Overview of the Fourth Flight of the ANITA Experiment Jiwoo Nam - - PowerPoint PPT Presentation

▶
overview of the fourth flight of the anita experiment
SMART_READER_LITE
LIVE PREVIEW

Overview of the Fourth Flight of the ANITA Experiment Jiwoo Nam - - PowerPoint PPT Presentation

Dec 11, 2022 359 likes •664 views

Overview of the Fourth Flight of the ANITA Experiment Jiwoo Nam (National Taiwan University) for The ANITA Collaboration The ANITA Collaboration Univ. College London Univ. of Delaware Ohio State Univ. Univ. of Chicago Washington Univ. St.

slide-1
SLIDE 1

Overview of the Fourth Flight of the ANITA Experiment

Jiwoo Nam (National Taiwan University) for The ANITA Collaboration

slide-2
SLIDE 2

The ANITA Collaboration

11 Institutes, ~50 collaborators in a 18 hour time zone

  • Univ. College London

National Taiwan Univ.

  • Univ. of Hawaii

Cal-Poly JPL

  • Univ. of California, LA
  • Univ. of Kansas

Ohio State Univ.

  • Univ. of Chicago

Washington Univ. St. Louis

  • Univ. of Delaware
slide-3
SLIDE 3

The ANITA Experiment

  • UHE Neutrino Detection (Primary Goal)
  • Askaryan signals in Antarctic ice.
  • Excellent sensitivity in 1019- 5x1020 eV.
  • Large volumes of ice
  • Excellent transparency of the Antarctic ice

(RF attenuation length: ~ 1km.)

  • UHE Cosmic Ray Detection
  • EAS with Geo-magnetic radiation
  • Large field of view
  • Partially coherent emission in ANITA’s
  • freq. band.

The ANITA (ANtarctic Impulsive Transient Antenna) is;

  • a NASA long-duration balloon payload with
  • an array of radio antennas (180-1200MHz)
slide-4
SLIDE 4

ANITA’s 3rd signal

Up-coming shower? A nu-tau signature?

A strong H-pol non-inverted signal seen!

  • Expected background events: 4x10-4
  • 27.4 deg below horizon, E = 0.60.40 EeV

Chord length: 5450 km (20000km water equivalent)

1600km SM interaction length @ 1 EeV

Difficult to be explained by SM (need to be factor 3-5 of cross-section)

For details; Andrew Romero-Wolf’s talk NU142, Monday 13:30 117, 071101 (2016)

slide-5
SLIDE 5

Prior ANITA Flights

35 days

ANITA-I (2006-2007) ANITA-II (2008-2009)

22 days

Each flight increased the sensitivity with improved instruments

30 days

ANITA-III (2014-2015)

32 Antennas Both H-pol/V-pol trigger (via LCP/RCP) No neutrino candidate seen Observation of 16 CR events Observation of 1 up-coming event 40 Antennas V-pol trigger only 1 neutrino candidate observed Additional 2 CR events 48 Antennas H-pol/V-pol trigger Data analysis in progress

slide-6
SLIDE 6

ANITA’s signatures

ANITA

1~4km

Antarctic ice sheet



 decay

CR

CR shower Askaryan effect

CR

1) 2) 3) 4) Origin RF production Polarization RF Direction Polarity 1) Neutrinos Askaryan V‐pol Below Horizon Normal 2) CR‐reflected Geo‐synchrotron H‐pol Below Horizon Inverted 3) CR‐direct Geo‐synchrotron H‐pol Above Horizon Normal 4) Tau Neutrino? Geo‐synchrotron H‐pol Below Horizon Normal

slide-7
SLIDE 7

ANITA-4 Instrument

GPS antennas + TDRSS & Iridium antennas Omni-directional solar array (top) Two 8 horn antenna clusters (top) ANITA electronics 16 horn antenna cluster (bottom) 16 horn antenna cluster (middle)

