Re: How does a masers and maser communications system help with our lives today

Greetings:

References:
Look up MASERS and ATOMIC CLOCKS in any encyclopedia.
For detailed information see:
Handbook of Laser Science and Technology, Volume 1, Section 5.1,
A. E. Popa, Masers, McGraw-Hill/CRC Press, 1982

BACKGROUND

During World War II (1939-1945) radar became the key sensor for the long range
detection of aircraft. After the war scientists all over the world were trying
to find new ways to make more sensitive microwave radar receivers that could detect
aircraft, missiles and rockets at greater distances. At that time vacuum tube
electronics that used electrons in vacuum tubes for amplification of weak signals
were the only type of receivers available.

In the mid 1950s two American scientists and one Russian scientist independently
came up with the concept of using microwave generation and absorption within
molecules and atoms to build more sensitive microwave amplifiers. In 1953
Professor Charles Townes and his students at Columbia University in New York built
the first microwave amplifier that used molecules of ammonia gas and in a
publication in 1954 they named the device a MASER, which stands for
Microwave Amplification by the Stimulated Emission of Radiation.

The Ammonia Maser was not a very good microwave amplifier; however, when
they made it into an oscillator, the microwave signal that it generated was so
pure that the maser became an Atomic Clock. In 1958 a solid state
maser amplifier using a ruby crystal cooled with liquid helium to -269 degrees
Celsus, which is near absolute zero temperature, was developed at the University
of Michigan.

ANSWERS

The Ruby Maser is the most sensitive amplifier ever made and today they are
used in all of the giant radio telescope antennas used in astronomy and in
the giant antennas in NASA's Deep Space Network (DSN) that are used to receive
signals and pictures from satellites visiting the planets in the solar system.
You can read about the Deep Space Network on the NASA DSN Web site:

http://deepspace.jpl.nasa.gov/ds n/


In 1960 Professor Norman Ramsey and his students at Harvard University built the
first Hydrogen Maser Atomic Clock which used a beam of hydrogen atoms at
room temperature. The Hydrogen Maser is the most accurate clock in daily use and
is being used to synchronize the smaller atomic clocks in the Global Positiong
System (GPS). GPS is a world wide satellite navigation system that is being used by aircraft,
ships and even in automobiles. Last Christmas I bought my son a hand held GPS receiver
that he uses for hiking in the mountains. You can read about the 24 satellites in the
GPS satellite navigation system on the following web site:

http:/ /www.colorado.edu/geography/gcraft/notes/gps/gps_f.html

For reliability each GPS satellite has four small atomic clocks that use either
Rubidium or Cesium atoms. These clocks are used to send precise time and location
information to users on or near the earth's surface. The satellite's atomic clocks
are very accurate, but not as accurate as larger Hydrogen Maser Atomic Clocks. So
Hydrogen Masers are located at ground stations around the earth to reset the satellite
clocks when they drift in time. In the future they may put the Hydrogen Masers in
larger GPS satellites. You can read about and see pictures of Hydrogen Masers on the
US Naval Observatory web site at:

http://tycho.usno.navy.mil/mas er.html

On May 16, 1960, Dr. Theodore Maiman demonstrated the world's first LASER, the
Ruby Laser. LASER stands for Light Amplification by the Stimulated Emission of Radiation.
At that time Dr. Maiman had been working on Ruby Masers at the Hughes Research
Laboratories for use in aircraft radar systems. His breakthrough accomplishment
changed the world, as we know it. From that historic moment, the myriad of
applications, the host of laser types and the birth of the electro- optics industry,
all followed. You can read about Dr. Maiman's Ruby Maser and Ruby Laser on the
Hughes Research Laboratories web site at:

http://www.h rl.com/ENTER/tradition/Tradition.1960s.html

Best Regards, Your Mad Scientist
Adrian Popa