Millimeter Anisotropy eXperiment IMaging Array

The Maxima balloon is readied for launch

The Millimeter Anisotropy eXperiment IMaging Array (MAXIMA)[1] experiment was a balloon-borne experiment funded by the U.S. NSF, NASA and Department of Energy, and operated by an international collaboration headed by the University of California, to measure the fluctuations of the cosmic microwave background. It consisted of two flights, one in August 1998 and one in June 1999. For each flight the balloon was started at the Columbia Scientific Balloon Facility in Palestine, Texas and flew to an altitude of 40,000 metres for over 8 hours. For the first flight it took data from about 0.3 percent of the sky of the northern region near the Draco constellation. For the second flight, known as MAXIMA-II, twice the area was observed, this time in the direction of Ursa Major.

Initially planned together with the BOOMERanG experiment, it split off during the planning phase to take a less risky approach by reducing flying time as well as launching and landing on U.S. territory.



Maxima's Feed horns and Bolometers

A 1.3-metre primary mirror, along with a smaller secondary and tertiary mirror, was used to focus the microwaves onto the feed horns. The feed horns have spectral bands centred at 150, 240 and 420 GHz with a resolution of 10 arcminutes. A bolometer array consisting of 16 NTD-Ge Thermistors measured the incident radiation.

The detector array was cooled down to 100 mK via a four stage refrigeration process. Liquid nitrogen cooled the outer layer of radiation shielding and He-4 was used to cool the two other layers down to a temperature of 2-3 K. Finally liquid He-3 cooled the array down to operation temperature. The shielding, together with the properties of the feed horns, gave a superb sensitivity of 40 μV/sec^1/2.

Two CCD cameras where used to provide accurate measurements of the telescope's orientation. The first wide-field camera pointed towards Polaris and gave a coarse orientation up to 15 arcminutes. The other camera was mounted in the primary focus and gives an accuracy of 0.5' for stars brighter than 6th magnitude, which in total gives an accurate position tracking of 10' for the telescope and hence of the microwaves.

For pointing the telescope, four motors were used.


MAXIMA CMB fluctuations map

Compared to MAXIMA's competitor the BOOMERanG experiment, MAXIMA's data covers a smaller part of the sky but with much more detail. By the end of the year 2000 the experiment provided the most accurate measurements of the cosmic background radiation (CMB) fluctuations on small angular scales. With this data it is possible to calculate the first three acoustic peaks from the CMB power spectrum. These greatly confirm the standard cosmological model by measuring a baryon density of about 4%, which agrees with the density calculated from Big Bang nucleosynthesis. The measurement of the flatness of the Universe also confirms a major prediction of inflationary cosmology, although BOOMERang was the first to discover this.

See also


  1. ^ "MAXIMA Press Release". University of California, Berkeley. 2000-04-09. Retrieved 2007-05-01. 

External links

Coordinates: 31°46′48″N 95°43′22″W / 31.78°N 95.72278°W / 31.78; -95.72278

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • List of cosmic microwave background experiments — A comparison of the sensitivity of WMAP with COBE and Penzias and Wilson s telescope. Simulated data. There have been a variety of experiments to measure the Cosmic microwave background (CMB) radiation anisotropies and polarization since its… …   Wikipedia

  • Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics       Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity.       Computer scientist Manindra Agrawal of the… …   Universalium

  • Outline of astronomy — Mauna Kea in Hawaii is one of the world s premier observatory sites. Pictured is the W. M. Keck Observatory, an optical interferometer. The following outline is provided as an overview of and topical guide to astronomy: Astronomy – studies the… …   Wikipedia

  • Maxima — may refer to: Maxima and minima, the highest and lowest values (points) of a function in calculus Maxima (comics), a character in the DC comics universe Maxima, musical note value in mensural notation Maxima of Rome, early Christian saint and… …   Wikipedia

  • MAXIMA — (acronyme de Millimeter Anisotropy eXperiment IMaging Array) est un instrument d observation des anisotropies du fond diffus cosmologique montée sur un ballon stratosphérique d observation américain qui a opéré à la fin des années 1990, à la même …   Wikipédia en Français

  • List of astronomy acronyms — This is a compilation of acronyms commonly used in astronomy. Most of the acronyms are drawn from professional astronomy and are used quite frequently in scientific publications. However, a few of these acronyms are frequently used by the general …   Wikipedia

  • X-ray crystallography — can locate every atom in a zeolite, an aluminosilicate with many important applications, such as water purification. X ray crystallography is a method of determining the arrangement of atoms within a crystal, in which a beam of X rays strikes a… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.