Observatorie CA HBT Workshop

StarBase Intensity Interferometry Update

D. Kieda, N. Matthews, N. Traeden,J. Skowronek

University of Utah

SII Workshop May 13, 2014

5/13/2014

Observatorie CA HBT Workshop5/13/2014

Observatorie CA HBT Workshop5/13/2014

Observatorie CA HBT Workshop5/13/2014

5/13/2014 Observatorie CA HBT Workshop

Observatorie CA HBT Workshop

Digitizer System• NI Flex-Rio digitizer Digitizer (250 Mhz sampling) & Virtex5 FPGA Front end (4

channels, 14 bit resolution (Truncate to 8 bit))

• Record to high speed 12 TB RAID system (750 Mbyte/sec)

Able to stream continuously for >6 hours

• Periodic GPS Time Stamp of FADC clock to better < 4 nsec rms

5/13/2014

5/13/2014 Observatorie CA HBT Workshop

Record all Streaming data: GPS timestamp• Post Processing (2, 3, ..N Telescope Coorrelations)• FFT Analysis• Develop/Apply Digital Filters to increase S/N

Observatorie CA HBT Workshop

Filtered PMT Spectrum

5/13/2014

DAQ System

5/13/2014 Observatorie CA HBT Workshop

PMT/APDPreamp/Fiber Optic transmitter

Pxie Bus

Virtex -5 FPGA

250 Mhz A/DConv

CPU

Streaming RAID Controller

12 TB 750 MB/Sec RAID

GPS Clock

I Gbit/sec

100 Mbyte/sec

Pxie Backplane (4 Gbit/sec)

Virtex-5 FPGA has multipleParallell-pipline FFT coresReal time data-Filtering/coorrelation?

5/13/2014 Observatorie CA HBT Workshop

Tele 1

Tele 2

Digital Filter

Digital Filter

y2

x2

x*y

Pipelined Data Analysis

This may be the only way of keeping up with the large dataflow in real time…..

Auto-correlation

Auto-correlation

Cross-correlation

Digitizer/Software Correlationtests with PMTs/Preamps

Simulated Single PMT Measured Single PMT

AutoCorrelation AutoCorrelation5/13/2014 Observatorie CA HBT Workshop

5/13/2014 Observatorie CA HBT Workshop

2 PMT Cross Correlation: Noise Pickup between adjacent PMTs -Radio Crosstalk generated by RF noise from PMTs firing-Encase in RF shielding/Use Fiber optics to sample light

4nsec

5/13/2014 Observatorie CA HBT Workshop

2 PMT Cross Correlation: Residual Correlation -Cosmic ray secondary particles striking both PMTs-Cosmic ray charged particles fluorescing in fiber optic cable

Digitizer/Software Correlation tests with PMTs/Preamps

Simulated 2-PMT Cross-correlation Measured PMT Cross-Correlation background

2G events seeded correlation = 1e-3 correlation noise < 1E-4

We should be able to measure correlation with excellent accuracy!

5/13/2014 Observatorie CA HBT Workshop

SII Lab Measurement/Hole diameters(Laser/Rotating Disk)

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Observatorie CA HBT Workshop5/13/2014

Observatorie CA HBT Workshop5/13/2014

5/13/2014 Observatorie CA HBT Workshop

Telescope Tracking Control System:

LabView Based Servo System

Remnant of “Telescope Array 1999”

5/13/2014 Observatorie CA HBT Workshop

50

70

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6383

2

6402

9

6422

6

6442

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6461

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6501

1

6520

7

6540

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6559

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6599

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6618

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6638

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6677

6

6697

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6717

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Time in Seconds (LST)

Azi

mut

h A

ngle

(deg

rees

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Az Position

Az Target

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6605

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6623

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Time in Seconds (LST)

Elev

atio

n A

ngle

(deg

rees

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El Position

El Target

80.2

80.25

80.3

80.35

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80.45

6395

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6395

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Time in Seconds (LST)

Elev

atio

n An

gle

(deg

rees

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El Position

El Target

Observed tracking Performance: Alpha Lyrae Tracking

Error < 0.01°

Observatorie CA HBT Workshop5/13/2014

Observatorie CA HBT Workshop5/13/2014

Observatorie CA HBT Workshop5/13/2014

5/13/2014 Observatorie CA HBT Workshop

Star Observations (April 2014):

αLeo (Regulus): V = +1.35

ε Leo (Algenubi) V= +2.98

Single Telescope Observations

• Study Telescope tracking• Night Sky Noise• Interference noise

• Needs some further investigation, pipelined filtering?

Two Telescope Observations In Summer 2014

Test SII & Pipelined RT analysis

NSB

VSCEL cutoff

Signal

VSCEL Filter

??

Observatorie CA HBT Workshop

Observation times with the StarBase telescopes

StarBase:

For T= 15 min ( V =1 )

T= 97 min (V = 2)

StarBase Baseline: 23m

Unresolved < 1 mas (400 nm)

Examples: α Leo, β Tau or η Uma

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5/13/2014 Observatorie CA HBT Workshop

5/13/2014 Observatorie CA HBT Workshop

FutureTesting at StarBase Summer 2014: 2-telescope correlations

Testing at VERITAS (late 2014?)

CTA observatoryNeed to write Science Requirements, Level A/B requirementsTechnical Design review period ending (30 days)After TDR design gets frozen: Difficult to add after!

High priority: Need to form working group!

5/13/2014 Observatorie CA HBT Workshop

CTA Design QuestionsPhoto-detectors (SST, MST, LST, SCT)Telescope-to-Telescope digitization synchronization (< 2 nsec)Digitization/Storage requirementsData processing requirements

Real Time Monitoring Higher order correlations