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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">izmertech</journal-id><journal-title-group><journal-title xml:lang="ru">Измерительная техника</journal-title><trans-title-group xml:lang="en"><trans-title>Izmeritel`naya Tekhnika</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">0368-1025</issn><issn pub-type="epub">2949-5237</issn><publisher><publisher-name>ФГУП "ВНИИФТРИ"</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.32446/0368-1025it.2025-2-78-87</article-id><article-id custom-type="elpub" pub-id-type="custom">izmertech-2327</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>ТЕПЛОФИЗИЧЕСКИЕ ИЗМЕРЕНИЯ</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>THERMOPHYSIC MEASUREMENTS</subject></subj-group></article-categories><title-group><article-title>Научная аппаратура для космического эксперимента «Солнце-Терагерц»: методы повышения частотной селективности детекторов</article-title><trans-title-group xml:lang="en"><trans-title>Scientific equipment for the space experiment “Sun-Terahertz”: methods for increasing the frequency selectivity of detectors</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0003-4302-0020</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Филиппов</surname><given-names>М. В.</given-names></name><name name-style="western" xml:lang="en"><surname>Philippov</surname><given-names>M. V.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Максим Валентинович Филиппов - Лаборатория физики Солнца и космических лучей, научный сотрудник.</p><p>Москва</p></bio><bio xml:lang="en"><p>Maxim V. Philippov</p><p>Moscow</p></bio><email xlink:type="simple">mfilippov@frtk.ru</email><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Физический институт им. П.Н. Лебедева Российской академии наук</institution><country>Россия</country></aff><aff xml:lang="en"><institution>Р.N. Lebedev Physical Institute of the Russian Academy of Sciences</institution><country>Russian Federation</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2025</year></pub-date><pub-date pub-type="epub"><day>06</day><month>06</month><year>2025</year></pub-date><volume>74</volume><issue>2</issue><fpage>78</fpage><lpage>87</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; ФГУП "ВНИИФТРИ", 2025</copyright-statement><copyright-year>2025</copyright-year><copyright-holder xml:lang="ru">ФГУП "ВНИИФТРИ"</copyright-holder><copyright-holder xml:lang="en">ФГУП "ВНИИФТРИ"</copyright-holder><license xlink:href="https://www.izmt.ru/jour/about/submissions#copyrightNotice" xlink:type="simple"><license-p>https://www.izmt.ru/jour/about/submissions#copyrightNotice</license-p></license></permissions><self-uri xlink:href="https://www.izmt.ru/jour/article/view/2327">https://www.izmt.ru/jour/article/view/2327</self-uri><abstract><p>Реализация космического эксперимента «Солнце-Терагерц» планируется на борту российского сегмента Международной космической станции в 2026–2029 гг. Цели эксперимента – получение данных о терагерцевом излучении Солнца, а также изучение солнечных активных областей и солнечных вспышек. Научная аппаратура эксперимента «Солнце-Терагерц» состоит из восьми детекторов, целевые частоты которых лежат в диапазоне 0,4–12,0 ТГц. Приведены ожидаемые спектральные характеристики научной аппаратуры и кратко описан метод их экспериментальной проверки с помощью установки дополнительного отрезающего фильтра. Отмечена необходимость повышения частотной селективности детекторов и рассмотрены два метода такого повышения. Для оценки чувствительности детекторов проведён эксперимент по измерению солнечного излучения с помощью одноканального макета. Макет