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As part of the NOvA upgrades in 2012, the Recycler was repurposed as a proton stacker for the Main Injector with the aim to deliver 700 kW. Since January 2017, this design power has been run routinely. The steps taken to commission the Recycler and run at 700 kW operationally will be discussed. Major improvements include a new collimation system to control transverse losses and diode damper system to damp the resistive wall instability during slip-stacking. Plans for future running will also be discussed.

The International Linear Collider reference design requires over 13000 magnets, of approximately 135 styles, which must operate with very high reliability. The Fermilab Main Injector represents a modern machine with many conventional magnet styles, each of significant quantity, that has now accumulated many hundreds of magnet-years of operation. We review here the performance of the magnets built for this machine, assess their reliability and categorize the failure modes, and discuss implications for reliability of similar magnet styles expected to be used at the ILC.

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.

A VME-based data acquisition system for beam-loss monitors has been developed and is in use in the Tevatron and Main Injector accelerators at the Fermilab complex. The need for enhanced beam-loss protection when the Tevatron is operating in collider-mode was the main driving force for the new design. Prior to the implementation of the present system, the beam-loss monitor system was disabled during collider operation and protection of the Tevatron magnets relied on the quench protection system. The new Beam-Loss Monitor system allows appropriate abort logic and thresholds to be set over the full set of collider operating conditions. The system also records a history of beam-loss data prior to a beam-abort event for post-abort analysis. Installation of the Main Injector system occurred in the fall of 2006 and the Tevatron system in the summer of 2007. Both systems were fully operation by the summer of 2008. In this paper we report on the overall system design, provide a description of its normal operation, and show a number of examples of its use in both the Main Injector and Tevatron., Comment: 24 pages

A two-year Large Aperture Quadrupole (WQB) Project was completed in the summer of 2006 at Fermilab. Nine WQBs were designed, fabricated and bench-tested by the Technical Division. Seven of them were installed in the Main Injector and the other two for spares. They perform well. The aperture increase meets the design goal and the perturbation to the lattice is minimal. The machine acceptance in the injection and extraction regions is increased from 40pi to 60pi mm-mrad. This paper gives a brief report of the operation and performance of these magnets., 2007 Particle Accelerator Conference (PAC07)

Two barrier RF systems were fabricated, tested and installed in the Fermilab Main Injector. Each can provide 8 kV rectangular pulses (the RF barriers) at 90 kHz. When a stationary barrier is combined with a moving barrier, injected beams from the Booster can be continuously deflected, folded and stacked in the Main Injector, which leads to doubling of the beam intensity. This paper gives a report on the beam experiment using this novel technology., Comment: 2007 Particle Accelerator Conference (PAC07)

High intensity operation of the Fermilab Main Injector has resulted in increased activation of machine components. Efforts to permit operation at high power include creation of collimation systems to localize losses away from locations which require maintenance. As a first step, a collimation system to remove halo from the incoming beam was installed in the Spring 2006 Facility Shutdown [1]. We report on commissioning studies and operational experience including observations of Booster beam properties, effects on Main Injector loss and activation, and operational results.

A collimation system has been created for removing proton beam halo in the 8 GeV transfer line from the Fermilab Booster to Main Injector. A pair of 1.14 meter long collimators with 5.08 cm rectangular apertures is installed in a 5-m straight section. Horizontal and vertical motion systems allow them to be positioned such that halo can be scraped from four sides. An additional pair of collimators, placed one cell (90 degrees) downstream, scrape halo which is of opposite phase. Each collimator pair can scrape about 600 Watts of beam power, limited by residual activation of beamline components and sump water outside of the beam line tunnel. Personnel exposure is reduced by surrounding the iron absorber with a layer of marble. Design features, radiation calculations and instrumentation considerations will be described.

Recently we have adopted a scheme, called “Mixed pbar Source Operation” in the Fermilab Main Injector (MI). The purpose of this mode of operation is to transfer pbar bunches from the Recycler and the Accumulator to the Tevatron for collider shots. In this scheme, four 2.5 MHz pbar bunches are injected in to the MI, re-bunched in four groups of 53 MHz bunches at 8 GeV, accelerated to 150 GeV, and coalesced in to four 53 MHz bunches before transfer to the Tevatron. A special magnet ramp is needed in the MI to allow for pbar beam of slightly different 8 GeV energies from the Recycler and the Accumulator. Here we will present the status of this scheme.

