f Tevatron Software Digital Receiver Beam Line Tuner Vic Scarpine Instrumentation Instrumentation Meeting July 13, 2005

f Instrumentation Meeting - TeV BLT2 Introduction Primary function of a Beam Line Tuner (BLT) is to measure turn-by-turn transverse beam positions for all bunches during transfers from one accelerator ring to another –Can measure betatron oscillations, fractional tune, coupling, time- of-arrival, synchrotron oscillations, emittance growth, etc Focus has been on betatron measurements for improved closing –Feed-forward correction system – correct magnets for next transfer BLT is a key component for reducing transverse emittances and increase luminosity

f July 13, 2005Instrumentation Meeting - TeV BLT3 Tevatron BLT Measure all proton and pbar transfers from Main Injector to Tevatron Requirements: 1.Measure initial injection oscillations for every proton and pbar bunch 2.Measure tunes, emittance growth, synchrotron frequency 3.Measure bunch time-of-arrival relative to RF Beam formats: –Pbar: Four 53 MHz bunches separated by 392 ns at 150 GeV –Protons: Single 53 MHz bunch at 150 GeV

f July 13, 2005Instrumentation Meeting - TeV BLT4 Basic BLT System

f July 13, 2005Instrumentation Meeting - TeV BLT5 Analog Signals - Striplines and Fanout TeV Stripline Parameters: –~ 30 dB directionality –1 meter long (< 1/4 ) –D = 83 mm –0.65 dB/mm Sensitivity –Located at near F0 Optimally separated proton and pbars Fanout Box –M/A-Com H-9 Junction Hybrid generates A+B and A-B

f July 13, 2005Instrumentation Meeting - TeV BLT6 Tevatron Scope BLT Use Tektronix TDS7104 as fast waveform digitizer –2.5 GSample/sec/channel –Segmented memory –Embedded PC/Windows Samples pbar bunches each transfer Signal processing analysis of waveform in Scope PC Decimate data to single position per bunch –Pbars – 64 turns –Too slow for protons Only used for closing pbars

f July 13, 2005Instrumentation Meeting - TeV BLT7 Tevatron Software Digital Receiver BLT Software Digital Receiver system for pbars (similar for protons) 30 MHz LP to ring single 53 MHz bunch Digitize bunches at 2*RF Transfer digital data to PC Down convert at 30 MHz Correlate with window function –Correlation max gives A and B Generate position and time-of- arrival for ~ 1000 turns

f July 13, 2005Instrumentation Meeting - TeV BLT8 Tev BLT Trigger UCD VXI trigger module –Use TCLK and BSCLK to trigger pattern generator turn-by-turn at injection –Use pattern generator to gate Struck digitizing card for injected proton or pbar bunches

f July 13, 2005Instrumentation Meeting - TeV BLT9 Tev BLT Digitizer Struck SIS3300 Digitizing card –8 ADC channels per board –12 bit ADCs –Digitizing clock at 106 MHz (2*RF) –128K samples per channel –128 sample per turn for 1024 turns 4 x 32 sample per pbar bunch (~ 320 ns window for each pbar bunch) 30 MHz signal damps out in ~150 ns

f July 13, 2005Instrumentation Meeting - TeV BLT10 Analog Signals 53 MHz signal too short for 106 MHz digitizer Stretch signal using 30 MHz low-pass filter

f July 13, 2005Instrumentation Meeting - TeV BLT11 Down Conversion Down convert digitized signal

f July 13, 2005Instrumentation Meeting - TeV BLT12 Windows for Convolution

f July 13, 2005Instrumentation Meeting - TeV BLT13 Convolution Use peak of each convolution bump for A and B values

f July 13, 2005Instrumentation Meeting - TeV BLT14 Store 4175 Proton Vertical Oscillations

f July 13, 2005Instrumentation Meeting - TeV BLT15 Store 4175 Proton Horizontal Oscillations

f July 13, 2005Instrumentation Meeting - TeV BLT16 Store 4175 Injections Oscillations

f July 13, 2005Instrumentation Meeting - TeV BLT17 Store 4210 Pbar Injections Why is 4 th bunch different closed orbit than first three bunches? (Of course it can’t be!)

f July 13, 2005Instrumentation Meeting - TeV BLT18 Proton Contamination on Pbars Two effects: 1.Proton reflection 600 ns later falls on pbar bunch (except for last pbar) 2.Proton signal generates some sort of structured reflection in pbar signal Fix: Add 10 db attenuators at stripline on proton signal cables

f July 13, 2005Instrumentation Meeting - TeV BLT19 Pbar Oscillations after Attenuators

f July 13, 2005Instrumentation Meeting - TeV BLT20 Pbar Fractional Tunes

f July 13, 2005Instrumentation Meeting - TeV BLT21 Pbar Time of Arrival Relative to RF Use real and imaginary portions of convolution to determine phase of bunch relative to RF T = 1/(2  f)*atan(Imag/Real)

f July 13, 2005Instrumentation Meeting - TeV BLT22 Summary Tevatron software Digital Receiver BLT measuring turn- by-turn transverse positions for all proton and pbar bunches for each shot for 1000 turns –Position information being used for emittance growth estimates BLT also determining bunch time-of-arrival relative to RF Presently system only used for time-of-arrival information Want to use system to close on protons (and possible close on pbars)

f July 13, 2005Instrumentation Meeting - TeV BLT23