astronomy

High Resolution Fly's Eye Cosmic Ray Detector

High Resolution Fly's Eye Cosmic Ray Detector is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand High Resolution Fly's Eye Cosmic Ray Detector rather than just read about it. In short: The High Resolution Fly's Eye or HiRes detector was an ultra-high-energy cosmic ray observatory that operated in the West Desert of Utah from 1981 until April 2006. HiRes (HiRes-I, HiRes-II, and HiRes prototype) used the "atmospheric fluorescence" technique that was pioneered by the Utah group first in tests at the Volcano Ranch experiment and then with the original Fly's Eye experiment.

Key takeaways

High Resolution Fly's Eye Cosmic Ray Detector belongs to astronomy; place it in that map before memorising details.
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Reproduce the core statement of High Resolution Fly's Eye Cosmic Ray Detector from memory before moving on to harder problems.

Reference excerpt

The High Resolution Fly's Eye or HiRes detector was an ultra-high-energy cosmic ray observatory that operated in the West Desert of Utah from 1981 until April 2006. HiRes (HiRes-I, HiRes-II, and HiRes prototype) used the "atmospheric fluorescence" technique that was pioneered by the Utah group first in tests at the Volcano Ranch experiment and then with the original Fly's Eye experiment. The experiment first ran as the HiRes prototype in a tower configuration operating in conjunction with the CASA (Chicago Air Shower Array) and MIA (Michigan Muon Array). The prototype was later reconfigured to view 360 degrees in azimuth. HiRes-II followed later and was located on a hilltop about 13km away. HiRes-I and HiRes-II operated in stereo. In 1991 it discovered the Oh-My-God Particle.

Hardware and development The High Resolution Fly's Eye used larger mirrors and smaller pixels as compared with the original Fly's Eye, hence the name. A prototype of the HiRes experiment operated between 1993 and 1996 at the original Fly's Eye-I site (Five Mile Hill). It was configured in a tower viewing a narrow wedge of sky from 3–73 degrees in elevation. First the Utah ground array and later the CASA and MIA (ground array and muon array) experiments were placed on the surface in the view of the HiRes prototype. This then became the first "hybrid experiment" collecting information both on the development of the air shower induced by the incident cosmic ray, but also measuring the shower's footprint at the Earth's surface and 3 m below surface (with the buried muon array). The HiRes prototype was disassembled early in 1997 to become part of the final HiRes configuration. In its final configuration, HiRes was composed of two sites separated by 12.6 km. The sites were located on hilltops in Dugway Proving Grounds, a U.S. Army test facility in the West Desert of Utah. HiRes-I (located on Five Mile Hill or Little Granite Mountain(40.1953°N 112.8363°W / 40.1953; -112.8363)) had one ring of 22 telescopes viewing from 3–17 degrees in elevation. HiRes-I was instrumented with sample and hold electronics which took a "snapshot" of the extensive air shower generated when the incident cosmic ray interacted with the atmosphere. Meanwhile, HiRes-II (located on Camel's Back Ridge (40.13194°N 112.95896°W / 40.13194; -112.95896)) had two rings of telescopes (42 telescopes) The first set viewed between 3 and 17 degrees elevation while the second set viewed 17 to 31 degrees in elevation. Thus the total field of view was 3 to 31 degrees in elevation and ~350 degrees in azimuth. HiRes-II was instrumented with a flash analog to digital converter (FADC) so that it essentially made movies of the cosmic ray events. Both observatory sites provided full azimuthal coverage (360 degrees in azimuth). They were operated independently on moonless clear nights. The duty cycle of HiRes was close to 10%.

Accomplishments The HiRes discovered the Oh-My-God particle, an ultra-high-energy cosmic ray, on 15 October 1991. The HiRes experiment made the first observation of the Greisen–Zatsepin–Kuzmin limit (GZK cutoff) which is an indication of the highest energy cosmic rays interacting with the cosmic microwave background and the universe becoming opaque to their propagation. In 2010 final results of the HiRes experiment confirmed the GZK cutoff. A follow-on experiment to the High Resolution Fly's Eye and Akeno Giant Air Shower Array (AGASA) experiments is the Telescope Array Project which began data collection in central Utah in 2007. A similar approach, but with the water-Cherenkov detectors, has been employed for the Pierre Auger Observatory which began collecting data in 2004.

Awards Dr. Pierre Sokolsky and Dr. George Cassidy, both of the University of Utah, received the 2007 Panofsky Prize for their work on the HiRes experiment.

See also List of astronomical observatories

References

External links "HiRes Fly's Eye". Cosmic-Ray.org. University of Utah. Archived from the original on 2010-02-18. Retrieved 2005-06-03. "HiRes Fly's Eye". physics.adelaide.edu.au. University of Adelaide. Archived from the original on 2023-03-02. Retrieved 2007-04-10.

Worked examples

Example 1 — a first encounter with High Resolution Fly's Eye Cosmic Ray Detector

Start with the simplest possible case. Write down what High Resolution Fly's Eye Cosmic Ray Detector claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to High Resolution Fly's Eye Cosmic Ray Detector before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about High Resolution Fly's Eye Cosmic Ray Detector ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of High Resolution Fly's Eye Cosmic Ray Detector

In research: High Resolution Fly's Eye Cosmic Ray Detector appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses High Resolution Fly's Eye Cosmic Ray Detector in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: High Resolution Fly's Eye Cosmic Ray Detector is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical observatories in Utah, Buildings and structures in Tooele County, Utah, Cosmic-ray experiments, so understanding it makes those chapters shorter.
In everyday life: Look for High Resolution Fly's Eye Cosmic Ray Detector outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study High Resolution Fly's Eye Cosmic Ray Detector in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what High Resolution Fly's Eye Cosmic Ray Detector means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
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Frequently asked questions

What is High Resolution Fly's Eye Cosmic Ray Detector in simple terms?

Why does High Resolution Fly's Eye Cosmic Ray Detector matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study High Resolution Fly's Eye Cosmic Ray Detector?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on High Resolution Fly's Eye Cosmic Ray Detector.