Meteor Activity Outlook for September 14-20, 2019

This is the same fireball presented in last week’s edition, only seen from a different angle. This photograph was obtained by Kyle Chuback from near Fort Saskatchewan, Alberta, Canada. This is one of the brightest fireballs reported to the AMS recently. For more information on this object visit: https://fireball.amsmeteors.org/members/imo_view/event/2019/4160 ©Kyle Chuback

During this period the moon reaches its full phase on Saturday September 14th. This will be the worst time of the month to try and view meteor activity as the bright moon will obscure all but the brightest meteors. Toward the end of this period the evening hours will be free of moonlight but rates during this time of night are low, seldom exceeding 5 meteors per hour. The estimated total hourly meteor rates for evening observers this week is near 3 for those viewing from the northern hemisphere and 2 for those located south of the equator. For morning observers the estimated total hourly rates should be near  8 as seen from mid-northern latitudes (45N) and 5 as seen from tropical southern locations (25S). The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Rates are reduced during this period due to moonlight. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brightest meteors will be visible from such locations.

The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning September 14/15. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies at the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.

 

Radiant Positions at 22:00 LDST

Radiant Positions at 22:00 Local Daylight Saving Time

Radiant Positions at 01:00 LDST

Radiant Positions at 1:00 Local Daylight Saving Time

Radiant Positions at 04:00 LDST

Radiant Positions at 4:00 Local Daylight Saving Time

These sources of meteoric activity are expected to be active this week.

Detailed descriptions of each source will continue next week when lunar conditions improve considerably.

SHOWER DATE OF MAXIMUM ACTIVITY CELESTIAL POSITION ENTRY VELOCITY CULMINATION HOURLY RATE CLASS
RA (RA in Deg.) DEC Km/Sec Local Daylight Saving Time North-South
Anthelion (ANT) 00:20 (005) +02 30 02:00 1 – 1 II
September Epsilon Perseids (SPE) Sep 11 03:34 (054) +40 65 05:00 1 – <1 II
nu Eridanids (NUE) Sep 24 04:34 (069) +05 67 06:00 <1 – <1 IV
eta Eridanids (ERI) Aug 11 04:57 (074) -02 65 06:00 <1 – <1 IV
Daytime Sextantids (DSX) Sep 29 09:26 (141) +04 33 11:00 <1 – <1 IV

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LS2 Report: CMS set to glitter with installation of new GEMs

CERN — European Organization for Nuclear Research logo.

18 September, 2019

The CMS muon system is being upgraded to help track muons with ever-higher precision 

Image above: The GEMs being installed in CMS (Image: Maximilien Brice/CERN).

Muons – heavy, weakly interacting particles – zip past the inner layers of the Compact Muon Solenoid (CMS), after being produced in collisions by the Large Hadron Collider (LHC). They are observed using special detectors placed on the periphery of the cylindrical device, where they are the particles most likely to register a signal. Although CMS, as the name suggests, was designed with the ability to observe with high precision nearly every muon produced within it, it will become more challenging to do so in a few years’ time. The High-Luminosity LHC (HL-LHC) will begin operations in 2026, providing on average over five times more simultaneous proton–proton collisions than before. Various components of CMS, including the muon system, are being upgraded during the ongoing second long shutdown (LS2) of CERN’s accelerator complex, in order to cope with the HL-LHC’s higher data rates.

Muon detectors contain different mixtures of gases that get ionised when high-energy muons fly through them, providing information about where the muon was at a given instant. The CMS muon system has so far used three different types of detectors: Drift Tubes (DT), Cathode Strip Chambers (CSC) and Resistive Plate Chambers (RPC). Around a decade ago, at about the time that CMS began collecting LHC collision data, it was decided to build a completely new type of detector called Gas Electron Multipliers, or GEM, to improve the muon-detection abilities of CMS in the HL-LHC era. After extensive R&D, the first GEMs were assembled and tested at CERN’s Prévessin site in a dedicated fabrication facility. In July, two of 72 so-called “superchambers” of GEMs were transported carefully to Point 5 and installed within CMS. Each superchamber had a bottle of gas strapped on top of it on the trolley so the detector could keep “breathing” the inert air. The remaining 70 superchambers will be installed later in LS2.

“The GEMs are new technology for CMS and Run 3 of the LHC will give us the opportunity to evaluate their performance,” says Archana Sharma, who has led the CMS-GEM team since 2009. “Of course,” she continues, “it’s not only there to be tested. The first GEMs will work with the existing CSCs to provide valuable triggering information to select the most interesting collision events.” Two more GEM stations with 288 and 216 modules respectively will be definitively installed in the coming years, in time for the HL-LHC.

The muon-system team have been busy upgrading the electronics of the 180 CSCs located closest to the beam line to prepare for the HL-LHC. “We have already removed, refurbished and reinstalled 54 CSCs this year,” notes Anna Colaleo, CMS muon-system manager. “Work on replacing the electronics for another batch of CSCs is in progress and we plan on completing this endeavour by the summer of 2020.”

CMS CSC chamber’s trip for new electronics

Video above: A timelapse showing the extraction of CSCs from the CMS endcap and their transport to the refurbishment area on the surface (Video: CMS/CERN).

CMS is also performing critical maintenance on the rest of the muon detectors during LS2. As expected, over the course of several years of operation, some components of these detectors have deteriorated slightly. The RPCs have been made more airtight to reduce gas leaks, while both DTs and RPCs have had some broken components replaced. In addition, neutron shielding is being added to the top of the DTs located in the central barrel to protect CMS from the neutron background caused by the particle beam interacting with the beam pipe.

With nearly a year and a half of LS2 left, the CMS experiment site at LHC Point 5 continues to be a hub of activity as the collaboration prepares for the LHC’s Run 3 and beyond.

More photos of the GEMs installation on CDS: https://cds.cern.ch/record/2684028

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 23 Member States.

Related links:

Compact Muon Solenoid (CMS): https://home.cern/science/experiments/compact-muon-solenoid

Large Hadron Collider (LHC): https://home.cern/science/accelerators/large-hadron-collider

High-Luminosity LHC (HL-LHC): https://home.cern/science/accelerators/high-luminosity-lhc

Second long shutdown (LS2): https://home.cern/tags/long-shutdown-2

The GEMs are new technology for CMS: https://home.cern/news/news/experiments/cms-tightens-its-net-around-muons

For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/

Image (mentioned), Video (mentioned), Text, Credits: CERN/Achintya Rao.

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