Transcript PPT - Astronomy - University of California, Berkeley

Transient SETI
Dan Werthimer
University of California, Berkeley
http://seti.berkeley.edu/
University of California, Berkeley SETI Program
• Graduate Students
Chen Chang, Pierre Droz, Aaron Parsons, David Purdy
• Undergraduate Students
Daniel Chapman, Henry Chen, Charlie Conroy, Wonsop Sim
• Astronomers, Computer Scientists and Engrs.
David Anderson, Bob Bankay, Jeff Cobb, Court Cannick, Eric Korpela,
Matt Lebofsky, Jeff Mock, Rom Walton, Dan Werthimer
Early Transient Transmitters
NOT FUNDED
NOT FUNDED
Porno in space:
FUNDED!
UC Berkeley SETI Programs
Name
Time Scale
Search Type
SERENDIP
seconds
radio sky survey
SETI@home
mS - seconds
radio sky survey
Astropulse
nS - mS
radio sky survey
SEVENDIP
nS
visible targetted
SPOCK
1000 seconds
visible targetted
DYSON
IR targetted
AstroPulse
• Arecibo Sky survey
– Covers decs 0 to 30, each beam 5 times
– 1420 MHz, 2.5 MHz bandwidth
– 7 years of data recorded so far (70 TB)
• Good time resolution
– Sensitive to 0.4 µs radio pulses at 21 cm
• DM range
– -1000 to +1000 pc/cm3
• Sensitivity
– 10-18 W/m2 peak (Coherent de-dispersion)
AstroPulse
• Only ~1.5 searches for single pulses on µs
timescale before (O’Sullivan, Phinney)
• Pulsar searches: ms time scales, folded
• SETI@home: 0.8 ms single pulses.
• Potential astrophysics as well as SETI
• evaporating primordial black holes?
(Hawking, Rees, Ekers)
– Pulsars, Other astrophysical exotica?
Piggyback ALFA Sky Survey
• Improved sensitivity
– Tsys, integration time
• Uniform sky sampling
– galactic plane concentration
• Multibeam RFI rejection
• Larger Bandwidth
Pulsed vs. CW
Concentrating power into short bursts can be more
efficient than a “constantly on” transmitter.
Pulsed signals can be easier to see above
background noise.
Dispersion
Coherent De-dispersion
-1000 < DM < +1000
Requires lots of Computing!!!
AstroPulse Testing
Sample batch of data
run through shows
expected noise
characteristics, and little
else …
… so (hopefully) little
RFI contamination for
this type of signal.
BOINC
• Berkeley Open Infrastructure
for Network Computing
– General-purpose distributed
computing framework.
– Open source.
– Will make distributed computing
accessible to those who need it.
(Starting from scratch is hard!)
Projects
•
Astronomy
– SETI@home
(Berkeley)
– Astropulse
(Berkeley)
– Einstein@home: gravitational pulsar search (Caltech,…)
– PlanetQuest
(SETI Institute)
– Stardust@home (Berkeley, Univ. Washinton,…)
•
Earth science
– Climateprediction.net
•
(Oxford)
Biology/Medicine
– Folding@home, Predictor@home
(Stanford, Scripts)
– FightAIDSathome: virtual drug discovery
•
Physics
– LHC@home
•
(Cern)
Other
– Web indexing/search
– Internet Resource mapping (UC Berkeley)
SETI@home Statistics
TOTAL
RATE
5,464,550 participants
(in 226 countries)
2,000 per day
2.3 million years
computer time
1,200 years per day
4*1021 floating point
operations
65 Tera-flops
Optical SETI Pulse Search
1961 Charlie Townes Paper
largely ingored until 1999
1971 Cyclops report calculates radio >> optical
Today’s lasers can communicate across galaxy
Optical SETI
• Uses Leuschner
Observatory (UCB)
– Automated 0.8m
telescope
• Targeted Search
– Nearby F,G,K,M stars
– ~10,000 stars
observed so far
– 100 galaxies
OSETI Detector
• 3-Photomultiplier fast
coincidence detector
– Sensitive to 1ns
pulses
• Low background
– False alarm rate: 1
per 300 hours (10-6
Hz)
– Double false alarm
rate: 1 per 600 years!
