HEP User Facilities

The High Energy Physics program supports the operation of the following national scientific user facilities:

Proton Accelerator Complex

The Proton Accelerator Complex at Fermi National Accelerator Laboratory is composed of the accelerator complex and several experiments—both actual and proposed--that utilize its protons. The complex currently operates two proton beams that are used to generate neutrinos for short and long baseline neutrino experiments.

Booster Neutrino Beam: The Booster accelerator is a ring 1500 feet in circumference that receives 400 MeV protons from the linac and accelerates them to 8 GeV. These protons then strike a 71-cm long beryllium target used to generate an intense muon neutrino beam used for two short baseline neutrino oscillation experiments, one currently operating, the other planned:

• MiniBooNE: The purpose of the MiniBooNE experiment is to either confirm or deny the controversial existence of a fourth type of neutrino, the so-called sterile neutrino. The MiniBooNE tank is a Cerenkov detector 12 meters in diameter, filled with approximately 800 tons of mineral oil, and has 1520 photomultiplier tubes lining the inside that are used to identify the oscillations of muon neutrinos into electron neutrinos. The MiniBooNE detector also sees neutrinos from the NuMI beam line (see below).
• MicroBooNE: This experiment will build and operate a large, approximately 100-ton, liquid Argon Time Projection Chamber (LArTPC). The experiment will measure low energy neutrino cross sections, and investigate the low energy excess events observed by the MiniBooNE experiment. The detector serves as the necessary next step in a phased program towards the construction of massive, kilo-ton range, LArTPC detectors.

Neutrinos at the Main Injector (NuMI): The Main Injector takes the 8 GeV protons from the Booster and accelerates them to approximately 150 GeV. As in the Booster, these highly energetic protons strike a target—in this case a carbon target—to generate muons that subsequently decay to muon neutrinos. The result is the most intense neutrino beam in the world. The muon neutrino beam is used for studies of both the disappearance of muon neutrinos and the appearance of non-muon neutrinos such as electron and tau neutrinos. Two experiments currently gather data from the NuMI beam line; a third is under construction:

• Main Injector Neutrino Oscillation Search (MINOS): The MINOS Experiment is a long-baseline neutrino experiment designed to observe the phenomena of neutrino oscillations, an effect which is related to neutrino mass. MINOS uses two detectors, one located at Fermilab, at the source of the neutrinos, and the other located 450 miles away, in northern Minnesota, at the Soudan Underground Mine.
• MINERvA: This is a neutrino scattering experiment that seeks to measure low energy neutrino interactions both in support of neutrino oscillation experiments and also to study the strong dynamics of the nucleon and nucleus that affect these interactions.
• NOvA: Under construction, the NOvA detector will utilize the NuMI beam from Fermilab to directly observe for the first time the transformation of muon neutrinos into electron neutrinos. NOvA will also make important indirect measurements of the mass ordering for the three known neutrino types (i.e., whether there are two “light” and one “heavier” type of neutrino or vice versa), which will be a key piece of information in determining the currently unknown masses of neutrinos.

Facility for Advanced Accelerator Experimental Tests (FACET)

FACET is a 23 GeV electron-beam driven plasma wakefield accelerator test facility located at SLAC National Accelerator Laboratory. It has been optimized for tests of plasma wakefield acceleration with high energy beams of electrons or positrons with short duration pulses. It is open to all users that need such beams with access based on peer review of annually solicited proposals.