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INTRODUCTION

This article discusses the upgrade of the beam position measurement systems in the Recycler BPM, Main Injector BPM, and Flying Wire in RR to meet the required physics precision. It also explores the implementation of dampers in MI and RR to improve beam stability.

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INTRODUCTION

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  1. INTRODUCTION • RECYCLER BPM – Original system not adequate to measure beam position precisely. It is being upgraded to meet the required physics precision. Expected to be ready by end of FY03. • MAIN INJECTOR BPM – Original system 20+ years old. Not able to see beams with different time structures. Physics requirements have been defined for the upgraded system. Technology review to take place. Expected by the end of 03. • FLYING WIRE IN RR – Not part of the original system. Built to detect emittance growth during beam transfer and to measure emittance of the stacked beam. System is being commissioned. • DAMPERS IN MI and RR – Please see the definition on DAMPER page. System to be being commissioned in FY03. • 2.5MHz ACCELERATION –Produce pbar bunches of eL< 2eVs & intensity ~6E10/bunch for Tevatron ppbar operation. Study in progress.

  2. RECYCLER BPM End View Top View COURTSEY – JIM CRISP Split tube BPM Design

  3.  400mA  400mA  30mA

  4. MEASUREMENT PRECISION OVER THE FULL DYNAMIC RANGE FOR RR This is 3s, or ~99.73% of the measurement should be within these limits.

  5. BEAM POSITION MEASUREMENT PRECISION WITH DDC CARD IN RR HP426 VP427 RMS=19mm RMS=9mm HP428 VP429 RMS=18mm RMS=13mm

  6. MAIN INJECTOR BPMs Large Aperture BPM Aperture 4.625”/1.9” MI Ring BPM Aperture 4.625”

  7. MI DYNAMIC RANGE

  8. MEASUREMENT PRECISION OVER THE FULL DYNAMIC RANGE IN MI

  9. DDC TEST RESULTS w/53MHz BEAM • Sampling of 84 consecutive 53MHz(19ns) waveform at every 17ns (60MHz clock). Under Sampled. But due to long train of pulses (84 bunches) one can get away with under sampling. • Beam moving around. • Measured resolution is 0.18% of the aperture. • Intrinsic resolution of the BPM will be better than the number presented here. Raw ADC Sample Number – 17ns Sampling Courtesy: WARREN SCHAPPERT

  10. FLYING WIRE FORK ASSEMBLY FOR THE RECYCLER SYSTEM 30mm Carbon Fiber Wire Resolver FORK Motor SYSTEM IS BEING COMMISSIONED High Vacuum Feedthrough

  11. HORIZONTAL FLYING WIRE IN THE RECYCLER RING ION PUMP TITANIUM SUBLIMATION PUMP FLYING WIRE CAN RECYCLER BEAM PIPE

  12. 2.5 MHz Acceleration Pbar 150 GeV Transition Energy (20.49 GeV) Pbar Beam Injection (From RR/AR) Bunch Rotation at 27 GeV and bunch transfer frm 25MHz bkt to53MHz bkt 53MHz Acceleration MI Ramp used for the 2.5MHz Acceleration and stages of Beam 0peration 2.5 MHz PBAR ACCELERATION IN MI Motivation: Produce pbar bunches of el<2eVs & intensity ~6E10/bunch for Tevatron ppbar operation • Status: • Studies have been conducted using four short batches of protons from the Booster • Produced 2.5 MHz bunches at 8 GeV • Open-loop acceleration to transition energy using 2.5 MHz RF system • Carried out bunch rotation at 27 GeV and four bunches are accelerated to 150 GeV • Work in Progress: • LLRF for 2.5MHz bunch PHIS and RPOS controls • 2.5MHz and 53MHz RF Beam-loading compensation system during acceleration

  13. BEAM DATA FOR 2.5MHz AND 53MHz ACCELERATION SHOWN SEPARATELY Beam Acceleration with 2.5 MHz RF system on a Slow Ramp Beam Acceleration from 27 to 150 GeV on a Fast Ramp } } Mountain Range of 2.5 MHz Acceleration up to Transition Energy Wall Current Monitor data with SBD Injection Beam in 2.5MHz bkts Beam close to Transition

  14. DAMPERS IN THE MI & RR • All MI dampers are controlled by a single digital filter card with a large FPGA (EchoTek) • Longitudinal • Remove coupled-bunch oscillations in beam from Booster • Prevent growth of coupled-bunch instabilities in the MI • Allow bunch rotation to be effective on stacking cycles • Increase coalescing efficiency and reduce momentum spread in TeV • Transverse • Reduce emittance growth from injection steering errors • Reduce any residual emittance growth during the ramp • Permit MI operation at increased intensity for NuMI

  15. ALL-COORDINATE DAMPER WITH ECHOTEK CARD Stripline Pickup FAST ADC Minimal Analog Filter Monster FPGA(s) 14 Transverse Dampers Identical X & Y FAST ADC Minimal Analog Filter Stripline Kicker Power Amp VME FAST DACs 2-10 > 27 MHz Resistive Wall Monitor 106 / 212 MHz FAST ADC Minimal Analog Filter Longi- tudinal (Z) Damper Broadband Cavity Power Amp FAST DACs 2-10 53 MHz, TCLK, MDAT,...

  16. MI TRANSVERSE BUNCH BY BUNCH DAMPERS -RESULTS Damping kick shared for Bunches #41 - #51 Pickup Signal from Bunch #43 CAN ALSO ANTI-DAMP TO BLOW SELECTED BUNCH OUT OF THE MACHINE Ashmanskas, Foster, Wildman, Schappert, Crisp, Nicklaus TURN NUMBER AFTER INJECTION

  17. THREE TURN FILTER FOR TRANSVERSE DAMPER Arbitrary Betatron Phase of Kicker can be accommodated Damper kick is calculated from a single BPM position reading on three successive turns.

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