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Analysis of Flasher Events in AMANDA: Insights from String 21 Data Collection

This report presents the analysis of flasher events from the AMANDA data collected during the String 21 run, focusing on the integration of Monolith software and filtering techniques. The study reveals insights into the multiplicity of triggers, GPS synchronization, and the relationship between IceCube and AMANDA triggers, highlighting a significant drop in coincidence rates. The analysis utilized John Pretz's merging routine and emphasizes the need for unbiased AMANDA data for more accurate results. The findings underscore the visibility range of flashers and synchronization accuracy.

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Analysis of Flasher Events in AMANDA: Insights from String 21 Data Collection

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  1. String 21 Flashers in Amanda Dom 23 flasher run from April 9th David Hardtke - UCB

  2. String 21 Flasher Events -- merging • Analysis details: • Monolith (software trigger) not run on flasher data. Run offline • Monolith Multiplicity trigger -- 10 or more DOMs in 5000 ns time window • Previous results had cut of 23 or more DOMS • L1 filtered AMANDA data from pole (still looking for unbiased data set) • Nobody seems to know what L1 filter does exactly • Used John Pretz merging routine (in SVN, works with version 1-06 of offline software) • Search for common IceCube/AMANDA triggers within -20 s < t < -5 s. 100% official IceCube software David Hardtke - UCB

  3. Data Analyzed David Hardtke - UCB

  4. Geometry DOM 12 DOM 23 DOM 32 Stuck String David Hardtke - UCB

  5. Local Ice Dust logger data DOM 32 DOM 23 David Hardtke - UCB

  6. Merging Rates • Most data I will show is from April. Flasher 23 run at high rate: • Nominal rate is 610 Hz • Monolith trigger rate is 611 Hz • Rate of common IceCube/Amanda triggers is 103 Hz • 28480 merged events from runs 2984 and 2985 • Number of IceCube Oms/Event unaffected by AMANDA coincidence requirement David Hardtke - UCB

  7. GPS Synchronization • Measure Trigger Time difference • No correction for physics (trigger def, scattering, etc.). Absolute offset not understood • UPPER LIMIT on GPS synch is 400 ns • Stable over 10 minute period David Hardtke - UCB

  8. Which strings are hit? Flasher 23 • Mean # of AMANDA OMs ≈ 50 • Biased sample • AMANDA online filtering • Will repeat with unbiased AMANDA/String 21 selection Stuck String David Hardtke - UCB

  9. Z-position of hit AMANDA OMs Flasher Location Flasher 23 David Hardtke - UCB

  10. Distance from flasher to AMANDA OM David Hardtke - UCB

  11. Distance from flasher to AMANDA OM ≈ 103 Hz David Hardtke - UCB

  12. Newer Runs • Recent runs use a lower flasher rate • Nominal Rate -- 10 Hz • Mult>9 rate from monolith -- 11.8 Hz • “Flasher Events” (Mult > 17) -- 9.7 Hz • Flasher Events that trigger AMANDA -- 0.01 - 0.04 Hz Something strange here -- the coincident rate has dropped from 1/6 to 1/1000. Could be data OR sieglinde pole filter David Hardtke - UCB

  13. Flasher Event Isolation Flasher Events Flasher 32 muons David Hardtke - UCB

  14. Strings Hit by Flasher 32 David Hardtke - UCB

  15. Z position of hits from flasher 32 Z in IceCube coordinate (m) David Hardtke - UCB Flasher 32

  16. Warning-- DOM Turn On David Hardtke - UCB

  17. DOM flasher LED configuration David Hardtke - UCB

  18. Conclusions • Able to see String 21 flashers in AMANDA • True for Flashers 12, 19, 23, and 32 • Flasher is very bright (visible 400 m away) • AMANDA and IceCube GPS clocks are synchronized to better than 400 ns David Hardtke - UCB

  19. Wish List • To get meaningful results: • Need unfiltered AMANDA data from pole (request submitted to black hole [help@icecube.wisc.edu]) • Need more data (higher repetition rate/longer runs) • IceCube data without local coincidence (compare light propagation in horizontal and vertical directions) • Some software improvements (working with Pretz) David Hardtke - UCB

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