Eric Prebys

IOTA (Integrable Optics Test Accelerator): facility and experimental beam physics program

The Integrable Optics Test Accelerator (IOTA) is a storage ring for advanced beam physics research currently being built and commissioned at Fermilab. It will operate with protons and electrons using injectors with momenta of 70 and 150 MeV/c, respectively. The research program includes the study of nonlinear focusing integrable optical beam lattices based on special magnets and electron lenses, beam dynamics of space-charge effects and their compensation, optical stochastic cooling, and several other experiments. In this article, we present the design and main parameters of the facility, outline progress to date and provide the timeline of the construction, commissioning and research. The physical principles, design, and hardware implementation plans for the major IOTA experiments are also discussed.

Application of Independent Component Analysis for Beam Diagnosis

The independent component analysis (ICA) is applied to analyze simultaneous multiple turn-by-turn beam position monitor (BPM) data of synchrotrons. The sampled data are decomposed to physically independent source signals, such as betatron motion, synchrotron motion and other perturbation sources. The decomposition is based on simultaneous diagonalization of several unequal time covariance matrices, unlike the model independent analysis (MIA), which uses equal-time covariance matrix only. Consequently the new method has advantage over MIA in isolating the independent modes and is more robust under the influence of contaminating signals of bad BPMs. The spatial pattern and temporal pattern of each resulting component (mode) can be used to identify and analyze the associated physical cause. Beam optics can be studied on the basis of the betatron modes. The method has been successfully applied to the Booster Synchrotron at Fermilab.

Electron Lens for the Fermilab Integrable Optics Test Accelerator

The Integrable Optics Test Accelerator (IOTA) is a research machine currently being designed and built at Fermilab. The research program includes the study of nonlinear integrable lattices, beam dynamics with self fields, and optical stochastic cooling. One section of the ring will contain an electron lens, a low-energy magnetized electron beam overlapping with the circulating beam. The electron lens can work as a nonlinear element, as an electron cooler, or as a space-charge compensator. We describe the physical principles, experiment design, and hardware implementation plans for the IOTA electron lens.

Hamamatsu PMT R7056 study for the extinction monitoring system of the Mu2e experiment at Fermilab

The Mu2e experiment at Fermilab proposes to search for the coherent neutrino-less conversion of muons to electrons in the presence of a nucleus. The experimental signature for an aluminum target is an isolated 105 MeV electron exiting the stopping target no earlier than ~700 ns after the pulse of proton beam hits the production target. Any protons that hit the production target in between the pulses can lead to fake conversion electrons during the measurement period. We define the beam extinction as the ratio of the number of protons striking the production target between pulses to the number striking the target during the pulses. It has been established that an extinction of approximately 10-10 is required to reduce the backgrounds to an acceptable level. It would be desirable to measure the extinction of the beam coming out of the accelerator in a minute or less. Studies for the fast extinction monitor based on Hamamatsu PMT R7056 is the subject of this presentation.

Extinction in the Mu2e Beam Line

The proposed Mu2e experiment at Fermilab has very specific requirements for the proton beam which is used to produce muons. It requires short proton bunches (<100 ns FW), separated by 1–2 μsec. It is vital that the beam outside of the bunches be suppressed at a level of at least 109 relative to the beam in the bunches. This note briefly presents the motivation for this “extinction” requirement, and then describes how the experiment hopes to achieve it. Finally, possible techniques for measuring the extinction will be discussed.