Optimal Signal-to-Noise Ratio

All PILATUS3 Hybrid Photon Counting detectors are inherently free of dark current and readout noise (Fig. 1). The absence of any detector noise guarantees data with an excellent signal-to-noise ratio. Compared to conventional detectors, this allows either the collection of superior data with similar exposure times or equally good data with shorter exposure times per image. A noise-free detector provides the largest benefit when recording weak signals from poorly diffracting samples or at highest resolution. The absence of detector noise is particularly beneficial in data acquisitions with weak laboratory sources.

Fig. 1: Absence of readout noise and dark current in PILATUS Hybrid Photon Counting detectors.
Images of a single PILATUS module without exposure to an X-ray source with 100 ms (a) or 1 hour (b) acquisition time. a)  After a short acquisition time all pixels have zero counts because no noise is added to the readout of the image. b) After 1 hour, most pixels still have zero counts since no dark current accumulates during long exposure and no noise is added during readout. All counts in the exposure arise from general background radiation, which accounts on average for 0.2 cts/h/pixel for 450 µm sensors.

Fast readout and shutterless operation

PILATUS3 R detectors for laboratory instruments read out complete images with lightning speed in only 7 ms. This allows shutterless, continuous acquisition of full images. Nearly instantaneous readout and continuous data acquisition maximize the efficiency and throughput of any instrument.

Customizable to match your requirements

In addition to the standard 450 µm thick silicon sensors, you can customize your PILATUS3 R detector with 1000 µm thick silicon sensors to match the energy of your X-ray source (Tab. 1). This achieves high quantum efficiency at all common laboratory X-ray energies. 

The water cooled models PILATUS3 R 300K and 300K-W offer optional vacuum compatibility. This customization allows to operate the detector in vacuum, e.g. in the flight tube of a SAXS instrument and eliminates all air and window scattering.

Photon energy 450 µm 1000 µm
5.4 keV (Cr) 94 % > 80 %
8.0 keV (Cu) 98 % 96 %
9.2 keV (Ga) 97 % 97 %
17.5 keV (Mo) 47 % 76 %
22.2 keV (Ag) 27 % 50 %

Table 1: Quantum efficiency of PILATUS sensors based on measurements at the PTB beamline at BESSY II.  

Excellent point-spread function

With hybrid pixel technology and direct conversion of X-rays into charge pulses, PILATUS3 R detectors spread virtually no intensity between pixels. This results in a sharp point-spread function of one pixel (FWHM) and offers a variety of benefits (Fig. 2). Closely spaced signals, even of largely differing intensity, can be accurately resolved and measured. Sharper signals reduce overlap with scattering or other background intrinsic to the experiment, thereby improving the signal-to-noise ratio.

High dynamic range

A counter depth of 20 bits (~1 million counts) combined with the absence of detector noise ensures unprecedented contrast and dynamic range, another hallmark of all PILATUS3 detectors leading to excellent image and data quality (Fig. 2). Extremely strong and weak signals can be accurately detected on a single image.

Fig. 2: Superior dynamic range and point-spread function of PILATUS Hybrid Photon Counting detectors.
Details of diffraction images showing the same reflection of an insulin crystal. The images were acquired at a synchrotron beamline with identical parameters except for the detector distance which was adjusted to achieve the same resolution at the detector edge, depending on the detector size.
PILATUS: The 20-bit counter depth of the PILATUS Hybrid Photon Counting detector provides sufficient dynamic range to record 727,716 counts in the highest intensity pixel. Thanks to the excellent point-spread function, the spot is well confined to a small area. Furthermore, the sharp reflection profile of the low mosaicity crystal is accurately represented with a more than one-thousand-fold difference in intensity between neighboring pixels.
CCD: The same reflection recorded with a CCD contains many overloaded pixels. The reflection intensity is smeared out over a large area.

High local and global count rates

PILATUS3 R features DECTRIS instant retrigger technology, which enables each pixel of a PILATUS3 to accurately detect up to ten million photons per second. Furthermore, no global count rate limit is detected up to 6 × 106 photons per second and pixel. This enables global count rates of more than 2 × 108 photons per second and square millimeter. Both local and global count rates of PILATUS3 detectors are far superior to those of counting detectors based on gas discharge or similar technologies. For the first time, photon-counting detectors are compatible with even the most demanding samples such as strongly diffracting small molecule crystals.

Fluorescence suppression

PILATUS3 R detectors feature an adjustable lower energy threshold to suppress fluorescence. Combining the high dynamic range with the excellent point-spread function, fast read-out and fluorescence suppression enables the pursuit of exciting new sciences, e.g. in diffuse scattering.

[A. Bosak et al., PRL 103, 076403 (2009), DOI:10.1103/ PhysRevLett.103.076403 and Ch. Bärlocher et al., Science 333, 1134 (2011); DOI: 10.1126/science.1207466].

Ease of maintenance and operation

PILATUS3 R detectors have low power and cooling requirements. All detector components are operated at room temperature, which vastly simplifies cooling. The PILATUS3 R 200K-A detector is fully air-cooled and maintenance-free. PILATUS3 R 300K, 300K-W, and 1M use low-maintenance, closed-circuit water-cooling for temperature stabilization at 23° C.