AMANDA Optical Modules
PSL has built almost 1000 optical modules for the AMANDA project over the past several years.
The modules are deployed into the Antarctic ice in holes drilled up to 2000 meters deep.
Each 330mm diameter optical module contains a large diameter photomultiplier tube and a
printed circuit board base potted in a clear glass hemisphere using an
optically clear silicone gel. The upper hemisphere contains a connection to
the outside world through which the power source and electronic controls on
the surface interact with the module. The sealed modules are frozen in the ice with
tubes pointing toward the center of the Earth. The Earth acts as a shield, blocking
out all radiation except for neutrinos which have no mass and no charge. Between
November 1996 and February 1997, 216 modules were placed into six holes at 36
modules per string.
The plan for a kilometer-scale array called IceCube would require a total of about 5000 modules.
Production rate would be about 1000 per year, with construction time limited by the
rate at which holes could be drilled in the ice during the short Antarctic installation season.
Ice Cube has been granted funding and is under way.
Visit the AMANDA website at UC-Berkeley or the Amanda website at UW-Madison. |
AMANDA Drill
In 1995, PSL designed and constructed the first hot water drill for the Antarctic Muon and Neutrino
Detector Array. The drill was used to drill holes in the Antarctic ice two
kilometers deep in which the detector arrays were placed. The drill had to be able to
withstand external pressure of 3400N/sq cm (5000 pounds per square inch), send and receive signals
through 3200 meters of cable, and deviate from straight by no more than 1 meter. To overcome
these difficulties, PSL created a modular drill head including a power and telemetry
module, a navigation pack module, and a sensor module. The drill works by shooting hot water
(about 90° C) out of a nozzle at the end. As the water melts the ice ahead, it cools
and then is pumped out of the hole and back into the water heaters to be reheated and
reused. Each hole took about three days of nonstop drilling.
As part of the preparation for Ice Cube and its operation, PSL helped to develop, commission, maintain and improve enhanced hot water drill capable of drilling over 2 kilometers deep in about 1.5 days. |
