discoveries big & small: anita and super-belleidlab/presentations/deptcolloq.pdf · noise with...

Discoveries Big & Small:ANITA and Super-Belle

Gary S. VarnerPhysics & Astronomy

Departmental ColloquiumOctober 14th, 2004

New Technology – Unexpected Results1912: Hess 5km balloon (Wulf {ionizing} chamber)

Expectation: “dimunition of ionization as a function of altitude”

– discovers “penetrating radiation”

* A debate raged over the nature of this radiation. Millikan argued they were γ from space, “cosmic rays”

1930’s: Cloud chamber observations:• Mounting evidence of energetic particle origin• Anderson – discovery of the “anti-electron” • Neddermeyer/Anderson – discovery of the muon

1938: Auger Geiger counter coincidence• Observation of “extensive air showers”• Correctly conjectured > 1015 eV events

(>10 million times previously observed) • 1949 Fermi – proposes shock acceleration

In the 1950s, a debate sprung up between partisans subscribing to Steady State versus (violently) Expanding Universe

In the absence of evidence, speculation rules

Cosmology Comes of Age

"The discovery of the cosmic microwave background by Penzias and Wilson transformed cosmology from being the realm of a handful of astronomers to a 'respectable' branch of physics almost overnight." – Michael Turner

"Thus, they looked for dung but found gold…” – Ivan Kaminow

Early 1960s: Penzias and Wilson, studying radio emissions from the Milky Way using ultra-sensitive microwave receiving systemfound an unexpected background of radio noise with no obvious explanation.

They spent hours searching for and removing the pigeon dung. Still the noise remained, and was later identified with the Big Bang -- 3K microwave background

The Universe began with a “Big Bang” about 15 billion years ago

?

heaelemstars agalaeneutrons quark "soup"

15 billion yea1 million year

1 second10-101015deg1010deg109deg6000o 255o

3 minuteshelium nuclei formedmicrowavbackgroradiatfills u

300,000 years

4000o

lifemofodominatesmatter and protons formed

1 billion years

s

Big BangBig Bang

Evolution of the Universe

Profound Implications

• The Universe is awash in 3K microwave background

• Why are we here ??

Impacts Directly on what we can observe

From E=mc2, how to get a stable Universe?

What about these background γ ?

Milky Way dia.

Andromeda

Virgo Cluster

“Far out”

Expectations:

1. Greisen, Zatsepin, Kuzmin (GZK)calculated a cutoff:

p * γ ∆ p + π ν

2. These interactionsproduce a corresponding neutrino flux

3. Provides a handle on what is going on for these “extra-GZK”events

GZK ν

Why so Hard?? The Flux Problem

• At E>10^20…

∫∫∫θφ

θφ,,r

ddrd

1 per m2 per second

“knee”1 per m2 per year

“ankle”1 per km2 per year

How to Observe?

1960’s: Askaryan predicted that the resultant compact cascade shower:

• would develop a local, relativistic net negative charge excess • would be coherent (Prf ~ E2) for radio frequencies• for high energy interactions, well above thermal noise• detectable at a distance (via antennas)• polarized – can tell where on the Cherenkov cone

neutrinoCascade: ~10m length

air

solid

RFCherenkov

ANITA concept

Antarctic Ice at f<1GHz, T<-20C :

• ~Lossless RF transmission

• Minimal scattering

• largest homogenous, RF-transmissive solid mass in the world

• RF quiet!Target ~ 1M km3

Antarctic Impulsive Transient Antenna (ANITA)

Requirements for Observing Askaryan

• Very snappy (antenna band limited)• >GSa/s, GHz bandwidth sampling

• While RF pulses are strong, most of the detection volume 100’s of km away

• Trigger << 3σ thermal noise

~320ps

Measured,(-ve polarity)

Signal/Background – Time Domain

Time [ns]

Vertical

Horizontal

Signal

Thermal Noise

Time [ns]

