No Arabic abstract
For Project X, it is planned to inject a beam of 3 10**11 particles per bunch into the Main Injector. To prepare for this by studying the effects of higher intensity bunches in the Main Injector it is necessary to perform coalescing at 8 GeV. The results of a series of experiments and simulations of 8 GeV coalescing are presented. To increase the coalescing efficiency adiabatic reduction of the 53 MHz RF is required, resulting in ~70% coalescing efficiency of 5 initial bunches. Data using wall current monitors has been taken to compare previous work and new simulations for 53 MHz RF reduction, bunch rotations and coalescing, good agreement between experiment and simulation was found. Possible schemes to increase the coalescing efficiency and generate even higher intensity bunches are discussed. These require improving the timing resolution of the low level RF and/or tuning the adiabatic voltage reduction of the 53 MHz.
At the end of its operations in 2011, the Fermilab antiproton production complex consisted of a sophisticated target system, three 8-GeV storage rings (namely the Debuncher, the Accumulator and the Recycler), 25 independent multi-GHz stochastic cooling systems, the worlds only relativistic electron cooling system and a team of technical experts equal to none. The accelerator complex at Fermilab supported a broad physics program including the Tevatron Collider Run II, neutrino experiments using 8-GeV and 120-GeV proton beams, as well as a test beam facility and other fixed target experiments using 120-GeV primary proton beams. This paper provides a brief description of Fermilab accelerators as they operated at the end of the Collider Run II (2011).
In conjunction with efforts to predict residual radiation levels in the Fermilab Main Injector, measurements of residual radiation were correlated with the time history of losses. Detailed examination suggested that the list of radioactive isotopes used for fitting was incomplete. We will report on activation studies of magnet steel and copper samples which we irradiated adjacent to the Fermilab Main Injector collimation system. Our results identified several additional radioactive isotopes of interest. The MARS15 studies using a simplified model are compared with measurements. The long half-life isotopes will grow in importance as operation stretches to a second decade and as loss rates rise. These studies allow us to predict limits on these concerns.
Ionization profile monitors (IPMs) are used in the Fermilab Main Injector (MI) to monitor injection lattice matching by measuring turn-by-turn sigmas at injection and to measure transverse emittance of the beam during the acceleration cycle. The IPMs provide a periodic, non-destructive means of performing turn-by-turn emittance measurements where other techniques are not applicable. As Fermilab is refocusing its attention on the intensity frontier, non-intercepting diagnostics such as IPMs are expected to become even more important. This paper gives an overview of the operational use of IPMs for emittance measurements and injection lattice matching measurements at Fermilab, and summarizes the future plans.
From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at ~400 kW beam power. Transmission was very high except for beam lost at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the improvements required to achieve high intensity, the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.
We have measured cross sections for forward neutron production from a variety of targets using proton beams from the Fermilab Main Injector. Measurements were performed for proton beam momenta of 58 GeV/c, 84 GeV/c, and 120 GeV/c. The cross section dependence on the atomic weight (A) of the targets was found to vary as $A^(alpha)$ where $alpha$ is $0.46pm0.06$ for a beam momentum of 58 GeV/c and 0.54$pm$0.05 for 120 GeV/c. The cross sections show reasonable agreement with FLUKA and DPMJET Monte Carlos. Comparisons have also been made with the LAQGSM Monte Carlo.