Haverah Park

Haverah Park was a research site operated by the Physics Department of the University of Leeds. For 20 years it was home to one of the largest extensive air shower arrays in the world with an area of 12 square kilometres. The array was made up of water Cerenkov detectors housed in wooden huts and operated until 1987 when it was switched off.

This map shows the huge scale of the Haverah Park array. The detector stations are marked with circles and the central research station, or hut, is shown at the centre.

During its lifetime many 1000's of extensive air showers were recorded including four exceptional ones of such size that the cosmic rays that generated them must have had energies greater than 10²⁰ eV. These particles are the highest energy form of radiation known to exist anywhere in the universe and their origin is one of science's greatest mysteries.

The main hut at Haverah Park with a GREX detector in the foreground.

For several years these findings were somewhat controversial being in disagreement with other experiments and theories which denied the possibility of such energetic cosmic rays. However in 1993 an experiment in Utah, called Fly's Eye reported the detection of a cosmic ray of energy 3x10²⁰ eV. Finally the existence of these remarkable particles was confirmed. Subsequently the Japanese experiment at Akeno has reported a further 6 events with energy >10²⁰ eV.

After the large array was decommissioned a smaller array called GREX was built to look for sources of high energy (>10¹⁴ eV) gamma rays. This array operated in conjunction with several other experiments such as the CERES air-Cerenkov detector and the PLASTEX particle tracking experiment. Finally in 1993 Haverah Park was closed down.

A party was held to mark the closure of the large array. After over 20 years one of the detectors was opened and the water was found to be crystal clear. In fact it was good enough to drink!

That's not the end of the story however. After the Fly's Eye group confirmed the existence of the very high energy cosmic rays detected at Haverah Park interest in this area of astrophysics grew. Construction of two giant air shower arrays covering thousands of square kilometres began in March 1999. The two arrays will be known collectively as the Pierre Auger Observatory in honour of the man who first discovered extensive air showers. Many aspects of the design of the array have been influenced by scientists from Leeds and in particular the detector design is based on the water Cerenkov tank utilised so successfully at Haverah Park.

Where is Haverah Park?

Haverah Park is situated on farmland on the North Yorkshire Moors, UK. It is 17 miles from the University of Leeds, and 3 miles from the nearest town, Harrogate.