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Example 1: Rigaku delivered a 4-Stripe Double Multilayer Monochromator (DMM) to the APS in Argonne National Lab. This advanced monochromator provides excellent reflectivity and resolution at four fixed energies without scanning. A simple transverse translation of the optic across the beam changes the X-ray energy output from the monochromator. Parameters for each stripe are listed (below/above/on the next slide). The following page shows the reflectivity curves for the low energy and high energy stripes. Parameters for the 4-Stripe DMM are shown above. In this monochromator, there is minimal theta translation. For this reason, each stripe was designed to reflect the desired energy at nearly the same angle. The goal also included a narrow bandpass requirement. Each stripe of the 4-stripe DMM is optimized for a given energy and bandpass. The trace above shows the performance of the first stripe as measured using 10 keV X-rays. This trace shows the performance of the fourth and highest resolution stripe, again measured using 10 keV X-rays. All the materials used in this monochromator were chosen for the highest resolution for the intended energy of each stripe. Example 2: This very advanced double monochromator is a Triple Stripe design using a Si <111> substrate for 5 keV to 30 keV energy range. The Si substrate serves as one of the stripes of the monochromator, complicating the manufacture since the final surface preparation techniques for good multilayers are different from those for perfect crystal monochromators. The unique construction of this monochromator provides 0.1%, 1.5% and 10% bandpass, depending on the stripe selected. As shown by the previous examples, DMM Stripes can be designed independently with any combination one can imagine. Example 3: The chart above shows the design target and experimental results for a wide-bandpass Double Multilayer Monochromator (WB DMM) in use at CHESS / Cornell University. The variations in actual peak reflectivity are caused by imperfect modeling and slight variations in the d-spacing produced throughout the multilayer stack. We have improved our modeling and production techniques to minimize these variations. The table above gives some characteristics of the WB DMM. Note that while we can increase bandpass, there is always some trade-off between peak reflectivity and bandpass. Integrated reflectivity remains high. Example 4: The chart above shows record-setting narrow-bandpass performance from a multilayer structure. This Double Multilayer Monochromator (DMM) is in use at HASYLAB in Hamburg. The design called for high energy selectivity and high reflectivity. The table above shows the basic parameters for this very narrow bandpass optic set. Because of the very narrow bandpass, the match between optics must also be extremely precise. In this case, the optics matched to within ± 0.05 Å. For applications requiring curved monochromators/analyzers, such as focusing/collimating of X-ray radiation in μ-XRF, TXRF and small-spot analysis etc, Rigaku's proprietary processes result in excellent reflectivity. Focusing of the beam gives you a lot of possibilities to increase signal to noise ratios for very weak signals as obtained in XRF on micrometric scales. Several such optics have been produced for small spot XRF using e-beam systems.Over 40% reflectivity for Al-Kα (E~1.5 keV) and Mg-Kα (E~1.3 keV) is possible for analyzer coatings on toroidal substrates. For B-Kα (E~0.18 keV) analyzer coatings, over 50% reflectivity can be achieved using ellipsoidal substrates. Multilayers: The possibilities are endless
Example 1: Rigaku delivered a 4-Stripe Double Multilayer Monochromator (DMM) to the APS in Argonne National Lab. This advanced monochromator provides excellent reflectivity and resolution at four fixed energies without scanning. A simple transverse translation of the optic across the beam changes the X-ray energy output from the monochromator. Parameters for each stripe are listed (below/above/on the next slide). The following page shows the reflectivity curves for the low energy and high energy stripes.
Parameters for the 4-Stripe DMM are shown above. In this monochromator, there is minimal theta translation. For this reason, each stripe was designed to reflect the desired energy at nearly the same angle. The goal also included a narrow bandpass requirement.
Each stripe of the 4-stripe DMM is optimized for a given energy and bandpass. The trace above shows the performance of the first stripe as measured using 10 keV X-rays.
This trace shows the performance of the fourth and highest resolution stripe, again measured using 10 keV X-rays. All the materials used in this monochromator were chosen for the highest resolution for the intended energy of each stripe.
Example 2: This very advanced double monochromator is a Triple Stripe design using a Si <111> substrate for 5 keV to 30 keV energy range. The Si substrate serves as one of the stripes of the monochromator, complicating the manufacture since the final surface preparation techniques for good multilayers are different from those for perfect crystal monochromators.
The unique construction of this monochromator provides 0.1%, 1.5% and 10% bandpass, depending on the stripe selected. As shown by the previous examples, DMM Stripes can be designed independently with any combination one can imagine.
Example 3: The chart above shows the design target and experimental results for a wide-bandpass Double Multilayer Monochromator (WB DMM) in use at CHESS / Cornell University. The variations in actual peak reflectivity are caused by imperfect modeling and slight variations in the d-spacing produced throughout the multilayer stack. We have improved our modeling and production techniques to minimize these variations.
The table above gives some characteristics of the WB DMM. Note that while we can increase bandpass, there is always some trade-off between peak reflectivity and bandpass. Integrated reflectivity remains high.
Example 4: The chart above shows record-setting narrow-bandpass performance from a multilayer structure. This Double Multilayer Monochromator (DMM) is in use at HASYLAB in Hamburg. The design called for high energy selectivity and high reflectivity.
The table above shows the basic parameters for this very narrow bandpass optic set. Because of the very narrow bandpass, the match between optics must also be extremely precise. In this case, the optics matched to within ± 0.05 Å.
For applications requiring curved monochromators/analyzers, such as focusing/collimating of X-ray radiation in μ-XRF, TXRF and small-spot analysis etc, Rigaku's proprietary processes result in excellent reflectivity. Focusing of the beam gives you a lot of possibilities to increase signal to noise ratios for very weak signals as obtained in XRF on micrometric scales.
Several such optics have been produced for small spot XRF using e-beam systems.Over 40% reflectivity for Al-Kα (E~1.5 keV) and Mg-Kα (E~1.3 keV) is possible for analyzer coatings on toroidal substrates. For B-Kα (E~0.18 keV) analyzer coatings, over 50% reflectivity can be achieved using ellipsoidal substrates.
