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Atmospheric Monitoring at HiRes Status Enhancements. Lawrence Wiencke HiRes NSF Review Nov. 22 2002 Washington DC. At 1999 ICRC - Preliminary results from monocular measurement of CR energy spectrum ~6 super GZK candidates - PowerPoint PPT Presentation
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Atmospheric Monitoring at HiRes
Status
Enhancements
Lawrence WienckeHiRes NSF ReviewNov. 22 2002Washington DC
• At 1999 ICRC - Preliminary results from monocular measurement of CR energy spectrum ~6 super GZK candidates
• At 2001 ICRC - HiRes reported monocular measurement of CR energy spectrum
~2x statistics, but ~2 super GZK candidates
What Happened?
Essential - The Calorimeter
Challenging - Light Propagation
Shower Detector
Atmospheric Monitoring
Clear Air Location - Go to a remote Desert
ReduceGround Effects - Put detectors on Hills
Location Matters
Technique
• Use Lasers as a “test” beam
• Observe the tracks they make with the same detector that observes tracks from extensive air showers
Laser Detector
Parameters Measured
• Vertical Aerosol Optical Depth
• Horizontal Scattering length at Ground Level
SimulationData
ph
oto
ns
Scattering Angle
Fit of Horizontal Laser Shot
Example of Extracting phasefunction
Mean 0.040
What is Vertical Optical Depth?
T = e-VOD
T = e-VOD/sinӨ
Ө
VAOD - Vertical Optical Depth of Aerosol Component
Mean 0.033
Mean 0.043
Normalize toClear Night Data
Normalize To Simulated Data (no aerosols)
north
south
HR1detector
laser
Test Horizontal Uniformity
DetectorLaser
3.5 km2.5 km
Compare VAODfor different heights
DetectorLaser
3.5 km
1.5 km
Check using showers observed by both eyes.
Why to we think the 0.04 average is correct?
HiRes 2 HiRes - I
Sh
ow
er
Axis
Pick commonly viewed track segment
For each eye, reconstruct amount of light from that segment
Correct fordistance and atmospheric attenuation
Compare results at both eyes
If the correction is too large the further reconstruction is brigher
VAOD = 0.1HAL = 12 kmSC = 1.2 km
VAOD = 0.0
VAOD = 0.04HAL = 25 kmSC = 1 km
Apply three different aerosol models to same data
Characterized the average atmosphere at Dugway
Average has been verified with stereo air shower data
This work also tests calibration
Vertical Aerosol Optical Depth (VAOD)VAOD(avg) = 0.04 +/- 0.02(sys) +/- 0.001 (stat)
Horizontal Aerosol Scattering Length at ground level (HAL)HAL(avg) = 25km
Combined VAOD*HAL -> effective scale heightSH(avg) = 1km
Also in Progress.. Reconstruction of inclined laser shots
Enhancements in Progress
Roving Laser TestsShoot The ShowerDistant Laser and Mirror
Shoot the Shower• HR1 detector -> HR2SLS
HR2
FADC
Request RequestedList
Check Requests
ServicedList
Shot Pattern
hr2sls
inte
rrup
t
RequestedList
Somethinginteresting
Date, Time, Mirror, 1st PMT, Last PMT, Pseudo Distance, Trigger Flag
Roving Laser
• Motivation– Portable “Test Beam”– Study Calibration and
detector response
• Features– 0.1 degree pointing
accuracy– 355nm wavelength– Absolute calibration to
within 10%
Energy Balance Simpsons Springs Roving Laser Shots
Adding a distant Laser and Mirror
• First HiRes results are consistent with GZK feature (cutoff?).
• How well do we understand detector response for GZK candidates? – Do the “Big? One’s” get away?
– Can we really see as far as we think we can?
• Dugway lockout provided motivation to test this.– Set up equipment off base
• Make routine, redundant measurements• Over 20-35 km distances• Of light sources we understand
– Increased sensitivity to atmospherics
– Less sensitivity to absolute calibration
35 km
25 kmhr1
hr2
Terra SiteInteresting Features
Similar Elevation to HR1, HR2Power and Phone available22 km to hr1, 35 km to hr2Nearly in line with hr1, hr2Not on Dugway!!!!!~1hr 20 minutes to U of U
hr2 hr1Terra
Terra Site
laser
Vertical Laser Shot Fired from Terra as recorded
by HiRes2 32.7 km distant
Laser Energy ~3.5mJLaser Wavelength 355nm
Npe ~300
Npe ~200
Npe ~40
Terra - StatusLaser Installed, will begin operation for next run
Mirror will follow in a month or two
Portable mirror in a “connex” shipping container.
HR1 HR2 Terra
Co-Linear Arrangement of mirrors and lasers
5km
10km
15km