Vertical

Horizontal

Impulsive Background

Vertical

Horizontal

Time [ns]

Frequency Domain Analysis

Frequency [GHz]

Am

plitu

de [d

B]

Time

Signal

Am

plitu

de [d

B]

Frequency [GHz]

Antropogenic

Sin(ωt) ω

F

Frequency

Radio Noise

TimeFrequency [GHz]

Am

plitu

de [d

B]

Vertical Horizontal

Major Hurdles

• No commercial waveform recorder solution

• 3σ thermal noise fluctuations occur at MHz rates (need ~2.3σ)

• Without being able to record or trigger efficiently, there is no experiment

Strategy: Divide and Conquer

• Split signal: 1 path to trigger, 1 for digitizer• Use multiple frequency bands for trigger• Digitizer runs ONLY when triggered to save power

Switched Capacitor Array Sampling

Input

Channel 1

Channel 2Few 100ps delay

• Write pointer is ~4-6 switches closed @ once

20fF

Tiny charge: 1mV ~ 100e-

Large Analog Bandwidth Recorder and Digitizer with Ordered Readout (LABRADOR)

“Wilkinson” ADC

-

• No missing codes

• Linearity as good as can make ramp

• Can bracket range of interest

Relatively slow:100µs/conversion

128 in parallel

LABRADOR size = 2.5mm2

8x HS Analog out, 1x MUX out

8 chan. * 256 samples

128x Wilkinson ADCs

Analog“Superbuffers”

8xDifferentialRF inputs

7mm3.2mm

MOSIS ID

ii

Sampling Unit for RF (SURF) board

LABRADOR Test Results

>3GSa/s sampling

>Nyquist limit for 1.2GHz

LABRADOR Sampling Freq.

0

0.5

1

1.5

2

2.5

3

3.5

1 1.5 2 2.5 3

Freq. Adj. Voltage (ROVDD) [V]

Sam

plin

g Fr

eq. [

GSa

/s]

Avg.

Excellent ADC linearity

LABRADOR Test Results

>1.2 GHz analog bandwidth

High-speed oscilloscope (repetetive sampling)

LABRADOR

<100ps risetime ping

Status: Full Steam Ahead

With these excellent results:

• On schedule for Austral Summer 2006 Launch• NASA Small Explorer Upgrade – 1st ever balloon mission

Build it, and they will come…

• Already running in the UH 20t Salt detector • Baseline for the future Salt-dome Shower Array and Radio Ice (RICE2 South Pole) experiments• Prototyping for Super Kamiokande, Belle Particle Identification readout upgrades

96 channelsRF sampling

Evolution with matter-antimatter symmetry

Eventually such a universe contains only photons(almost true for our Universe - cosmic microwave background)

The Sakharov conditions

Antimatter can turn into matter if:

(a) proton decay occurs(b) there is a matter-antimatter

asymmetry (CP violation)(c) there is thermal non-

equilibrium

Sakharov (1964)

Parity violation

Macroscopic systems obey the same physical laws in a mirror system, e.g. planetary motion “parity conservation”.

β-decay (weak interaction) does not conserve parity.

Discovered in 1956 in polarized 60Co decay.

θ θ

θθ cos1)(cvI −=

P violation - CP conservation

Parity violation leads to an asymmetry for neutrinos -only left-handed ones exist.

νL

νL

νR

νR

CPC

P

Changing particle to antiparticle (C) then applying the parity operation (P) produces the right-handed antineutrino, which exists

“CP conservation”

CP violation in K0 decays

d

s-

s

d-

K0 K0-W W

u,c,t

u,c,t- - -

Phases of the amplitudes for the two processes are not equal‘CP violation’ (1964)

Occurs only because there are three families of quarks

s-

d

d-

s

K0K0-

u,c,t

u,c,t- - -

W W

However, the effect is tiny (~10-3)

