AXAS-D back with preamplifier output and USB port
AXAS-D front with standard 100mm finger


Analytical X-ray
Acquisition System - Digital

Short facts

  • Digital system complete with VITUS SDD, reset type preamplifier and DPP
  • Detector sizes from 7mm² to 50mm² available
  • Customized finger length available
  • Highly integrated design
  • Filtering for SDD operating voltages
  • SDD operating temperature readout
  • Peaking times from 1.32µs to 13.3µs

Sample Spectrum

Sample Spectrum

Figure 1: Typical spectrum of a 30mm² KETEK VITUS SDD in AXAS-D, taken with KETEK DPP Software at 8µs shaping time.


Figure 2, Throughput: The diagram provides the throughput behaviour of the AXAS-D. It shows the dependency of the output count rate with the input count rate for different digital peaking times. The lower the peaking time, the higher is the maximum throughput for a system.

Energie Resolution

Figure 3, Energy Resolution with Input Count Rate: The energy resolution of the digital system is mostly independent from the input count rate. The graph shows the dependency of the Full Width at half maximum with the incoming photons (input count rate) for different digital peaking times.

Figure 4, Peak Position: The graph shows the independency of the peak position of the Mn-Ka line with the input count rate for different digital peaking times.

Block Diagram

Figure 5: DPP Operation Block Diagram

Figure 5: The Block Diagram shows the principle of operation of the Digital Pulse Processor (DPP). The main clock frequency is 25MHz, using a 12-bit ADC at 40MSPS. It has both an analogue gain before digitizing and a digital gain right after the digital filtering, which consists of digital shaping a digital Baseline Restoration (BLR), a Peak Detection and a digital Pile-Up Rejector (PUR). Also the SDD operating parameters can be set and read by an additional ADC in combination with a SPI Interface. The DPP is FPGA based and uses USB 2.0 Interface.

Figure 6: AXAS-D Operation Block Diagram

Figure 6, AXAS-D Operation Block Diagram: The diagram shows the principle of operation of the AXAS-D. It consists of a Low voltage Power supply for 3.3 and 1.2V, a thermoelectric cooler controller for the SDD Peltier, a high voltage (-180VDC) power supply, a sensor parameters control and measurement unit, the preamplifier and the Digital Pulse Processor (DPP) itself. It provides an overvoltage and polarity reversal protection. Connectors are USB 2.0, a Lemo Coax Preamplifier Output and for the SDD.


AXAS-D Housing Geometry

Figure 7: All AXAS have compact aluminium housings plated with Nickel. All screws are stainless steel and the systems can be fixed to a plate by using M3 screws. The mounting plates are compatible for all AXAS.

Versions and Ordering Codes

Available options for AXAS-D:


FWHM [Mn Kα]

length [mm]

energy limits

Vacuum-tightness of snout

* with low-energy window

Premium Class ≤ 133 eV*
Standard Class ≤ 139 eV*
≤ 136 eV and ≤ 144 eV for H18LE


20 keV or 30 keV

yes / no


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