Time of Flight
Fast Flight-2 Digital Signal Averager

With its ability to process up to 100 averaged spectra per second, while responding proportionally to multiple ions in each detector pulse, the FASTFLIGHT-2 is a superior solution for data acquisition in LC/TOF-MS and GC/TOF-MS applications. Chromatograph technology is advancing towards shorter retention times, and this pushes the time-of-flight
mass spectrometer (TOF-MS) to acquire averaged spectra much more rapidly. FASTFLIGHT-2 improves the TOF spectra processing rate by a factor of 10 compared to first-generation digital signal averagers, thus enabling much faster chromatographs.

Because it employs a sampling ADC and a hardware digital signal averager, FASTFLIGHT-2 can handle the high ion rates encountered in LC/TOF-MS, GC/TOF-MS, Ion-Trap/TOF-MS and MALDI I TOF-MS without suffering the dead-time distortions inherent in a time-to-digital converter (TDC). Compared to transient digitizers and digital sampling oscilloscopes, which suffer from slow software averaging, FASTFLIGHT-2 delivers averaged spectra many orders of magnitude faster.

The innovative, automatic correlated noise subtraction feature means FASTFLIGHT-2 can also be a productive solution for the lower ion rates encountered in quadrupole/quadrupolefTOF mass spectrometers (QqTOF-MS), previously considered to be the exclusive domain of TDCs and time digitizers.

FASTFLIGHT-2 does it all!

How Does It Achieve Such Impressive Performance?
Starting With the Chromatograph/TOF-MS, the sample from the chromatograph is typically injected into the acceleration region of the TOF-MS through an electrospray nozzle. Although the detail is not depicted in Figure 1, the result is a cloud of ionized molecules between the acceleration electrode and the grounded grid in the source region of the TOF-MS. Periodically, a brief high-voltage pulse is applied to the acceleration electrode. This causes the ionized molecules to accelerate and travel along the field-free drift tube. The molecules are separated according to mass, with the lighter molecules attaining higher velocities and arriving at the detector before the heavier molecules reach that end of the flight path. The flight time is proportional to the square root of the mass-to-charge ratio, m/z, of the ionized molecule. As a group of molecules of a particular m/z arrives at the detector, it causes the detector to generate an analog output pulse whose amplitude is nominally proportional to the number of molecules in that group. Thus, the time at which the detector pulse is produced represents the m/z value, and the amplitude is proportional to the number of ions of that specific mass and charge. Accordingly, the spectrum of flight times is measured to generate the mass spectrum.

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    Hardware Performance
    Amplitude Digitizing Resolution 8 bit- ADC nominally spans 500 mV at the Analog Input.
    Precision Enhancer Extends the limiting ADC resolution to 12 bits (for input noise <2 mV) when circa 256 or more records are averaged3.Optionally, on or off.
    Differential and Integral Non-Linearity (DNL and INL) Measured from 5% to 95% of full scale using a 500 mV, 70 µs ramp, with Precision Enhancer on.
    DNL within ±0.1 LDB referred to the 8-bit ADC.
    INL within ±0.4% of full scale.
    Analog input Bandwidth DC to 500 MHz; rise adn fall times <1 ns.
    Equivalent input Noise (Measured with 500 ps sampling and 50 µs record lenght.)
    Uncorrelated with the Trigger <2 mV rms.
    Correlated with the Trigger <0.02 mV (typically 0.01mV rms)
    with Automatic Correlated Noise Substruction.
    Automatic Correlated Noise Substruction Automatically assesses the correlated noise in each spectrum and substracts it without compromising data throughout rates. Optionally, on or off.
    Analog DC Offset (Vertical Offset) Zero offset of the ADC is computer adjustable from -250 mV to +250 mv with 0.03 mV resolution, referred to the Analog input.
    Sampling intervals Hardware 500 ps, 1 ns or 2 ns real-time sampling with one scan per pound; 250 ps interleaved sampling with two scans per second4.
    Software can display 250 ps interpolated sampling from a spectrum sampled at 500 ps.
    Record Size (Hardware) 8 bits per sampled point and up to 1.5 M points per record (at 250, 500, 1000 ir 2000 ps/point. Record length selectabel from a minumum of 10 µs to a maximum of 1.5 M points in steps of 512 points.
    Spectrum Size (Hardware) Identical to Record Size, except 24 bits per sampled point, providing rapid hardware summing of up to 65,535 records ub a spectrum.