CP violation in B0 decays

Similar effect were expected in B0 – but large

d

b-

b

d-

B0 B0-W W

u,c,t

u,c,t- - -

d

d-

b

B0B0-

u,c,t

u,c,t- - -b-

W W

B0 B0-Large effect, however time dependent

Required the development of Silicon Micro-strip Detectors

Measuring Time-Dependent CP-Violation: Proper-time difference (∆t)

e− e+e−: 8.0 GeVe+: 3.5 GeV

BCP

∆z

Btag

ϒ(4S)βγ ~ 0.425

fCPfCP

∆z ≅ cβγτB ~ 200 µm

Flavor tagFlavor tag tzc βγ

∆∆＝

resolution

300µ

m

Double sided silicon detector (DSSD)

Double metal layerDouble metal layer

n+ siden+ side

p+ sidep+ side

5 KΩcm n-type

readout (Al)

n+ implantationn+ implantation

PP--stopstop

p+ implantationp+ implantation

Belle Silicon Vertex Detector

Flex circuit

DSSDs

support ribs

hybrids

bridges

hybrid circuit mounting 4 VA1TA chips :512 strips are readout

In the belly of the Beast

110,592 channels

z

r-φ view

Stunning Success of the Standard Model

sin2φ1= 0.73±0.06

Went from Discover to Precision Measurement

Within 2 years!!!

• After a rough start (we killed our first vertex detector in 1 week of running – I played a key role in solving the problem), excellent performance has been the rule

B0 φ Ks “anomaly”

©スタジオR

KEK (“Super”) B factory upgrade strategy

Present KEKBL=1.3x1034

2002 03 04 05 080706 09 10 11

L=2x1035

L~1036

∫Ldt =350fb-1ILER=1.5A

ILER=9.4A

ILER=20AConstraint:8GeV x 3.5GeVwall plug pwr.<100MW

L=2x1034ILER=1.5A

Crab crossing

One year shutdown to:install ante chamberincrease RFmodify IR

Increase RF

L=5× 1035

~10Hz B pairs, 100Hz “physics”

~500Hz B pairs, kHz “physics”

Trouble Ahead

World’s Highest L=1034

~10% ~4%

~2% ~2%

Crab Cavity Installation:Increase 2x Luminosity

Occupancy vs . DSSD r adi us

1

10

100

1000

0 2 4 6 8r adi us ( cm)

occupancy (%)

pr es ent

Must develop a detector with better hit handling capability

>1035 Luminosity Occupancy Problem

>100% occupancy!

Monolithic Active Pixel Sensors30

0µm

• Readout electronics integrated• No long traces thin detector

• Can segment in fine detail (<10µm pixels)• 3D space points• Low voltage operation

VDD VDD

GND

M1

M2

M3

Reset

ColumnSelect

Row BusOutput

CollectionElectrode

Cont. Acq. Pixels (CAP) 1 Prototype

TSMC 0.35µm Process

Column Ctrl Logic

1.8mm 132col*48row ~6 Kpixels

CAP1: simple 3-transistor cell

Pixel size:

22.5 µm x 22.5 µm

CAPs sample tested: all detectors (>15) function.

Source follower buffering of collected charge

Restores potential to collection electrode

Reset

Vdd Vdd

Collection Electrode

Gnd

M1

M2

M3Row Bus Output

Column Select

Correlated Double Sampling (CDS)

( - )

Frame 1 - Frame 2 = 8ms integration

- Leakage currentCorrection

~fA leakage current (typ)~18fA for hottest pixel shown

Hit candidate!

Test Configuration

All LVDS digital I/O

300-600Mbaud link

On board ADC

Pixel chip: 132x48=6336 channels

~1mm x 3mm

The 4 F2 boards

Beam test bench

Beam line

19APR04, Evt22.

