In search of huts. I have been on a mission to locate and document the remaining huts from a cosmic ray detection experiment at Haverah Park on the Pennine moorland in North Yorkshire.
When high-energy cosmic rays enter the atmosphere, they set off a chain-reaction particle cascade known as an extensive air shower. The Haverah Park experiment was home to one of the largest extensive cosmic ray air shower arrays in the world.
It was operated by the Physics Department of the University of Leeds for 20 years, closing in 1987. An array of over 200 water-Cherenkov detectors covering 12 km2 were active during its operation and many 1000’s of extensive air showers were recorded, including ones of such size that the cosmic rays that generated them had energies previously unthought of, adding to the mystery of where they come from.
The large energy density of cosmic rays is close to that of starlight, adding their own glow to the sky as they blast across the universe. Cosmic rays are the atomic nuclei of elements ranging from hydrogen to uranium accelerated to high energies, with half being protons and most positively charged.
Much of the technology used to observe cosmic rays has changed little over the decades since first inventions and still plays a role within newer technologies.
It appeals to me that the excitement of observing particles from other galaxies happened at these unassuming structures.
Sharing the landscape of Haverah Park cosmic ray air shower detector array huts are the striking white radomes that shield secret radar equipment at RAF Menwith Hill. The spy station has been there since the cold war space race began in the mid-fifties. Little is known about what goes on here but broadly it is said to gather electronic intelligence and is operated by US National Security Agency (NSA) and UK Government Communications Headquarters (GCHQ). As satellite technology has increased so has the number of radomes which now number 37 at the site. It is worth noting that satellites are vulnerable to unpredictable space weather and cosmic ray interference.
The total number of particles detected in a shower can be used to estimate the energy of the primary cosmic ray. Some particles contain the highest energy form of radiation known to exist anywhere in the universe and their origin is one of science’s greatest mysteries. Air showers of secondary particles generated from a primary cosmic ray hitting the Earth’s atmosphere are spread over many kilometres when they hit the ground so it is useful to have detectors spread over a large area. The difference in the time of arrival of recorded particles at multiple detectors can be used to estimate the arrival direction of the primary cosmic ray. However, this does not necessarily reveal the origin of the particle as magnetic fields within the galaxies bend their trajectories so that the memory of their original direction is obfuscated.
The cosmic ray detectors I made for the The Breath of Stars use a block of plastic scintillator which emits a short burst of UV light when a charged particle passes through it which is picked up by a single-photon-sensitive device. The detectors used at Haverah Park are water Cherenkov detectors. These are large steel tanks of purified water with photon sensitive detectors in the water.
While the speed of light in a vacuum is a universal constant its speed through a material may be significantly reduced as it is slowed by the medium. A particle passing through a material faster than that at which light can travel through the material loses electrons thereby emitting light. When cosmic rays pass through the water tanks, they emit Cherenkov radiation because they travel faster than the speed of light in water. Cherenkov light is similar to the production of a sonic boom when an airplane is traveling through the air faster than sound waves can move through the air. Pavel Cherenkov along with Ilya Frank and Igor Tamm discovered and demonstrated this phenomenon in 1934, astonishingly, it had been predicted in 1888 by Oliver Heaviside, and in 1910 Marie Curie had noticed a strange blue glow from her radium experiments.
Other huts from the Haverah Park experiment are in a state of collapse.
There are so many high energy particles hurtling around the universe that they almost equal starlight in energy density. Cosmic rays travel at almost the speed of light and because they are charged particles most cosmic rays are confined, spiralling within our galaxy for a million years or more, by the magnetic fields which permeate it.
Five million cosmic rays pass through your body each day. Some will collide with atomic nuclei. A particle passing through a material at a velocity greater than that at which light can travel through the material emits light. Maybe we glow a little.
Following the disappearing trail. Haverah Park hut with an intriguing hexagon tank.
Inside Hut no. 7 is a dumping ground. Waste is a big problem in space as well as on Earth. The thickening shell of space junk in low Earth orbit, if left to accumulate, could cause a conductive shield to form, weakening the effectiveness of the magnetosphere, which protects life on earth from most cosmic radiation.