We describe methods used to measure and control tunes in the Fermilab Main Injector (FMI). Emphasis is given to software implementation of the operator interface, to the front-end embedded computer system, and handling of hysteresis of main dipole and quadrupole magnets. Techniques are developed to permit control of tune of the Main Injector through several acceleration cycles: from 8.9 GeV/c to 120 GeV/c, from 8.9 GeV/c to 150 GeV/c, and from 150 GeV/c to 8.9 GeV/c. Systems which automate the complex interactions between tune measurement and the variety of ramping options are described. Some results of tune measurements and their comparison with the design model are presented.

Changes made to the Fermilab Main Ring lattice and the Main Ring's future importance for the HEP program require a new study of its physical aperture. This task has been carried out using a computer program that automatically and systematically measures the available aperture around the ring. This program and its performance are described along with a preliminary analysis of the results. Further systematic analysis of aperture data is underway in preparation for modifications to be made in the coming summer shutdown. >

A programmable system has been constructed to provide an easy means to display beam intensities and efficiencies from the various Fermilab accelerators. The purpose of these displays is to provide an alternative display method for this information. The system consists of a central microprocessor, a data acquisition subsystem, an interface to the Fermilab control system, and a link driver to drive multiple displays consisting of the name of the parameter being displayed, the units for the parameter displayed, the time the data was taken, and the actual data. The final system will have a display box at each control console in the main control room. >

The Fermilab Main Ring has three different systems for measuring the betatron tune. The three systems are designed around a resonant beam pickup which interfaces to independent data collecting hardware. The data collecting hardware systems consist of a Hewlett Packard 35665A dynamic signal analyzer, a Tektronix 3052 DSP and a generic finite state data acquisition (GFSDA) microprocessor system. This paper will describe the systems and the methods for measuring the betatron tune and chromaticity in the Fermilab Main Ring.

Increasing the proton intensity available for antiproton production is part of a plan for increasing the luminosity in the Fermilab Tevatron in the near future. We intend to increase the proton intensity using a kind of momentum stacking in the Main Injector called Slip Stacking. We report the status of the effort towards its implementation.

In this report we present the results of beam dynamics simulations as well as experiments with protons for deceleration from 150 GeV to 8.9 GeV in the Fermilab Main Injector (MI). The simulations are carried out on two different deceleration schemes: deceleration with a fast recovery MI cycle and with a slow recovery cycle. As a proof of principle we have carried out the first successful deceleration using proton beam in the Main Injector from the Tevatron extraction energy of 150 GeV to the Recycler injection energy of 8.9 GeV.

We discuss both simulations as well as experimental studies of a potentially beneficial acceleration scheme in the MI for pbars from the Accumulator Ring or Recycler Ring. The scheme involves accepting the pbar bunches with 2.5 MHz RF structure from either of these two synchrotrons. Re-bunching using the 53 MHz RF system isoadiabatically and accelerating using 53 MHz RF system from 8 GeV to 150 GeV. Further we try to coalesce the beam using the 2.5 MHz RF system. Various stages of RF manipulation are discussed and some improvements are also suggested.

Many times there is a need to establish ratio communication between the surface and a beam enclosure. When one solicits communication companies for solutions, the answer is often to purchase expensive communication equipment such as repeaters or radiax type cable which can cost in the tens of thousands of dollars. This TM will describe an inexpensive solution to this problem and the results that can be expected. The cost of a passive repeater is $100--$200 depending on how elaborate one wants to be. A passive repeater system consists of two antennas connected together with a transmission line. When using VHF or UHF transceivers, one can use 5/8 wave mobile antennas, such as the Larson NMO406-CK for the 400--420 MHz range, with the antenna connected to a 19 inch square piece of aluminum to act as a ground plane. This type of antenna has reasonably good gain, seems to be adequate, and is inexpensive. Another antenna choice is to cut a dipole out of bus wire and solder this wire to a female N connector. Using a dipole seems to work OK in the tunnel and avoids the problem of having a wire sticking down for people to poke their eye with. The cable connecting the antennas should be of good quality so that the signal lost in the cable is minimal. The authors chose Belden 9913 coax. This cable has a characteristic impedance of 50 ohms and has 2.7 dB/100 ft. of attenuation at 400 MHz.