X-Y stages

Test Beam/KEK π2-area

B2 / ACQ monitoringempty tables (1st day)

CAP targets ! / “do not touch” sign

4 F2s / Pixel Sensor/ 1st very rough alignment

Mechanical alignment

y

x

Initial Det. /Det. correlations

Det.3 vs. Det.1 Det.3 vs. Det.2 Det.3 vs. Det.4

In X

~1mm x 3mm “rice grain”

L1

L2

L3

L4

beam

Improved correlations

Hits! alignment proof

Hit resolution measurement

L3L4

L2

“hit”x-plane

Residuals for 4GeV pions:- 11µm in x plane- 14µm in y plane

(in mm)

(in

mm

)

250µm Si1mm plastic

1mm Alumina substrate

3.4 cm3.6 cm4.6 cm

Critical R&D Items

1. Radiation Hardness20MRad demonstrated OK

2. Readout SpeedCAP2: pipelining test in CAP2

3. Full-Sized Detector CAP3: first detector array

4. Thinning Detector

Increased readout speed: CAP2

Col8

VAS

VddPixel Reset

Sense

Output Bus

REFbias

Col2

Col1Sample1

Sample8

Sample2

CAP2: 8x mini-pipeline in each cell

TSMC 0.35µm

22.5 µm x 22.5 µm

(one of 6336)3-transistor cell

132x48=6336 channels(50688 samples)

An approved FNAL Experiment: T943

• Meson Test Beam FacilityScheduled Dec. 13-20*• 120 GeV/c protons

• Multiple-scattering will not be an issue

• Goals• Intrinsic resolution studies• Operation of irradiated

detectors• CAP2 (pipelined) operation

Pixel Detector Concept

e- e+

# of Detector / layer ~ 32

End view

128 x 928 pixels, 22.5µm2

~120 Kpixels / CAP3

0.25 µm process

CAP3

5-layer flexPIXRO1 chip

Pixel Readout Board (PROBE)

Side view

Half ladder scheme

Double layer, offset structure

r~8mm

Length: 2x21mm ~ 4cm

17o30o

r~8mm

A firehose!

• This detector, about the size of a highlighter pen– ~7.7M channels

– 10kHz Trigger rate for Super-Belle

~75 Giga-bytes/second (~20 data DVD/second)

• CAP3, PIXRO1 in design– Submission very soon

• KEK PS experiment T569 just approved

Status: Full Steam Ahead

With these excellent results:

• Upgrade possible before “Super-Belle”• Improved vertex reconstruction will improve the physics reach

Build it, and they will come…

• Interest for Linear Collider Detector vertex

Big and Small

Summary (not a Conclusion)

Very exciting times ahead:

• While their existence and means of observation was predicted decades ago, to date NO GZK neutrinos have been observed

New techniques developed for ANITA will answer definitivelyopens exciting new possibilities: e.g. µ-black holes

• While a deluge of new precision measurements are now pouring in, to date NO violations of the Standard Model have been observed

New techniques developed for Super-Belle will push the envelopeopens exciting new possibilities: e.g. SUSY, mSUGRA

In both cases, the unexpected is by far the most interesting

I don’t know the answer, but I know where to lookand how to get the tools built that will get answers Just catching the wave -- Stay tuned!

Back-up slides

Evolution of a Discipline

Askaryan Pulse Measurements

• Measured pulse field strengths follow shower profile very closely• Charge excess also closely correlated to shower profile (EGS simulation)• Polarization completely consistent with Cherenkov—can track particle source

Sub-ns pulse,Ep-p~ 200 V/m!

simulated showercurve

2GHz data

Reflection from side wall

100%polarized

In properplane

Existing Neutrino Limits and Potential Future Sensitivity

• RICE, AGASA, Fly’s Eye limits for νe only

• GLUE limits νµ & νe

– ~80 hours livetime– Goal: 300 hrs over next 3 years

• SALSA & ANITA sensitivity:– Based on 2 independent Monte

Carlo simulations

Models:• Topological Defects: Sigl; Protheroe et al.; Yoshida et al.• AGN: Protheroe et al.; Mannheim• GZK neutrinos: Engel et al. ‘01

