The xMap is a multi-channel digital pulse processor designed for high-rate x-ray spectroscopy and fast-mapping applications at synchrotron beamlines, and offers the following advantages:

  • Compatible with SDD, HPGe and other x-ray detector types
  • Output Count Rates approaching 1 Mcps per channel
  • Sophisticated pile-up inspection
  • 4-channel PXI card easily expandable to 100+ channels
  • Auto gain adjust/calibration across all channels
  • Onboard dual memory for deadtimeless MCA, SCA and List Mode mapping
  • Open source driver libraries for custom DAQ control




Based on the CompactPCI/PXI standard with data rates up to 100 MB/s, the xMap is uniquely suited for high-speed XAFS and x-ray scanning applications at synchrotron and other beamline facilities.

Applications include:

  • XAFS, EXAFS, and other scanning applications
  • High resolution x-ray spectroscopy from 150 eV– 100 keV
  • Multi-element SDD and HPGe detector arrays
  • Quad SDDs: Only one card required

More about Applications…


Technical Data

The xMap’s trapezoidal digital FIR filters offer significantly enhanced throughputs and achieve energy resolutions comparable to analog systems, but at a lower cost per channel. Energy resolution is nearly independent of count rate up to maximum throughput. The full computer interface allows all data taking and calibration operations to be automated, greatly reducing the possibility of human error. Data can be collected either into a full spectrum of up to 8K channels or into up to 32 regions of interest (ROI’s) and passed to the host without stopping data collection. The full spectrum allows peak fitting and/or deconvolution on a detector by detector basis, leading to more accurate intensity extractions, particularly where scatter peaks are changing rapidly with energy.

The xMap offers several timing modes, including fast scanning with full MCA readout or multiple ROI’s, as well as list mode readout, where time and energy are stored for each event. The onboard memory manager allows full access to the data even during data collection. For deadtimeless operation for fast scanning, the memory is organized into two completely independent banks, allowing readout of one bank while the other is filled. Peak readout speeds across the PCI interface exceed 100 MB/sec permitting sub-millisecond scanning dwell times.


  • Single PXI/CompactPCI module contains 4 channels of pulse processing electronics with full MCA per channel.
  • 4 MB of high-speed memory allows ample storage for timing applications such as mapping with full spectra or multiple ROI’s. Memory can be read at the full PCI speed.
  • Peak PCI transfer rates exceed 100 MB/sec.
  • Peaking time range: 0.1 to 100 microsec
  • Maximum throughput up to 1,000,000 counts/sec/channel.
  • Digitization: 14 bits at 50 MHz
  • Low noise front end offers excellent resolution, and provides excellent performance in the soft x-ray region (150 – 1500 eV).
  • 16 bit gain DAC and input offset are computer controlled.
  • Pileup inspection criteria are computer selectable.
  • Accurate ICR and livetime for precise deadtime correction and count rate linearity.
  • Multi-channel analysis for each channel allows optimal use of data.
  • Facilitates automated gain setting and calibration to simplify tuning array detectors.
  • External Gate allows data acquisition on all channels to be synchronized.
  • All runs can be synchronized between modules using the LBUS signal connecting all the modules together.


Inputs Analog Four preamplifier inputs, jumper-selectable input gain. 0dB (x1): 10 kohm impedance, +/- 5V range. 12dB attenuation (1/4 gain): 1kohm, +/- 20V, jumper selectable. Works with common reset preamplifiers of either polarity.
Digital (TTL) Each module has a single LEMO connector which can be programmed to be used for any of the following functions:

Gate: Logic input for externally timed data collection. Halts data acquisition when asserted.

Sync: Clock input to control time resolved data collection, such as scanning.

LBUS: Logic input/output used to extend the backplane bussed run synchronization line between PXI bus segments.

All digital signals are bussed along the PXI backplane. For Gate and Sync, only one signal per backplane segment must be provided.

Data I/O Interface Compact PCI standard, 33 MHz, 32-bit
Data Transfer Rate Memory readout to host: 109 MB/sec
Resolution State of the art, detector dependent.
Count Rate OCR to 1 Mcps max (at ICR > 2 Mcps)
Throughput The output count rate (OCR) approaches theoretical values based on input count rate (ICR) and deadtime td, where td equals 2 times peaking time plus dwell time: OCR = ICR * exp(-ICR* td).
Integral Non-linearity <= 0.1% over full scale output range.
Pileup Inspection Pulse-pair resolution typically better than 50 ns unless limited by signal risetime.
Digital Controls Gain 100x range, controlled by 16-bit DAC. Preamplifier gain range 0.1 to 10 mV/keV at standard settings.
Thresholds Up to three adjustable thresholds are used simultaneously to support soft x-ray work while maintaining good pileup rejection.
Filtering Peaking times 0.1 – 160 microseconds. Adjustable flat top to eliminate ballistic deficit effects.
Pileup Fast channel filter time, pulse detection threshold, and fast channel pileup inspection test limits may be set independently to achieve best results in every x-ray energy regime.
Data collection MCA limits, bin widths, ROIs
Data Outputs MCA Single Spectrum Mode: 256-16384 bins (32 bits deep).
Multi-Spectrum Mode:   256-16384 bins (16 bits deep).
ROIs Up to 32 regions of interest can be defined.
Timing Multiple spectra or sets of ROIs can be stored; continuous operation is possible using memory in dual-bank configuration.
Statistics Statistics: All values required for pileup correction are available: livetime, realtime, input events, output events.
Diagnostics ADC and filter output traces, baseline distribution, baseline history
Software Overview XIA provides ProSpect, a software package for setting up detector arrays and generating configuration files for use by other control into existing data collection packages. Handel, a comprehensive set of C libraries, simplifies integration of xMap control into existing data collection packages.
Diagnostics ADC trace, filter outputs, baseline distribution, baseline history
Run Control Start/stop under host control or according to user provided TTL/CMOS logic signals. Run can be ended according to preset realtime, livetime, input or output events, or number of pixels.