the telescope array low energy extension (tale)
DESCRIPTION
Pierre Sokolsky University of Utah. The Telescope Array Low Energy Extension (TALE) . Spectrum: Ankle and Cutoff. Ankle Pair production? Galactic to extragalactic transition? Cutoff GZK feature Sources getting tired?. Spectrum: Second Knee. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/1.jpg)
The Telescope Array Low Energy Extension
(TALE)
Pierre SokolskyUniversity of Utah
![Page 2: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/2.jpg)
Spectrum: Ankle and Cutoff
Ankle Pair production? Galactic to
extragalactic transition?
Cutoff GZK feature Sources getting
tired?
![Page 3: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/3.jpg)
Spectrum: Second Knee Left: Cosmic ray
spectra measured by the Fly’s Eye, HiRes/MIA, Akeno, and Yakutsk experiments.
Right: Aligning the flat parts of the spectra from the four experiments, a “second knee” appears
The energy and origin of the feature is unknown – needs to be measured with other features
![Page 4: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/4.jpg)
Composition
Changes in composition and how they correlate with changes in spectral shape tell us about the sources – width and <X
max>
HiRes-MIA data imply a change from heavy to light from 1017 – 1018 eV
HiRes data imply a constant light composition for E>1018 eV
![Page 5: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/5.jpg)
TALE Goal: Reach 1016.5 eV
Study the Transition Region from Galactic to Extra-galactic cosmic ray flux
Extend the coverage of the TA experiment to include all three cosmic ray spectral features in the ultrahigh energy regime:– The GZK Suppression– The Ankle– The Second Knee
It is important than we establish a single unified energy scale for the measurement of all three features
![Page 6: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/6.jpg)
Telescope Array – High Energy
The High Energy component of Telescope Array – 507 scintillator surface detectors and 28 fluorescence telescopes at 3 stations is
complete and operational as of 1/2008.
![Page 7: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/7.jpg)
7
Long Ridge Black Rock Mesa
Middle Drum
TA-FDFrom HiRes
New FDs
![Page 8: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/8.jpg)
Example stereo hybrid event
BRM CAMERA7
BRM CAMERA8
LR CAMERA7
![Page 9: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/9.jpg)
Absolute Energy Calibration in situ by 40 MeV electron beamreleased vertically into the sky.
![Page 10: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/10.jpg)
TA Stage-1 The energy region > 1019 eV is
well-covered by the existing TA detectors
Ground Array becomes fully efficient at ~5x1018 eV
The three FD stations TA-FD0 at Black Rock Mesa TA-FD1 at Long Ridge TA-FD2 at Middle Drum
provide ~100% coverage of the ground array at 1019 eV and above
![Page 11: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/11.jpg)
Below 1019 eV However, Stage-1 of TA was
not designed for physics below 1019 eV.
There is no overlap at all in the aperture of the three fluorescence detectors at 1018
eV The ground array efficiency
drops quickly in the 1018-1019 eV decade
![Page 12: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/12.jpg)
Low Energy Extension to TA
4th Fluorescence Station - 6 km separation 24 telescopes (3-31o elevation) – “ring 1 & 2” 15 large area Tower telescopes (31-73o elevation)
Infill scintillator array 111 detectors at 400 m Graded muon array – 25 detectors, buried 3 m
![Page 13: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/13.jpg)
Lessons from HiRes Stereo
HiRes Stereo aperture falls too rapidly through the ankle region to extend flux measurements much below ~31018eV.
There are two primary reasons for this:
– The 12.6 km separation of the two stations is too large: the overlap between the two shrinks very quickly below 31018eV
– HiRes-1 only covers elevation angles up to 17, which further limits the aperture near and below the ankle itself
![Page 14: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/14.jpg)
6 km Stereo and Tower
•24 low elevation (ring 1 & 2) telescopes; mirrors the same effective area as HiRes and Auger
•15 higher elevation (rings 3-5) telescopes; mirrors 3x larger area
![Page 15: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/15.jpg)
Aperture
The 6 km stereo provides
• a much flatter stereo aperture than HiRes
• a 10x increase in aperture at 1018 eV
![Page 16: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/16.jpg)
HiRes Prototype 92-96 14 (HiRes-1) + 4 (HiRes-2) mirror
prototype detector operated between 1992 and 1996
HiRes-1 field of view up to ~70. HiRes-1 operated in hybrid mode with
the MIA muon array (16 patches64 underground scintillation counters each):
![Page 17: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/17.jpg)
HiRes Prototype/MIA Hybrid
![Page 18: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/18.jpg)
Left: TALE-1 site, showing 3rd 4th and 5th rings
Right: Prototype 4th ring detector
3 additional rings of mirrors, 31° – 72º Each mirror 3x HiRes mirror area
TALE Tower Fluorescence Detector:
![Page 19: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/19.jpg)
Improved Sensitivity The increased mirror
size will improve substantially the sensitivity of TALE in the 1016.5-1017.5 eV energy decade
Note the gain in sensitivity comes from the improvement in signal.
![Page 20: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/20.jpg)
Tower helps with <Xmax
> Bias
Comparison of <Xmax
> (solid
line) measured by the HiRes and HiRes-MIA experiments and the distribution of X
max of HiRes
events (2-D box histogram), demonstrating the trigger bias (towards light composition) inherent in a “2-ring” fluorescence detectors like those used by HiRes and PAO.
need the Tower to cover this region, which contains the Second Knee Structure
![Page 21: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/21.jpg)
Infill Array Will place 111 additional surface array counters overlapping with main ground array: 4km x 4km
16 of the counters in the main ground array will form part of the infill
![Page 22: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/22.jpg)
1017 eV showers, 30° zenith at TA ground(CORSIKA/EPOS)
TALE Methods:
![Page 23: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/23.jpg)
![Page 24: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/24.jpg)
TALE: Underground Muon Detectors
Preferred design, if BLM permitsReduced costSimpler
Reclamation, reseeding required
![Page 25: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/25.jpg)
/e ratio signal for transition in log(E) = 17 decade
![Page 26: The Telescope Array Low Energy Extension (TALE)](https://reader036.vdocuments.mx/reader036/viewer/2022062723/56813bfb550346895da54b83/html5/thumbnails/26.jpg)
Conclusion:
TA/TALE will bring together four different detector systems with overlapping energy ranges to give continuous coverage from 1016.5 eV to the highest energies.
The cost will be shared between U.S., Japan, South Korea, and Russia.
TA/TALE will be able to study all three spectral features in the UHE regime.
TALE will have two orthogonal composition measurements in galactic/extragalactic transition region: FD shower profile and /e ratio.