The PILATUS3 X CdTe series are large area, single-photon counting detectors. They combine the advantages of the PILATUS3 X hybrid photon counting (HPC) detector models with the outstanding high-energy detection capabilities of the cadmium telluride (CdTe) sensor material.
PILATUS3 X CdTe detectors are the first large area, singlephoton counting detectors offering highly efficient detection up to 100 keV. They make the unique properties of the PILATUS3 detector technology available for hard X-ray applications without any compromise.
Time-resolved and scanning beam experiments can make use of frame rates of up to 500Hz with sub-millisecond readout times, without the drawbacks of any image lag. Noise-free single-photon counting alongside a 20-bit counter and direct conversion enables weak signals adjacent to strong peaks to be measured with very good signal-to-noise ratio.
The PILATUS3 CdTe detector allows us measuring diffuse scattering data from strongly absorbing samples. These measurements are only possible with lose noise, high dynamic range detector with sufficient efficiency at the required high X-ray energies.
A Lexei Bosak, ESRF
Cadmium Telluride Sensors for Highest Quantum efficiency
Each CdTe detector module comprises two large CdTe crystals (sensors) each measuring 42×34mm dimensions, with a horizontal gap of just three pixels between the two crystals. The thickness of the CdTe is 1000µm in order to provide high quantum efficiency for hard X-ray energies up to 100keV.
Optimal Signal-to-Noise Ratio
Free of dark current and readout noise. As there is no detector noise, data with an excellent signal-to-noise ratio can be guaranteed. The photon-counting CdTe detector only has considerably less noise resulting in better visibility of weak diffraction rings (Fig 1).
Fig. 1: Comparison of data quality of flatpanel and PILATUS3 X CdTe detector. The photon-counting CdTe detector shows significantly less noise resulting in improved visibility of weak diffraction rings. Image credit: Dectris Ltd.
High Dynamic Range
A counter depth of 20bits (~1million counts) combined with the no-noise feature ensures exceptional contrast and dynamic range, thereby enabling outstanding image and data quality. Very strong and weak signals can be correctly detected on a single image (Fig. 2). In the case of high-energy photons, it is an significant benefit that each photon only produces a single count free of the photon energy, because it will aid in preserving the detector's high dynamic range at all energies.
Fig. 2: Reciprocal space map showing X-ray Diffuse Scattering of a Bismuth sample studied at 69.7 keV. Image credit: Dectris Ltd.
High Local and Global Count Rates
It matches count rates of more than 5x106 counts/s/pixel corresponding to approximately 2×108 counts/s/mm2. The DECTRIS instant retrigger technology helps to provide high count rates. Count rate correction is used to provide exact intensity measurements over the full range of count rates. Superior long-term stability assures stable operation, which is less than 1% signal variation (reduction through polarization) observed at 2.5 × 106 counts/s/pixel over several hours.
Excellent Point-Spread Function
The point-spread function (PSF) illustrates the spatial resolution of an imaging detector. As the X-rays are directly converted into charge pulses, there is no intensity between pixels. Only limited signal is spread by fluorescence to the neighboring pixels even when above the absorption edges of the CdTe sensor. Therefore the PSF is basically provided by its pixel size (172µm) and allows good sharp images to be captured. These are free of artifacts such as intensity tails, blur, blooming or streaking. The combination of sharp point-spread operation along with the high dynamic range of the detector enable closely spaced signals even of largely differing intensity to be precisely resolved and measured.
Short Readout Times
Short readout times of below 1ms and high frame rates of up to 500Hz (250Hz for the 2M) help to greatly decrease measurement time and increase throughput and efficiency. Compared with scintillator-based CCDs and flat panels, the direct conversion CdTe detector does not produce any image lag, which enables top level scanning speed for experiments. Along with versatile trigger and gating features, dynamic processes on fast time scales can be tested in-situ.
Exposure times can be changed from a few nanoseconds to several hours. This can be controlled internally or by applying an external gate signal. Synchronization between the detector and other hardware is very easy because of the combination of the external trigger input with a programmable delay operation.
Modifiable lower energy threshold helps to reduce fluorescence. When the high dynamic range is coupled with the unique PSF, fluorescence suppression, and fast readout, several new applications, e.g. in diffuse scattering (Fig. 3) are possible.
Electronically gated without the need for a mechanical shutter; thereby simplifying the measurement setup. Additionally, the noiseless readout also enables continuous data acquisition, which paves the way for different perspectives in imaging and time-resolved experiments.
The PILATUS3 CMOS readout chips contain radiation-tolerant layout techniques developed for high-energy physics to avoid any damage caused by the incoming X-rays. The detectors can handle the doses coming out from long-term operation at advanced synchrotrons.
Multiple modules can be integrated to form large-area detector arrangement with varied geometries. DECTRIS can help develop and manufacture application and customer-specific systems, such as custom module arrangements and in-vacuum detectors.
The detector systems can be operated at room temperature. They only need dry air or N2 for operation. Easy to set up and does not require regular maintenance or service. The CdTe detector software guarantees simple and fast integration.
The PILATUS3 X hybrid photon counting detectors offer the following benefits:
- Easy integration
- Outstanding count rate stability
- Overflow-free 20-bit counter
- Outstanding point-spread function
- Noise-free single-photon counting
- High quantum efficiency, up to 100keV
- No image lag or afterglow
- Frame rates of up to 500Hz
- Low-maintenance at room temperature
The PILATUS3 X hybrid photon counting detectors can be used in the areas listed below:
- Small animal/pre-clinical computed tomography
- Non-destructive testing (NDT) and security
- X-ray computed tomography (CT)
- X-ray projection imaging (Radiography)
- X-ray phase-contrast imaging (PCI)
- High-energy X-ray diffraction (HE-XRD)
- Inelastic X-ray scattering (IXS)
- Time-resolved / in situ experiments
- High-pressure/high-temperature XRD (HP-XRD/HT-XRD)
- X-ray diffraction tomography and microscopy (XRD-CT/XDM)
- X-ray diffuse scattering (XDS)
- X-ray powder diffraction and Pair-Distribution Function analysis (XPD, PDF)