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