Canadian Penning Trap Mass Spectrometer
Encyclopedia
The Canadian Penning Trap Mass Spectrometer (CPT) is one of the major pieces of experimental equipment that is installed on the ATLAS
superconducting heavy-ion linac facility at the Physics Division of the Argonne National Laboratory
. It was developed and operated by physicist Guy Savard and a collaboration of other scientists at Argonne, the University of Manitoba
, McGill University
, Texas A&M University
and the State University of New York
.
in Chalk River, Ontario, Canada. However, it was transferred to Argonne National Laboratory when the TASCC accelerator was decommissioned in 1998 due to funding issues.
The CPT spectrometer
is designed to provide high-precision mass measurements of short-lived isotopes using radio-frequency (RF) fields. Accurate mass measurements of particular isotopes such as selenium-68
are important in the understanding of the detailed reaction mechanism
s involved in the rapid-proton capture process
, which occurs in astrophysical events like supernovae explosions
and X-ray bursts. An X-ray burst is one possible site for the rp-process mechanism which involves the accretion
of hydrogen and helium from one star onto the surface of its neutron star
binary companion. Mass measurements are required as key inputs to network calculations used to describe this process in terms of the abundances of the nuclides produced, the light-curve
profile of the X-ray bursts, and the energy produced. In the current configuration, more than 100 radioactive
isotopes have been measured with half-lives much less than a second and with a precision (Δm/m) approaching 10-9.
Recently, a novel injection system, the RF gas cooler
, has been installed on the CPT to allow fast reaction products to be decelerated, thermalized and bunched for rapid and efficient injection. This enhances the investigative capabilities of the CPT on isotopes around the N=Z line with particular emphasis on isotopes of interest to low-energy tests of the electroweak interaction
and the rp-process.
Argonne Tandem Linear Accelerator System
The Argonne Tandem Linac Accelerator System is a scientific user facility at Argonne National Laboratory. ATLAS is the first superconducting linear accelerator for heavy ions at energies in the vicinity of the Coulomb barrier....
superconducting heavy-ion linac facility at the Physics Division of the Argonne National Laboratory
Argonne National Laboratory
Argonne National Laboratory is the first science and engineering research national laboratory in the United States, receiving this designation on July 1, 1946. It is the largest national laboratory by size and scope in the Midwest...
. It was developed and operated by physicist Guy Savard and a collaboration of other scientists at Argonne, the University of Manitoba
University of Manitoba
The University of Manitoba , in Winnipeg, Manitoba, Canada, is the largest university in the province of Manitoba. It is Manitoba's most comprehensive and only research-intensive post-secondary educational institution. It was founded in 1877, making it Western Canada’s first university. It placed...
, McGill University
McGill University
Mohammed Fathy is a public research university located in Montreal, Quebec, Canada. The university bears the name of James McGill, a prominent Montreal merchant from Glasgow, Scotland, whose bequest formed the beginning of the university...
, Texas A&M University
Texas A&M University
Texas A&M University is a coeducational public research university located in College Station, Texas . It is the flagship institution of the Texas A&M University System. The sixth-largest university in the United States, A&M's enrollment for Fall 2011 was over 50,000 for the first time in school...
and the State University of New York
State University of New York
The State University of New York, abbreviated SUNY , is a system of public institutions of higher education in New York, United States. It is the largest comprehensive system of universities, colleges, and community colleges in the United States, with a total enrollment of 465,000 students, plus...
.
Development
The CPT was originally built for the Tandem Accelerator Superconducting Cyclotron (TASCC) facility at Chalk River LaboratoriesChalk River Laboratories
The Chalk River Laboratories is a Canadian nuclear research facility located near Chalk River, about north-west of Ottawa in the province of Ontario.CRL is a site of major research and development to support and advance nuclear technology, in particular CANDU reactor...
in Chalk River, Ontario, Canada. However, it was transferred to Argonne National Laboratory when the TASCC accelerator was decommissioned in 1998 due to funding issues.
The CPT spectrometer
Spectrometer
A spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization...
is designed to provide high-precision mass measurements of short-lived isotopes using radio-frequency (RF) fields. Accurate mass measurements of particular isotopes such as selenium-68
Selenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
are important in the understanding of the detailed reaction mechanism
Reaction mechanism
In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical change occurs.Although only the net chemical change is directly observable for most chemical reactions, experiments can often be designed that suggest the possible sequence of steps in...
s involved in the rapid-proton capture process
Rp-process
The rp-process consists of consecutive proton captures onto seed nuclei to produce heavier elements. It is a nucleosynthesis process and, along with the s process and the r process, may be responsible for the generation of many of the heavy elements present in the universe...
, which occurs in astrophysical events like supernovae explosions
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
and X-ray bursts. An X-ray burst is one possible site for the rp-process mechanism which involves the accretion
Accretion (astrophysics)
In astrophysics, the term accretion is used for at least two distinct processes.The first and most common is the growth of a massive object by gravitationally attracting more matter, typically gaseous matter in an accretion disc. Accretion discs are common around smaller stars or stellar remnants...
of hydrogen and helium from one star onto the surface of its neutron star
Neutron star
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
binary companion. Mass measurements are required as key inputs to network calculations used to describe this process in terms of the abundances of the nuclides produced, the light-curve
Light curve
In astronomy, a light curve is a graph of light intensity of a celestial object or region, as a function of time. The light is usually in a particular frequency interval or band...
profile of the X-ray bursts, and the energy produced. In the current configuration, more than 100 radioactive
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
isotopes have been measured with half-lives much less than a second and with a precision (Δm/m) approaching 10-9.
Recently, a novel injection system, the RF gas cooler
RFQ Beam Coolers
RFQ stands for Radio-Frequency Quadrupole , an instrument that is used in mass spectrometry. The RFQ was invented by Prof. Wolfgang Paul in the late 50's / early 60's at the University of Bonn...
, has been installed on the CPT to allow fast reaction products to be decelerated, thermalized and bunched for rapid and efficient injection. This enhances the investigative capabilities of the CPT on isotopes around the N=Z line with particular emphasis on isotopes of interest to low-energy tests of the electroweak interaction
Electroweak interaction
In particle physics, the electroweak interaction is the unified description of two of the four known fundamental interactions of nature: electromagnetism and the weak interaction. Although these two forces appear very different at everyday low energies, the theory models them as two different...
and the rp-process.