# Presentation: 661720

## String 21 Flashers in Amanda

- Dom 23 flasher run from April 9th

- David Hardtke - UCB

- July 26, 2005

## 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

- July 26, 2005

## Data Analyzed

| Run | DOM flashing | Rate (Hz) | Mean # IceCube DOMs hit |
| --- | --- | --- | --- |
| 2984/2985 | 23 | 610 | 19.63 |
| 11635 | 12 | 10 | 17.66 |
| 11922 | 19 | 10 | 19.35 |
| 11758 | 32 | 10 | 19.14 |
|  |  |  |  |

- David Hardtke - UCB

- July 26, 2005

## Geometry

- Stuck String

- David Hardtke - UCB

- July 26, 2005

## Local Ice

- Dust logger data

- DOM 23

- DOM 32

- David Hardtke - UCB

- July 26, 2005

## 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

- July 26, 2005

## 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

- July 26, 2005

## Which strings are hit?

- Mean # of AMANDA OMs ≈ 50
- Biased sample
- AMANDA online filtering
- Will repeat with unbiased AMANDA/String 21 selection

- Stuck String

- Flasher 23

- David Hardtke - UCB

- July 26, 2005

## Z-position of hit AMANDA OMs

- Flasher Location

- Flasher 23

- David Hardtke - UCB

- July 26, 2005

## Distance from flasher to AMANDA OM

- David Hardtke - UCB

- July 26, 2005

## Distance from flasher to AMANDA OM

- ≈ 103 Hz

- David Hardtke - UCB

- July 26, 2005

## 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

- July 26, 2005

## Flasher Event Isolation

- Flasher 32

- Flasher Events

- muons

- David Hardtke - UCB

- July 26, 2005

## Strings Hit by Flasher 32

- David Hardtke - UCB

- July 26, 2005

## Z position of hits from flasher 32

- Z in IceCube coordinate (m)

- Flasher 32

- David Hardtke - UCB

- July 26, 2005

## Warning-- DOM Turn On

- David Hardtke - UCB

- July 26, 2005

## DOM flasher LED configuration

- David Hardtke - UCB

- July 26, 2005

## 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

- July 26, 2005

## 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

- July 26, 2005