• Good sensitivity
– 10-8 W/m2 peak
– 10-19 W/m2 average
Transient Instrumentation
Compute Module Diagram
4GB DDR2 DRAM
12.8GB/s (400DDR)
Memory
Controller
FPGA
Fabric
FPGA
Fabric
@
bit
4
6
MGT
5 FPGAs
2VP70FF1704
IB4X/CX4
40Gbps
MGT
MGT
DRAM
DRAM
IB4X/CX4
20Gbps
100BT
Ethernet
DRAM
Memory
Controller
DRAM
DRAM
DRAM
DRAM
DRAM
IB4X/CX4
40Gbps
DR
0D
0
3
FPGA
Fabric
Memory
Controller
DRAM
DRAM
DRAM
DRAM
IB4X/CX4
40Gbps
IB4X/CX4
40Gbps
FPGA
Fabric
MGT
MGT
FPGA
Fabric
138 bits 300MHz DDR 41.4Gb/s
Memory
Controller
Memory
Controller
DRAM
DRAM
DRAM
DRAM
DRAM
DRAM
DRAM
DRAM
19” 48RU Rack Cabin Capacity
• 40 compute nodes in 5 chassis (8U) per rack
• Up to 16 trillion CMac/s performance per rack
• 250 Watt AC/DC power supply to each blade
• 12.5 Kwatt total power consumption
• Hardware cost: ~ $1M
Global Interconnects
Ethernet Switch
• Commercial Infiniband switch
from Mellanox, Voltaire, etc.
– Packet switched, nonblocking
– 24 ~ 144 ports (4X) per
chassis
– Up to 10,000 ports in a
system
– 200~1000 ns switch latency
– 400~1200 ns FPGA to FPGA
latency
– 480Gbps ~ 2.88Tbps full
duplex constant cross section
bandwidth
– <$400 per port
Compute
Node
#1
Compute
Node
#N
Infiniband Crossbar Switch
Unified Digital Processing Architecture
imaging
Infiniband
Swtich
Channel
Reorder
Buffer
XMAC
Beamforming
An #N
Polyphase
Filter
Banks
Channel
Reorder
Buffer
Infiniband Swtich
An #1
Polyphase
Filter
Banks
• Distributed per antenna spectral channel processing
• Multiple reconfigurable backend application processing
• Commercial packet switched interconnect
• Backend data pulling through remote DMA access
Spectrometer
Pulsar
Searching
Moore’s Law in FPGA world
Computational Density Comparison
Processor Peak
1000000
FPGA 32-bit int MAC
100X More efficient
than micro-processors!
100000
10000
FPGA maximum sustained performance
1000
10/28/19 3/11/199 7/24/199 12/6/199 4/19/200 9/1/2002 1/14/200
95
7
8
9
1
4
100000
Release Date
3X improvement
per year!
10000
MOPS (32 bit MAC)
(MOPS/MHz)*lamda^2
10000000
1000
100
10
1
12/1/19 6/19/19 1/5/199 7/24/19 2/9/199 8/28/19 3/15/20 10/1/20 4/19/20 11/5/20 5/24/20
96
97
8
98
9
99
00
00
01
01
02
Release date
Future Spectrometers
2015
4 THz
2020
128 THz
400 beams
10 GHz each
12,800 beams
2025
4000 THz
40,000 beams
2030
128,000 THz 1M beams
Why you might not want to
collaborate with us on
Transient Observations
Seti Haiku
Searching for life
Answers are revealed
About ourselves
Paula Cook, Duke University
One million earthlings
Bounded by optimism
Leave their PC’s on
Dan Seidner
The SETI@home Client
Triplets
• Three evenly spaced
spikes above 7.75X
the mean power.
(5.3X10-25 W/m2)
Pulses
• Modified Fast folding
algorithm w/ dynamic
threshold
• Logarithmically
spaced periods from
3ms to 35s
• Sensitivity as low as
10-26 J/m2