Natural Salt Domes: Potential PeV-EeV Neutrino Detectors

• Natural salt can be extremely low RF loss: ~ as radio clear as Antarctic ice• ~2.4 times as dense

• typical salt dome: 50-100 km3 water equivalent in top ~3km

3-8 km

5-10km

Qeshm Island, Hormuzstrait, Iran, 7km diameter salt dome

Isacksen salt dome, Elf Ringnes Island, Canada 8 by 5km

Caprock visible from space

Salt domes: found throughout the world…

Roadmap to a large-scale salt detector

1. Verify Askaryan process: silica sand, SLAC T444, 20002. Identify radio-transparent natural salt structures 2001

• GPR tests from 1970’s give strong indications• Hockley salt dome tests (Gorham et al. 2002) confirm La>250m

3. Extend accelerator results to rock salt 2002– SLAC T460: salt behaves as predicted!

4. Cosmic-ray testbed for antenna development/signal characterization 2002• In progress since early August 2002 – DAQ upgraded May 2004

5. Deploy an on site test string in a salt bore hole [Texas] Dec. 2004• Small antenna array—study backgrounds

6. Site studies and selection 2005-20067. Detector construction & deployment 2007-2010

Daily int. lum.

600pb-1/day

Integrated luminosity

158 fb-1

sin2φ1=0.731±0.057±0.028Xse+e− Xsµ+µ−

Xsl+l− Xse+µ−+c.c.

Mbc distr. after ∆E cut

BelleJuly 2002

Startling Success of the B-FactoriesHigh Luminosity Time dep. CP meas. Inclusive b sll meas.

We probably know how toaccumulate >109 B decays.

Time dependent CP can be measured with verysmall systematic error.

FCNC decays can bemeasured inclusively.

Search for new sources of flavor mixing and CP violation.

CPV in penguin decays

Belle (August 2003)

ACP(φKS)=−0.96±0.50

ACP(η’KS)=+0.43±0.27

ACP(J/ψKS)=+0.731±0.057

Expected errors in ACP’s

ACP(φKS, η’KS) = ACP(J/ψKS)

In SM,

New phase in penguin loop may change this relation.

KEKBPEPII

Next B factory

10-2

10-1

1

102

103

104

S(φKs)S(η ,Ks)

sin2φ1sin2φ1

total error

sys. errorstat. error

SππAππ

78fb-1 (Jul. 2002)

Target in Jul. 2005

Jul. 2007 - 20xx(Super KEKB)

Integrated luminosity (fb-1)

Err

or

on

CP

Asy

mm

etry

The e+e− B factories are competitive!!

Difference in the pattern of deviation from SM

+++++++++U(2) Flavor symmetry

++++++--SU(5)SUSY GUT + νR(non-degenerate)

-+-+ +-SU(5)SUSY GUT + νR(degenerate)

+-----mSUGRA

b->sγdirect CP

B->Msγindirect CP

B->φKs∆ m(Bs)εBd- unitarity

Unitarity triangle Rare decay

- : small deviation+: sizable++: largeOkada department store

Consequence of the achievement

Searches for new physics can be done at e+e− B factory.

ObservablesTime dep. CP asymm.Decay rate asymm.Branching fractionsγ polarization in b sγAFB in b sllτ polarization in B DτνCKM matrix elements. . . .

Large and clean BBsample >> 109 +

New physics effects will appear as a quantum effect.

These are measurable quantities in e+e− B factory.

An e+e− collider with L>>1035 is feasible.

Resolution: GEANT Expectation

3µm input resolution

250um Si1mm plastic

1mm Alumina substrate

3.4 cm3.6 cm4.6 cm

Irradiation: leakage currents

IEEE Trans. Nucl. Sc. 48, 1796-1806,2001

Leakage Current [fA]

# of

pix

els

Before irrad.

200 Krad