Home Page	Products	Price List	Links & PDFs	Contact Us

Amptek DPPMCA Display and Acquisition Software

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.

DPPMCA is compatible with FW6 devices only:

• DP5
• X-123 (with DP5 inside)
• DP5G
• PX5
• Gamma-Rad5
• MCA8000D

Click here for DPP installation instructions.

Features

• Full control of all hardware features. Typically includes acquisition presets, gain, peaking time, detector HV, detector temperature, number of channels, risetime discrimination parameters, and many more.
• Live display of the spectrum with many options. Includes linear and logarithmic vertical scaling, manual or auto-ranging, and zoom on the horizontal scale. Displays live spectrum and multiple stored or processed spectra.
• Spectral analysis features include energy calibration, setting regions of interest (ROI), computing ROI information (centroid, total area, net area, FWHM), spectrum smoothing, summing of spectra, subtraction and scaling of background spectra.
• Active link to the XRF-FP Quantitative Analysis Software Package using fundamental parameters, which can be purchased separately.
• Supports Microsoft Windows XP, Vista, and Windows 7.

Figure 1. The DPPMCA main display window.

Hardware Control

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.

Display and User Interface

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.

Spectrum Analysis

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.

File Formats

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.

System Requirements

Supports Microsoft Windows XP SP3, Vista, Windows 7, WIndows 8. DPPMCA will run under both 32 and 64-bit versions.

Using DPPMCA

Installation

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.

Quick Use

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.

Changing the Gain: This changes the full scale energy range.

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.

Calibration: Changing the Channel scale to Energy.

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.

• Chose the two peaks that will be used for the calibration and make note of their energies.
• Mark an ROI (region of interest) around each peak. This can be done by clicking the cursor at the left base of the first peak and then holding down the “U” key on the keyboard until the whole peak is highlighted, or by using the Edit ROI button on the toolbar and then clicking and dragging across the peak until it is highlighted. For more information on marking ROIs please see the Help file under Analyzing Data with the DPPMCA Software -> Regions of Interest and How to Define Them.
• Now click in the toolbar button “Calibrate” to open the calibration dialog box.
• Move the dialog box such that both peaks are visible and then click the cursor into the first peak. The peak should be highlighted and the Peak Information section on the right-hand information panel should be filled in. If the peak is highlighted and there is no peak information, then the ROI is not marked correctly. Try adjusting the start and end points of the ROI.
• Click the Centroid button on the dialog box. This will enter the center position of the peak into the Channel box. Then enter the energy of that peak into the Value box, e.g. 6.4, and click Add.
• Now click the cursor into the second peak (it will highlight). Click on Centroid, enter the second energy, e.g. 17.48, and click Add. There should now be two lines in the box.
• In the Units box type in the energy units, e.g. keV.
• Click OK. The scale should now be in energy. If it is not press F7, this toggles between calibrated units and channels.

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.

Keyboard Shortcuts

For a complete list go to the Help menu and select Keyboard Map. Here are a few:

• The "Space Bar" Starts and Stops an acquisition.
• The "A" key clears the data and resets the time.
• Pressing and holding down the "U" key marks an ROI to the right, and the "Y" key marks an ROI to the left.
• F8 sets the LLD Threshold to the current cursor position.
• F1 opens the Help File.

Troubleshooting

Digital Processor Products (DP4, DP5, DP5G, PX4, PX5, X-123 (all versions), Gamma-Rad, Gamma-Rad5)

1. Sometimes no spectrum (or a distorted spectrum) will appear if the fast and slow thresholds are not set properly. Remove any source from in front of the detector and click the “Tune Slow/Fast Thresholds” button on the toolbar. Put the source back and check if the spectrum appears. The input counts should always exceed the counts. If the auto tune fails, or if the counts exceed the input counts, perform the manual adjustment in the next step.
2. The Fast and Slow Thresholds can be adjusted manually. First turn off pile-up rejection (DPP Properties->Shaping tab). Then click the cursor to channel 1 and press F8. This will set the Slow Threshold (LLD) to channel 1. This will show the noise of the system. Click the cursor just to the right of the noise and then press F8. Press the “A” key to clear. There should be no counts accumulating in the spectrum display. Now put the device into “Delta” mode by clicking the Delta button on the toolbar. Open the DPP Properties and go to the Shaping page. Adjust the Fast Threshold until 1 to 15 counts per second appear in the Input Counts in the right-hand Info Panel. Now turn on PUR and click OK. Click the Delta button to get back to normal MCA mode and put the source back in front of the detector. The Input Counts should slightly exceed the Counts.
3. In the DPP Properties->Gain tab, use the default input offset option.
4. If the HV on the right hand info panel indicates something similar to "-7V Check Polarity" then the HV polarity in the boot flags of the DPP Properties is set incorrectly. For Amptek Si-PIN and CdTe detectors the HV polarity must be positive (and the input polarity negative). For SDD detectors the HV polarity must be negative (and the input polarity positive). Note that for Amptek detectors the input polarity and the HV polarity are opposite.
5. If you still have problems, please email Amptek a saved .mca file from the DPPMCA software (see below for instructions).

Instructions for saving and emailing a .mca file to Amptek

1. Connect with the software
2. Take a spectrum for about 30 seconds. It does NOT matter if there is no spectrum. The file saves important information about the system that will help Amptek troubleshoot the problem.
3. Go to the File menu and select Save as.
4. Save the file and email it to Amptek.
5. Do not send screen shots or configuration files, only the .mca file.

Revised January 24, 2013