Glossary

A. Q. Khan

Abdul Qadeer Khan is often referred to as the father of the Pakistani nuclear bomb. He provided the government of Pakistan with centrifuge designs obtained from URENCO and sold nuclear technology to Libya, Iran, and the DPRK.

Absolute timing accuracy

The allowable deviation from Coordinated Universal Time (UTC) for any particular data sample. UTC is the international basis of civil and scientific time, implemented in 1964.  UTC is widely broadcast by precisely coordinated radio signals; these radio time signals ultimately furnish the basis for the setting of all public and private clocks.  Since 1 January 1972, UTC has been obtained from atomic clocks. The unit of UTC is the atomic second (SI).  

Acquisition computers

The devices that record the digital data acquired by the sensors that track seismic events. The acquisition computers record the data for transmission to Vienna and subsequent processing and analysis.

Ad-hoc Group of Scientific Experts

A group of international scientists that started in 1976 to research monitoring technologies and data analysis methods for the verification of a nuclear test ban. The GSE, set up at the Conference on Disarmament in Geneva, was essential in laying the scientific groundwork for and during the CTBT negotiations in 1994-96.  

African Nuclear-Weapon-Free-Zone

The African nuclear-weapon-free-zone treaty was opened for signature in Cairo on 11 April 1996. This treaty prohibits the research, development, manufacturing, stockpiling, acquisition, testing, possession, control, and stationing of nuclear explosive devices in the members' territory. The treaty also prohibits the deposit of radioactive waste originating from outside the continent within the region. Under the treaty, signatories are required to put all their nuclear programmes under International Atomic Energy Agency safeguards. The treaty also provides for the establishment of the African Commission on Nuclear Energy (AFCONE), which will supervise treaty implementation and ensure compliance. As of March 2008, there were 21 parties to the treaty: in addition 51 states had signed by not ratified it. China, France and the UK had ratified the treaty’s protocols while the Russian Federation and the United States had not ratified them.

Agency for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (OPANAL)

An intergovernmental agency created by the 1967 Treaty of Tlatelolco, which created a nuclear-weapon-free zone in Latin America and the Caribbean, to ensure that the obligations of the treaty are met. OPANAL also supervises all the contracting parties' compliance with the Treaty of Tlatelolco. This was the world’s first international agreement aimed at excluding nuclear weapons from an inhabited region of the globe.

Agreed framework

The 1994 agreement between the United States and North Korea (Democratic People's Republic of Korea, DPRK) to "freeze" the DPRK nuclear programme. The agreement outlined a 10-year programme during which the United States, the Republic of Korea (South Korea) and Japan would construct two new proliferation-resistant, light-water-moderated nuclear reactors in the DPRK in exchange for the shutting down of all its existing nuclear facilities. In addition, the DPRK agreed to remain a party to the nuclear Nonproliferation Treaty (NPT) and accept International Atomic Energy Agency (IAEA) full-scope safeguards. The multilateral Korean Peninsula Energy Development Organization (KEDO) would oversee implementation of the agreement.

Alva Myrdal

Winner of the 1982 Nobel Peace Prize, Alva Myrdal was a lifelong international activist on social and disarmament issues. In 1962 she was nominated as Sweden's representative to the Geneva Conference on Disarmament and in 1967 she became a member of the Swedish Cabinet, entrusted with the special task of promoting disarmament. During the negotiations in Geneva, she played an extremely active role, emerging as the leader of the group of non-aligned nations which endeavoured to bring pressure to bear on the two superpowers to show greater concern for concrete disarmament measures. The experiences from her Geneva years found an outlet in her book "The Game of Disarmament: How the United States and Russia Run the Arms Race". She also actively contributed to the establishment of the Stockholm International Peace Research Institute, SIPRI. Through her many articles and books, Alva Myrdal has exercised a significant influence on the current disarmament debate.

Annex 2 State

The 44 countries that participated in the negotiations of the CTBT from 1994-1996 and that possessed nuclear power reactors or research reactors at that time. All of these countries must sign and ratify the CTBT before it can enter into force. As of February 2012, there were eight countries outstanding (China, the Democratic People’s Republic of Korea, Egypt, India, the Islamic Republic of Iran, Israel, Pakistan and the United States of America.)