A decaying wall map of the entire Haverah Park experiment is just visible through a window of one of the huts in the central hub, but not much else remains inside.
It looks like these huts have been recently emptied into a skip which, by chance, was collected while I was there. Unfortunately, the driver had no enlightening information for me about the future of the huts.
Cherenkov radiation is a form of energy that gives off a blue glow when electrically charged particles are moving at speeds faster than light is able to travel through the same medium. The experimental physicist Blackett, who received the 1948 Nobel Prize in Physics for his investigations into cosmic rays, believed that extensive air showers should produce flashes of light that could be perceived by the human eye when lying down and looking upwards under dark skies. Whether he achieved seeing this phenomena himself is not known, but he inspired colleagues Galbraith and Jelley, in 1952, to devise an experiment to detect light from air showers using a rubbish bin painted black on the inside, a recycled searchlight mirror and a small phototube. With these simple items, they made the first observation of Cherenkov light produced by cosmic rays passing through the atmosphere. Not all the twinkling in the night sky is starlight.
During the Haverah Park experiment, the water Cherenkov detectors deployed across the moors were connected by underground cables and transmitted information to the control huts via radio signals in the microwave frequency range. All communication is now severed. Cut cables coil in rain filled tanks. The cosmic rays are still pounding down upon these new unwatched ecosystems but the detectors have moved elsewhere.
I am looking forward to meeting Professor Alan Watson FRS here in the autumn. He is eminent in the field of cosmic rays and helped initiate the extensive air shower project, working at Haverah Park for 25 years. He has kindly agreed to meet and share his insider knowledge of the history and operations at the site.
The idea to build a truly giant shower array was launched by Alan Watson and Jim Cronin shortly after Haverah Park was decommissioned and thanks to the ground breaking work undertaken in these huts, it evolved to become the vast Pierre Auger Observatory in Argentina, named in honour of the man who first discovered extensive air showers.
Peering into the darkness, trying to fathom the structures of the universe or what’s inside the hut, and the nature of that relationship.
The ultra high energy particles detected at Havarah Park and new arrays across the globe are very rare, possibly less than one per square kilometre per century, so it is big news when one arrives. Because they have such high energy, it is thought they shouldn’t be affected by galactic magnetic fields, and therefore, the direction of the particle could be determined and the source located. The Amaterasu particle, named after the sun goddess in Japanese mythology, the second most powerful particle to be recorded, appears to have emerged from the Local Void, ana area with no astronomical objects that might produce such a particle. There is no explanation of where these particles come from, just hints of bigger mysteries to unfold.
Many water tanks remain around Haverah Park, stripped of their purpose as water Cherenkov detectors they now reflect the sky in the rainfall they collect rather than record showers of particles from space.
During operation, huts were built in groups of three, each with six large galvanised steel tanks lined with white plastic to diffuse the light and filled with local purified water. Each tank was monitored by extremely sensitive photon detectors which recorded the Cherenkov light emitted as particles passed through the water. At the end of the large array experiment, one of the detectors was opened, and the water was found to be crystal clear and good enough to drink. The proof that water could be kept bacteria-free in a sealed container for over 25 years gave confidence in using the same technology for a future larger cosmic ray detector array to be developed.
Haverah Park was once one of the largest extensive air shower arrays in the world, with an area of 12 km2, but in the end, it just wasn’t big enough.
When Alan Watson and Jim Cronin proposed building a new 3000 km2 shower array, the question from funders was, ‘why do you want to make the array so large?’. The answer is, of course, to discover those known and unknown unknowns, but funders don’t usually like unpredictable outcomes. Luckily their plea was bolstered by the Fly’s Eye Cosmic Ray Detector Array out in the Utah Desert recording the Oh-My-God particle in 1991, it’s energy was 40 million times greater than that of any particles ever produced in any terrestrial particle accelerator. This and other evidence of extremely high energy particles sparked interest in the field of astrophysics and validated the discovery of similar particles at Haverah Park, which had not been taken seriously at the time. This ambitious proposal gained momentum during the 1990s to become the Pierre Auger Observatory in Argentina, with the detector design developed from the water Cherenkov tanks so successfully operated at Haverah Park. The huts here may be in ruins, but their legacy lives on at the world’s largest extensive air shower detector array, which is edging closer to answer the question ‘Where do ultra-high-energy cosmic rays come from?’