Credit P. Gorham

Omni-directional solar array (bottom)

slide-8
SLIDE 8

Trigger/ Digitizer Data Stream

By O. Banerjee

1) Frontend (see next slide) 2) Tunable notch filter (see next slide) 3) 90o hybrid coupler & trigger

ANITA-3 trigger: H-pol or V-pol  ANITA-4 trigger: LCP & RCP (linearly polarization only)

slide-9
SLIDE 9

ANITA-4 Frontend

ANITA-3: Band-pass Filter (180-1200MHz) ANITA-4: only Low-pass  Reduce transmission loss and noise Customized (utilized) LNAs ANITA-3: only on 32 channels ANITA-4: all 96 channels A big improvement of noise figure (30-40K)  20% improvement of energy threshold

ANITA-4 Frontend NTU LNA

ANITA-3 ANITA-4

Noise Temp. vs Freq

(by B. Fox and L. Batten)

K

freq(MHz)

slide-10
SLIDE 10

Tunable Universal Filter Frontend (TUFF)

Figures by O. Banerjee

-sector masking fraction ANITA-3 ANITA-4

ANITA 3: Unexpected EMI due to newly deployed military satellites CW noise at 260 MHz and 360 MHz masking -sectors to minimize effect  but overall acceptance reduced ANITA-4: use TUFF Each channel has 3 independent tunable-, switchable- notch filters (~50MHz width)

 CW effect under control except near McMurdo  factor ~2.5 improvement for acceptance

ANITA-3

  • freq. (MHz)

power (dBm/MHz)

ANITA-4

  • freq. (MHz)

power (dBm/MHz)

Time (M-D)

Masking fraction by Ben Strutt

slide-11
SLIDE 11

ANITA-4 Flight

Launched on December 2nd 2016 at Williams Field, Antarctica Landed on December 30 2016 near South Pole (232 km away)

 28 days at float

A spiral pattern of trajectory: keep away from McMurdo Station (highest noise source) Two follow-up payloads (HiCal) were also launched

Credit S. Prohira Credit S. Prohira Credit S. Prohira

HiCal launch HiCal

slide-12
SLIDE 12

ANITA-4 Recovery

A partial recovery done on Jan 10th 2016

  • All Data disks were fully recovered
  • Small- and important- items (AMP etc)

Full recovery is planned in November 2017

Credit C. Miki Credit C. Miki

slide-13
SLIDE 13

ANITA-4 Performance

ANITA-4 was in pristine condition for most of the flight. Recorded ~100M events Maintained 94% live on average  27.3 days of live time:1.46 times

 1.46 time than ANITA-3 (18.7 days)

2.5 times for acceptance (TUFF) 1.45 times for live time  ~ 3.6 times improvement in exposure

Live time vs. flight time ANITA-3 ANITA-4

All figures by O. Banerjee

slide-14
SLIDE 14

Validation and Calibration

Two ground pulsers in McMurdo and WAIS were used for

  • System Validation
  • Trigger characterization
  • Amplitude / Timing calibration
  • Test Angular reconstruction

Angular reconstruction

  • btained by interferometry

technique shows an excellent pointing capability; =0.5 deg, =0.15 deg

(Andrew Ludwig)

slide-15
SLIDE 15

Example events (very preliminary)

Many candidate events were found in telemetry data during

  • peration/monitoring shifts

 Detailed characterizations will be done

in following data analysis

Here, two examples found when ANITA was in deep field Top: H-pol dominant Bottom: V-pol dominant

H-pol V-pol

slide-16
SLIDE 16

Improvements in Data Analysis

Energy estimation of CR events: spectral slope analysis

1.

Advanced digital filtering, such as CW noise subtraction

2.

Template search method based on improved understanding

  • f signals and the system response

3.

Binned approach to optimize cuts depending on RF noise environment Steady improvement in MC simulation

slide-17
SLIDE 17

Summary & Plan

ANITA successfully completed the fourth flight with improved performance;

  • 20% lower energy threshold

  • Factor 3.6 increased exposure

Data analysis of ANITA-3 and ANITA-4 in progress

  • well positioned for neutrino discovery!

