1. Aaron Chippendale, Ravi Subrahmanyan, Ron Ekers 20 January 2009
The Cosmological Reionization Experiment CoRE
Aaron Chippendale, Ravi Subrahmanyan, Ron Ekers
20 January 2009
RRI

2. Overview Science Instrument Results Expected signal 30 mK / 5 MHz
Design implication
1 mK / 1 MHz target
Instrument
Frequency independent antenna
Correlation spectrometer
Results
System stability ~ 1% (bandpass and constant)
~ 10 K / 2.5 MHz residuals in bandpass calibration
Constant not yet calibrated

3. Theoretical Limits on 21 cm Monopole
possible signal (qualitative)

4. Reionization Bubble ModelH
Lya
Ts = TCBR H
Ts = Tm H H H H H H H
Lya H e- H+ H+ H H H H
Lya e- H H H+ e- H H H H H
Tm >> TCBR
Lya
Tm < TCBR H H H
Sethi, 2005

5. Expected Signal (WMAP3 Parameters)
~1 mK/MHz
multiply all numbers by for He correction
~6 mK/MHz

6. Correlation Receiver r

7. Correlation Receiver Integrating Down

8. Frequency Independent Antenna
~1% error at half power

9. Frequency Independent vs. Log Periodic
Frequency Independent defined by angles
Log Periodic defined by geometric ratio

10. Bandpass Calibration Residuals

11. Bandpass Calibrated Spectra ~10 K Residuals

12. Bandpass Calibration Residuals Reference Symmetric About Galactic Centre

13. Measurement Resembles Simulation of Squinted Beam Rotating About Boresight

14. Normalized Drift-scans at all Frequencies Measurement vs. Model

15. Band Average Drift-scan Measurement vs. Model

16. System Stability ~ 1% or better

17. Future
Future work:
rotating antenna
split in free space

18. The End
End of main presentation
Design details follow for discussion

19. RFI Comparison
Culgoora, Narrabri (pop. 6000)
Murchison (pop. 110)

20. Wiener Model used for RF Amplifier

21. Nonlinear Response to Galaxy and RFI
RFI power equivalent to strongest narrowband interferer at Narrabri

22. RFI power equivalent to strongest narrowband interferer at MRO

23. Aliased Bandpass

24. Quantization Distortion Simulation Design

25. Quantization Distortion Simulation Results
a=25 dB*
90th percentile at MRO
50th percentile at Narrabri

26. Ideal ADC Signal to Distortion and Quantization Noise Ratio
Gaussian noise truncated at ks

27. Ideal ADC Saturation Distortion as Fraction of Total Power with Single Narrowband Interferer
Gaussian noise truncated at ks
(10 dB)

28. RFI Comparison
Culgoora, Narrabri (pop. 6000)
Murchison (pop. 110)

29. Receivers and Correlator

31. Correlation Receiver