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Mass spectrometry is an analytical technique used to identify the chemical composition of a sample. The method typically works by bombarding a sample with electrons and breaking it into charged molecules or molecule fragments. These ionized particles are then separated, normally by accelerating them in an an electromagnetic field, and the mass to charge ratio for each compound is then determined. To detect the ionized particles an electron multiplier is normally used and the results are displayed as a spectra which plots the number of detected ions as a function of their mass to charge ratio. The electron multiplier plays a crucial role in detecting the ions and producing the electrical signals that need to be analyzed.

For situations that require fast and accurate capture of the electrical signals Spectrum has a range of digitizers that can be employed. For example, 8 bit digitizers are available that offer from 1.25 GS/s up to 5 GS/s sampling rates and 1.5 GHz bandwidth. These products are ideal for capturing and analyzing pulses that go down into the nano-second and sub-nanosecond region. The ultra-fast sampling rates also ensure excellent timing resolution in time-of-flight mass spectrometry systems (TOF-MS). When larger dynamic range and more sensitivity is required high-resolution 14 and 16 bit digitizers are available with sampling rates from 130 MS/s up to 500 MS/s. These high-resolution products deliver outstanding signal-to-noise ratio's (up to 72 dB) and spurious free dynamic range (of up to 90 dB) so that even the smallest signals can be detected and analyzed.  

Small and compact the digitizers can be installed directly in any free PCIe slot in most modern PC's. They are equipped with ultra-fast trigger circuits so that the dead-time between acquisitions can be extremely small (down to as little as 16 ns). Together with  large on-board memories (up to 4 GSamples/card) and advanced streaming and readout modes this makes the digitizers ideal for applications where acquisitions need to be made over long periods of time and where high trigger rates may be encountered. Data can be stored in the on-board memory or streamed in FIFO mode over the fast PCIe bus of the digitizer to a PC at rates up to 3.4 GB/s. To help with data analysis and data reduction Spectrum's M4i series of digitizers also feature on-board FPGA based processing functions that can be perform on-the-fly Averaging and Peak detection routines. Averaging a signal helps remove unwanted noise and improves sensitivity while Peak Detection can be used to help locate pulses and provide time interval analysis.

Each digitizer card can have from one to four channels and up to eight cards can be linked together with Spectrum's StarHub system to create instruments with up to 32 fully synchronous channels. The flexibility allows you to match your system perfectly whether it be for use with a single detector or for applications where multiple detectors and detector arrays are deployed.

To allow easy integration into mass spectrometry systems Spectrum makes available software and instrumentation drivers that work with 32 bit and 64 bit versions of Windows and Linux.  Programming of the cards is possible using a wide range of languages such as LabVIEW, LabWindows/CVI, C++, MATLAB, Borland Delphi, Visual Basic, VB.NET, C#, J# and IVI.

Typical mass spectrometry applications include chemical analysis and life science measurements using TOF-MS (including MALDI-TOF), accelerator mass spectrometry (AMS), inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry (TIMS). Mass spectrometry can also be combined with chromatographic compound separation methods such as liquid chromatography (LC-MS), gas chromatography (GC-MS) and ion mobility mass spectrometry (IM-MS).

Spectrum Product Features

  • High Sampling Rates up to 5 GS/s and 1.5 GHz bandwidth
  • 14 and 16 bit Resolution
  • Fast Trigger and Read-Out Rates
  • External Clock and Reference Inputs
  • FPGA based Block Average and Block Statistics (Peak Detect) Options

Matching Card Families

  • M4i.22xx: 8 bit 5 GS/s to 1.25 GS/s digitizer
  • M4i.44xx: 14/16 bit 500 MS/s to 130 MS/s digitizer
  • M3i.21xx: 8 bit 1 GS/s to 250 MS/s digitizer

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Software Based Block Averaging

The block, or segmented memory, averaging mode is used with Digitizers for different applications where incoherent noise needs to be removed from a signal. Independent of the manufacturer of the digitizer all FPGA based hardware implementations of the block averaging mode limit the maximum size of the segment to be averaged. The limit depends on the capacity of the FPGA and usually ranges from 32k up to 500k samples.

Signal Processing for DigitizersSignal Processing for Digitizers

Modular digitizers allow accurate, high resolution data acquisition that can be quickly transferred to a host computer. Signal processing functions, applied in the digitizer or in the host computer, permit the enhancement of the acquired data or the extraction of extremely useful information from a simple measurement.