Operational Use of Ionization Profile Monitors at Fermilab*

Ionization profile monitors (IPMs) are installed in the Fermilab Booster, Main Injector and Tevatron. They are used routinely for injection matching measurements. For emittance measurements the IPMs have played a secondary role to the Flying Wires, with the exception of the Booster (where it is the only profile diagnostics). 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 and injection matching measurements at Fermilab, and summarizes the future plans. INSTALLATION LOCATIONS AND OPERATING CONDITIONS IPMs are used in three accelerators at Fermilab. Booster and Main Injector IPMs are designed to collect a data sample once per machine revolution. The Booster has two electrostatic units that collect ions using an 8 KV clearing field. These units collect data in the Booster throughout its complete operating cycle of about 20,000 turns. At injection (400 MeV) the revolution period is 2.25 μsec. At extraction (8 GeV) this period drops to 1.5 μsec. The Main Injector has two electrostatic units, one horizontal and one vertical, operating at 28 KV, collecting ions and producing data each 11.1 μsec. An additional horizontal unit was installed with a 1 KGauss magnetic field, and 10 KV clearing field which allows the collection of electrons,. The magnetic field confines liberated electrons to orbits smaller than the anode pickup strips which minimizes the deleterious effect of space charge from the beam. The Main Injector IPMs are limited to the 65K samples of the current digitizer, however by skipping turns during acquisition, the full cycle can be measured. The Tevatron has two magnetic units of 1KGauss and a 10 KV clearing field. As explained later, these units are capable of sampling 36 proton and 36 antiprotons (pbars) bunches, turn by turn, for up to 1000 turns.