Temperature Control for an Intra-Mirror Etalon in Interferometric Gravitational Wave Detector Fabry–Perot Cavities
The sensitivity of interferometric gravitational wave detectors is optimized, in part, by balanced finesse in the long Fabry–Perot arm cavities. The input test mass mirrors of Advanced Virgo feature parallel faces, which creates an etalon within the substrate, adding variability in the total mirror...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-12-01
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| Series: | Galaxies |
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| Online Access: | https://www.mdpi.com/2075-4434/8/4/80 |
| _version_ | 1827701086830460928 |
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| author | Jonathan Brooks Maddalena Mantovani Annalisa Allocca Julia Casanueva Diaz Vincenzo Dattilo Alain Masserot Paolo Ruggi |
| author_facet | Jonathan Brooks Maddalena Mantovani Annalisa Allocca Julia Casanueva Diaz Vincenzo Dattilo Alain Masserot Paolo Ruggi |
| author_sort | Jonathan Brooks |
| collection | DOAJ |
| description | The sensitivity of interferometric gravitational wave detectors is optimized, in part, by balanced finesse in the long Fabry–Perot arm cavities. The input test mass mirrors of Advanced Virgo feature parallel faces, which creates an etalon within the substrate, adding variability in the total mirror reflectivity, in order to correct imbalanced finesse due to manufacturing tolerances. Temperature variations in mirror substrate change the optical path length primarily through varying the index of refraction and are tuned to correct for a finesse imbalance of up to 2.8% by a full etalon fringe of 0.257 K. A negative feedback control system was designed to control the mirror temperature by using an electrical resistive heating belt actuator for a heat transfer process modeled as a two-pole plant. A zero controller filter was designed which achieves temperature control within 2.3% of the etalon fringe and recovers to within 10% of the working point within 32 hours after a step input of one etalon fringe. A preliminary unlock condition control designed to compensate when the interferometer unlocks shows that the control remains stable even after a drastic change in the plant due to the absence of the laser heating. Further improvements to the control must also consider the full heat transfer mechanisms by using modern control state space models. |
| first_indexed | 2024-03-10T14:24:52Z |
| format | Article |
| id | doaj.art-fef87056338d4177ae5976de298a773f |
| institution | Directory Open Access Journal |
| issn | 2075-4434 |
| language | English |
| last_indexed | 2024-03-10T14:24:52Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Galaxies |
| spelling | doaj.art-fef87056338d4177ae5976de298a773f2023-11-20T23:05:55ZengMDPI AGGalaxies2075-44342020-12-01848010.3390/galaxies8040080Temperature Control for an Intra-Mirror Etalon in Interferometric Gravitational Wave Detector Fabry–Perot CavitiesJonathan Brooks0Maddalena Mantovani1Annalisa Allocca2Julia Casanueva Diaz3Vincenzo Dattilo4Alain Masserot5Paolo Ruggi6European Gravitational Observatory, 56021 Cascina, ItalyEuropean Gravitational Observatory, 56021 Cascina, ItalyIstituto Nazionale di Fisica Nucleare (INFN), Sezione di Pisa, I-56127 Pisa, ItalyEuropean Gravitational Observatory, 56021 Cascina, ItalyEuropean Gravitational Observatory, 56021 Cascina, ItalyLaboratoire d’Annecy de Physique des Particules (LAPP), CNRS/IN2P3, Université Savoie Mont Blanc, F-74941 Annecy, FranceEuropean Gravitational Observatory, 56021 Cascina, ItalyThe sensitivity of interferometric gravitational wave detectors is optimized, in part, by balanced finesse in the long Fabry–Perot arm cavities. The input test mass mirrors of Advanced Virgo feature parallel faces, which creates an etalon within the substrate, adding variability in the total mirror reflectivity, in order to correct imbalanced finesse due to manufacturing tolerances. Temperature variations in mirror substrate change the optical path length primarily through varying the index of refraction and are tuned to correct for a finesse imbalance of up to 2.8% by a full etalon fringe of 0.257 K. A negative feedback control system was designed to control the mirror temperature by using an electrical resistive heating belt actuator for a heat transfer process modeled as a two-pole plant. A zero controller filter was designed which achieves temperature control within 2.3% of the etalon fringe and recovers to within 10% of the working point within 32 hours after a step input of one etalon fringe. A preliminary unlock condition control designed to compensate when the interferometer unlocks shows that the control remains stable even after a drastic change in the plant due to the absence of the laser heating. Further improvements to the control must also consider the full heat transfer mechanisms by using modern control state space models.https://www.mdpi.com/2075-4434/8/4/80etalongravitational wavesinterferometernegative feedback controlclassical control |
| spellingShingle | Jonathan Brooks Maddalena Mantovani Annalisa Allocca Julia Casanueva Diaz Vincenzo Dattilo Alain Masserot Paolo Ruggi Temperature Control for an Intra-Mirror Etalon in Interferometric Gravitational Wave Detector Fabry–Perot Cavities Galaxies etalon gravitational waves interferometer negative feedback control classical control |
| title | Temperature Control for an Intra-Mirror Etalon in Interferometric Gravitational Wave Detector Fabry–Perot Cavities |
| title_full | Temperature Control for an Intra-Mirror Etalon in Interferometric Gravitational Wave Detector Fabry–Perot Cavities |
| title_fullStr | Temperature Control for an Intra-Mirror Etalon in Interferometric Gravitational Wave Detector Fabry–Perot Cavities |
| title_full_unstemmed | Temperature Control for an Intra-Mirror Etalon in Interferometric Gravitational Wave Detector Fabry–Perot Cavities |
| title_short | Temperature Control for an Intra-Mirror Etalon in Interferometric Gravitational Wave Detector Fabry–Perot Cavities |
| title_sort | temperature control for an intra mirror etalon in interferometric gravitational wave detector fabry perot cavities |
| topic | etalon gravitational waves interferometer negative feedback control classical control |
| url | https://www.mdpi.com/2075-4434/8/4/80 |
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