Reducing heat load density with asymmetric and inclined double-crystal monochromators: principles and requirements revisited
Asymmetric double-crystal monochromators (aDCMs) and inclined DCMs (iDCMs) can significantly expand the X-ray beam footprint and consequently reduce the heat load density and gradient. Based on rigorous dynamical theory calculations, the major principles and properties of aDCMs and iDCMs are present...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
International Union of Crystallography
2025-01-01
|
| Series: | Journal of Synchrotron Radiation |
| Subjects: | |
| Online Access: | https://journals.iucr.org/paper?S1600577524009755 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1841556126862147584 |
|---|---|
| author | XianRong Huang Lahsen Assoufid Albert T. Macrander |
| author_facet | XianRong Huang Lahsen Assoufid Albert T. Macrander |
| author_sort | XianRong Huang |
| collection | DOAJ |
| description | Asymmetric double-crystal monochromators (aDCMs) and inclined DCMs (iDCMs) can significantly expand the X-ray beam footprint and consequently reduce the heat load density and gradient. Based on rigorous dynamical theory calculations, the major principles and properties of aDCMs and iDCMs are presented to guide their design and development, particularly for fourth-generation synchrotrons. In addition to the large beam footprint, aDCMs have very large bandwidths (up to ∼10 eV) and angular acceptance, but the narrow angular acceptance of the second crystal requires precise control of the relative orientations and strains. Based on Fourier coupled-wave diffraction theory calculations, it is rigorously proved that the iDCM has almost the same properties as the conventional symmetric DCM, including the efficiency, angular acceptance, bandwidth, tuning energy range and sensitivity to misalignment. The exception is that, for the extremely inclined geometry that can achieve very large footprint expansion, the iDCM has (beneficially) a larger bandwidth and wider angular acceptance. Inclined diffraction has the `rho-kick effect' that can be cancelled by the second reflection of the iDCM (even with misalignment), except that inhomogeneous strains may cause non-uniform rho-kick angles. At present, fabrication/mounting-induced strains pose low risk since they can be controlled to <0.5 µrad over large areas. The only uncertain challenge is the thermally induced strains, yet it is estimated that these strains are naturally lowered by the large footprint and may be further mitigated by optimized cryogenic cooling to the 1–2 µrad level. Overall, aDCMs and iDCMs have more stringent requirements than normal DCMs, but they are feasible schemes in practice. |
| format | Article |
| id | doaj-art-e1f7d1fe629b427b9c8eb1e98e687ff4 |
| institution | Kabale University |
| issn | 1600-5775 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | International Union of Crystallography |
| record_format | Article |
| series | Journal of Synchrotron Radiation |
| spelling | doaj-art-e1f7d1fe629b427b9c8eb1e98e687ff42025-01-07T14:26:38ZengInternational Union of CrystallographyJournal of Synchrotron Radiation1600-57752025-01-01321909910.1107/S1600577524009755zhu5005Reducing heat load density with asymmetric and inclined double-crystal monochromators: principles and requirements revisitedXianRong Huang0Lahsen Assoufid1Albert T. Macrander2Advanced Photon Source, Argonne National Laboratory (ANL), 9700 South Cass Avenue, Lemont, IL 60439, USAAdvanced Photon Source, Argonne National Laboratory (ANL), 9700 South Cass Avenue, Lemont, IL 60439, USAAdvanced Photon Source, Argonne National Laboratory (ANL), 9700 South Cass Avenue, Lemont, IL 60439, USAAsymmetric double-crystal monochromators (aDCMs) and inclined DCMs (iDCMs) can significantly expand the X-ray beam footprint and consequently reduce the heat load density and gradient. Based on rigorous dynamical theory calculations, the major principles and properties of aDCMs and iDCMs are presented to guide their design and development, particularly for fourth-generation synchrotrons. In addition to the large beam footprint, aDCMs have very large bandwidths (up to ∼10 eV) and angular acceptance, but the narrow angular acceptance of the second crystal requires precise control of the relative orientations and strains. Based on Fourier coupled-wave diffraction theory calculations, it is rigorously proved that the iDCM has almost the same properties as the conventional symmetric DCM, including the efficiency, angular acceptance, bandwidth, tuning energy range and sensitivity to misalignment. The exception is that, for the extremely inclined geometry that can achieve very large footprint expansion, the iDCM has (beneficially) a larger bandwidth and wider angular acceptance. Inclined diffraction has the `rho-kick effect' that can be cancelled by the second reflection of the iDCM (even with misalignment), except that inhomogeneous strains may cause non-uniform rho-kick angles. At present, fabrication/mounting-induced strains pose low risk since they can be controlled to <0.5 µrad over large areas. The only uncertain challenge is the thermally induced strains, yet it is estimated that these strains are naturally lowered by the large footprint and may be further mitigated by optimized cryogenic cooling to the 1–2 µrad level. Overall, aDCMs and iDCMs have more stringent requirements than normal DCMs, but they are feasible schemes in practice.https://journals.iucr.org/paper?S1600577524009755inclined double-crystal monochromatorasymmetric monochromatordynamical theorynon-coplanar diffractionhigh heat load |
| spellingShingle | XianRong Huang Lahsen Assoufid Albert T. Macrander Reducing heat load density with asymmetric and inclined double-crystal monochromators: principles and requirements revisited Journal of Synchrotron Radiation inclined double-crystal monochromator asymmetric monochromator dynamical theory non-coplanar diffraction high heat load |
| title | Reducing heat load density with asymmetric and inclined double-crystal monochromators: principles and requirements revisited |
| title_full | Reducing heat load density with asymmetric and inclined double-crystal monochromators: principles and requirements revisited |
| title_fullStr | Reducing heat load density with asymmetric and inclined double-crystal monochromators: principles and requirements revisited |
| title_full_unstemmed | Reducing heat load density with asymmetric and inclined double-crystal monochromators: principles and requirements revisited |
| title_short | Reducing heat load density with asymmetric and inclined double-crystal monochromators: principles and requirements revisited |
| title_sort | reducing heat load density with asymmetric and inclined double crystal monochromators principles and requirements revisited |
| topic | inclined double-crystal monochromator asymmetric monochromator dynamical theory non-coplanar diffraction high heat load |
| url | https://journals.iucr.org/paper?S1600577524009755 |
| work_keys_str_mv | AT xianronghuang reducingheatloaddensitywithasymmetricandinclineddoublecrystalmonochromatorsprinciplesandrequirementsrevisited AT lahsenassoufid reducingheatloaddensitywithasymmetricandinclineddoublecrystalmonochromatorsprinciplesandrequirementsrevisited AT alberttmacrander reducingheatloaddensitywithasymmetricandinclineddoublecrystalmonochromatorsprinciplesandrequirementsrevisited |