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

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

Theoretical Limits on 21 cm Monopole possible signal (qualitative)

Reionization Bubble Model H 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

Expected Signal (WMAP3 Parameters) ~1 mK/MHz multiply all numbers by 0.752 for He correction ~6 mK/MHz

Correlation Receiver r

Correlation Receiver Integrating Down

Frequency Independent Antenna ~1% error at half power

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

Bandpass Calibration Residuals

Bandpass Calibrated Spectra ~10 K Residuals

Bandpass Calibration Residuals Reference Symmetric About Galactic Centre

Measurement Resembles Simulation of Squinted Beam Rotating About Boresight

Normalized Drift-scans at all Frequencies Measurement vs. Model

Band Average Drift-scan Measurement vs. Model

System Stability ~ 1% or better

Future Future work: rotating antenna split in free space

The End End of main presentation Design details follow for discussion

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

Wiener Model used for RF Amplifier

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

RFI power equivalent to strongest narrowband interferer at MRO

Aliased Bandpass

Quantization Distortion Simulation Design

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

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

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

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

Receivers and Correlator

Correlation Receiver