Hard X-ray Modulation Telescope
| Hard X-ray Modulation Telescope | |
|---|---|
| Type: | Space telescope |
| Country: |
 People's Republic of China
|
| COSPAR-ID : | 2017-034A |
| Mission dates | |
| Dimensions: | 2.8 t |
| Size: | 2.0 × 2.0 × 2.8 m |
| Begin: | June 15, 2017 at 3:00 UTC |
| Starting place: | Jiuquan Cosmodrome Ramp 603 of launch facility 43 |
| Launcher: | CZ-4B |
| Status: | in orbit |
| Orbit data | |
| Track height: | 540 km |
| Orbit inclination : | 43 ° |
The Hard X-ray Modulation Telescope ( Chinese 硬X射線調製望遠鏡 / 硬X射线调制望远镜 , Pinyin ying X-Shexian Tiaozhi Wàngyuǎnjìng shortly HXMT ) in China also Huiyan (慧眼, knowledge called) abroad Insight , is a chinese space telescope .
It was launched into low- earth orbit from the Jiuquan Cosmodrome on June 15, 2017 at 3:00 UTC with a Changzheng-4B launcher . In addition to the HXMT, the rocket launched three smaller earth observation satellites: the Zhuahi-1 (01) and Zhuahi-1 (02), each weighing around 50 kilograms, which are both to become part of the Chinese "Orbita" earth observation system, and the 37 kilogram Argentine satellite NuSat-3, which forms the third unit in the Aleph-1 constellation of Satellegic SA, which will one day comprise 25 satellites.
The three-axis stabilized satellite is equipped with three X-ray telescopes and is intended to examine cosmic objects such as pulsars , neutron stars and black holes in the range of high-energy radiation.
One of the telescopes works in the high energy range between 20 and 250 kiloelectron volts (keV) and has a collector area of 5,100 square centimeters. The X-ray telescope in the medium energy range between 5 and 30 keV has a collector surface of 952 square centimeters and the telescope for low-energy X-rays between 1 and 15 keV has a collector surface of 384 square centimeters.
The high energy X-ray telescope (HE) comprises 18 sodium iodide / cesium iodide Phoswich detectors, which are arranged in the central area of the payload module, using two concentric circles with six elements in the inner circle and 12 elements in the outer circle. The scintillators consist of sodium iodide doped with thallium and cesium iodide doped with sodium . Each Phoswich crystal element has a diameter of 19 centimeters, the 3.5 mm thick sodium iodide crystal lies directly behind a beryllium window and the 40 mm thick cesium iodide crystal is located below the sodium iodide crystal . The full energy of an incident X-ray beam is converted into the sodium iodide crystal, while the cesium iodide crystal is used as an active shield to reject events from behind. The sensor's cesium iodide crystal can also be used as a detector for gamma radiation bursts in the range from 200 keV to 3 MeV. Below the Phoswich stack is a quartz separator that connects the scintillator to the photoelectron multiplier , in which the light pulses are converted into electrical signals. In front of the detectors themselves are made of tantalum and tungsten existing collimators , which define the field of view for each detector. Fifteen of the detectors have a field of view of 1.14 by 5.71 °, two have a larger 5.71 of 5.71 ° for background detection and the last element is completely blocked with a 2mm tantalum shield for dark current measurements. The entire active instrument has a viewing angle of 5.71 by 5.71 °. Additional particle detectors serve to protect the instrument from overload and to filter out unwanted signals.
The X-ray telescope in the medium energy range uses a total of 1,728 silicon PIN diodes as detectors, which are divided into three boxes of six modules each with 32 diodes. This instrument also has three different fields of view. A main area with 1 × 4 ° for the actual observation object, a wide field of view of 4 × 4 ° for background measurements and a completely blocked detector group for the dark current measurements for calibration.
The low-energy X-ray detector (LE) focuses on sky surveillance. It differs from the detectors working in the similar energy range on Chandra and XMM-Newton through the collimator optics. It comprises three identical detector boxes which are arranged at a 120 ° angle to one another. These each contain eight collimators, each with four “ swept charge devices ”, which enable a continuous readout mode, whereby the energy and arrival time of the incident photons are recorded, and thus achieve a higher time resolution than conventional CCD detectors . Of the 32 SCD pixels in each detector box, 20 have narrow fields of view of 1.6 × 6 °, six have wide fields of view of 4 × 6 °, four are wide-area pixels with a field of view of approximately 50-60 ° × 2-6 ° and two are blocked detectors used for calibration. The instrument achieves an energy resolution of 140 eV and a time resolution of 1 ms.
The connection of the three telescopes results in a so far unique combination of a wide observation angle, broadband spectral and temporal resolution, the ability to scan the entire sky in search of new objects as well as targeted point-like observation of individual objects. It was built by the Chinese Academy of Space Technology (CAST) based on the Ziyuan-2 / Phoenix-Eye-2 satellite bus, and the payload was developed by the Institute of High Energy Physics of the Chinese Academy of Sciences (IHEP) and Tsinghua University . The physicist Li Tibei (李 惕 碚, * 1939) from IHEP had already made the proposal to build such a satellite in 1993, studies started in 2000. The start was originally planned for 2010, but this was delayed due to the addition of further payloads and optimization of the satellite for working conditions in near-earth orbit. When funds from the 12th Five-Year Plan (2011–2015) were released for the project on January 25, 2011 via the Space Science Priority Program of the Academy of Sciences , constant further development was stopped and the production of a first prototype began. Construction of the actual satellite began in 2013.
On July 2, 2020, the Journal of High Energy Astrophysics published a special issue in which the first research results were presented, for example on the periodicity of the X-ray binary star system Scorpius X-1 , the spectrum of Aquila X-1 , and the spin parameters of the black hole in Cygnus X-1 and much more.
Web links
- Manufacturer website
- CAS website
- Jin Jing, Chen Yong, Zhang Shuang-Nan, Zhang Shu, Li Xin-Qiao, Li Gang: A study of the pointed observation methods and sensitivity of HXMT . In: Chinese Physics C . tape 34 , no. 1 , January 2010, p. 66 , doi : 10.1088 / 1674-1137 / 34/1/012 ( PDF ).
Individual evidence
- ↑ a b c d e SpaceFlight101: HXMT - Spacecraft & Satellites , accessed June 22, 2017.
- ↑ The Orion: China Launches Huiyan X-ray Telescope , accessed June 22, 2017.
- ↑ Realization of HXMT's main detector - Design and implementation of the NaI (Tl) / CsI (Na) detectors output signal generator
- ^ Strategic Priority Program on Space Science. In: english.nssc.cas.cn. Retrieved June 12, 2020 .
- ↑ 院士 专家 李 惕 碚. In: sourcedb.ihep.cas.cn. July 9, 2009, accessed June 12, 2020 (Chinese).
- ↑ NASASpaceFlight.com: China launches X-ray telescope via Long March 4B , accessed June 22, 2017.
- ↑ HXTM in the NSSDCA Master Catalog , accessed on June 22, 2017 (English).
- ↑ Diego Torres: Special Issue on Performance and Early Results of China's 1st X-ray Astronomy Satellite Insight-HXMT. In: sciencedirect.com. July 2, 2020, accessed on July 9, 2020 .