APEX instrumentation

Facility instruments

Instrument	Type	Mode	Frequency [GHz]	HPBW [arcsec]	IF range [GHz]	# of beams	Location	Status	Comment
APEX-1 (SHFI)	Heterodyne SIS	SSB	211 - 275	30 - 25	4 - 8	1	Nasmyth-A
APEX-2 (SHFI)	Heterodyne SIS	SSB	275 - 370	23 - 17	4 - 8	1	Nasmyth-A
APEX-2A	Heterodyne SIS	DSB	279 - 381	18	4 - 8	1	Nasmyth-A		Decommissioned in Feb 2008 and replaced by APEX-2
APEX-3 (SHFI)	Heterodyne SIS	SSB?	385 - 500	17 - 13	4 - 8	1	Nasmyth-A		awaits mixer delivery
APEX-T2 (SHFI)	Heterodyne HEB	DSB	1250 - 1390	5	2 - 4	1	Nasmyth-A		Science Verification pending
LABOCA	Bolometer array		345	19		295	Cassegrain
SABOCA	Bolometer array		850	8		39	Cassegrain

• SHFI receivers

  This is a set of SIS heterodyne receivers covering the bands at 211-275 GHz, 275-370 GHz, and 385-500 GHz, and a heterodyne HEB receiver operating at 1.25-1.39 THz. All receivers are mounted in a single dewar in the Nasmyth A cabin. Band 2 has replaced the APEX-2A receiver.
  For more information consult APEX Facility Heterodyne Receivers.

• LABOCA

  The Large Apex BOlometer CAmera is a 295-pixel, 345 GHz (870 µm) bolometer array build by the bolometer development group at MPIfR Bonn. The field of view is 11x11 arcmin². It was successfully commissioned in May 2007. More information:LABOCA A&A paper

• SABOCA

  The Submillimetre APEX Bolometer Camera (SABOCA), a 39-channel bolometer array operating at 850 GHz (350 µm), has been commissioned in March 2009.
  More information here

• APEX-2A

  APEX-2A is a heterodyne receiver remotely tunable in the range 279-381GHz. It is a double-sideband (DSB) receiver with typical receiver temperatures of T_rec=60-80 K. Under good weather conditions, this leads to DSB system temperatures of ~150 K over most of the tuning range, but up to 250 K towards 370 GHz.
  APEX-2A was decommissioned in February 2008.

PI instruments

Apart from the facility receivers, PI instruments will be installed at APEX during longer or shorter time periods. Some of them can be used by the community in collaboration with people from the corresponding PI group. In case of the MPIfR instruments, contact Rolf Güsten (rguesten(at)mpifr-bonn.mpg.de) before submitting any proposals.

Instrument	Type	Usage	Frequency [GHz]	HPBW [arcsec]	# of beams	Location	Status	Comment
FLASH	Heterodyne SIS	PI (MPIfR)	430 - 492	14	1	Nasmyth-A
			780 - 887	7	1
CHAMP+	Heterodyne SIS	PI (MPIfR)	602 - 720	9-7	7	Nasmyth-B
			790 - 950	7-6	7
ASZCA	Bolometer array	PI (MPIfR)	150	42	330	Cassegrain
ARTEMIS	Bolometer array	PI (ESO)	670, 1500	9, 4	256	Nasmyth-A		Available March 2011
PolKa	Polarimeter	PI (MPIfR)	345	19	295	Cassegrain		Commissioning pending

• FLASH

  FLASH is a dual channel DSB receiver, with one channel covering the 460 - 495 GHz range, and the other one the 790 - 840 GHz range with typical T_rec (DSB) = 200 K and 400 K, respectively. For time estimates, proposers should assume system temperatures of 650 K and 2000 K, respectively, for 1 mm precipitable water vapour and 80 degrees elevation.
  More information: FLASH Fact Sheet (pdf)

• PolKa

  PolKa - A new concept of polarimeter, named PolKa after the German "Polarimeter fur Bolometer-Kameras", was developed by the Bolometer Group at the MPIfR in Bonn and installed on APEX in October 2009. PolKa works in combination with LABOCA to produce high-resolution maps of linear (and possibly also circular) polarization. The new polarimeter has the unique cjaracteristic of being tunable and of producing a negligible absorption.

• CHAMP⁺

  CHAMP⁺ is dual channel heterodyne receiver array of 7 pixels operating in the 602-720 GHz and 790-950 GHz atmospheric windows.

• ASZCA

  ASZCA is a close-packed bolometer array operating at 2 mm. The field of view is 0.4x0.4 degrees.

• ARTEMIS

  ARTEMIS is a bolometer array working at 200, 350, and 450 μm. It is developed by CEA Saclay (France), and its final version is expected at APEX at March 2011.

Backends

• FFTS

  The facility Fast Fourier Transform Spectrometer consists of two units with a bandwidth of 1 GHz each. Both units are configurable to provide up to 8192 spectral channels, thus providing a spectral resolution of up to 122 kHz. The two units can be connected to one receiver each, or the two units can be configured to produce a single backend with almost 2 GHz bandwidth. The placement of each unit is restricted by the IF range of the receiver. FFTS Fact Sheet (pdf)

• ABBA

  ABBA - The ADC Backend for Bolometer Arrays uses commercial DAQ boards to digitize the 320 analog signals from the electronics of LABOCA over 16-bits. The AC bias frequency is provided by the data acquisition system as a submultiple of the sampling frequency (usually set to 1000 Hz) thus synchronising the bias to the data sampling. This electronics scheme is fundamental to the stability of the post-detection signals at low frequencies.

Calibration plan

• Calibration plan

  The APEX calibration plan for SABOCA, LABOCA and the SHFI receivers.