представляет собой полный аналог одного детектора научной аппаратуры с возможностью замены полосовых терагерцевых фильтров. Для одноканального макета изготовлены двухосная поворотная платформа и датчик облачности. По итогам экспериментальной проверки сделаны выводы о достаточной чувствительности детекторов научной аппаратуры для выделения солнечного сигнала на фоне собственных шумов и возможности улучшения характеристик в отношении частотной селективности. При этом целесообразно использовать метод линейной комбинаций сигналов детекторов. Полученные результаты полезны экспериментаторам, занимающимися спектрометрическими научными приборами на базе оптоакустических преобразователей (ячеек Голея) и других чувствительных элементов.</p></abstract><trans-abstract xml:lang="en"><p>The future space experiment «Sun-Terahertz» is aimed at studying the Sun in the unexplored terahertz range, obtaining new data on the terahertz radiation of the Sun, solar active regions and solar fl ares. The scientific equipment being developed is a set of eight detectors sensitive to radiation of various frequencies in the range 0.4–12.0 THz. In this paper, we consider the expected spectral characteristics of scientific equipment and briefl y describe the method of their experimental verification by installing an additional cutoff filter. Two methods for increasing the frequency selectivity of detectors are considered. To assess the sensitivity of the detectors, an experiment was conducted to measure solar radiation using a single-channel model, which is a complete analogue of the detector of scientific equipment with the ability to replace bandpass terahertz filters. Also, a two-axis rotating platform and a cloud sensor were made for the single-channel model. Based on the results of the experimental verification, conclusions were made about the sensitivity of the detectors of scientific equipment and the possibility of improving the characteristics in terms of frequency selectivity. This article may be useful to experimenters involved in spectrometric scientific devices based on optoacoustic converters (Golay cell) and other sensitive elements.</p></trans-abstract><kwd-group xml:lang="ru"><kwd>Солнце</kwd><kwd>солнечные вспышки</kwd><kwd>терагерцевое излучение</kwd><kwd>оптическая система</kwd><kwd>температурный эффект</kwd><kwd>ячейка Голея</kwd></kwd-group><kwd-group xml:lang="en"><kwd>Sun</kwd><kwd>solar fl ares</kwd><kwd>terahertz radiation</kwd><kwd>optical system</kwd><kwd>temperature effect</kwd><kwd>Golay cell</kwd></kwd-group><funding-group><funding-statement xml:lang="ru">Автор заявляет, что во время подготовки данной рукописи не было получено никаких средств, грантов или другой поддержки</funding-statement><funding-statement xml:lang="en">The author declares that no funds, grants, or other support were received during the preparation of this manuscript</funding-statement></funding-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Kinnison J., Vaughan R., Hill P., Raouafin., Guo Y. and Pinkine N. Parker Solar Probe: A Mission to Touch the Sun. IEEE Aerospace Conference, 1–14 (2020). https://doi.org/10.1109/AERO47225.2020.9172703</mixed-citation><mixed-citation xml:lang="en">Kinnison J., Vaughan R., Hill P., Raouafin., Guo Y., Pinkine N. Parker Solar Probe: A Mission to Touch the Sun. IEEE Aerospace Conference, 1–14 (2020). https://doi.org/10.1109/AERO47225.2020.9172703</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Russell A. Howard, Angelos Vourlidas, Clarence M. Korendyke, et al. The solar and heliospheric imager (SoloHI) instrument for the solar orbiter mission. Proceedings SPIE Optical Engineering + Applications, 2013, San Diego, California, United States, 8862 (2013). https://doi.org/10.1117/12.2027657</mixed-citation><mixed-citation xml:lang="en">Russell A. Howard, Angelos Vourlidas, Clarence M. Korendyke, et al. The solar and heliospheric imager (SoloHI) instrument for the solar orbiter mission. Proceedings SPIE Optical Engineering + Applications, 2013, San Diego, California, United States, 8862 (2013). https://doi.org/10.1117/12.2027657</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">Domingo V., Fleck B., Poland A. I. SOHO: The Solar and Heliospheric Observatory. Space Science Reviews, 72, 81–84 (1995). https://doi.org/10.1007/BF00768758</mixed-citation><mixed-citation xml:lang="en">Domingo V., Fleck B., Poland A.I. SOHO: The Solar and Heliospheric Observatory. Space Science Reviews, 72, 81–84 (1995). https://doi.org/10.1007/BF00768758</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Joseph M. Davila, David M. Rust, Victor J. Pizzo, Paulett C. Liewer. Solar Terrestrial Relations Observatory (STEREO). Proceedings SPIE’s 1996 International Symposium on Optical Science, Engineering, and Instrumentation, 2804 (1996). https://doi.org/10.1117/12.259724</mixed-citation><mixed-citation xml:lang="en">Joseph M. Davila, David M. Rust, Victor J. Pizzo, Paulett C. Liewer. Solar Terrestrial Relations Observatory (STEREO). Proceedings SPIE’s 1996 International Symposium on Optical Science, Engineering, and Instrumentation, 2804 (1996). https://doi.org/10.1117/12.259724</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Kaufmann P., White S. M., Marcon R. et al. Bright 30 THz impulsive solar bursts. Journal of Geophysical Research (Space Physics), 120, 4155 (2015). https://doi.org/10.1002/2015JA021313</mixed-citation><mixed-citation xml:lang="en">Kaufmann P., White S.M., Marcon R. et al. Bright 30 THz impulsive solar bursts. Journal of Geophysical Research (Space Physics), 120, 4155 (2015). https://doi.org/10.1002/2015JA021313</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">Калинин Е. В., Филиппов М. В., Махмутов В. С. и др. Исследование температурного эффекта резонансных оптических прерывателей в космической научной аппаратуре. Космические исследования, (1), 3–8 (2021). https://doi.org/10.31857/S0023420621010040</mixed-citation><mixed-citation xml:lang="en">Kalinin E. V., Philippov M. V., Makhmutov V. S. et al. A study of the characteristics of a terahertz radiation detector for the Solntse-Terahertz scientific apparatus. Cosmic Research, 59(1), 1–5 (2021). https://doi.org/10.1134/S0010952521010032</mixed-citation></citation-alternatives></ref><ref id="cit7"><label>7</label><citation-alternatives><mixed-citation xml:lang="ru">Kaufmann P., Raullin J.-P., de Castro C. G. G. et al. A New Solar burst spectral component emitting only in the terahertz range. Astrophysical Journal, 603, L121–L124 (2004). https://doi.org/10.1086/383186</mixed-citation><mixed-citation xml:lang="en">Kaufmann P., Raullin J.-P., de Castro C. G. G., et al. A New Solar burst spectral component emitting only in the terahertz range. Astrophysical Journal, 603, L121–L124 (2004). https://doi.org/10.1086/383186</mixed-citation></citation-alternatives></ref><ref id="cit8"><label>8</label><citation-alternatives><mixed-citation xml:lang="ru">Kaufmann P., Correia E., Costa J. E. R. et al. Solar burst with millimetre-wave emission at high frequency only. Nature, 313, 380–382 (1985). https://doi.org/10.1038/313380a0</mixed-citation><mixed-citation xml:lang="en">Kaufmann P., Correia E., Costa J. E. R. et al. Solar burst with millimetre-wave emission at high frequency only. Nature, 313, 380–382 (1985). https://doi.org/10.1038/313380a0</mixed-citation></citation-alternatives></ref><ref id="cit9"><label>9</label><citation-alternatives><mixed-citation xml:lang="ru">Kaufmann P. Submillimeter/IR solar bursts from high energy electrons. Proceedings AIP conference, 374, 379–392 (1996). https://doi.org/10.1063/1.50945</mixed-citation><mixed-citation xml:lang="en">Kaufmann P. Submillimeter/IR solar bursts from high energy electrons. Proceedings AIP conference, 374, 379–392 (1996). https://doi.org/10.1063/1.50945</mixed-citation></citation-alternatives></ref><ref id="cit10"><label>10</label><citation-alternatives><mixed-citation xml:lang="ru">Kaufmann P., Costa J. E. R., Castro C. G. G., et al. The new submillimeter-wave solar telescope. Proceedings of the 2001 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference, 439–442 (2001). https://doi.org/10.1109/SBMOMO.2001.1008800</mixed-citation><mixed-citation xml:lang="en">Kaufmann P., Costa J. E. R., Castro C. G. G. et al. The new submillimeter-wave solar telescope. Proceedings of the 2001 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference, 439–442 (2001). https://doi.org/10.1109/SBMOMO.2001.1008800</mixed-citation></citation-alternatives></ref><ref id="cit11"><label>11</label><citation-alternatives><mixed-citation xml:lang="ru">Kaufmann P., Castro C. G. G., Makhmutov V. S. et al. Launch of solar coronal mass ejections and submillimeter pulse bursts. Journal of Geophysical Research, 108(A7), 1280 (2003). https://doi.org/10.1029/2002JA009729</mixed-citation><mixed-citation xml:lang="en">Kaufmann P., Castro C. G. G., Makhmutov V. S. et al. Launch of solar coronal mass ejections and submillimeter pulse bursts. Journal of Geophysical Research, 108(A7), 1280 (2003). https://doi.org/10.1029/2002JA009729</mixed-citation></citation-alternatives></ref><ref id="cit12"><label>12</label><citation-alternatives><mixed-citation xml:lang="ru">Krucker S., Castro C. G. G., Hudson H. S., et al. Solar fl ares at submillimeter wavelengths. Astron Astrophys Review, 21, 58 (2013). https://doi.org/10.1007/s00159-013-0058-3</mixed-citation><mixed-citation xml:lang="en">Krucker S., Castro C. G. G., Hudson H. S., et al. Solar fl ares at submillimeter wavelengths. Astron Astrophys Review, 21, 58 (2013). https://doi.org/10.1007/s00159-013-0058-3</mixed-citation></citation-alternatives></ref><ref id="cit13"><label>13</label><citation-alternatives><mixed-citation xml:lang="ru">Luthi T., Magun A., Miller M. First observation of a solar X-class fl are in the submillimeter range with KOSMA. Astronomy and Astrophysics, 415, 1123–1132 (2004). https://doi.org/10.1051/0004-6361:20034624</mixed-citation><mixed-citation xml:lang="en">Luthi T., Magun A., Miller M. First observation of a solar X-class fl are in the submillimeter range with KOSMA. Astronomy and Astrophysics, 415, 1123–1132 (2004). https://doi.org/10.1051/0004-6361:20034624</mixed-citation></citation-alternatives></ref><ref id="cit14"><label>14</label><citation-alternatives><mixed-citation xml:lang="ru">Makhmutov V. S., Raulin J. P., Castro C. G. G., Kaufmann P., Correia E. Wavelet decomposition of submillimeter solar radio bursts. Solar Physics, 218, 211–220 (2003). https://doi.org/10.1023/B:SOLA.0000013047.26419.33</mixed-citation><mixed-citation xml:lang="en">Makhmutov V. S., Raulin J. P., Castro C. G. G., Kaufmann P., Correia E. Wavelet decomposition of submillimeter solar radio bursts. Solar Physics, 218, 211–220 (2003). https://doi.org/10.1023/B:SOLA.0000013047.26419.33</mixed-citation></citation-alternatives></ref><ref id="cit15"><label>15</label><citation-alternatives><mixed-citation xml:lang="ru">Махмутов В. С., Курт В. Г., Юшков