XDAS detector boards V3

The XDAS X-Ray Data Acquisition System provides a highly flexible means of creating an array of linear X-rays sensors, read out in digital format.  The XDAS-V3 version has recently been launched to replace XDAS-V2 and provides many new features.  The XDAS-V2 version remains available.

The system has a modular architecture, enabling system designers to build their own detectors with detector boards arranged as required.  This may be in a linear or 'L' shaped format or with multiple rows for CT detector applications, where the detectors are arranged around a ring.

The building blocks are the Detector Head Boards, XDAS-DH3-xxx, which provide an analogue output and the Signal Processing Boards, XDAS-SP3-xx, which provide a 16-bit digital output.  Each detector head board has 128 channels and up to 24 detector head boards can be connected to a single signal processing board.  For a 24 board system the detector head boards are arranged in 2 strings of 12 boards, with interconnection provided by 50-way ribbon cables, which carry power and data.  Up to 7 signal processing boards can be used in a single system, giving a total channel count of 21504 channels.  Larger systems can be designed using multiple data outputs.

Detector boards can be butted end-to-end, to form a flat array, or can be arranged on an arc or 'L' shape with each board at 90 degrees to the X-ray source.

Data output from the signal processing board is via a 50-way cable to a USB2, RS485 or Ethernet adaptor board, which also provides power conditioning.

Detectors can be supplied with 2.5mm, 1.6mm, 0.8mm or 0.4mm pitch.

Dual and Single Energy XDAS Boards

An XDAS detector head board can be supplied as a single energy or dual energy version.  Dual energy boards may be supplied as a stacked detector with high and low energy boards on the same side of the board or with the low energy detector on the upper side and the high detector on the lower side.  A small footprint board is also available. Dual energy on a single board is available only for 1.6mm pitch detector or 2.5mm pitch to special order.

Dual energy with 0.4mm and 0.8mm pitch requires separate boards for high and low energy.

Gain Matching

The gain of the detector head board can be adjusted in 8 steps.  Different gains can be set for high and low energy channels and for separate boards.  This feature enables signal-to-noise to be maximized for all parts of the detector array.

Multi-view System

The XDAS Multiview system has 6 inputs, one for each view.  Each view can have up to 12 detector head boards.  This enables up to 72 boards to be run form a single signal processing board.

Processor interface

The unit can be interfaced to a processor via a range of interface adaptor boards:

• USB2 cable directly to the processor.  In this case, the maximum cable length is 5M.
• Ethernet
• PCI7300A card - RS485 output, via a 50-way SCSI cable to a XDAS-485A-TTL adaptor which connects to a PCI7300A card.  SCSI cable can be up to 100M long.
• USB2 remote - as for PCI7300A-TTL but with a convertor box, XDAS-USB, instead of the XDAS-485A-TTL.
• Frame Grabber card - as for PCI7300A with XDAS-485-DFG adaptor board.

Control signals are transmitted to the unit via the USB2 connection, Ethernet or the RS232 serial port for PCI7300A and frame grabber options.

Control  Signals

Scan time, number of sub-samples and detector head board gain is controlled from the processor.  An external trigger input (nScan) is provided if required.

Features

• Single and dual energy versions
• 20keV to 300keV
• 0.4mm, 0.8mm, 1.6mm and 2.5mm detector pitch
• Gadox, CsI, CdWO4, GOS Ceramic scintillators or bare silicon for direct conversion of X-rays to charge
• Minimum scan time is 51.2µs per board
• Facility for 1,2 and 4 sub-samples
• 1.875pC to 15pC charge capacity for a detector channel
• 16-bit output
• Up to 36000:1 electrical signal-to-noise, without X-rays

Software

Users will be required to use their independent software applications to provide system control, data acquisition and image processing.  To assist in this task a XAPI is available.  Standard software is supplied to permit basic operation and evaluation of the system.  The software enables single lines of data to be acquired and stored, data acquisition time to be set, and offset and gain correction to be applied.

PowerSupply requirements

• 6V to 9V, depending on the number of boards

Environmental Specification

• Temperature (operating) +5°C to +35°C
• Humidity (non-condensing) 93% at 30°C
• Pressure for transportation, withstands pressure reductions from 100kPa (1 bar) to 68kPa (0.68 bar)