DPPMCA is a Windows software application that provides data acquisition, display, and control for Amptek’s signal processors. This software is free and can be downloaded from the Software Download page.
Click here for DPP installation instructions.
Figure 1. The DPPMCA main display window.
All hardware parameters can be accessed by clicking the “Acquisition Setup” toolbar button. Controls are grouped by tabs. “MCA” tab controls acquisition presets, number of channels, LLD (threshold), setup of single channel analyzers (SCA’s), etc. “Shaping” tab controls peaking time, flat top, baseline restoration, pile-up rejection, and risetime discrimination. Common controls also set by shortcuts. Gain can be controlled by increment and decrement buttons on the toolbar, or by setting a specific value in the Setup display. “AutoTune” controls are available to automatically tune key parameters, such as the input offset and the fast and slow thresholds. Customized hardware configurations may be stored as .cfg files. DPPMCA is shipped with a library of .cfg files for the common configurations of Amptek’s detectors.
Figure 2. The DPP Properties dialog box of DPPMCA. Controls all hardware functions.
All functions can be accessed via the command menus. Many functions are also accessed by toolbar buttons. Includes “hot keys” for the most common functions, i.e. starting and stopping acquisition, rescaling the display, setting ROIs, etc. User control of display parameters such as log vs. lin scaling, auto-scaling, zoom along the energy axis, setting colors and grids, and many more. Oscilloscope mode displays pulse shapes for tuning of hardware parameters.
User can set regions of interest (ROIs) for peaks. Software computes centroids, FWHM, net area, and other quantities. Data are display on the screen for he selected ROI or in a table for all ROIs. Simple energy calibration, using two points or a linear regression for multiple points. Typically based on the centroids of known ROIs. Includes capability for simple arithmetic manipulation, e.g. subtracting a “blank” or “background” spectrum, scaling to match previous data, etc. For quantitative X-ray analysis, DPPMCA includes an active link to the XRF-FP software sold by Amptek. For other sophisticated spectral analyses, the data are saved in an ASCII format, that most software will recognize. Data can also be copied to the clipboard and pasted, e.g. in Excel.
Data saved as .MCA file (in an ASCII format), which includes the raw spectrum data, a header with calibration and ROI information, and a footer containing the hardware configuration parameters. The ASCII data can be read by most standard analysis software packages.
Supports Microsoft Windows XP SP3, Vista, Windows 7, WIndows 8. DPPMCA will run under both 32 and 64-bit versions.
Copy the DPPMCA directory from the CD (or download it) to the local drive (e.g. C:\Program Files\DPPMCA). You must have full read-write access to the DPPMCA directory. DPPMCA CANNOT run from the CD.
For Digital Pulse Processors (DPP) like the DP5, PX5, X-123, or Gamma-Rad5, you will have to install the WINUSB driver. Please see the DPP installation instructions.
Please read the Quick Start Guide for your product. It contains specific instructions for the operation of your device. The information below is generic to DPPMCA. There are different options depending on the product in use.
A common task is to change the energy range of a system. This is done by adjusting the gain of the amplifier. A lower gain corresponds to a higher energy range, and a higher gain to a lower energy range. For example, in Amptek’s digital systems a gain of x100 may correspond to a 15 keV full scale and a gain of x50 to a 30 keV full scale. To adjust the energy range it is always the gain of the system that must be changed. It is not enough to change the software calibration only. The software calibration is only in software. If the software’s calibration is changed without the amplifier’s gain changing appropriately, the software will be displaying the wrong energy range and peaks will be incorrectly identified.
If you are using one of Amptek’s digital processors (DP5, X-123, Gamma-Rad5 etc.), the gain is adjusted through the DPPMCA software on the Gain & Pole Zero tab of the DPP Properties, or by using the gain buttons on the toolbar It is necessary to readjust the thresholds whenever the gain is changed. This can be done automatically by starting an acquisition (pressing space bar) and clicking the “Tune Slow/Fast Thresholds” button on the toolbar of the DPPMCA application with no source exciting the detector. See the quick start guide of the appropriate product for more information.
Once the appropriate gain (full scale energy) is found, the software can be calibrated. The software must always be calibrated in order to change the channel scale into an energy scale. To accurately calibrate a spectrum there must be at least two known peaks in the spectrum. For example, an iron (Fe) peak at 6.40 keV and molybdenum (Mo) peak at 17.48 keV. It is best to use peaks that are on the two ends of the energy range of interest. Peaks that are too close together may not produce an accurate calibration. For example, do not use Mn at 5.9 keV and Fe at 6.4 keV to calibrate a 30 keV full scale.To calibrate the scale in the Amptek DPPMCA software follow these steps:
Figure 3. The DPPMCA display window showing the Calibrate dialog box. The spectrum that is shown has two regions of interest (ROI's) marked.
If the same energy range is to be used (i.e. the gain has not changed), DPPMCA can be set to load a calibration automatically on startup. Save a spectrum that has been calibrated by following the steps above. Click on the View menu and select Preferences. On the General tab in Spectrum Template enter in the path and file name of the file that was just saved. Check Load Calibration on Startup and click OK. DPPMCA will now automatically load that calibration every time it opens.
In addition, a calibration can be applied from one file to another. For this procedure see the Help file (F1) under Analyzing Data with the DPPMCA Software -> Calibrating a Spectrum / Applying a Calibration.
For a complete list go to the Help menu and select Keyboard Map. Here are a few:
Revised January 24, 2013