Amptek’s MCA-8000D is a state-of-the-art, compact, high performance, digital MultiChannel Analyzer (MCA). It replaces the MCA-8000A, providing the same functionality with reduced dead time, modern communications interfaces (USB, RS-232, and Ethernet), and much higher data transfer rates. Because it does not implement digital pulse shaping, it is compatible with analog pulse shaping systems.
Superior performance is obtained from a high speed ADC (a 100 MHz 16 bit ADC) and sophisticated digital logic. The MCA-8000D digitizes the input signal (the output of an analog shaping amplifier) to measure the pulse height and obtain the pulse height spectrum. The high speed ADC, with a 10 ns conversion time, reduces dead time thus increasing throughput. The digital circuitry yields high accuracy and stability.
The MCA-8000D includes three interfaces, USB (USB 2.0 full speed), RS-232 (up to 115 kB), and Ethernet (10base-T). It uses the same DPPMCA software package as Amptek’s digital signal processors, including the DP5, PX5, and X-123. The MCA-8000D can be powered over USB or with an external AC/DC power supply.
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.
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:
|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.|
Certificate #: CU 72131640 01
Tested to: UL 61010-1:2012
CAN/CSA-C22.2 NO. 61010-1-12
|Status Light||Steady red light: power is ON and no data acquisition in progress.
Flashing red light: data acquisition in progress. (Same as amber light on Ethernet connector.)
|Operating Power||2 W|
|Input Power||+5 V at 0.4 A|
|Input Power Range||+4 V to +5.5 V (0.5 to 0.4 A typical)|
|Input Power Sources||USB power or AC/DC adapter (supplied)|
|Input||The analog input accepts positive unipolar or bipolar semigaussian type pulses of shaping time constants ≥200 ns or peaking time ≥500 ns.
The dynamic range is 0 to +1 V or 0 to +10 V, software selectable.
Minimum pulse height is 5 mV.
Input impedance is 1 kΩ (MCA-8000D) or 100 kΩ (MCA-8000D Option PA).
The input has overload protection up to ±20 V.
The DC level of the input signal must be zero.
|Gates||The MCA-8000D has two logic gates: GATE1 is generally used to synchronize acquisition with external hardware while GATE2 is generally used for pileup rejection.
Each gate can be commanded to ACTIVE HIGH, ACTIVE LOW, or DISABLED. When set to ACTIVE HIGH, if the input is high, then pulse heights are recorded and the live time clock runs. The active state of each GATE input is evaluated at the time of the input analog pulse is detected.
|Interface (I/O)||USB: Standard USB Mini-B jack.
Ethernet: Standard Ethernet jack.
RS232: Standard 2.5 mm stereo audio jack.
Power plug mates with 3.5 mm x 1.3 mm x 9.5 mm female barrel, center positive, plug connector.
|Dimensions||5 x 2.8 x 0.8 in (125 x 71 x 20 mm).|
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.
|V Scale||Offset @ 100 mV||Gain|
|0-1 V Scale||±0.2 mV||±0.2% @ 0.8 V|
|0-10 V Scale||±2 mV||±0.5% @ 8 V|
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.
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.
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.
Amptek MCA-8000D Rear View
Complete Pulse Height Analysis System
Example of Unipolar Input Pulse
Example of Bipolar Input Pulse
MCA-8000D Peak Detection Modes
MCA-8000D Front and Back Panels
MCA-8000D Top View with Dimensions
MCA-8000D Bottom View
MCA-8000D Side View