Б. Ю. и др. Спектральные особенности высокоэнергичного рентгеновского, гамма-излучения и субмиллиметрового радиоизлучения в импульсной фазе солнечной вспышки. Известия Российской академии наук. Серия физическая, 75(6), 796–799 (2011). https://www.elibrary.ru/nxqnjp</mixed-citation><mixed-citation xml:lang="en">Makhmutov V. S., Kurt V. G., Yushkov B. Yu. et al. Spectral peculiarities of high energy X-ray radiation, gamma radiation, and Submillimeter radio emission in the impulsive phase of a solar fl are. Bulletin of the Russian Academy of Science: Physics, 75(6), 747–750 (2011). https://doi.org/10.3103/S106287381106030X</mixed-citation></citation-alternatives></ref><ref id="cit16"><label>16</label><citation-alternatives><mixed-citation xml:lang="ru">Wedemeyer S., Bastian T., Brajša R. et al. Solar Science with the Atacama Large Millimeter/Submillimeter Array – A New View of Our Sun. Space Science Reviews, 200, 1–73 (2016). https://doi.org/10.1007/s11214-015-0229-9</mixed-citation><mixed-citation xml:lang="en">Wedemeyer S., Bastian T., Brajša R. et al. Solar Science with the Atacama Large Millimeter/Submillimeter Array – A New View of Our Sun. Space Science Reviews, 200, 1–73 (2016). https://doi.org/10.1007/s11214-015-0229-9</mixed-citation></citation-alternatives></ref><ref id="cit17"><label>17</label><citation-alternatives><mixed-citation xml:lang="ru">Филиппов М. В., Махмутов В. С., Максумов О. С. и др. Блок электроники для научной аппаратуры «СолнцеТерагерц». Приборы и техника эксперимента, (3), 108–117 (2024). https://elibrary.ru/ousxkn</mixed-citation><mixed-citation xml:lang="en">Philippov M. V., Makhmutov V. S., Maksumov O. S. et al. Electronics unit for “Sun-Terahertz” scientific equipment. Instruments and Experimental Techniques, 67(3), 545–553 (2024). https://doi.org/10.1134/S0020441224700829</mixed-citation></citation-alternatives></ref><ref id="cit18"><label>18</label><citation-alternatives><mixed-citation xml:lang="ru">Квашнин А. А., Логачев В. И., Филиппов М. В. и др. Оптическая система прибора для измерения солнечного терагерцового излучения. Космическая техника и технологии, (4(35)), 22–30 (2021). https://elibrary.ru/siartl</mixed-citation><mixed-citation xml:lang="en">Kvashnin A. A., Logachev V. I., Philippov M. V. et al. Optical system design of the detector for solar terahertz emission measurements. Space engineering and technology, (4(35)), 22–30 (2021). (In Russ.) https://elibrary.ru/siartl</mixed-citation></citation-alternatives></ref><ref id="cit19"><label>19</label><citation-alternatives><mixed-citation xml:lang="ru">Филиппов М. В., Махмутов В. С., Максумов О. С. и др. Исследование температурного эффекта резонансных оптических прерывателей в космической научной аппаратуре. Космическая техника и технологии, (1(40)), 8–18 (2023). https://www.elibrary.ru/wzamjn</mixed-citation><mixed-citation xml:lang="en">Philippov M. V., Makhmutov V. S., Maksumov O. S. et al. A study of thermal effect of resonant optical shutters in space scientific equipment. Space engineering and technology, (1(40)), 8–18 (2023). (In Russ.) https://www.elibrary.ru/wzamjn</mixed-citation></citation-alternatives></ref><ref id="cit20"><label>20</label><citation-alternatives><mixed-citation xml:lang="ru">Филиппов М. В., Махмутов В. С., Логачев В. И., Разумейко М. В. Расчёт чувствительности детекторов для космического эксперимента «Солнце-Терагерц». Журнал технической физики, 93(9), 1377–1382 (2023). https://doi.org/10.21883/JTF.2023.09.56226.167-23</mixed-citation><mixed-citation xml:lang="en">Philippov M. V., Makhmutov V. S., Logachev V. I., Razumeyko M. V. Preliminary calculation of sensitivity of detectors for the future space experiment “Sun-Terahertz”. Technical Physics, 93(9), 1281 (2023). https://doi.org/10.21883/JTF.2023.09.56226.167-23</mixed-citation></citation-alternatives></ref><ref id="cit21"><label>21</label><citation-alternatives><mixed-citation xml:lang="ru">Филиппов М. В., Логачев В.