Detectors

Depending on user requirements (optimizing for scanning speed and/or spatial resolution), several scintillators are available. The LuAG:Ce scintillators are most frequently used for our standard experiments as they provide a good compromise between speed and resolution. The following table lists the most commonly used scintillators:

Note that the thickness of the scintillator affects the overall spatial resolution! The thicker a scintillator, the poorer the spatial resolution due to light scattering within the scintillator material. The thickness should thus be matched with the effective pixel size of the optical system. 

Other scintillator options are available. If you need a specialized setup, please contact beamline staff in advance of your experiments. Users are also welcome to bring their own scintillators, but should contact beamline staff in advance to ensure that the scintillator fits onto the microscope and a proper mount is available and ready to use.

TOMCAT has a pool of optical microscopes that are compatible with all of our standard cameras. The following paragraphs give a detailed information on each microscope.

Microscope 1: Standard High-resolution Microscope (Optique Peter)

This microscope is based on a revolver system that can accommodate up to three objectives at the same time. The diffraction-limited objective type and magnifications available are listed in the table below. It is not compatible with high X-ray photon flux, i.e. filtered white beam and monochromatized undulator beam. 

Microscope 2: 1:1 Optics (Optique Peter)

This system is based on a high numerical aperture, tandem 1:1 configuration, accepting a diagonal up to 40 mm. It is typically used for the DPC (differential phase contrast) imaging setup or for large samples that do not require high spatial resolution. It can be used in combination with all our cameras and can be operated using both polychromatic and monochromatic radiation. This is the microscope offering the largest effective pixel size option. 

Macroscope 5: High Numerical Aperture 4x White-Beam Macroscope (Optique Peter)

This novel, high quality, custom-made macroscope offers a 4x magnification and has a very high numerical aperture of 0.35, making it highly efficient. The macroscope is modular, flexible and can be mounted both in a horizontal and vertical configuration, to best match the sample environment and imaging requirements. It has been designed for high-resolution time-resolved X-ray tomographic microscopy and can be operated using both polychromatic and monochromatic radiation, coupled either to a pco.edge camera or a GigaFRoST detector. The macroscope has a tunable aperture which can be used to optimize the spatial resolution for different imaging setups. The high efficiency and superior image quality of the macroscope have made tomographic studies with a time resolution of 20 Hz and beyond at TOMCAT a reality. A detailed description of the macroscope performance can be found here (DOI: 10.1107/S1600577519004119).

Microscope 6: Dual-Head (10x and 20x) White-Beam Macroscope (Optique Peter) 

This is a dual-head, high-magnification, white beam microscope from Optique Peter. Our model is equipped with long working distance objectives offering a 10x (NA=0.28) and 20x (NA=0.42) magnification with integrated lead glass. Each head has it’s own scintillator support. It can be operated using both polychromatic and monochromatic radiation, coupled either to the pco cameras or GigaFRoST detector. A detailed specification of this microscope is listed below.

Microscope 7: High Numerical Aperture 10x White-Beam Microscope (Optique Peter) 

This is the latest long-working distance generation of white beam, single-objective microscope from Optique Peter. Our model is offering a 10x magnification with a numerical aperture of 0.4. The macroscope is modular, flexible and can be mounted both in a horizontal and vertical configuration, to best match the sample environment and imaging requirements. It has been designed for high-resolution, time-resolved X-ray tomographic microscopy and can be operated using both polychromatic and monochromatic radiation, coupled either to the pco cameras or GigaFRoST detector. The special head design allows the beam to go through and perform multi-scale imaging at the same time. A detailed specification of this microscope is listed below.

Microscope 8: Single-Head (13.5x or 27x) White-Beam Macroscope (Optique Peter) 

This is a single head, high magnification, white beam microscope from Optique Peter. Our model is equipped with long working distance objectives which can be exchanged between 10x (NA=0.28) and 20x (NA=0.42) high magnification lenses with integrated lead glass. In combination with a tube lens, it offers a magnification of 13.5x and 27x, respectively. It can be operated using both polychromatic and monochromatic radiation, coupled either to the pco cameras or GigaFRoST detector. A detailed specification of this microscope is listed below.

The following detectors are routinely in use at TOMCAT and fully supported in the data acquisition and controls system. The choice of detector is governed mostly by the requirements in terms of the achievable pixel size, field of view, image quality and acquisition speed. The table below gives the key specifications for these cameras, while the paragraphs below contain more specific information about each camera model.

Legend RS: Rolling Shutter, GS: Global Shutter, FS: Fast scan, SS: Slow scan

pco.edge 5.5

This is the low noise and large field of view camera by pco, and the work-horse camera for standard measurements at TOMCAT. It is built on sCMOS technology and features a sensor size of 2560 x 2160 pixels, 6.5μm pixel size and a 16-bit nominal dynamic range → technical specifications.

pco.edge 4.2

This is the slightly smaller brother of the pco.edge 5.5, featuring even slightly lower noise levels, but at the expense of a reduced sensor size (2048 x 2048 pixels). It is also based on sCMOS technology with a 6.5μm pixel size and a 16-bit nominal dynamic range → technical specifications.

pco.edge 10  

This is the latest generation camera, featuring a large sensor size (4416 x 2368 pixels) and small pixel size (4.6 μm). It is also based on sCMOS technology and a 16-bit nominal dynamic range with a high QE.  → technical specifications.  

pco.dimax

The pco.dimax is the high-speed camera offered by pco. The imaging chip is built on CMOS technology and features 2016 x 2016 pixels, 11μm pixel size and a 12-bit nominal dynamic range. The camera has an on-board memory of 36 GB and is read out via a USB2.0 connection (slow!) → technical specifications. 

This camera is rarely used at present and mostly replaced by the GigaFRoST camera.

GigaFRoST

The GigaFRoST camere is a PSI in-house development incorporating the same imaging chip as the pco.dimax, but featuring a novel readout system providing continuous and sustained data streaming at up to ~8GB/s to a dedicated high-performance data backend server. This allows for the high-speed acquisition of long time series to observe dynamic phenomena in a time-resolved manner during long perdiods of time. 

For an in-depth description of the GigaFRoST camera system refer to R. Mokso, C. M. Schlepütz, G. Theidel, H. Billich, E. Schmid, T. Celcer, et al., "GigaFRoST: The Gigabit Fast Readout System for Tomography", J. Synchrotron Rad., 24 (6), 1250-1259 (2017). DOI: 10.1107/S1600577517013522.