Annex 2 States

The 44 countries that participated in the negotiations of the CTBT from 1994-1996 and that possessed nuclear power reactors or research reactors at that time. All of these countries must sign and ratify the CTBT before it can enter into force. As of February 2012, there were eight countries outstanding (China, the Democratic People’s Republic of Korea, Egypt, India, the Islamic Republic of Iran, Israel, Pakistan and the United States of America.)

Anomalous anthropogenic sample

In the context of radionuclide samples, anomalous refers to an event which deviates from what is expected (an anomaly) according to existing rules or scientific theory, while anthropogenic refers to any effects, processes, objects or materials that are derived from human activities, as opposed to those occurring in natural environments without human influences. On a scale of Level 0 (lowest)  to Level 5 (highest), such samples would be evaluated as “Level 4” samples with radionuclide concentrations outside the range typically observed at an IMS station.

Antarctic Treaty

This Treaty was opened for signature on 1 December 1959 and entered into force on 23 June 1961. It internationalizes and demilitarizes the Antarctic continent. It specifies that Antarctica be used for peaceful purposes only; all activities of a military nature, including testing of any type of weapon (e.g. nuclear), are prohibited. No military activities, armaments or prohibited nuclear activities have been observed on the continent during inspections by member states since the treaty went into force. A total of 46 countries have become Parties to the Antarctic Treaty. Of these, seven claim territory in Antarctica, 12 are Original Signatories, and 27 are Consultative Parties. The Treaty entered into force on 23 June 1961.

Anti-Aliasing Filter

A signal-processing technique used to improve the quality of recorded data and reduce “aliasing", an effect caused by digital sampling of continuous data that distorts the signal.

Anti-ballistic missile

An anti-ballistic missile is a weapon designed to intercept and destroy ballistic missiles, which are vehicles used to deliver nuclear, chemical, biological or conventional warheads in the course of a ballistic flight (i.e. missiles moving under their own momentum and the force of gravity).

Anti-Ballistic Missile (ABM) Treaty

Treaty from 1972 between the United States and the Soviet Union which constrained strategic missile defenses to a total of 200 launchers and interceptors per country -100 at each of two widely separated deployment areas. These restrictions were intended to prevent the establishment of a nationwide defense of the creation of a base for deploying such a defense. The treaty was modified in 1974, reducing the number of ABM deployment areas permitted each side from two to one and the number of ABM launchers and interceptors from 200 to 100. The Treaty was signed on May 26, 1972, and entered into force on October 3, 1972. The United States withdrew from the treaty in 2001. 

Argon

A chemical element in gaseous form.  It is called a noble gas since it is inert and rarely reacts with other chemicals. A radioactive isotope of this chemical element, argon-37, can only be produced by a nuclear reaction and is therefore measured to detect clandestine underground nuclear explosions. See also Radionuclide monitoring and noble gas.

Arms control

Any unilateral or multilateral measure taken to reduce or control any aspect of either a weapon system or armed forces. Such reductions or limitations might affect the size, type, configuration, production, or performance characteristics of a weapon system, or the size, organization, equipment, deployment, or employment of armed forces.

ARR

Automatic Radionuclide Report.  Lists the results of the automatic analysis of a radiation spectrum from a radionuclide monitoring station.

Array

An array is a spatially distributed set of sensors, which, for IMS facilities, transmit their outputs to a central recording facility to be recorded against a common time base. Using an array rather than just one sensor to collect signals improves data quality.

Array Passband

The passband at which any given array operates, this comprises a band of frequencies, limited by a lower and an upper frequency, at which the array attenuates signals by 3 dB below maximum transmissibility. It is defined by system or data requirements that maximize the usefulness of the needed data. See also pipe array system.

Arrays

Arrays are spatially distributed sets of sensors, which, for IMS facilities, transmit their outputs to a central recording facility to be recorded against a common time base. Using an array rather than just one sensor to collect signals improves data quality.

