• Source: Hegra

Hegra is a village in the municipality of Stjørdal in Trøndelag county, Norway. The village is located in the Stjørdalen valley, about 10 kilometres (6.2 mi) east of the town of Stjørdalshalsen along the Stjørdalselva river and it is therefore a good site for fishing. The 0.41-square-kilometre (100-acre) village has a population (2018) of 524 and a population density of 1,278 inhabitants per square kilometre (3,310/sq mi).
The village is served by the unmanned Hegra Station on the Meråker Line. The European route E14 highway also runs through the village, just south of Hegra Church. Hegra has its own grocery store, gas station, kindergarten, school and a local bank. Hegra is also one of the centers for the resurgence of the Dole Gudbrandsdal horse in Norway.




History


The village was the administrative centre of the old municipality of Hegra which existed from 1874 until 1962.
The ancient rock carvings (Leirfald), as well as the small border fort Hegra Fortress (formerly known as Ingstadkleven Fort) are both located in Hegra. The fortress withstood the invading German army from 10 April to 5 May 1940, not surrendering before all other Norwegian units in Southern Norway and Mid-Norway had capitulated.




Media gallery































Notable people


Ida Basilier-Magelssen (1846–1928 in Hegra) an opera singer
Andreas Fleischer (1878–1957) a bishop in the Church of Norway
Johan Peter Trøite (1880–1977) politician with the Venstre party
Ludvik Buland (1893–1945) a trade unionist
Jon Leirfall (1899–1998) politician with the Senterpartiet
Arnstein Øverkil (1937–2014) police chief
Heidrun Kringen, (Norwegian Wiki) (born 1941) an artist
Gøril Kringen (born 1972) soccer player
and




References






External links


Hegra Fortress (in Norwegian)
Stjordalsnett.no on Hegra (in Norwegian)
• Source: HEGRA

HEGRA, which stands for High-Energy-Gamma-Ray Astronomy, was an atmospheric Cherenkov telescope for Gamma-ray astronomy. With its various types of detectors, HEGRA took data between 1987 and 2002, at which point it was dismantled in order to build its successor, MAGIC, at the same site.
It was located at Roque de los Muchachos Observatory on La Palma at a height of 2200 m above sea level. It was operated by an international collaboration of research institutes and universities, such as the Max Planck Institute for Physics in Munich, the Universidad Complutense de Madrid, the German Max Planck Institute for Nuclear Physics, the University of Wuppertal, the IFKKI in Kiel or the University of Hamburg. It consisted of several detector types for observing secondary particles from particle cascades in the atmosphere. The particle cascades detected by HEGRA were produced by cosmic ray particles in the energy range of 1012 eV to 1016 eV.
The detectors with the lowest energy threshold were the atmospheric Cherenkov telescopes with "cameras" of photomultiplier tubes. They were sensitive to showers above 1012 eV (1 TeV) but had to look towards possible sources and could be operated only during clear, moonless nights. They detected Cherenkov light from relativistic secondary particles in the air showers. The field of view was about 4.6°. There were a total of six of these telescopes in operation. They were dismantled in September 2002.
The reflectors of the telescope is 3.9 meter in diameter and consisted of 30 spherical mirrors. The area of the reflector is 5 m2.
Another detector type for Cherenkov light was AIROBICC (AIRshower Observation By angle Integrating Cherenkov Counters) with one large photomultiplier looking at the sky above it. 49 of these detectors were spread in a 7-by-7 grid to observe the amplitude and the time of arrival of the front of Cherenkov light. Another 48 were added later on. These counters had a wide field of view but could only be operated during clear, moonless nights, like the atmospheric Cherenkov telescopes. Their energy threshold was a few 1013 eV. The AIROBICC array has been dismantled.
The first detector type of HEGRA was the array of 1 m2 scintillation counters which were used to measure the numbers and arrival times of secondary particles in air showers arriving at ground level. More than 250 of these
counters were in operation, spread over a 180-by-180 m2 area. These detectors were operated day and night at any weather. The energy threshold of the scintillator array was between 40 and 100 TeV, depending on the kind of primary cosmic ray particle. The scintillator array has been dismantled as well.
The scintillator array was sensitive to all types of charged secondary particles. To be able to select secondary muons in air showers there were the Muon 'Towers' with 16 m2 area each. Seventeen of these detectors were installed on La Palma.
There were two more types of detectors at the HEGRA site: the CRT (Cosmic Ray Tracking)[1] and the CLUE (Cherenkov Light Ultraviolet Experiment)[2] Archived 2020-05-20 at the Wayback Machine.

A remarkable achievement of the instrument was the detection of the most energetic photons observed from an extragalactic object, at 16 TeV, originating from Markarian 501 (Mrk 501).
It was shut down in 2002 in order to build the follow-up telescope MAGIC at the same site. A direct successor to the stereoscopic system of Cherenkov telescopes is the HESS experiment.




See also


The MAGIC Telescope, successor to HEGRA




References






External links


The official HEGRA site
The HEGRA Atmospheric Cherenkov Telescope System
Cosmic ray showers
HESS

Kata Kunci Pencarian:

• Mada'in Salih
• Meråker
• Bahasa Arab Nabath
• MAGIC
• Saleh
• Surah Al-Hijr
• Astronomi sinar gama
• Lihyan
• Bahasa Aram Nabath
• Daftar desa di Nord-Trøndelag
• Hegra
• HEGRA
• Hegra (Mada'in Salih)
• Hegra Fortress
• Hegra (disambiguation)
• Battle of Hegra Fortress
• Al-Ula
• Nabataeans
• Thamud
• Hegra Municipality