The Alpha Magnetic Spectrometer , also called AMS-02 , is a particle physics experiment module installed at the International Space Station (ISS). This module is a detector that measures antimatter in cosmic rays, this information is needed to understand the formation of the universe and search for evidence of dark matter.
The lead researcher is the Nobel laureate particle physicist, Samuel Ting. The launch of the Space Shuttle Endeavor carrying the STS-134 AMS-02 took place on May 16, 2011, and the spectrometer was installed on May 19, 2011. On April 15, 2015, AMS-02 recorded more than 60 billion cosmic ray events and 90 billion after five years of operation since its installation in May 2011.
In March 2013, at a seminar at CERN, Professor Samuel Ting reported that AMS has observed over 400,000 positrons, with positrons to an increasing electron fraction from 10 GeV to 250 GeV. (The next result shows a decrease in the positron fraction in the energy above about 275 GeV). There is "no significant variation over time, or the desired direction." This result is consistent with positrons derived from the destruction of dark matter particles in space, but not yet convincing enough to rule out other explanations. " The results have been published in Physical Review Letters . Additional data is still being collected.
Video Alpha Magnetic Spectrometer
Histori
The alpha magnetic spectrometer was proposed in 1995 by the MIT particle physicist, Samuel Ting, shortly after the cancellation of the Super Collider Superconductor. The proposal was accepted and Ting became the lead researcher.
AMS-01
The AMS prototype designed to detect AMS-01, a simplified version of the detector, was built by an international consortium under Ting's direction and flown into space over Space Shuttle's Discovery in STS- 91 in June 1998. By not detecting any antihelium, AMS-01 set the upper limit of 1,1ÃÆ' â € "10 -6 for the helium antihelium flue ratio and proves that the concept of a detector works in outer space. The space shuttle mission is the last shuttle flight to the Space Station Mir. AMS-02
After the prototype flight, Ting started the development of a complete research system designated AMS-02. This development effort involves the work of 500 scientists from 56 institutions and 16 countries organized under the sponsorship of the US Department of Energy (DOE).
The instrument ultimately resulting from a long evolutionary process has been called "the most sophisticated particle detector ever sent into space", rivaling the enormous detector used on the main particle accelerator, and cost four times more than its ground-based counterparts.. The goal has also evolved and has been perfected over time. Because it was built as a more comprehensive detector, it has a better chance of finding evidence of dark matter along other destinations.
The power requirements for AMS-02 are considered too large for a practical, practical spacecraft. So AMS-02 is designed to be installed as an external module on the International Space Station and uses power from the ISS. The post-space shuttle Space Shuttle Columbia was to send AMS-02 to the ISS by spacecraft in 2005 at the UF4.1 station assembly mission , but technical difficulties and shuttle scheduling problems add more delays.
AMS-02 successfully completed final integration and operational testing at CERN in Geneva, Switzerland which included exposure to energetic proton beams generated by the CERN SPS particle accelerator. AMS-02 was then shipped by a haulier specialist to ESA, ESEEC, where they arrived February 16, 2010. Here he underwent a thermal vacuum, electromagnetic compatibility and electromagnetic interference testing. AMS-02 is scheduled to be shipped to Kennedy Space Center in Florida, USA. at the end of May 2010. However, this was delayed until August 26, as AMS-02 underwent a final alignment block test at CERN.
The cryogenic superconducting magnet system was developed for AMS-02. With the Obama administration's plan to expand International Space Station operations by 2015, the decision was made by AMS management to exchange the AMS-02 superconductor magnet for a non-superconducting magnet previously flown at AMS-01. Although non-superconducting magnets have weaker field strengths, the operating time on their orbits in the ISS is estimated to be 10 to 18 years compared to just three years for the superconducting version. In January 2014 it was announced that funding for ISS has been extended to 2024.
In 1999, after the success of the AMS-01 flight, the total cost of the AMS program was estimated at $ 33 million, with AMS-02 being planned for a flight to the ISS in 2003. After the Columbia Disaster Disaster in 2003 , and after a number of technical difficulties with AMS-02 development, the cost of the program swelled to about $ 2 billion. Maps Alpha Magnetic Spectrometer
Installation at the International Space Station
For several years it was uncertain whether AMS-02 would ever be launched because it did not materialize to fly on one of the remaining Space Shuttle flights. After the 2003 Columbia disaster, NASA decided to reduce the shuttle space and stop the remaining freight in 2010. A number of flights were removed from the remaining manifest including flights for AMS-02. In 2006 NASA studied alternative ways to send AMS-02 to the space station, but it all proved too expensive.
