Comparison of mm-wave interferometers

Antenna Parameters:	-	-	-	-	-	-	-	-
		ATCA	IRAM	OVRO	NMA	BIMA	ALMA	ALMA prototype
Location	-	Australia	France	US	Japan	US	Chile	VLA site
Altitude	[m]	200	2560	1216	?	1043	5000	?
Operation	-	2002	current	current	current	current	2005?	2002
Number of antennae	n	5(6)	5(6)	6	6	10	64	2
Number of baselines	N	10(15)	10(15)	15	15	45	2016	1
Antenna diameter	D [m]	22	15	10.4	10	6.1	12	12
Mapping speed	N*D^2	2.1(3.2)	1.0(1.5)	0.7	0.7	0.65?	?
Antenna area	A [m^2]	1900(2280)	885(1060)	510	470	292	7236
Single dish equivalent	[m]	50(54)	34(37)	26	25	19	96
Surface accuracy	[mm]		0.060	0.035		0.021
Surface efficiency	n_sf	0.60-0.75	0.92-0.95	0.98	?	0.99?
Pointing accuracy	[arcsec]	?	?	4	5	5	?	?
Longest baseline	[km]	3(6)	0.41	0.24	0.36	2	10
Shortest baseline	[m]	30	24	25?	15	7.2	?
Receiver Parameters:	-	-	-	-	-	-	-	-
Frequency range	[GHz]	85-115 16-26	81-115 210-250	80-116+	80-115+	70-116 210-270	70-900
Dual freq. observing	-	partly	yes	yes	fast switching	yes
Receiver temperature	T_rec [K]	?	30-50 40-60	50-150?	40-70	50-150
System temperature	T_sys [K]	180	?	200-800	150-300	200-600
Polarization	-	2	1	1	1	1
Correlator Parameters:	-	-	-	-	-	-	-	-
Bandwidth	B [MHz]	4 x 128 (2IF,2pol)	310 (6 units)	4 x 128	1000	800 hybrid
Number of channels	-	?	64-256	?	?	2048
Performance @ 90 GHz	-	-	-	-	-	-	-	-
Antenna sensitivity	[Jy/K]	16	25	?	?	? 0
Aperture efficiency	n_a	0.45	0.6	>0.70	0.57	0.7
Efficiency	-	0.88*?		?	?	?
System Temperature	T_sys	230	150?	?	?	250
Sensitivity	mJy	0.55(0.45)	0.3(?)	?	?	?

Australia Telescope National Facility