ページを印刷するo Sometimes no spectrum will appear if pile-up-rejection (PUR) is enabled and the Fast Threshold is set improperly (in the
Properties-Shaping tab). Turn PUR off and check if the spectrum appears. If it does, then the Fast Threshold needs to be
set correctly as described below.
o The Fast and Slow Thresholds must be adjusted either automatically or manually. To automatically set the thresholds,
start an acquisition with no source. Then click the tune Slow/Fast button on the toolbar. To manually adjust the
thresholds, first turn off PUR as described above. 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
(where noise counts top) and press F8. Press the "A" key to clear. There should be no noise counts accumulating. 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 you get roughly 5 to 20 Input Counts per second. 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.
o If problems persist, there may be a communication or configuration problem. Unplug the DP4 USB cable and whatever
powers the unit and close the software. Then open the software, plug in the USB cable, and apply power. In the bottom
left-hand corner of the software you should see a 1 Detected for the USB connection. Once you see this, click on
Connect. Then go to the DP4/PX4 Properties page and reload the appropriate default configuration as discussed above
and try the acquisition again.
o Always use a single point earth ground. The power supplies in many laptop computers inject large ground currents.
Isolate these grounds. A 3:2 prong plug is a powerful tool for isolating grounds but make certain that some point is tied
to earth ground.
DP4 Software and Documentation
The "DPP API" directory contains the DP4 Application Programming Interface (API) DLL along with appropriate
documentation and examples.
The "DP4 Additional Software" directory contains
A VB program (with source code) that was written to control the DP4 without the use of the DLL. This test
o
application that should be used for troubleshooting and reference if custom code needs to be written on a
non-windows platform.
All technical documentation on the DP4.
o
DP4 Quick Start Guide Rev A1
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