I am looking forward to developing work responding to the legacy of the Haverah Park experiment and building on my experience of creating The Absolute Hut (of absolute potential) New surfaces to explore, more moss, and also lichens here.
‘The Belly of a Rock’ video has waited a long time for its crusted shell. A hybrid between rock, mollusc, and technology inspired by the chemical conversations and urge to create described by Italo Calvino in his story ‘The Spiral’. We don’t always know what we are creating. Within ‘the belly’ surfaces slide and scrape along lines of fissure, distended innards ooze and rocks moan as they are distorted by untold pressure. The turbulent spiralling of the core births rock and lifeforms acted upon by the drag of the oscillating magnetic field.
I have acquired a large number of photochromic optical lenses. These I have sorted by diameter, thickness and distortion. Initial thoughts about their use include using them as petri dishes to grow crystals which are embedded into small concrete hexagonal pillars of differing heights with reference to the geology of giants causeway. Using them to create composite windows into a new hut structure filled with video projections referencing the fly’s eye cosmic detector array.
A good workout on the guillotine making 201 cuts in copper sheet in preparation for a new concrete tablet in the Instruments of the Anemoi sculpture series.
Gallery and other outings:
Beverley Duckworth’s installation Surplus at Goldsmiths MFA final show. Beverley’s work is grown through a diligent process of care. Found materials are literally given new life in the seeds which are embedded into them, which then transform and colour them. The installation includes an intermittent sound element of recordings of the melody played by waste trucks in Taiwan to call people to bring out their rubbish.
Apparently I wasn’t the first person to be struck by similarities to the landscape of Yangshuo near Guilin China. I visited in 1984 and think it is no longer a quiet little village.
It was the first time I had been back inside the Ben Pimlott building at Goldsmiths since by own graduation, a scary twenty years ago. The building was brand new then and the views with little visible green fed into my installation Re:construction – a large screen print with tiny viewing hole to a tiny oasis amidst the grey, albeit a synthetic one.
Yinka Shonibare Suspended States at Serpentine South. Horrors of war and colonialism are filed under dazzling colour, birds on the brink of extinction stare in plea or accusation, beacons of light in the darkness come from miniature replicas of sanctuaries.
Yinka’s socially engaged inclusive practice spills over into real help for artists and communities. The exhibition celebrates Guest Projects and G.A.S. Foundation in Lagos. Guest Projects is such a generous idea and I have been so lucky to benefit from it with the project Laboratory of Dark Matters
Being awarded a month’s residency at Guest Projects was crucial to the success of Laboratory of Dark Matters as a site for developing ideas and subsequently touring the project. Wonderful to meet Yinka and also to be part of the selection committee for the next round of projects.
Judy Chicago Revelations at Serpentine North. The highlight of this show is the video documenting The Dinner Party (1974-79) installation and the preparatory drawings and sample plate. What a shame the actual installation wasn’t here, I will have to visit the Brooklyn Museum, New York sometime to see it. The research, collaborations, crafts and designs that went into creating it was phenomenal.
Saw Complicité’s excellent Mnemonic at The National Theatre, 25 years after first seeing it at Riverside Studios. ‘A body is found in the ice, and a woman is looking for her father while a man searches for his lost lover. Mnemonic is as much about origins as it is about memory, and remembering what is lost. Mnemonic asks us: what is our place in the natural world? How have human relationships with the environment shaped patterns of migration? Who are we, and where do we come from? ‘
Visited the delightful mellow brick country home and extensive gardens of pioneering naturalist Gilbert White at Selborne. His book ‘The Natural History of Selborne’ (1789) has never been out of print since it was published more than 230 years ago. He was brought to many people’s attention, including mine, during the pandemic and lockdowns of 2020 when writer Melissa Harrison included his diary readings in her podcast The Stubborn Light of Things.
Susan Eyre 