 |
|
 |
 |
 |
|
|
|||
CHICOS is a collaborative project involving Caltech, Cal State Northridge, UC Irvine, community colleges, and local junior and senior high school physics teachers to site a large array of particle detectors at schools in the Los Angeles area. The scientific goal of the project is to detect and characterize a sample of the highest energy elementary particles ever observed. At the same time, the project offers students and teachers in local schools a unique opportunity to collaborate with researchers at Caltech and address fundamental issues at the forefront of present-day astrophysics and particle physics. Due to the ethnic and racial diversity of the Los Angeles high schools it is expected that this program will provide a novel mechanism for broadening the participation of underrepresented groups in society in scientific research. Thus, in addition to establishing an important experimental facility for ultra-high energy cosmic ray studies, this project provides an exceptional educational opportunity for junior and senior high school students in the Los Angeles area.
The project is coordinated through the Kellogg Radiation Laboratory at Caltech under the direction of Professor of Physics Robert McKeown. Cal State Northridge provides a coordinated educational program for high school teachers to enable their participation in the research project and its incorporation in the high school curriculum. Initial funding for the project has been provided by the Weingart Foundation, the National Science Foundation and Caltech. The Los Alamos National Laboratory has donated over 180 surplus detectors from the decommissioned CYGNUS array (another cosmic ray project), and computers have been donated by IBM.
Monroe HS student studies a GIS map showing the proposed
siting of CHICOS stations in
high schools and middle schools in the San Fernando and
San Gabriel valleys.
During the last decade, the
community of high-energy cosmic ray physicists has constructed a number of very
large (1-100 sq. km) arrays to study cosmic rays at the very highest energies ever
detected (1020 eV). These particles are over one hundred million
(108) times more energetic than those that can be produced in modern
accelerator laboratories. The astrophysical origin of these particles is still
unknown, but it has been generally assumed that they are protons (Hydrogen nuclei).
These particles produce huge ``showers'' of many secondary particles when they
collide with atomic nuclei in the upper atmosphere; the most energetic of these
showers can simultaneously trigger detectors over a several kilometer radius at the
earth's surface. The rate of incidence at the highest energies (1020 eV)
is quite low: in a 100 square kilometer area one observes only about one event per
year. Therefore, it is essential to sample a large surface area (hundreds of square
kilometers) to observe a significant number of these ultra-high energy particles.
In the last several years, the largest previously built array (in Japan) has produced extremely interesting results (see article Science, vol. 281, August 14, 1998, page 891). It appears that these primary particles can be more energetic than previously thought, and so the assumption that they are protons is being seriously questioned. There is even speculation that one could identify ``point'' sources of these particles in the sky. These results have energized the field and even larger arrays are being proposed and built. The primary research goal is to collect more events at these ultra-high energies and characterize their energies and apparent direction of origin.
Crew of students, high school teachers, and research
personnel retrieving detectors in the mountains
of New Mexico in summer 2000.
The Los Angeles basin is ideal for this type of project as there is a very large area (> 5000 km2) of uniformly dense population with available high school infrastructure. We have obtained over 180 scintillation detectors (see Figure 2) from a decommissioned cosmic ray experiment in New Mexico, and are presently instrumenting these detectors in an array with area of more than 400 km2.
Potential CHICOS installation sites in the Los Angeles area are
shown as blue triangles.
Sites operating as of January 2003 are indicated in
yellow, and orange triangles are sites in progress.
Each site has a detection system with a computer to acquire data, and operates in an autonomous mode using GPS time-stamping of events. The data from each site is transmitted via internet to a central computer at Caltech where the data is logged, analyzed, and accessible to the high schools. The availability of existing infrastructure in the Los Angeles school system with internet connections, power, shelter, and willing collaborators provides an excellent opportunity to develop such a large array. Very capable PC's, GPS receivers, and high-speed computer network connections are all recent technical developments that are now ripe for exploitation in a project like CHICOS. Deployment of the CHICOS array began in Fall 2001, resulting in 46 detector sites currently installed and active. We plan to continue deployment of this array in the next 2 years (2003-2004) and operate it as a major research facility.
An educational program for high school teachers at California State University
at Northridge (CSUN) provides teachers with the necessary knowledge to
participate in CHICOS and also to incorporate relevant aspects into the high
school curriculum. CHICOS affords teachers with a unique
opportunity for professional development and participation in forefront
research. They are engaged in a program to develop high school level
curriculum materials relevant to cosmic ray research that are closely coupled
to the California state science education standards. The educational component
of CHICOS has been developed over the past two years by Professor R. Seki of
CSUN, who administers this program as the CHICOS Associate Director for
Education. High school teachers are presently engaged in developing curriculum
materials for the junior and senior high school level and will serve as
mentors for additional teachers as we develop the program. Developed
curriculum materials are available on the
CHICOS classroom website.
The participation of high school teachers, the presence of the CHICOS
apparatus in the school, and the availability of curriculum materials
enables junior and senior high school students to also participate in the
project. As part of their high school science experience, they will be able
to run their site hardware and software just like scientists on experiments
at accelerator facilities. They will perform diagnostics, analyze data, and
develop upgrades to the hardware. High school students and teachers may
participate in summer workshops at Caltech to construct new hardware for
additional sites. Note that the collaborative nature of CHICOS establishes
novel contacts between schools with strong science programs and those that
need improvement.
In the future we would like to expand the scope of this project to cover a larger fraction of the Los Angeles area and include a much larger percentage of junior and senior high schools. Increasing the area to over 1000 km2 would establish a major world-class facility in ultra-high energy cosmic ray physics. Not only would CHICOS then be an important facility for ultra-high energy cosmic ray research in the Northern Hemisphere, but the educational program would then reach more than 10,000 high school students and 300 high school teachers. This proposed project would have a major impact on both cosmic ray research and high school science education in the Los Angeles area. Clearly, CHICOS represents a unique and timely opportunity to combine state-of-the-art research and high school science education.
For more information contact Dr. Theresa Lynn, CHICOS project coordinator, at chicos@caltech.edu.
