, “Show ROIs” is not
checked, or the cursoris not over an ROI, these boxes will be blank. The first of these two displays the name
given to the ROI, and the second shows the total (integrated) number of counts in that ROI. If a background
spectrum has been loaded, the count displayed will reflect the background-subtracted counts if “Show
Background Subtracted” has been selected under the “View” menu.
The final two boxes (towards the right) display overall data for the spectrum. The first of these two displays
the total number of counts for the spectrum and the second displays an approximation of the overall count
rate based on an average of the last 20 seconds of spectrum data. The overall count data will not reflect
background subtraction. The overall count rate box may display misleading data for approximately the first 20
seconds following the start of an acquisition.
Acquisition Controls and Indicators
The four buttons along the top of this section control the acquisition of spectra. From left toright, these are
“Start,” “Stop,” “Clear,” and “Clear and Restart.”
The Start button begins an acquisition. If a spectrum is currently displayed but is not currentlyaccumulating
the acquisition will re-start, adding data to the existing spectrum. If a spectrum iscurrently accumulating, this
button will have no effect.
The Stop button ceases spectrum acquisition. No data is destroyed, and the acquisition can berestarted if
desired. This button has no effect if the acquisition has previously been stopped.
The Clear button erases all data from the spectrum, and resets the elapsed time to zero. If
a spectrum is currently acquiring, acquisition will stop. No warning is given before data is
deleted.
The Clear and Restart button is equivalent to pressing the Clear button followed by the Start
button, and is provided for convenience. Again, no warning is given before data is deleted.
Immediately below these buttons are two status displays. The top one of these will always be
visible, and gives some information about the status of URSA-II. The text of this display may be:
“Spectrum Clear” (red background). Indicates that the spectrum display contains no data, and URSA-II is not
acquiring data.
“Acquiring” (light green background). Indicates that a spectrum is currently accumulating.
“Acquisition Stopped” (yellow background). Indicates that URSA-II is not currently acquiring data, but the
spectrum display contains data.
“Spectrum Loaded” (yellow background). Indicates that URSA-II is not currently acquiring data, but the
spectrum display contains data that has been loaded to Live from a file.
The second (and lower) of these displays gives information about the background spectrum, and will only be
visible if a background spectrum has been loaded. The text of this display may be:
“Bkgd Subtracted” (green background). Indicates that a background spectrum has been loaded and is currently
being subtracted from the visual spectrum display. It will also be subtracted from any spectral analysis
performed, including peak searches.
“Bkgd Loaded” (green background). Indicates that a background spectrum has been loaded but is not being
subtracted from the visual spectrum display. The background spectrum will still be subtracted from any
