List of cosmic microwave background experiments


This list is a compilation of experiments measuring the cosmic microwave background radiation anisotropies and polarization since the first detection of the CMB by Penzias and Wilson in 1964. There have been a variety of experiments to measure the CMB anisotropies and polarization since its first observation in 1964 by Penzias and Wilson. These include a mix of ground-, balloon- and space-based receivers. Some notable experiments in the list are COBE, which first detected the temperature anisotropies of the CMB, and showed that it had a black body spectrum; DASI, which first detected the polarization signal from the CMB; CBI, which made high-resolution observations and obtained the first E-mode polarization spectrum; WMAP; and the Planck spacecraft, which has produced the highest resolution all-sky map to-date of both the temperature anisotropies and polarization signals. Current scientific goals for CMB observation include precise measurement of gravitational lensing, which can constrain the mass of the neutrino; and measurement of B-mode polarization as possible evidence for cosmic inflation.
The design of cosmic microwave background experiments is a very challenging task. The greatest problems are the receivers, the telescope optics and the atmosphere. Many improved microwave amplifier technologies have been designed for microwave background applications. Some technologies used are HEMT, MMIC, SIS and bolometers. Experiments generally use elaborate cryogenic systems to keep the amplifiers cool. Often, experiments are interferometers which only measure the spatial fluctuations in signals on the sky, and are insensitive to the average 2.7 K background.
Another problem is the 1/f noise intrinsic to all detectors. Usually the experimental scan strategy is designed to minimize the effect of such noise. To minimize side lobes, microwave optics usually utilize elaborate lenses and feed horns. Finally, in ground-based instruments, water and oxygen in the atmosphere emit and absorb microwave radiation. Even at frequencies where the atmospheric transmission is high, atmospheric emission contributes photon noise that limits the sensitivity of an experiment. CMB research therefore uses of air- and space-borne experiments, as well as dry, high altitude locations such as the Chilean Andes and the South Pole.

