APEX instrumentation

Facility instruments

Instrument	Type	Mode	Frequency [GHz]	HPBW [arcsec]	IF range [GHz]	# of beams	Location	Status	Comment
APEX-1 (SHeFI)	Heterodyne SIS	SSB	211 - 275	30 - 25	4 - 8	1	Nasmyth-A
APEX-2 (SHeFI)	Heterodyne SIS	SSB	275 - 370	23 - 17	4 - 8	1	Nasmyth-A
APEX-3 (SHeFI)	Heterodyne SIS	SSB?	385 - 500	17 - 13	4 - 8	1	Nasmyth-A		Science Verification pending
APEX-T2 (SHeFI)	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		warmed up
APEX-2A	Heterodyne SIS	DSB	279 - 381	18	4 - 8	1	Nasmyth-A		Decommissioned in Feb 2008 and replaced by APEX-2

• SHeFI 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.
  To estimate the integration time use Integration Time Estimator

• 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: ESO Messenger 139

• 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)	280 - 370	17-22	1	Nasmyth-A
			420 - 510	12-14	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		Decommissioned in December 2010
ARTEMIS	Bolometer array	PI (ESO)	670, 1500	9, 4	256	Nasmyth-A		Available March 2013
PolKa	Polarimeter	PI (MPIfR)	345	19	295	Cassegrain		Commissioning pending

• FLASH

  FLASH is a dual-frequency MPIfR principal investigator (PI) receiver, operating simultaneously - on orthogonal polarizations - in the 345GHz and the 460GHz atmospheric windows. Design and construction of the instrument was launched in late 2003; the receiver has been in continuous operation since June 2004. In its first incarnation, equipped with a 460 GHz and a 810 GHz channel, FLASH was the high frequency heterodyne workhorse during the commissioning of the APEX and its first years of operation. After successful installation of the CHAMP+ array, covering also the 810 GHz atmospheric window, we decided in late 2009 to replace the FLASH high frequency channel with a state-of-the-art sideband separating 345 GHz detector. The 2SSB mixer was provided by IRAM (D.Maier et al. 2005). 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 characteristic of being tunable and of producing a negligible absorption.
  More information: Proc. SPIE 2010 - PolKa at MPIfR

• 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.
  It was decommissioned in December 2010.

• 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 2013.

Facility backends

• FFTS (Decommisioned June 2011)

  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)

• XFFTS

  The RPG eXtended bandwidth Fast Fourier Transform Spectrometer (XFFTS) is optimized for a wide range of radio astronomical applications. The new digitizer and analyzer boards make use of the latest versions of GHz analogue- to-digital converters (ADC) and the most complex field programmable gate array (FPGA) chips commercially available today. These state-of-the-art chips made it possible to build a digital spectrometer with instantaneous bandwidth of 2.5 GHz and 32768 (32K) spectral channels. The APEX facility XFFTS consists of two units which have a fixed overlap region of 1.0 GHz, hence covering the entire IF bandwidth of SHFI. The number of spectral channels is fixed at 32768 channels.

• 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 SHeFI receivers.