ATM

Atmospheric Transport Modelling. The calculation of the travel path of a given radionuclide, using meteorological data. This calculation can be performed as back tracking, trying to identify the area where a radionuclide may have been released, calculated from the location where it was observed. Forward ATM predicts where radionuclides may travel from their known point of release, again using meteorological data.

Atmospheric Boundary Layer

Also known as the planetary boundary layer or peplosphere, this is the lowest part of the atmosphere and its behavior is directly influenced by its contact with a planetary surface. In this layer physical quantities such as flow velocity, temperature, moisture etc., display rapid fluctuations (turbulence) and vertical mixing is strong. See also surface forcings.

Atmospheric Transport Modelling

The calculation of the travel path of a given radionuclide, using meteorological data. This calculation can be performed as back tracking, trying to identify the area where a radionuclide may have been released, calculated from the location where it was observed. Forward ATM predicts where radionuclides may travel from their known point of release, again using meteorological data.

Atmospheric Transport Modelling (ATM)

The calculation of the travel path of a given radionuclide, using meteorological data. This calculation can be performed as back tracking, trying to identify the area where a radionuclide may have been released, calculated from the location where it was observed. Forward ATM predicts where radionuclides may travel from their known point of release, again using meteorological data.

Atomic bomb

A weapon that uses fissile material in isotopes of uranium or plutonium to provide explosive power.

Atomic bombs

Weapons that use fissile material in isotopes of uranium or plutonium to provide explosive power.

Atomic energy

Energy released in nuclear reactions. Of particular interest is the energy released when a neutron initiates the breaking up or fissioning of an atom's nucleus into smaller pieces (fission), or when two nuclei are joined together under millions of degrees of heat (fusion). It is more correctly called nuclear energy.

Atoms for Peace

The U.S. programme announced by President Dwight D. Eisenhower at the United Nations in December 8, 1953, to share nuclear materials and technology for peaceful purposes with other countries. This programme required countries receiving nuclear materials to agree to inspections of the transferred technology to ensure it was not used for military purposes. The programme was formally established in 1954, following the passage of the Atomic Energy Act.

Authenticated data

Data collected from monitoring stations that have undergone the process of authentication. This involves measures taken to ensure that the integrity of the data from the monitoring stations in the International Monitoring System network has not been compromised, either accidentally or maliciously, by some action at the station or in transmission to the International Data Centre, or at any time thereafter.

Automatic Event Screening

The identification of potentially suspicious events by applying several screening criteria. These criteria are listed in the Protocol to the CTBT and help identify an event’s character as either natural or man-made. An event that is proved to be of natural origin is filtered out and discarded. Events that are clearly identified as man-made or where the application of screening criteria did not provide a clear answer are listed in the Standard Screened Event Bulletin, SSEB.

Automatic Radionuclide Report (ARR)

Lists the results of the automatic analysis of a radiation spectrum from a radionuclide monitoring station.

Auxiliary seismic

Provides data on a seismic event to the CTBTO’s International Data Centre (IDC) in Vienna that supplements information gathered by primary seismic stations. The data from the 120 auxiliary seismic stations are available upon request by the IDC.

Auxiliary seismic station

Provides data on a seismic event to the CTBTO’s International Data Centre (IDC) in Vienna that supplements information gathered by primary seismic stations. The data from the 120 auxiliary seismic stations are available upon request by the IDC.

Auxiliary seismic stations

Provides data on a seismic event to the CTBTO’s International Data Centre (IDC) in Vienna that supplements information gathered by primary seismic stations. The data from the 120 auxiliary seismic stations are available upon request by the IDC.

Azimuth

Defines a horizontal angle usually measured clockwise from true north.  Expressed in degrees, the azimuth provides information on the location of an object on the Earth’s surface by identifying its direction on a horizontal plane. 

Azimuths

Defines a horizontal angle usually measured clockwise from true north.  Expressed in degrees, the azimuth provides information on the location of an object on the Earth’s surface by identifying its direction on a horizontal plane.