MCA-8000D Digital Multichannel Analyzer

The MCA-8000D is one component in a complete pulse height analysis system. We illustrate below a typical system: the radiation detector is connected to a charge sensitive preamplifier, which is connected to a shaping amplifier. The output of the shaping amplifier is a pulse with peak amplitude proportional to the energy deposited in the detector. The MCA measures the amplitude of the peak and produces a histogram representing the pulse height spectrum. This histogram, an integer array of the number of events in each pulse height channel, is the primary output of the MCA and is transferred to a computer over USB, Ethernet, or RS232 interfaces.

Our MCA-8000D does not include pulse shaping circuitry but only the MCA circuitry. The MCA-8000D must be preceded by pulse shaping circuits. We provide examples below of typical pulse shapes input to the MCA-8000D. Amptek has other products (including the DP5, DP5G, PX5, and PX5-HPGe) which include both pulse shaping and MCA circuitry. These use digital pulse processing for the very best performance. Please contact us for information on these integrated systems. Note that some manufacturers use the term “MCA” for modules which include both the pulse shaping and the traditional MCA functions.

The MCA-8000D is most often used to measure the energy spectrum from a radiation detector, where the pulse height is proportional to energy but can be used in other applications. For example, instruments used to monitor cleanrooms produce an output pulse proportional to the size of the particle, so the MCA-8000D is used to measure the particle size spectrum. Some radiation detection systems used in timing produce a pulse height proportional to the time between events (using a time to amplitude converter), so the MCA-8000D yields a timing spectrum.

NOTE: The input to the MCA-8000D must be a positive going unipolar or bipolar shaped pulse of peaking time greater than 500 ns.

Repeat Measurements

The DPPMCA software has a repeat measurement capability. This routine automatically saves a complete spectrum at user defined intervals, and in addition produces a file consisting of the total counts in each spectrum. This total counts file can then be plotted in Excel.

This mode can be used for:

• Characterization of X-Ray Tubes
• Long Term Radiation Monitoring of the Environment
• Study of Detector Stability as a Function of Time

How does the MCA-8000D differ from the previous MCA-8000A?

1. It now supports USB, Ethernet, and RS232 interfaces with much faster data transfers. It makes operation with modern computers very easy.
2. It uses a completely new and different communication protocol. The MCA-8000D software is NOT backwards compatible with the MCA-8000A.
3. It uses the DPPMCA acquisition software, a new version of the older ADMCA software.
4. It can be powered by USB or an external plug. It does not contain a battery.
5. It has 8k data channels and is specified for pulse risetimes >500 ns.
6. It is an all digital solution, with a fast ADC and digital peak detection.
7. It is smaller and lighter.

General Characteristics

Pulse-Height Digitizer	High speed 100 MHz, 14 bit ADC with digital pulse height measurement.
Input Ranges	0 to 1 V or 0 to 10 V (software selectable) (over range events are discarded)
Number of Channels	256, 512, 1k, 2k, 4k, or 8k (software selectable)
Minimum Input Risetime	≥500 ns to meet specifications.
Dead Time Per Pulse	10 ns plus pulse shaping time
Peak Detection Modes (See Figure 6)	Separate Peaks (V1): Standard to nuclear instrumentation MCAs. Absolute Peak Above Threshold (V2): Typically used in airborne particle sizing analyzers, in environmental air monitoring systems and in aerosol research.
Acquisition Modes	MCA and MCS (multichannel scaling) down to 10 ms/channel.
Differential Nonlinearity	<±0.6% from 5 mV to full scale.
Integral Nonlinearity	<±0.02% over full scale.
Gain Stability	±10 ppm/°C (typical).
Zero Drift	±10 ppm/°C (typical)
Low Level Discriminator	Software selectable threshold, in increments of one channel.
Counts per Channel	Maximum = 16.7 x 106 counts (3 bytes).
Real and Live Timers	Data acquisition real or live time preset. Maximum preset time 4,294,967.29 seconds (10 mS precision), or 999,999.999 seconds (1 mS precision). Shorter accumulation times can be achieved by gating the input signal with Gate 1 or Gate 2. : ; 999,999.999 s (0.001 s precision). : 99,999,999.9 s (0.1 s precision) : 4,294,967,295 (232-1) in channel or ROI
Real and Live Time	4,294,967.295 s (0.001 s precision)
Acquisition Time	1,677,721.599 s (0.001 s precision)
Preset Counts	4,294,967,295 (2³²-1) in channel or ROI
Interface	RS232: 115.2 or 57.6 Kbaud USB: Standard 2.0 full speed (12 Mbps) Ethernet: Standard 10base-T (UDP)
Operating Temperature	-20 °C to +60 °C.
	TUV Certification Certificate #: CU 72131640 01 Tested to: UL 61010-1:2012 CAN/CSA-C22.2 NO. 61010-1-12

Exterior Controls and Indicators

Power

Connections

Mechanicals

Option PA for Particle Counting/Sizing

The Option PA package has been developed to facilitate the use of the MCA-8000D 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 MCA-8000D 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.

¹Sommer, H.T. “IMPLEMENTING PARTICLE COUNTER CALIBRATION PER ISO 11171-1999.”; TEAM Service, Inc., P.O. Box 220, Merlin, OR 97532, (541)476-4744, HolgerTSo@aol.com; Copyright Society of Automotive Engineers

See Option PA for more information on airborne and suspended particle sizing and counting.

Tolerances

Figure 6. MCA-8000D Peak Detection Modes.

The MCA-8000D can be controlled by the Amptek DPPMCA display and acquisition software. This software sets the configuration (number of channels, input range, etc), can start and stop acquisitions, can display the spectra, and supports basic analysis functions such as defining regions of interest (ROI), performing calibrations, peak searching, and so on. Data are saved in an ASCII file format. The DPPMCA software is also used with Amptek’s digital pulse processors, including the DP5, Gamma-Rad5, PX5, etc.

The MCA-8000D comes with a complete Software Development Kit (SDK). The user can use this platform to easily develop software to control the MCA for custom applications or to interface it to a larger system. Examples are provided in VB, VC++, etc. The standard DPPMCA software runs only on Windows operating systems but users can develop interface software running on Linux or other operating systems using documentation and sample code which are provided.

The MCA-8000D software is NOT backwards compatible with the MCA-8000A.

Mechanical Drawings

FIgure 7. MCA-8000D front and back panels.

FIgure 8. MCA-8000D top view.

FIgure 9. MCA-8000D bottom view.

FIgure 10. MCA-8000D side view.

Ordering Information

MCA-8000D Includes

• MCA-8000D
• AC Power Adapter
• BNC signal cable (1 meter length)
• USB cable
• Software Installation CD

MCA-8000D Option PA Includes

• MCA-8000D (see above)
• NIST Traceable Calibration
• Certificate of Calibration
• 100k Input Impedance

Click here for more information on the Option PA Package.

Option PA is NOT recommended for standard nuclear instrumentation applications. It is for particle counting in airborne (Size Calibration) and liquid suspended (Number Calibration) particle applications only.