Tube Base Multi Channel Analyzer (MCA)

A Multichannel Analyzer (MCA) is a crucial digital processing instrument that converts the output from a scintillation detector (typically in the form of a stream of voltage pulses) into a digital format for further analysis. There are two major modes of multichannel analyzer when used, the Pulse Height Analysis (PHA) mode and Multichannel Scaling (MCS) mode, depending on the needs of the user. The fundamental function of an MCA is to distribute incoming signals into discrete channels, with each channel corresponding to a specific voltage range representing a narrow band of energies or time intervals. The multichannel analyzer then counts the number of events in each channel, generating a histogram or spectrum for analysis. Pulse height analysis mode focuses on the analysis of energies and can be used for applications like gamma spectrometer or radioisotope identification, the channels are sorted and accumulated according to the pulse amplitude (related to the peak voltage of the pulses), and the number of occurrences of pulses with a specific height is recorded, the resulting graph is a energy spectrum of energies versus the events at each energy level. Multichannel scaling focuses on time measurement and collects events over a period of time, and the number of events occurring in each time interval is recorded.

Multichannel analyzers, although both used to process signals from radiation detectors, are inherently different from single-channel analyzers. A Multichannel Analyzer (MCA), on the other hand, analyzes the full range of energy levels over many channels (often hundreds or thousands of channels). A single channel analyzer (SCA), on the other hand, outputs a logic pulse when the input pulse meets a certain amplitude. A multichannel analyzer can be viewed as a combination of numerous SCAs where every individual SCA is connected to an exclusive counter. 

Multichannel analyzers are critical components for a diverse range of detection applications, including gamma spectroscopy which is the dominant technique utilized for RIID radiation detectors, Positron Emission Tomography (PET) for medical imaging, neutron spectroscopy, etc. 

A Tube Base Multichannel Analyzer (Tube Base MCA) is a specialized type of MCA that integrates a built-in preamplifier, high-voltage modules, and power supplies for the Photomultiplier Tube (PMT) of the scintillation detector. The tube base multichannel analyzers contain a pin base for PMTs, which can better interface with PMTs. Tube base MCA facilitates the coupling of the PMT to the MCA, enabling efficient signal processing and analysis of the pulse signals from the tube.

Hangzhou Shalom EO offers tube base multichannel analyzers (tube base MCA), the MCA are optimized for energy spectroscopy based on scintillation detectors. Our tube base MCA is compatible with various popular scintillation detectors, including Thallium doped (NaI), LaBr3(Ce), CeBr3, and SrI2, where compatibilities with other detectors can also be achieved on customers’ requirements. The tube base MCA consist of an Ethernet port, PMT base socket, and high voltage module for the PMT, preamplifier, multichannel pulse amplitude analyzer, and software in the upper computer end. The tube base MCA is compatible with 14-pin E687-14W pin base PMT. The resolution of channels includes 1024 channels, 2048 channels, and up to 4096 channels depending on the user’s settings.

The Ethernet RJ45 connector has a Power over Ethernet (PoE) function so that only one cable is needed for delivering electric power and transferring digital data. The collected nuclear pulse signals are processed into digital forms, the data are transmitted to a specialized software running on the PC side through an Ethernet port, and the software performs several critical analyses, like nuclear waveform analysis, gamma spectrum analysis, and radioactive activity calculation.

Our tube base multichannel analyzers also highlight a software API that enables users for integration and further development, this allows users to customize the MCA system to meet their specific needs, whether for data analysis, automation, or other specialized tasks. By supporting measurement time synchronization, the gated logic system within our tube base MCA permits the integration of several multichannel analyzers into one system. This is essential in scenarios where precise timing coordination between different units is crucial, such as in experiments that require synchronized measurements across multiple detectors or in large-scale detector networks. The suitable applications include remote monitoring, where different detectors are distributed over a wide area, detector networks, and detector arrays. 

We also provide a matching software:

The MCA multichannel pulse amplitude analyzer embedded software can be connected to the PC via Ethernet port or USB connector. The energy spectrum measurement and analysis software have automatic spectrum stabilization function, this enables the software system to perform accurate spectral measurements and analysis for identification and quantification of radiated signals of different energies.

The software and can realize manifold tasks offers flexible functions, including: setting the parameters for multiple channels, energy spectrum acquisition and analysis, energy efficiency scaling, nuclide analysis, automatic spectrum stabilization, automatic measurement and other analysis functions, which can be customized according to user’s needs. The software API port is provided to support system integration or secondary development.

Application Notes:

How does a multichannel analyzer (MCA) work in the pulse height analysis mode?

MCA for scintillation detetor consist three parts in essence, analog-to-digital converters (ADC), onboard processor, and digital signal processing. 

In a pulse height analysis (PHA) procedure, the high-speed ADC first receives the incoming signal from the preamplifier of the detector and converts the amplitude of these analog pulse signals into digital data. Usually this process will distribute the amplitude of the pulses to several "bins" or "channels", where the channels are divided despending upon their respective voltage ranges. 

The onboard processor can be either be microcontroller, a CPU, or a Field-Programmable Gate Array (FPGA) if more flexble function is required. The onboard processor builds a picture of the pulse event. There’s a trigger threshold, which is a preset voltage value. The onborad processor stores the pre-trigger data as the baseline for comparison, while uses the triggering algorithms to decide when to initiate the analysis. Once the trigger is activated, the processor begins to analyze the signal characteristics of pulse signals (such as amplitude, duration, etc.) via comparing the amplitude of the pulse to the baseline level (from the pre-trigger data).

The last digital processing signal processing uses algorithms (e.g. trapezoidal forming) to shape the input pulse, allow the highest-possible resolution measurement of the pulse amplitude and improve signal-to-noise ratio. As time passes and the number of pulses are accumulated and stored in the channels, and an energy spectrum graph will be formed.