In May 2008, a bill was proposed to launch AMS-02 to the ISS on additional space shuttle flights in 2010 or 2011. The bill was ratified by the full Representative Council on June 11, 2008. The bill was then submitted to the Trade, Science and Commerce Senate The transport of the place also passed. It was later amended and ratified by the full Senate on 25 September 2008, and ratified again by the House of Representatives on September 27, 2008. It was signed by President George W. Bush on October 15, 2008. The NASA authorities draft to add another spacecraft flight to the schedule before the shuttle program is stopped. In January 2009 NASA restored AMS-02 to the shuttle manifest. On August 26, 2010, AMS-02 was shipped from CERN to Kennedy Space Center by Lockheed C-5 Galaxy.
It was sent to the International Space Station on May 19, 2011 as part of the ULF6 assembly flight flight on the STS-134 shuttle flight, ordered by Mark Kelly. It was ejected from the freight cargo space using the shuttle robot arm and handed over to the robot arm of the station to be installed. AMS-02 is installed on top of Integrated Truss Structure, on USS-02, zenit side of S3 element of frame.
Specifications
- Mass: 8,500 kg
- Power: 2,500 W
- Internal data rate: 7 Gbit/s
- Data speed to ground: 2 Mbit/s (typical, average)
- Main mission duration: 10 to 18 years
- Magnetic field intensity: 0.15 teslas generated by 1,200 kg permanent neodymium magnets
- The original superconducting magnet: 2 niobium-titanium windings at 1.8Ã, K yields a central field of 0.87 tesls
- The AMS-02 flight magnet is converted to non-superconductor AMS-01 version to extend the trial period and to solve reliability problems in the operation of superconductor systems
Approximately 1,000 cosmic rays are recorded by instruments per second, generating about one GB/sec of data. This data is filtered and compressed to about 300 kB/sec for download to the POCC operations center at CERN.
Design
The detector module consists of a series of detectors that are used to determine the various characteristics of radiation and particles as they pass through. Characteristics are determined only for particles passing from top to bottom. Particles entering the detector at another angle are rejected. From top to bottom subsystems are identified as:
- The radiation detector transition measures the velocity of the highest energy particles;
- Time on the flight table, along with a lower flight time, measures the velocity of lower energy particles;
- Star tracker sets the module's orientation in outer space;
- The silicon tracer measures the coordinates of charged particles in the magnetic field;
- Permanent magnets bend the path of charged particles so they can be identified;
- The anticonnection counter rejects the particles entering through the sides;
- Cherenkov Detector ring imaging measures rapid particle velocity with extreme accuracy;
- The electromagnetic calorimeter measures the total energy of the particles.
Scientific goal
AMS-02 will use a unique space environment to advance knowledge of the universe and lead to an understanding of its origin by searching antimatter, dark matter and cosmic ray measuring.
Antimatter
Experimental evidence suggests that our galaxy is made of matter; However, scientists believe there are about 100-200 billion galaxies in the universe and some versions of Big Bang's theory of the origin of the universe require the same amount of matter and antimatter. Theories that explain this clear asymmetry violate other measurements. Whether or not there is a significant antimatter is one of the fundamental questions about the origin and nature of the universe. Any observation of the antihelium nucleus will provide evidence of the existence of antimatter in space. In 1999, AMS-01 set a new upper limit of 10 -6 for the antihelium/helium flux ratio in the universe. AMS-02 will search with a sensitivity of 10 -9 , a threefold increase over AMS-01 , sufficient to reach the edges of the expanding universe and solve the problem definitively.
Dark matter
The material seen in the universe, like a star, adds up to less than 5 percent of the total mass known to exist from many other observations. The other 95 percent are dark, either dark matter, which is estimated to be 20 percent of the heavy universe, or dark energy, which forms a balance. The exact nature of both is still unknown. One of the main candidates for dark matter is neutralino. If neutralinos exist, they must collide with each other and remove the excess charged particles that can be detected by AMS-02. Any peak in the positron background, antiproton, or gamma-ray flux can signal the presence of neutralinos or other dark matter candidates, but it needs to be distinguished from unfamiliar astrophysical signals that are not known.
