eMorpho MCA

usbBase and oemBase

usbBase at the top with sealed connectors for USB and GPIO. The oemBase at the bottom is sealed as well, but exposes pin headers for all functions.

Introduction

  • The MCA
    • Large histogram 4Kx32 or more; Measures time and count rates.
    • Read data without interrupting data acquisition, avoiding dead time losses.
    • Special features (in parallel): pulse shape capture, list mode, pulse shape discrimination.
    • Custom functionality through firmware extensions.
  • Interfacing
    • Analog: Use the same hardware for all types of scintillators.
    • Digital: USB, SPI, serial for easy system integration on ARM, x86, x64.
    • Open-source data formats and control software, on Win, Linux.
  • Software structure
    • Device driver and API in Python; Internet data server with web interface.
    • Sever/Client software structure bridges distance and programming languages
    • Client application can be written in any programming language

Brief Specifications

  • Works with any scintillator
  • Energy histogram (on board) 4096 x 32bit
  • Accurate count rate measurements
  • Oscilloscope: 1024-point waveform capture
  • Waveform digitizing ADC: 12 bit, 40MSPS, 80MSPS, and 120MSPS options
  • List mode: Stores energies and time stamps
  • Pulse shape analysis: For pile up rejection and particle identification
  • Non-volatile memory, 256 byte to 128 kByte
  • Powers and operates hvBase plug-on PMT power supplies
  • USB-power: +5V, 45mA (std., 12-bit, 80MSPS ADC)
  • Open source application programmer's interface; Python API
  • wxPython based wxMCA GUI for Windows and Linux
  • MCA Data Server can be accessed from any programming language.
  • With custom firmware, histograms, traces and list mode buffers can be extended in size.

Histogram performance

137Cs spectrum with B380 at high count rates. Red graph: without pile up rejection; blue graph: with pile up rejection.

  • Histogram variants
    • 4Kx32 (standard), 20 time slices 1Kx16 (streaming)
    • Dual-port memory allows reading while DAQ is ongoing.
    • Split-memory for loss-less reading (2 banks)
    • 1Kx16 histograms + count-rates at 10 frames per second, for alarming.
  • Throughput
    • Up to 1.3Mcps at 4Mcps input rate.
    • The limiting factor is typically the scintillator, not the electronics.
    • It takes some time to collect eg 90% of the scintillation light.
    • That is the only dead time.
  • High count rate spectra
    • Acquired on a 1.5x1.5-inch LaBr3 (B380) detector.
    • 80 MHz ADC
    • B380 pile-up rejection module (non-standard)

Standard list mode

  • Two list mode data formats
  • Single memory bank (2kB) with 340 events (standard). Number of valid events reported at the end of the memory. There are two standard operating modes:
    ModeFormat
    016-bit energy; 32-bit time stamp, LSB = 1 ADC clock cycle, ie 25ns at 40MSPS
    116-bit energy; 16-bit PSD word; 16-bit time stamp, LSB = 0.80μs

Enhanced list mode

  • Two memory banks with 2730 events each
  • Firmware automatically switches from one bank to the next as a bank fills up. → loss-less data acquisition.

Pulse Shape Capture

Two 1024-point NaI(Tl) pulses at very different temperatures.

The ability of the eMorpho to record pulse shapes is very useful when studying changing scintillator pulse shapes. The motivation may be to provide gain and performance stabilization over an extended temperature range. For instance, if pulses get slower, it may be necessary to increase the integration time in order to keep the energy resolution constant.

If the scintillator exhibits differently shaped pulses for two different particles, the pulse capture capability can be used to collect a large set of either pulse type. After a suitable pulse shape algorithm has been developed using off-line data analysis, developers may work with Bridgeport Instruments to implement that algorithm directly in the eMorpho FPGA.

  • Pulse shape recording
    • 1024 ADC values at full ADC speed.
    • Trigger point can be moved from 0 (left) to 1023 (right).
    • Customizable to 20x1024 samples.

usbBase / oemBase
Positive High Voltage Dividers

Part numberDescriptionApplication
P81L R6231 or compatible 8-stage PMT, linear divider High gain; For plastic scintillators, BGO, CsI(Na), SrI2
P81T R6231 or compatible 8-stage PMT, tapered divider For NaI(Tl), LaBr3
P10L R878 or compatible 10-stage PMT, linear divider High gain; For plastic scintillators, BGO, CsI(Na), SrI2
P10T R878 or compatible 10-stage PMT, tapered divider For NaI(Tl), LaBr3
List of common positive high voltage dividers; Call for other pinouts.

usbBase / oemBase
Negative High Voltage Dividers

Part numberDescriptionApplication
N81L R6231 or compatible 8-stage PMT, linear divider High gain; For plastic scintillators, BGO, CsI(Na), SrI2
N81T R6231 or compatible 8-stage PMT, tapered divider For NaI(Tl), LaBr3
N10L R878 or compatible 10-stage PMT, linear divider High gain; For plastic scintillators, BGO, CsI(Na), SrI2
N10T R878 or compatible 10-stage PMT, tapered divider For NaI(Tl), LaBr3
List of common negative high voltage dividers; For best spectroscopy above 100kcps use a detector that can be operated at negative high voltage. Call for other pinouts.

usbBase
Common Part Numbers

Part numberDescriptionApplication
usbBase-40M-N81L 40MSPS ADC, negative high voltage, R6231 or compatible PMT Plastic scintillators, BGO
usbBase-80M-P10T 80MSPS ADC, positive high voltage, standard 10-dynode PMT NaI(Tl)
usbBase-80M-N81T 80MSPS ADC, negative high voltage, R6231 or compatible PMT NaI(Tl), LaBr3(Ce)
usbBase-120M-N81T 120MSPS ADC, negative high voltage, R6231 or compatible PMT LaBr3(Ce)
Frequently ordered part numbers. Fill out our detector questionnaire and we can help to identify the correct part number. Part numbers for oemBases are similar; just replace the word usbBase with oemBase.

Downloads and Pricing

The functionality of all eMorpho and slimMorpho PCB is exactly the same. The slimMorpho offers 10 GPIO pins whereas the round eMorpho has 14 GPIO

Configure your PMT MCA

Round eMorpho

slimMorpho

www.bridgeportinstruments.com 11740 Jollyville Rd. Austin, TX 78759, phone: 512-533-9933.

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