bPAD is a compact microcontroller-based Intelligent Single Channel Analyzer. The device contains a Preamplifier-Amplifier-Discriminator with TTL digital output. The bPAD also includes its own high voltage power supply for operating standard 14-pin photomultiplier tubes, which are commonly used with scintillator-type radiation detectors [e.g. PVC, NaI(Tl), LaBr, CeBr, etc].
The device is therefore useful as a compact system to monitor the count rate in an energy region of interest.
The detected signal is output as a TTL pulse, making it compatible with most industrial, environmental and laboratory counting systems. In contrast with traditional SCAs the bPAD is fully controlled by a microprocessor, providing easy setup and “smart” modes of operations. bPAD parameters can be conveniently set via USB with a PC and the provided configuration software.
The bPAD is an advanced, microprocessor-based, compact electronic device that integrates a charge sensitive preamplifier, a variable-gain amplifier and a window discriminator; all in a 14-pin photomultiplier tube base. This electronic device outputs a TTL pulse per photo-event detected by a scintillator detector in the energy range of interest. This type of device is also often referred to as a Single Channel Analyzer (SCA). bPAD also includes a miniature, programmable and efficient high-voltage supply to provide the power necessary to operate the most widespread range of photomultipliers used with scintillator detectors. The output voltage can be set in the range from 0 to 1500 Volts with a resolution of 4096 steps.
Since the bPAD is a microprocessor-controlled device, it benefits from being easy to setup. The device connects to a PC via its USB interface, and by using the provided software all the operational settings can be configured and fine-tuned for any kind of scintillator detector. Once the setup is complete, all the settings are saved into the device’s non-volatile memory. The PC software also comes with a “pseudo-PHA” acquisition mode. In this mode, the software slides the single-channel window over the whole input range, constructing in such a way an energy spectrum. By using this spectrum, the user can visually identify the energy range of interest and immediately set the boundaries of the bPAD discriminator window. This represents a large improvement over the traditional “blind” method used with most other SCAs.
bPAD has two modes of operation:
The output pulses correspond to counted events in the energy window of interest. They are 5-volt TTL signals with 2.5 µsec duration. The bPAD can be ordered to output pulses with a duration of 10 µsec instead.
The bPAD can be powered via the USB connection or by an external DC power supply of 6 to 36 volts.
Three color LEDs are used for status indications: Red for detector high voltage, Yellow for incoming count rate (ICR) and Green for power and communication status.
The bPAD is a compact device with a size of 65 mm diameter by 71 mm high (60 mm not counting the TTL output connector) . bPAD weights less than 80 grams.
All the above-mentioned features make the bPAD a very attractive component for industrial and automated applications involving photon detection and counting.
Device and Digital Settings
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