Optics are the most important part of a beamline. The optics of the μSAXS/WAXS beamline have been designed so that the brilliant synchrotron radiation beam from the PETRA III high-β spectroscopic undulator is monochromated and focused on the sample with minimal loss of intensity. The undulator will have it's brilliance maximum at 10 keV.
Monochromators and mirrors
In a setup which allows various measurement energies, a double-crystal Si (111) monochromator with a large off-set of the crystals will monochromate the synchrotron radiation coming from high-β undulator U29-2. Alternatively a pair of multilayer crystals may be used to obtain highest possible intensity at 10 keV energy. All crystals will be cryogenically cooled to obtain maximum stability of the beam.
Higher harmonics, which have higher energy compared to the first harmonic, cannot fully be rejected by a double-crystal monochromator. The intensities of the higher harmonics are going to be further suppressed by using two planar mirrors. With different coatings of mirror surface the whole energy range from 8 to 23 keV can be accessed when using the Si (111) double-crystal monochromator.
Focusing
For μSAXS measurements microfocusing optics are needed. At the MINAXS beamline beryllium compound refractive lenses are used both for collimation and for focusing of the beam. The focus of the lens systems depends on the energy of the beam. It is necessary to be able to change the focal point of the beam so two lens changers will be mounted directly after the optics hutch in direct connection to the first experimental hutch. With the lens changers the number of lenses in the beam can be changed.
For μUSAXS the focusing is done using a lenses located in the optics hutch.
For the nanofocusing experiments, waveguides will be situated in experimental hutch 2.
Overview over all optical components and their positions at MINAXS beamline, 05.09.2007
| Position | Length symm. | Height | Priority | Comment | Monitor | Type | |
| from source point | to position | number | |||||
| IM | 29000 | 100 | 0 | 1 | 1st Intensity monitor, incoming intensity | 1 | IM1 |
| FE-CRL | 29500 | 100 | 0 | 2 | Front-end lens, two different radii of curvature + 1 free slot | ||
| BPM | 30000 | 150 | 0 | 1 | 1st BPM white beam, diagnostics, PSD | 2a | BPM1 |
| OM | 30500 | 150 | 0 | 1 | 2a | OM1 | |
| IM | 30700 | 100 | 0 | 1 | 2a | IM1 | |
| WALL | 32000 | 0 | |||||
| Valve | 44900 | 200 | 0 | 1 | |||
| MLX1 | 46000 | 1000 | 0 | 2 | Monochromator / Multilayer / 1st crystal / cryocooled | ||
| OM | 46575 | 150 | 0 | 1 | X-ray beam monitor, intensity, removeable | 3a | OM1 |
| IM | 46700 | 100 | 0 | 1 | 3a | IM1 | |
| LODCM | 53680 | 3000 | 0 | 1 | Monochromator / Si(111) / cryocooled | ||
| IM | 53680 | 100 | variable | Movable with DCMX1 | 3b | OM1 | |
| OM | 53680 | 150 | variable | Movable with DCMX1 | 3b | IM1 | |
| MLX2 | 54050 | 1000 | -490 | 2 | Monochromator / Multilayer / 2nd crystal / cryocooled | ||
| OM | 54625 | 150 | -490 | 1 | X-ray beam monitor, intensity, removeable | 4 | OM1 |
| IM | 54750 | 100 | -490 | 1 | 4 | IM1 | |
| HO-Mirror | 56000 | 2000 | -490 | 1 | 1st mirror higher harmonics suppression, removeable | ||
| HO-Mirror | 58203 | 2000 | -500 | 1 | 2nd mirror higher harmonics suppression, removeable | ||
| OM | 59000 | 150 | -500 | 1 | 5 | OM2 | |
| IM | 59200 | 100 | -500 | 1 | 5 | IM1 | |
| BPM | 59350 | 150 | -500 | 1 | BPM diagnostics, fixed | 5 | BPM1 |
| lens | 61500 | 500 | -500 | 2 | µUSAXS option single position | ||
| NBS | 63000 | 700 | -500 | 1 | Safety shutter for µSAXS1,2 and EH1,2 | ||
| Diamond window | 75000 | 50 | -500 | 1 | Separation UHV / Beamline vacuum | ||
| slit | 76147 | 30 | -500 | 2 | Beam defining aperture for µUSAXS, Cleaning for µSAXS1,2 | ||
| lens | 76747 | 1200 | -500 | 1 | µSAXS1, upto N=25 BeCRLs | ||
| lens | 81747 | 1200 | -500 | 1 | µSAXS2, upto N=56 BeCRLs | ||
| shutter | 82830 | 300 | -500 | 1 | Safety shutter for EH1+EH2 | ||
| fast shutter | 84000 | 70 | -500 | 1 | Fast shutter for detectors | ||
| IM | 84898 | 100 | -500 | 7 | IM1 | ||
| BPM | 84998 | 1 | -500 | 1 | BPM in front of sample, reference, PSD, e.g. diamond | 7 | BPM2 |
| slit | 84999 | 1 | -500 | 1 | Guard slit, L-type | ||
| sample | 85000 | 2000 | -500 | 1 | Sample at 85000mm, microSAXS/WAXS | ||
| OM camera | 85150 | 300 | -500 | 1 | Camera at sample position | 8 | OM2 |
| IM | variable | 1 | e.g. diode in Beamstop | 8 | IM2 | ||
| NBS | 97830 | 700 | -500 | 1 | Safety shutter for nanofocus hutch | ||
| IM | 100000 | 100 | -500 | 2 | 9 | IM1 | |
| BPM | 100210 | 1 | -500 | 2 | BPM for diagnostics nanofocusing | 9 | BPM2 |
| lens | 100310 | 100 | -500 | 2 | Nanofocusing optics with focal distances ~2cm | ||
| slit | 100275 | 10 | -500 | 2 | Guard slit | ||
| sample | 100330 | 1000 | -500 | 2 | Sample at 100330mm, nanoSAXS/WAXS | ||
| OM camera | 100480 | 300 | -500 | 2 | Sample at 100330mm, nanoSAXS/WAXS | 10 | OM2 |
| IM | variable | 1 | e.g. diode in Beamstop | 10 | IM2 | ||
| FE | |||||||
| Focusing optics between OH and EH1 | |||||||
| OH | |||||||
| EH1 | |||||||
| EH2 | |||||||
| Separation to beamline vacuum | |||||||
| IM | Intensity Monitor | ||||||
| OM | Optical Monitor | ||||||
| BPM | Beam Position Monitor | ||||||
| OH | Optics Hutch | ||||||
| EH | Experimental Hutch | ||||||
