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MCA8000A Option PA

The Option PA package has been developed to facilitate the use of the MCA8000A for particle counting in airborne (Size Calibration) and liquid suspended¹ (Number Calibration) particle applications. The unit is calibrated and certified traceable to the National Institute of Standards and Technology (NIST). The Option PA package is capable of detecting pulses from 5 mV to 10 V. The MCA8000A is typically connected to the output of a particle sensor. It detects and displays a spectrum of pulse heights allowing the user to determine if a given particle size is producing the correct voltage. The software included with the MCA provides information on the peak center (centroid and mean calculation) making it easy to determine if the peak is in the correct position. The supplied calibration curves convert the MCA channel scale to a mV scale. The calibration curves can be set to load automatically when the software opens.

Features & Specifications

• Pulse detection from 5 mV to 10 V
• 3 Voltage scales: 0-0.5 V, 0-5 V, 0-10 V
• 100 k input impedance (all three scales)
• NIST Traceable calibration
• Certificate of calibration
• Absolute or first peak detection mode (see figure 1)
• Option P or Basic units can be upgraded to Option PA

The PA package is accurate to within 1% at 1 µs peaking time. Do not use a square wave to test the MCA8000A Option PA response. The time to peak of the input pulse must be at least 1 µs to guarantee accuracy.

Figure 1. Absolute and First Peak Detection Modes

The Option PA Package is NOT recommended for standard nuclear instrumentation applications.

Option PA Calibration Curves, Instructions, and Software Updates

Critical Update (1/31/07). All customers should update their sofware with version 1.0.0.12 or later. This update resolves an issue that prevents the MCA8000A from being set in Absolute Peak Mode. Absolute Peak Mode is necessary as described above and to prevent noisy pulses with jagged rising edges from causing an incorrect peak value. Amptek recommends always using Absolute Peak Mode for particle applications. NOTE: To set the MCA8000A in Absolute Peak Mode, connect to the MCA then go to the Acquisition Setup (F9). Select Absolute from the Peak Mode drop-down. This must be done with the MCA connected but NOT acquiring data.

Version 1.0.0.16

The Option PA calibration curves are only for use with Option PA equiped MCA8000A units. They do not apply to the Basic Package, or the Option P package. The Option PA package can be identified as having the three position voltage range switch (0.5V / 5V / 10V) instead of the two position switch (5V / 10V). MCA8000As ordered with Option PA all use the same calibration curves (the MCA has been internally calibrated to those curves).

Option PA Cal. Curves (2k)

Option PA Instructions in PDF - 97k

References

Revised June 20, 2007