Flasher Asymmetry and Hole Ice Properties

Doug RutledgePenn State University

Doug Rutledge Berkeley Tuesday July 25 2005 1

Flasher Data

Set ATWD Channel(s).Set FADCRecord Data.

Flash LEDs. Do Not record data.

● 2 Data Sets– Dom 23 (Lemur)

● Earlier in the year● Mini String (~10 DOMs) ● Full ATWD Readout

– Dom 52 (Nitrogen)● More Doms than mini string● Bottom of the String● 32 Samples in each ATWD

Channel● Only the first ATWD Channel

Doug Rutledge Berkeley Tuesday July 25 2005 2

Flasher Asymmetry: Run 428

Dom 22

Dom 21

Dom 20

Dom 19

Dom 24 Dom 25

Dom 26Dom 27 Dom 28

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Waveforms

Dom 24

Dom 22

ATWD Channel0

ATWD Channel 1

ATWD Channel 2

Doug Rutledge Berkeley Tuesday July 25 2005 4

Waveforms II

Dom 25

ATWD Channel 0

ATWD Channel 1

ATWD Channel 2

Dom 21

Doug Rutledge Berkeley Tuesday July 25 2005 5

Flasher Asymmetry II: Run 2993

Dom 54

Dom 55

Dom 45

Dom 46

Dom 56

Dom 51 Dom 50 Dom 49

Dom 48

Dom 47

Dom 53

Saturation

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Waveforms III

No ATWD Channel 1

ATWD Channel 0

No ATWD Channel 2

Dom 49

Dom 55

Doug Rutledge Berkeley Tuesday July 25 2005 7

Waveforms IV

ATWD Channel 0

No ATWD Channel 1

No ATWD Channel 2

Dom 48

Dom 56

Doug Rutledge Berkeley Tuesday July 25 2005 8

Photonics Studies I:Geometry

Michelangelo's Photonics Special features

hole radius: 0.3 m

flasher wavelength: 405 nm

Hole Ice Scattering Length: variable

Doug Rutledge Berkeley Tuesday July 25 2005 9

Photonics w/ Hole

Ice

http://amanda.berkeley.edu/~mdagost/photonics/

Plots courtesy of Michelangelo D'Agostino

Doug Rutledge Berkeley Tuesday July 25 2005 10

6 horizontal flashersScattering in & out of the hole

Photon Flux I:Hole Ice scattering length =

50m

Doug Rutledge Berkeley Tuesday July 25 2005 11

Flux, in arbitrary units

Photon Flux II: Hole Ice scattering length =

1cm

Doug Rutledge Berkeley Tuesday July 25 2005 12

Flux, in arbitrary units

Photon Flux comparison

Doug Rutledge Berkeley Tuesday July 25 2005 13

So why is there no difference?

● RHole

– RDom

≈ 10 cm▬ Few sacttering events in the hole

New Flasher data ● Data w/ just horizontal

flashers● Data w/ just angled

flashers● Full ATWD Readout● Wish List:

– OM in the dust Layer– Full ATWD Readout

● 128 Samples● All three channels

– Flasher data for each DOM– A lot of these conditions are

met with new data

Doug Rutledge Berkeley Tuesday July 25 2005 15

Further Photonics Studies

● New Photonics tables– Only horizontal Leds– Only angled Leds

● Simulate out to other strings

Doug Rutledge Berkeley Tuesday July 25 2005 16

Further Studies

● Detect flashers with AMANDA?– Probably not– Try it with new

strings? (next year)● Waveform studies

– Length of waveform tail

● In Principle, depends on scattering length

Doug Rutledge Berkeley Tuesday July 25 2005 17

Conclusions

● Hole Ice scattering length has little effect– Detector is insensitive to dramatic changes

● Up/Down asymmetry– New flasher data

● Test the effects of angled vs horizontal LEDs● Make Q Vs D plots

– Use channel switching– More participating Doms

Doug Rutledge Berkeley Tuesday July 25 2005 18

Doug Rutledge Berkeley Tuesday July 25 2005 19

This is why it is called a “mini-string”

Hole size studies I:Hole Radius = 1.5m

Doug Rutledge Berkeley Tuesday July 25 2005 20

Hole size studies II:Hole radius = 5.0m

Big Difference!

Doug Rutledge Berkeley Tuesday July 25 2005 21

Ratio of Qabove

to Qbelow

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Doug Rutledge Berkeley Tuesday July 25 2005 23

Dust Layer