Cosmic microwave background experiments

The list below consists of a partial list of past, current and planned CMB experiments. The name, start and end years of each experiment are given, followed by the basis of the experiment—whether space, balloon or ground based—and the location where appropriate. The frequency and amplifier technologies used are given, as is the main targets of the experiments.
ImageNameStartEndBasisLocationFrequency Detector technologyTargetsReferences
Advanced Cosmic Microwave Explorer
Also HACME: HEMT+ACME		19881996GroundSouth Pole26–35; 38–45HEMTTemperature anisotropies
Antarctic Plateau Anisotropy Chasing Experiment 19951996GroundAntarctic100, 150, 250BolometerTemperature anisotropies
Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission 20012006Balloon3, 5, 7, 10, 30, 90HEMTCMB Spectrum
Archeops19992002Balloon143, 217, 353, 545BolometerMeasured large and intermediate scale with improved precision at the larger scales.
Arcminute Cosmology Bolometer Array Receiver 20012008GroundSouth Pole150, 219, 274BolometerTemperature anisotropies
Arcminute Microkelvin Imager 2005—GroundUK: Mullard Radio Astronomy Observatory12-18InterferometerSZ effect, Temperature anisotropies
Q U I JOint TEnerife 2012—GroundTenerife11, 13, 17, 19, 30, 40Polarizer / OMTPolarization on degree angular scales
ARGO1988, 1990, 19931993Balloon150-600Bolometer
Array for Microwave Background Anisotropy 2007—GroundHawaii: Mauna Loa86-102Interferometer/MMICSZ effect; Polarization
Atacama B-Mode Search 2012—GroundChile: Atacama Desert145BolometerPolarization
Atacama Cosmology Telescope 2008—GroundChile: Atacama Desert148, 218, 277BolometerSmall-scale temperature and polarization anisotropies
Atacama Pathfinder Experiment 2007—GroundChile: Atacama Desert150, 217BolometerTemperature anisotropies; SZ effect
Australia Telescope Compact Array 19911997GroundPaul Wild Observatory, New South Wales, Australia8.7HEMT
Background Emission Anisotropy Scanning Telescope 2000—Balloon, Ground25-35; 38-45HEMTA ground single dish CMB observatory at the University of California's White Mountain Peak Research station.
Background Imaging of Cosmic Extragalactic Polarization 20062008GroundSouth Pole100, 150, 220BolometerMeasured degree-scale polarization with improved precision.
BICEP220092012GroundSouth Pole150BolometerDegree-scale B-mode polarization.
Keck Array2010GroundSouth Pole95, 150, 220BolometerDegree-scale B-mode polarization.
Balloon-borne Anisotropy Measurement 19951998BalloonUniversity of British Columbia and Brown University balloon experiment110-250SpectrometerUsed differential Fourier Transform Spectrometer to measure degree scale anisotropy
Balloon-borne Radiometers for Sky Polarisation Observations Cancelled—Balloon32, 90Polarizer / OMT
Berkeley-Illinois-Maryland Association 19862004GroundHat Creek Radio Observatory, California, USA70-116; 210-270SIS
BOOMERanG experiment19972003BalloonLong-duration balloon above Antarctica90-420BolometerIntermediate scale fluctuations
B-mode RAdiation INterferometer Never—GroundDome-C, Antarctica
CloverCancelled—Ground97, 150, 230BolometerCancelled experiment to measure the small scale fluctuations and to search for B-mode polarization.
Cobra19821990Sounding RocketUniversity of British Columbia27-900Bolometers/ FTSFrequency spectrum of CMB
Cosmic Anisotropy Polarization Mapper 20022008GroundCrawford Hill Telescope, New Jersey40, 90MMIC/HEMT
Cosmic Anisotropy Telescope 19941997GroundMullard Radio Astronomy Observatory13-17Interferometer / HEMTVery small scale fluctuations in small regions of the sky.
Cosmic Background Imager 20002008GroundLlano de Chajnantor Observatory, Chile26-36HEMTVery small scale temperature and polarization anisotropies in a small patch of sky.
Cosmology Large Angular Scale Surveyor 2015—GroundLlano de Chajnantor Observatory, Chile40, 90, 150, 220TES BolometerB-mode polarization signal at multipoles from 2 to 100
Primordial Inflation Polarization Explorer Future—Balloon200, 270, 350, 800TES bolometersB-mode polarization signal
COSMOSOMAS19982007GroundTeide Observatory, Tenerife, Spain10-18HEMTCircular scanning experiments for CMB and foregrounds
Cosmic Background Explorer 19891993SpaceEarth orbit31.5, 53, 90 Temperature anisotropies; frequency power spectrum; solar system and galactic dust foregrounds.
Cosmic Background Explorer 19891990SpaceEarth orbit68-3000 200 frequencies BolometersCMB Spectrum; CMB Temperature; CIB spectrum; Temperature anisotropies; frequency power spectrum; solar system and galactic dust foregrounds.
TRIS19942001GroundCampo Imperatore0.6, 0.82, 2.5CMB frequency power spectrum
COMPASS20012001GroundPine Bluff, Wisconsin26 to 36HEMTPolarization on degree angular scales
Cosmological Gene 19992009GroundRATAN-600, Caucasus, Russia0.6 to 32HEMT
Degree Angular Scale Interferometer 19992003GroundSouth Pole26-36HEMTTemperature and polarization anisotropy on degree angular scales
The E and B Experiment 20122013BalloonAntarctica150-450BolometerInflationary gravitational-wave background signal in B-mode polarization
Far Infra-Red Survey 19891989BalloonNational Scientific Balloon Facility, Fort Sumner, New Mexico170-680BolometerTemperature anisotropy on large angular scales.
KU-band Polarization IDentifier 2003—GroundCrawford Hill Telescope, New Jersey12-18HEMT
Medium Scale Anisotropy Measurement 19921997Balloon150-650Bolometer
Millimeter Anisotropy eXperiment IMaging Array 1995, 1998, 19991999BalloonNear Palestine, Texas150-420BolometerIntermediate scale temperature fluctuations.
Millimeter Interferometer 20012002GroundCerro Toco, Chile145SISTemperature anisotropies around multipole 1500
Millimeter-Wave Bolometric Interferometer Future—Ground90Bolometer
Mobile Anisotropy Telescope 1997, 19981998GroundCerro Toco, Chile30-140HEMT / SIS
Polarization Observations of Large Angular Regions 20002000GroundPine Bluff, Wisconsin, USA26-46HEMTPolarization at large angular scales
POLARBEAR2012—GroundChajnantor plateau 150Antenna-coupled TESCMB Polarization. Primordial and lensed B-modes.
PolatronNever—Ground100Bolometer
Princeton I, Q, and U Experiment 20022002GroundPrinceton University90Bolometer
Python19921997GroundSouth Pole30-90HEMT / BolometerTemperature anisotropy on intermediate angular scales
QMAP19961996Balloon30-140HEMT / SIS
QUaD20052007GroundSouth Pole100, 150BolometerPolarization at intermediate angular scale
QubicFuture—Ground97, 150, 230BolometerB-mode polarization on intermediate angular scale.
Q/U Imaging ExperimenT 20082010GroundLlano de Chajnantor Observatory, Chile40, 90HEMT
RELIKT-119831984SpaceEarth orbit37Temperature anisotropies
Saskatoon experiment19931995GroundSaskatchewan26-46HEMT
Simons Observatory2021-GroundAtacama27/39, 93/145, 225/280 GHzBolometersB-mode polarization, SZE galaxy clusters, sources
Sky Polarization Observatory Cancelled—SpaceInternational Space Station22-90Polarization
South Pole Telescope2006GroundSouth PoleSmall scale temperature and polarization.
SPIDER2015BalloonAntarctica90, 150, 220BolometerLarge scale polarization.
Sunyaev-Zeldovich Array 20042008GroundOwens Valley Radio Observatory26-36; 85-115InterferometerProduced sensitive CMB anisotropy constraints at l ~ 4000, measured the SZ effect in 100s of galaxy clusters. Now part of CARMA
MUltiplexed Squid/Tes Array for Ninety Gigahertz 2007—GroundGreen Bank Telescope 90TES bolometersSunyaev-Zeldovich effect
Sunyaev-Zeldovich Infrared Experiment 1996—GroundCaltech Submillimeter Observatory, Mauna Kea, Hawaii150, 220, 350BolometerSZ effect
Tenerife Experiment19842000GroundTenerife10, 15, 33HEMTTemperature anisotropies from degree to arcminute angular scales
TopHat20012001BalloonAntarctica150-720Bolometer
Very Small Array20022008GroundTenerife26-36Interferometer / HEMTIntermediate and small scale fluctuations in small regions of the sky.
Wilkinson Microwave Anisotropy Probe 20012010SpaceLagrange 223-94HEMTTemperature anisotropies; Polarization
Planck20092013SpaceLagrange 230-857HEMT / BolometerTemperature and polarization anisotropies; foregrounds