    ADC Sampling
    Interval (ps)
    Min. Spectrum
    Length (µs)
    Max. Spectrum
    Lenght (µs)
    250 10 375
    500 10 750
    1000 10 1500
    2000 10 3000

    Data Acquisition Delay (Time Offset) Computer selectable digital delay after trigger from 0 to 1048.56 µs in 16-ns steps. The record starts after the selected delay.
    Dead Time End-of-Scan 0.8 µs.
    End-of-Spectrum 0.8 µs.
    Sampling Clock 2 GHz ±5 ppm; temperature sensitivity: within ±2.5 ppm, 0ºC to 50ºC.
    Trigger-to-First-Sample Jitter Trigger Input within 500 ps (next clock pulse).
    Trigger Output <50 ps FWHM. (The Trigger Output is alternatively delayed by 0 and 250 ps relative to the sampling clock in the 250 ps interleaved sampling mode.)
    Operating Temperature Range 0 to 50ºC
    Averaging Method Linear summation of sequential records.
    Selectable Stop-Acquisition Limits Maximum Time 1 second to 65,535 seconds ( 8 hr.), in 1-second steps, or disabled.
    Max. Number of Spectra > 18,000. Limited only by available memory in the supporting PC and the data storage disk.
    Data Compression Implemented in the hardware with no compromise in data throughout.
    LossiessCompression down to 2/3 the normal 24-bit file size
    in spectra dominated by background, and with no loss of
    original data.
    Peak-Preserving and Background-Rejecting5
    Automaticallly separates peaks from background. Transmits
    peaks and adjacent background points. Typically decimates
    98% of the background points between peak regions. Data
    compression by a factor of 10 to 30, depending on peak
    Peak Centroid and Net Area Tranmits only the centroid and
    net area of automatically detected peaks. Provides an
    additional factor of 9 data compression relative to Peak-
    Preserving and Background-Rejecting compression.

    Maximum Data (Spectra) Transfer Rate Up to 100 spectra/s transferred to PC RAM and hard disk for a 50 µs spectrum length and 500 ps sampling in the Chromatograph/TOF-MS mode.
    Total-ion/Specific-ion Chromatographs Automatic hardware computation of real-time Chromatograph displays with each point in the chromatograph linked to the supporting time-of-flight spectrum. Provides exact time synchronization of the chromatograph with the TOP-MS when analyzing the output of an LC or GD. The vertical chromatograph coodinates is:
    Total-ion Chromatograph The sum of the areas above
    background for all peaks in each spectrum.
    Specific-ion Chromatograph The net area above background
    in the TOF-MS peak selected by the operator. Optional pre- and
    post-acquisition selection.
    Time Stamp 42 bits in the spectrum header are allocated to recording the starting time of each spectrum with 10 µs precision. Maximum: circa 1.4 years.
    Spectrum Number 21 bits in the spectrum header are allocated to recording the sequential spectrum number. Maximum limit is circa 2 million. Reset to zero on each acquisition start. Otherwise, this counter runs continuously, even when software stops reading the 32 MB FIFO output.
    Output Buffering During the last record in each spectrum the sum of all records in the spectrum is written to a one-spectrum-deep output buffer, and the summing memory is released to acquire the next spectrum. this limits end-of-spectrum dead time to 0.8 µs. After data processing in the compressor, the spectrum is loaded into a 32 MB output FIFO memory to accommodate intermittent data transfer over the USB-2 bus to the PC without loss of spectra. the output FIFO has a capacity of at least 7 spectra.
    Rapid Protocol Selection Provides a hardware interface to change acquisition parameters in real time with 10 µs. Includes 4 bits to select the hardware parameters defined in one of 16 products, and an additional 4 bits to insert one of 16 tags in the spectrum header. The tags can be used to identify unique acquisition conditions from other parts of the mass spectometer.
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