Intensity Measurements through the Stacking Cycle

Recycler/Pbar Beam Physics Meeting

Keith Gollwitzer

January 14, 2005

What Intensities?

• Currently ~5x1012 protons on target.

• Secondaries in AP2 and early in the Debuncher ~109 particles

• Circulating in Debuncher and transferred to Accumulator is ~7.5x107 pbars

• Accumulator core increases up to ~1.5x1012 pbars

Different Measurements• One pass

– Toroids (Dave P.)– SEMs relative measurements; blows up beam– Ion Chamber small blow up of beam– Gap Monitor INJFLX; first pass in Debuncher

• Circulating in Debuncher – BPM Intensity require bunch/debunch during

stacking cycle– DCCT (Dave P.)– FFT prior to extraction Longitudinal coherence

• Circulating in Accumulator– FFT on injection orbit Longitudinal coherence– BPM Intensity for free during ARF1 ramp– Deposition orbit new stacktail monitor

One Pass Measurements During Stacking

Toroid SEM Gap Monitor (INJFLX)Ion ChamberSolid – Existing Dashed – FutureDotted – Not Stack

DtoA Transfer

SEM Intensity measurement from area of fit

Dependent upon being able to subtract noiseWires intercept beam and cause beam blow-up

Shown here is special Debuncher SEM403.

Two vertical peaks are the injection pass and closed orbit.

Beam is completely killed by multiple closed orbit passes.

Different Measurements• One pass

– Toroids (Dave P.)– SEMs relative measurements; blows up beam– Ion Chamber small blow up of beam– Gap Monitor INJFLX; first pass in Debuncher

• Circulating in Debuncher – BPM Intensity require bunch/debunch during

stacking cycle– DCCT (Dave P.)– FFT prior to extraction Longitudinal coherence

• Circulating in Accumulator– FFT on injection orbit Longitudinal coherence– BPM Intensity for free during ARF1 ramp– Deposition orbit new stacktail monitor

Flux capacitor (INJFLX) from mixing the gap monitor with the RF signal

Being updated to be a java OAC.

Overhead seems to limit to 3-4sec per update; being worked upon.

Different Measurements• One pass

– Toroids (Dave P.)– SEMs relative measurements; blows up beam– Ion Chamber small blow up of beam– Gap Monitor INJFLX; first pass in Debuncher

• Circulating in Debuncher – BPM Intensity require bunch/debunch during

stacking cycle– DCCT (Dave P.)– FFT prior to extraction Longitudinal coherence

• Circulating in Accumulator– FFT on injection orbit Longitudinal coherence– BPM Intensity for free during ARF1 ramp– Deposition orbit new stacktail monitor

DRF1 bunching pbars prior to the end of the stacking cycle in the Debunchers

P2 curve design ; time is with respect to $80

Beam Injection

Beam Extraction

Sample BPMduring 20ms

flat top

Sample timefor ACNET DAQ

Switching plate BPM signal sent through a SA at zero span and small resolution bandwidth (averaging) and its video

output sent to an oscilloscope input triggered via D:TBT ($83)

Injection of secondaries and

debunching

Bunch and Debunch beam for intensity sampling

Not the same P2 curve as previous slide

Blow-up time scale and pull trace of “flat-top” signal and process height for ACNET variable

In the future, SA and scope setup will be replaced by Ashmanskas board

Simple comparison of Intensities

TOR109 (10^12 protons)

BPM Intensity (arb)

IC728 (10^8 secondaries)

Histogramming of Intensities

BPM Intensity

IC728 / TOR109

BPM / TOR109

BPM / IC728 ~3% Width

Different Measurements• One pass

– Toroids (Dave P.)– SEMs relative measurements; blows up beam– Ion Chamber small blow up of beam– Gap Monitor INJFLX; first pass in Debuncher

• Circulating in Debuncher – BPM Intensity require bunch/debunch during

stacking cycle– DCCT (Dave P.)– FFT prior to extraction Longitudinal coherence

• Circulating in Accumulator– FFT on injection orbit Longitudinal coherence– BPM Intensity for free during ARF1 ramp– Deposition orbit new stacktail monitor

Recent Changes to FFT 1st look at “stability”

Previous version had averaging and history involved.

Coherence would affect signal for awhile.

Also saw periodic behavior.

Now trying to place in OAC

Averaging but no history.

Coherence – What to do

Paul Derwent is investigating

AccumulatorDebuncher

Different Measurements• One pass

– Toroids (Dave P.)– SEMs relative measurements; blows up beam– Ion Chamber small blow up of beam– Gap Monitor INJFLX; first pass in Debuncher

• Circulating in Debuncher – BPM Intensity require bunch/debunch during

stacking cycle– DCCT (Dave P.)– FFT prior to extraction Longitudinal coherence

• Circulating in Accumulator– FFT on injection orbit Longitudinal coherence– BPM Intensity for free during ARF1 ramp– Deposition orbit new stacktail monitor

New Stacktail Monitor• Main purpose is to

watch deposition area and monitor how efficiently the stacktail system clears the deposition orbit area (the width of ARF1 bucket).– Essentially measures

power prior and after ARF1 deposits beam.

• Can use as relative measure of beam on deposition orbit(?) To be Seen.

Comment about Events & Timeline

• It has been noticed that the “stability” of intensity signals during stacking is dependent upon Event and Timeline– There can be a yield difference between pure

$29 slip stacking events and $21 mixed mode stacking + switchyard event: up to 10% for IC728/TOR109

– The TLG does not make it easy for consistent $80 spacing; in general stacking cycle time varies.

– One shots and other study cycles