The following are pictures of the QUIET experiment components coming together. See the QUIET web site for more information about the science, the site, the people, and the technology.
Some Assembly Required -- (anon)
Some of the new deck parts from Accurate Manufacturing.
[2008 April 28]
The telescope, waiting for the deck to be built. The nearly on-edge disk to the left is the secondary mirror, and the other mirror is the primary. The horizontal section of the white framework just to the right of the primary mirror is where the receiver will be mounted. The first receiver, under tests nearby in the same building, is a "Q-band" instrument, sensitive to radiation at about 40 Gigahertz. The team from Columbia University under Prof. Amber Miller built it, and included components built by several other groups at other universities and labs. They are eagerly waiting for the telescope and deck to be made ready.
The telescope was built at IAM Systems near Dayton, Ohio, based on an optical design by Bill Imbriale at JPL and mechanical design by Tim Thurston, Ben Bosma, and KLT (Stanford).
[2008 April 29]
Deck main framework comes together. Telescope in background will mount in the middle of the deck rails. Robert Dumoulin (Columbia University) at the crane controls.
The deck was designed by KLT and built at Accurate Manufacturing in Glendale.
[2008 April 30]
First trial fit of the groundscreen, without the telescope on the deck. Laura Newburgh (foreground, Columbia University) and Ali Brizius (background, University of Chicago) guide it in. Robert Dumoulin at the crane controls again. The groundscreen will have Emerson & Cuming Eccosorb on the inside to provide a uniform and uncontaminated source for the telescope's sidelobes to see. Sidelobes are directions off to the sides, away from where the telescope is actually pointed, from which a receiver can (inconveniently) see radiation. For our experiment, these directions must either be reflected up to the sky or "stopped" by uniform and unchanging absorbing material. We are choosing the latter option, and making absolutely sure all sidelobes are "caught" by making a box with a hole at the top, where the microwaves are supposed to come in, and blocking all other directions with the absorbing material.
The groundscreen was designed and built under the direction of Dr. Mike Jones at Oxford University (design by Liz Mills), and the assembly at Caltech is being supervised by Colin Baines of Manchester University.
[2008 May 1]
Columbia's Q-band receiver, undergoing a few final tests on the test stand while waiting for everything else to be ready. The metalic hoses carry helium, part of a refrigerator system that keeps the receiver as cold as 25 Kelvin, cold enough to freeze air solid. The low temperatures are used to reduce the random noise of the detectors as much as possible. Because of the low temperatures, everything inside must be in a vacuum, and the entire assembly is called a cryostat.
The window through which the microwaves pass is seen edge-on, with a metal plate and screws clamping it to the right end of the cryostat. It is made of polyethylene, similar to the white kitchen cutting boards one can buy nowadays. It is transparent to microwaves, and keeps the air out even though it bows in a couple inches due to the vacuum inside the cryostat.
The green/gray enclosure in the background holds all the electronic circuits necessary for powering the detectors as well as reading and storing data. The cables attached to the back of the cryostat (currently wrapped in yellow caution tape, mostly so we don't step on them) plug into the enclosure, and these cables carry the necessary signals to and from the detectors. In this configuration we can send test signals into the cryostat and determine the array performance capabilities.
The cryostat was designed by Laura Newburgh.
[2008 May 1]
The telescope being fitted to the deck. Ross Williamson (Columbia University) is at the crane controls, Ali Brizius on the telescope structure behind the secondary mirror, Ricardo Bustos (Chajnantor Observatory and University of Miami) and Laura Newburgh in the forground attaching a lifting strap. Colin Baines assesses the situation from the background.
[2008 May 2]
The groundscreen fitted over the telesocpe on the deck. Ricardo Bustos is tightening a screw to hold the groundscreen to the deck. Martin Shepherd (Caltech) is on the left, inspecting the work.
The camera on the right is being held by Colin Baines. It is peering through the hole that the receiver will look through. The receiver is like the "camera body" of an SLR, in that it detects light--in this case, microwaves--but needs something else to form an image. The primary and secondary mirrors seen in the pictures above are like the "lens" of an SLR. They form an image of the sky that the receiver can detect. And just like an SLR "lens" that is actually made of several pieces of glass with precise concave and convex surfaces in order to give better images, our telescope is made of two mirrors rather than one, each with a special shape. In our case the primary mirror is an off-axis paraboloid and the secondary mirror is an off-axis hyperboloid.
[2008 May 5]
The telescope seen through the groundscreen access door.
This is only part of the groundscreen. The bottom and lower sides also will be covered, and most importantly the top will have a cylindrical aperture to restrict the angles that can be seen by the receiver (taking care of those sidelobes mentioned above). You also see the bare absorber material, but it will be covered by a weather-protecting layer of foam. Curiously enough, the absorber is black, so absorbs visible light pretty well in addition to the microwaves for which it is designed.
This picture also gives a better view of the back of the primary mirror. Most of the aluminum on the back side was machined away, leaving only a network of narrow ribs to stiffen the mirror surface. What is left is less than 1/2 an inch thick, but it started 4 inches thick. That means it is vastly lighter and allows the structure that holds it up to be a reasonable weight as well. The secondary mirror is built the same way.
[2008 May 7]
Some mundane bits: where the cables go. The holes in the rectangular tube on the left will have cables passing through on their way to the mount's control electronics, the system that aims the telescope and moves it around exactly as we command it. The galvanized "expanded metal" surface will support those cables, as well as a number of other cables and hoses, keeping them secure and out of harm's way. No, not exciting, but for every exciting gizmo there are dozens of ordinary parts that are just as necessary. Still, some of us appreciate a simple and functional part simply because of its simplicity and functionality.
[2008 May 7]
Some of the team members.
Left to Right:
Robert Dumoulin (Columbia University)
Alison Brizius (University of Chicago)
Laura Newburgh (Columbia University)
Ross Williamson (Columbia University)
Colin Baines (Manchester University)
Keith Thompson, foreground (Stanford University)