Geiger tube telescope
Encyclopedia
The Geiger Tube Telescope is a scientific instrument that measures the intensities, energy spectra, and angular distribution of energetic electron
s and proton
s in interplanetary space and near Jupiter
and Saturn
.
On Pioneer 10
, the instrument used an array of seven miniature Geiger-Müller tube
s, collectively known as a Geiger Tube Telescope (GTT). Each tube was a small gas-filled cylinder. When a charged particle passed through the gas, an electrical pulse was generated by the applied voltage. Individual pulses from five of the tubes and coincident pulses from three combinations of the seven tubes were transmitted. Protons of energy greater than 5 MeV
and electrons with energies greater 40 keV were detected.
On Pioneer 11
, one Geiger-Müller tube was replaced by a thin silicon wafer to detect protons in the specific energy range 0.61 to 3.41 MeV. Other minor changes were made to improve the characteristics of the detector system.
The trains of pulses were passed through quasi-logarithmic data processors and then to the radio telemetry system of the spacecraft. Angular distributions were measured as the spacecraft rotated. This telemetry data was transmitted to the earth by an 8 watt S band
transmitter
within the Pioneer probe at one of eight data rates (from 16 to 2048 bits per second).
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s and proton
Proton
The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
s in interplanetary space and near Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
and Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
.
On Pioneer 10
Pioneer 10
Pioneer 10 is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System. The project was managed by the NASA Ames Research Center and the contract for the construction of the...
, the instrument used an array of seven miniature Geiger-Müller tube
Geiger-Müller tube
A Geiger–Müller tube is the sensing element of a Geiger counter instrument that can detect a single particle of ionizing radiation, and typically produce an audible click for each. It was named for Hans Geiger who invented the device in 1908, and Walther Müller who collaborated with Geiger in...
s, collectively known as a Geiger Tube Telescope (GTT). Each tube was a small gas-filled cylinder. When a charged particle passed through the gas, an electrical pulse was generated by the applied voltage. Individual pulses from five of the tubes and coincident pulses from three combinations of the seven tubes were transmitted. Protons of energy greater than 5 MeV
Electronvolt
In physics, the electron volt is a unit of energy equal to approximately joule . By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electric potential difference of one volt...
and electrons with energies greater 40 keV were detected.
On Pioneer 11
Pioneer 11
Pioneer 11 is a 259-kilogram robotic space probe launched by NASA on April 6, 1973 to study the asteroid belt, the environment around Jupiter and Saturn, solar wind, cosmic rays, and eventually the far reaches of the solar system and heliosphere...
, one Geiger-Müller tube was replaced by a thin silicon wafer to detect protons in the specific energy range 0.61 to 3.41 MeV. Other minor changes were made to improve the characteristics of the detector system.
The trains of pulses were passed through quasi-logarithmic data processors and then to the radio telemetry system of the spacecraft. Angular distributions were measured as the spacecraft rotated. This telemetry data was transmitted to the earth by an 8 watt S band
S band
The S band is defined by an IEEE standard for radio waves with frequencies that range from 2 to 4 GHz, crossing the conventional boundary between UHF and SHF at 3.0 GHz. It is part of the microwave band of the electromagnetic spectrum...
transmitter
Transmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...
within the Pioneer probe at one of eight data rates (from 16 to 2048 bits per second).