И., Махмутов В. С. и др. Расчет потоков солнечного терагерцевого излучения, регистрируемого приёмниками научной аппаратуры на борту Международной космической станции. Космическая техника и технологии, (2(45)), 68–83 (2024). https://www.elibrary.ru/xdheun</mixed-citation><mixed-citation xml:lang="en">Philippov M. V., Logachev V. I., Makhmutov V. S., et al. Calculating solar terahertz radiation fluxes recorded by scientific instrumentation detectors onboard the International space station. Space engineering and technology, (2(45)), 68–83 (2024). (In Russ.) https://www.elibrary.ru/xdheun</mixed-citation></citation-alternatives></ref><ref id="cit22"><label>22</label><citation-alternatives><mixed-citation xml:lang="ru">Филиппов М. В., Махмутов В. С., Разумейко М.В. Научная аппаратура для космического эксперимента «СолнцеТерагерц»: исследование температурного эффекта ячейки Голея. Измерительная техника, 73(3), 20–25 (2024). https://doi.org/10.32446/0368-1025it.2024-3-20-25</mixed-citation><mixed-citation xml:lang="en">Philippov M. V., Makhmutov V. S., Razumeyko M. V. Scientific equipment for the Sun-Terahertz space experiment: study of the temperature effect in the Golay cell. Measurement Techniques, 67(3), 195–202 (2024). https://doi.org/10.1007/s11018-024-02335-9</mixed-citation></citation-alternatives></ref><ref id="cit23"><label>23</label><citation-alternatives><mixed-citation xml:lang="ru">Филиппов М. В., Махмутов В. С., Разумейко М. В. и др. Характеристики и калибровка будущей научной аппаратуры «Солнце-Терагерц». Успехи прикладной физики, 12(4), 361–370 (2024). https://doi.org/10.51368/2307-4469-2024-12-4-361-370</mixed-citation><mixed-citation xml:lang="en">Philippov M. V., Makhmutov V. S., Razumeyko M. V., et al. Characteristics and issues of calibration of future scientific equipment “Sun-Terahertz”. Advances in Applied Physics, 12(4), 361–370 (2024). https://doi.org/10.51368/2307-4469-2024-12-4-361-370</mixed-citation></citation-alternatives></ref><ref id="cit24"><label>24</label><citation-alternatives><mixed-citation xml:lang="ru">Philippov M. V., Makhmutov V. S., Razumeyko M. V. et al. Method for checking the spectral sensitivity of optical paths of the Sun Terahertz scientific instrumentation in the frequency range 0.4–20 THz. Solar System Research, 59, 26 (2025). https://doi.org/10.1134/S0038094624601683</mixed-citation><mixed-citation xml:lang="en">Philippov M. V., Makhmutov V. S., Razumeyko M. V. et al. Method for checking the spectral sensitivity of optical paths of the Sun Terahertz scientific instrumentation in the frequency range 0.4–20 THz. Solar System Research, 59, 26 (2025). https://doi.org/10.1134/S0038094624601683</mixed-citation></citation-alternatives></ref><ref id="cit25"><label>25</label><citation-alternatives><mixed-citation xml:lang="ru">Angström A. On the counter-radiation of the atmosphere. Meteorologische Zeitschrift, 22(6), 761–769 (2013). https://doi.org/10.1127/0941-2948/2013/0550</mixed-citation><mixed-citation xml:lang="en">Angström A. On the counter-radiation of the atmosphere. Meteorologische Zeitschrift, 22(6), 761–769 (2013). https://doi.org/10.1127/0941-2948/2013/0550</mixed-citation></citation-alternatives></ref></ref-list><fn-group><fn fn-type="conflict"><p>The authors declare that there are no conflicts of interest present.</p></fn></fn-group></back></article>
