IceCube is an international project sponsored and conducted by the United States and several non-U.S. countries and funding agencies. The project is defined by the IceCube Science Requirements necessary to realize the scientific goals of the project. These science requirements in turn impose an extensive set of engineering requirements on the entire IceCube system. With several different institutions involved in all phases of the project, clear allocation of responsibilities and coordination of effort is key to project efficiency and success. Each collaboration participant has it's own established practices, traditions, and local requirements, which must be accommodated by collaboration management practices while being tailored to meet collaboration needs. Communication and maintenance of the engineering requirements, and when necessary, managing their modification, are critical tasks. Much of the construction and operation of the project will take place in an extremely harsh and difficult environment, making the issues of reliability and safety of paramount importance.
IceCube is a neutrino observatory for astrophysics to be installed at the South Pole during Austral summers over approximately six years. The IceCube In-Ice detector will consist of a minimum of 4200 optical modules deployed on 70 vertical strings buried 1450 to 2450 meters under the surface of the ice, and an IceTop surface air-shower detector array comprised of a minimum of 280 optical modules. Once a significant fraction of the IceCube array is completed it will be operated and used for scientific investigations as the maturity of the system allows. The completed detector will be operated for 20 years. The detector is being designed, built, installed and used for research by an international collaboration. Funding institutions in the home countries of the collaborators provide funds for the construction of the detector and for research using the detector. The United States National Science Foundation supplies funds for the design, development, fabrication, procurement, testing, drilling and operations of the project at the South Pole. Funding for construction is provided through the Major Research Equipment and Facilities Construction (MREFC) budget account. Operations funding will be provided through the Research and Related Activities (R&RA) budget account. As the host institution, the University of Wisconsin-Madison, with support from the National Science Foundation, provides oversight and staffing for the execution of the project and development of key components. The AMANDA Project now in operation at the South Pole serves as a prototype for the improved and expanded IceCube Project.
Many parts of the universe are inaccessible for study using other types of cosmic rays: protons do not carry directional information because of their deflection by magnetic fields, neutrons decay before reaching the earth and high-energy photons are absorbed. IceCube will open unexplored wavelength bands for astronomy including the PeV (1015 eV) energy region. IceCube will answer such fundamental questions as to the physical conditions in gamma ray bursts and whether the multi-TeV photons, originating in the Crab supernova remnant and near the super massive black holes of active galaxies (AGNs), are of hadronic or electromagnetic origin. Data from the Chandra X-ray satellite demonstrate that the "diffuse" extragalactic X-ray background (as observed with instruments of low angular resolution like IceCube) consists mostly of accumulated radiation from all AGN sources. Models of the radiation producing processes in AGNs can provide a prediction as to the "diffuse" flux of high-energy neutrinos. Figure 1-1 shows the results of a variety of such models and illustrates the discovery reach of IceCube. The broad, dark, steep spectrum is the atmospheric background. IceCube also occupies a unique place in the multi-prong attack on the particle nature of dark matter. With unmatched sensitivity to cold dark matter particles approaching TeV masses, IceCube will be sensitive to supernova within our galaxy. As a particle physics detector capable of detecting neutrinos with energies far above those produced at accelerators, IceCube will search for super-symmetric particles and the topological defects created during grand unified phase transitions in the early universe. The detection of cosmic neutrino beams will also make it possible to study neutrino oscillations over megaparsec baselines.
As history has demonstrated, the opening of each new astronomical window has led to unexpected discoveries. The true possibility of IceCube is discovery.
The target geometry of the IceCube Neutrino Observatory consists of a regularly spaced array of a minimum of 4200 photomultiplier tubes buried between 1450 to 2450 meters below the surface of the South Pole ice and a surface air shower detector, IceTop, Consisting of four photomultiplier tubes in two surface tanks at each In-Ice string location. The array covers an area of about 1 square km as shown in Figure 1-2.
The photomultiplier tubes will record Cerenkov radiation from charged particle progenitors of neutrino interactions in the ice. Each photomultiplier is enclosed in a transparent pressure sphere, a Digital Optical Module (DOM). The DOM also contains a digitally controlled high voltage supply to power the photomultiplier, an analog transient waveform digitizer and LED flashers. The configuration of an IceCube string is depicted schematically in Figure 1-3. The AMANDA array will be contained within the plan view projection of the IceCube detector. The SPASE scintillator array on the surface is also over the IceCube detector. The signals digitized in the Digital Optical Modules (DOM) are communicated to the surface, via twisted pairs, to the data acquisition and data analysis system at the surface. Data is transmitted via satellite from the South Pole to data storage facilities accessible to the collaboration for its data analysis effort.
The NSF is the Executive Agent with responsibility for seeing that the Project meets its baseline requirements of cost, schedule, scope, and technical performance. The NSF has a special role in IceCube because of its Host Laboratory responsibilities in managing operation of the Amundson-Scott South Pole Station. These responsibilities include: safety; physical qualification of project staff; environmental protection; transport of personnel, fuel and equipment; and the provision of housing, food service, support personnel, logistical support, IT support, and general infrastructure support.
An International Oversight and Finance Group will provide oversight and financial support for the IceCube project. The Group organizes annual oversight reviews of the construction project and meets annually to discuss project performance. The Group also sets policies for receiving periodic progress reports on all aspects of the project and by all the performers in the project, and for conducting external reviews when appropriate.
A representative of the National Science Foundation chairs the IOFG. Membership is comprised of representatives of the funding agencies in the partner countries supporting the construction and operation of IceCube Neutrino Observatory. The Group is informed by the Spokesperson of the Collaboration, the Project Director, the Principal Investigator and others as appropriate.