  • hundreds of CR events expected!

  • search for partners to the up-coming event!
slide-18
SLIDE 18

Backup Slides

slide-19
SLIDE 19

The ANITA Collaboration

11 Institutes, ~50 collaborators in a 18 hour time zone

  • Univ. College London

National Taiwan Univ.

  • Univ. of Hawaii

Cal-Ploy JPL

  • Univ. of California, LA
  • Univ. of Kansas

Ohio State Univ.

  • Univ. of Chicago

Washington Univ. St. Louis

  • Univ. of Delaware
slide-20
SLIDE 20

GZK Neutrino: Guaranteed UHE Neutrinos

p + cmb→ +→ n++ n → lower energy protons

 → GZK neutrino)

GZK Cutoff Process Presence of UHE Cosmic Rays requires UHE neutrinos Lack of neutrinos:

 UHECRs not hadrons?  Lorentz invariance wrong?  New physics?

CR spectrum

Universe of EHE remainspuzzled, until GZK neutrinos are confirmed

Looks like there is the GZK Cut-off

slide-21
SLIDE 21

New Concept for Neutrino Detection

Askaryan Effect (1962)

Gurgen Askaryan (1928-1997)

It has been confirmed experimentally for various media (sand, rock salt and ice.)

Shower RF field strength profile (SLAC, 2002) 20 m

Blue: ~0.01GHz  yellow: 2GHz

neutrino

RF Cherenkov Shower ~10m length (20% e- excess)

Particle induces shower → Contained ~20% negative charge excess → Produces Cherenkov radiation Coherent, MHz – GHz frequency range, Linearly polarized and detectable at distances

slide-22
SLIDE 22

Ice Attenuation Measurements

RF attenuation length ~1km

  • 2004 South Pole,
  • 2006 Taylor Dome
  • 2010 South Pole

(2004 South Pole, S. Barwick et al.)

Tx Rx

Bedrock

~940 meters @Taylor Dome Pulser Input ~70 m

slide-23
SLIDE 23

SLAC Beam Test (2006 June)

Absolute gain calibration with real Askaryan pulse Mini-Antarctica with 10 tons of ice target 28.5 GeV electron beam (109 electrons) First measurement of Askaryan effect in Ice

PRL 99, 171101 (2007) 10 ns Askaryan pulse

slide-24
SLIDE 24

ANITA UHECR Events

Unfolded waveforms Geomagnetic field correlation

16 UHECR Events : 14 reflected + 2 direct from ANITA-I 2 events from ANITA-II  H-pol trigger was off (optimized for neutrino)

PRL 105, 151101 (2010)

slide-25
SLIDE 25

Laboratory Confirmation of The geo-synchrotron radio pulse

T-510 experiment @ SLAC, Jan 2014

Experimental setup Expected emission field map 1000 G magnetic coils PRL 116 (2016)

slide-26
SLIDE 26

Energy and Flux of CRs

Observed point (c) : largest systematics

However, spectral analysis can measure c

  • 42-50% error in energy measurement

APP 77 (2017)

slide-27
SLIDE 27

Neutrino signals vs. EAS signals

RF Cherenkov

neutrino

Shower ~10m length (20% e- excess)

ANITA ANITA Geomagnetic Field

Synchrotron Emission (H-pol.)

Neutrino Detection

RF Cherenkov by Askaryan Effect Low Fresnel coeff. for transverse electric waves at the air-ice boundary.

  • H-pol signal suppressed
  • Predominately V-pol

EAS Detection

H-pol predominate RF signal by geosynchrotron emission V-pol component is further suppressed in the reflection

  • Predominately H-pol

V-pol predominated after refraction

slide-28
SLIDE 28

Trigger/ Digitizer Data Stream

By O. Banerjee

slide-29
SLIDE 29

Trigger/ Digitizer Data Stream