Strangelets
Six types of quarks (top, bottom, weird, charm, down, and up) have been found experimentally; However, most of the material on Earth consists only of upper and lower quarks. This is a fundamental question of whether there is a stable material consisting of strange quarks combined with top and bottom quarks. Such material particles are known as strangelets. Strangelets may have very large masses and very small charge-to-mass ratios. It will be a completely new form of matter. AMS-02 can determine whether this remarkable material exists in our local environment.
Space radiation environment
Cosmic radiation during transit is a significant obstacle to sending humans to Mars. Accurate measurements of the cosmic ray environment are needed to plan appropriate countermeasures. Most cosmic ray studies were performed using balloon instruments with flight times measured within days; these studies have shown significant variation. AMS-02 will operate on the ISS, accumulate large amounts of accurate data and enable measurement of long-term variations of cosmic ray flux through a wide energy range, for the nucleus of protons to iron. In addition to understanding the radiation protection required for astronauts during interplanetary flights, this data will allow the spread of interstellar and cosmic ray origins to be identified.
Results
As of July 2012, it was reported that AMS-02 has observed over 18 billion cosmic rays.
In February 2013, Samuel Ting acknowledged that he would publish his first scientific paper in a few weeks, and that in the first 18 months of its operation the AMS has recorded 25 billion particle events including nearly eight billion fast and positron electrons. The AMS paper reported a positron-electron ratio in the mass range from 0.5 to 350 GeV, providing evidence of the weak dark particles interacting (WIMP) of dark matter.
On March 30, 2013, the first results of the AMS experiment were announced by the CERN press office. The first physics results were published in Physical Review Letters on April 3, 2013. A total of 6.8 Æ' 10 6 positrons and electron events were collected in the energy range from 0.5 to 350 GeV. Positron fractions (from total electrons plus positron events) continue to increase from 10 to 250 GeV, but the slope decreases with the order of magnitude above 20 Gev, although the positron fraction is still increasing. There is no fine structure in the positron fraction spectrum, and no anisotropy is observed. The accompanying view Physics says that "The first results of the Alpha Space Magnetic Spectrometer confirm the excess of unexplained energy in cosmic rays attached to Earth." This result is consistent with positrons derived from the destruction of dark matter particles in space, but not yet convincing enough to rule out other explanations. Samuel Ting said, "Over the next few months, AMS will be able to tell us confidently whether this positron is a signal for dark matter, or whether they have other origins."
On September 18, 2014, a new result with nearly twice the data was presented in a lecture at CERN and published in Physical Review Letters. New measurements of the positron fraction up to 500 GeV are reported, suggesting that the positron fraction peak reaches a maximum of about 16% of the total positron electron event, approximately 275 Â ± 32 GeV. At higher energies, up to 500 GeV, the positron ratios of electrons begin to fall again.
The AMS was presented for 3 days at CERN in April 2015, covering new data on 300 million proton and helium flux events. It was revealed in December 2016 that it has found some signals consistent with the antihelium core in the midst of several billion helium nuclei. The results still have to be verified, and the team is currently trying to rule out contamination.
See also
- List of the Astronomical Space Observatories
- The Load for Antimatter Exploration and Astrophysics of Light-Nuclei (PAMELA) - Italy's international cosmic ray mission launched in 2006 with a similar purpose
- Scientific research on ISS
References
This article incorporates public domain material from National Aeronautics and Space Administration documents "AMS project pages".
Further reading
- Sandweiss, J. (2004). "Strangelet search overview and Magnetic Alpha Spectrometer: when are we going to stop looking?". Journal of Physics G: Nuclear Physics and Particles . 30 (1): S51-S59. Bibcode: 2004JPhG... 30S..51S. doi: 10.1088/0954-3899/30/1/004.
External links
- AMS Collaboration Homepage
- AMS Site at CERN. Inc. construction diagram.
- Home of AMS at Johnson Space Center
- NASA Project Fact Sheet AMS-02
- NASA AMS-02 Project Home page with real-time cosmic rays
- STS-134 mission animation film showing AMS-02 (72MB) installation
- Alpha Magnetic Spectrometer - picture collection - AMS-02 on Facebook
- Expensive Search for the Dark Heart of the Cosmos (New York Times, November 16, 2010)
- Route to the Space Alliance - European Transport for Aeronautics and Aeronautical Industry
Source of the article : Wikipedia
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