1.    Introduction

Since May 6, 2009, SSRF X-ray Imaging and Biomedical Application Beamline (BL13W1) has been put into operation and formally opened to users. BL13W1 is composed of a 1.9 Tesla wiggler, 6 set of filters for high heat load reducing, and double crystal monochromator cooled with liquid nitrogen. The monochromator can work well at the photon energy range of 8-72.5keV. Up to now, the filters and the monochromator could work well at 200mA, 3.5GeV and 17mm wiggler gap. At the end station, three sets of digital X-ray detectors are employed with the pixel size range from 0.37 to 13 micrometers. Imaging methods of microscopic computer tomography (micro-CT), in-line phase contrast imaging (IL-PCI) and X-ray fluorescence imaging could be provided for scientific researches on high Z and low Z samples in field of biomedical, material, archaeology, environmental science and so on. Spatial resolution of 0.8μm and time resolution of 1ms could be achieved. For X-ray fluorescence imaging, the minimal beam size is 30μm.

2.    Scientific case

Soft tissues and low Z materials

Low dose, Nondestructive, High resolution, Dynamic and 3-dimensional X-ray Imaging for the inner microstructure

Paleontology, archaeology and geology

Nondestructive, High resolution, 3-dimensional X-ray Imaging for the inner microstructure

3.    Imaging techniques

Absorption-contrast Imaging: Dynamic Imaging; Microscopic Computer Tomography

In-line Phase-contrast Imaging: Dynamic Imaging; Microscopic Computer Tomography

X-Ray Fluorescence Imaging: 2D scanning; Computer Tomography

4.    Beamline Specifications

Unfocused monochromatic beam

Photon energy range: 8－72.5keV

Energy resolution (DE/E): <5×10^-3

Beam size: 45mm (H) ×5mm (V) @34m@20keV

Flux output: 5×10¹⁰ phs/s/mm² @ 20keV @ Si (111)

                     2×10⁸ phs/s/mm² @ 70keV @ Si (311)

5.    Beamline Layout

6.    Wiggler source

The light source is hybrid-type wiggler whose periodic length is 14cm and the number of the period is 8. Maximum K-value is designed to be 24.8 at minimum wiggler magnet gap of 17 mm. The fundamental radiation covers the energy range from 8.0 to 72.5keV by tuning the gap from 17 to 35mm. The heatload power of 10kW is a big challenge for this beamline. The power is controlled in an acceptable range by tuning the gap for different optimized energy range.

7.    Optics

l  Double crystal monochromator (DCM): Bragg angle range is 2.98~14.34 degrees and the corresponding photon energy range is 8~38.1keV@Si (111); 38.1~72.5keV@Si (311).

l  6-axis C sheet filter: each axis placed on with 2 C sheets to absorb low-energy X-ray photons and reduce thermal load on the water-cooled beryllium window and liquid nitrogen cooled monochromator, combining several filter plates of different thickness for different energy range.

8.    End station

The experimental station consists of two very flexible experimental tables. The first experimental table is 2.5m long and 1.5m wide. The second one is 5.0m long and 1.5m wide. The rail on the tables is used to adjust the distance between the sample and the X-ray CCD.

l  Attenuator (5 aluminum sheets with different thicknesses: 10mm, 5mm, 3mm, 2mm and 1mm)

l  Ionization chambers (window size: 55mm*10mm; effective length of ionization chamber: 140mm; electrode spacing: 12.5mm)

l  X-ray shutter (aperture: 50mm*10mm, blade material: WC; exposure time>20ms)

l  6 dimensional sample stage:

l  Detectors:

                  1. High resolution X-ray imaging detectors (CCD camera coupled with optical  lens)

                  2.  X-ray imaging detectors (CCD camera coupled with optical fibre)

                 3. Fluorescence detectors

                 1) LEGe (Canberra, Active Area ~50 mm², 140eV@5.9keV)   

                2) Vortex Silicon EX-90 (SII NanoTechnology, Active Area ~50 mm²，140eV@5.9keV)

              9.    Biomedical sample preparation room

Biomedical sample preparation room is located at Room 1050 in the experimental hall and available around the clock. The conventional small animal operation, like arterial operation for angiography, is conducted where equipped with operating microscope, syringe injection pump, and light source. The chemical agent (anaesthetic agent, contrast agent) and surgical instruments are suggested to be brought by user for their specific experiment purpose. Room 1050 is also used to temporally keeping the small animals, like mice and rats.

10.Data Process

Software：

PITRE: A CPU based software package that supports phase retrieval for propagation-based phase-contrast imaging/tomography (PPCI/PPCT), extracting apparent absorption, refractive and scattering information from DEI, and CT reconstruction

H-PITRE: CT reconstruction software accelerated by GPU

X-Tract-SSRF: An image analysis and processing application with functionality targeting researchers working in imaging science and technology fields, especially in optical, electron and X-ray microscopy and astronomy. It is developed by international cooperation with the CSIRO in Australia. Phase contrast reconstruction, fast micro CT reconstruction and other image processing is armed. Remote data processing and transfer has also been realized. (https://ct.ssrf.ac.cn)

VGStudio MAX 2.1: Provides unique functionality for precise and fast analysis of voxel data. Visualization and analysis of CT data in combination with the optional add-on modules

Amira 4.1: 3D software platform for visualizing, manipulating, and understanding biomedical data coming from all types of sources and modalities

Hardware:

Data storage server: 12TB for users’ data storage. This capacity allows us to keep users data for one month after the experiment.

Data process computer: One workstation for 3D rending, one GPU server for the software X-Tract-SSRF and one GPU server for the software PITRE.

11.Contacts

Fu Yanan

fuyannan@sinap.ac.cn

+86-21-33933210