RR pbar Longitudinal Emittance during Beam Stacking and Unstacking and Some Issues Chandra Bhat MI/RR Group February 12, 2003 • Data Collection – RTD720 scope and RR wall current monitor and R86 ( by Ming-Jen) – A TCLK event for multiple triggers in sequence (by Craig McClure and Greg Vogel) • Case Studied – Pbar Stacking – Pbar Un-stacking – De-bunching and Re-bunching in 2.5 MHz rf buckets – Compression and De-compression • Issues { With protons
Data Collection RTD720 scope and RR wall current monitor and R86 ( by Ming-Jen)
Jan 13, 2016
{. With protons. RR pbar Longitudinal Emittance during Beam Stacking and Unstacking and Some Issues Chandra Bhat MI/RR Group February 12, 2003. Data Collection RTD720 scope and RR wall current monitor and R86 ( by Ming-Jen) - PowerPoint PPT Presentation
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RR pbar Longitudinal Emittance during Beam Stacking and Unstacking
and Some IssuesChandra Bhat MI/RR Group
February 12, 2003
• Data Collection– RTD720 scope and RR wall current monitor
and R86 ( by Ming-Jen)
– A TCLK event for multiple triggers in sequence
(by Craig McClure and Greg Vogel)
• Case Studied – Pbar Stacking
– Pbar Un-stacking
– De-bunching and Re-bunching in 2.5 MHz rf buckets
– Compression and De-compression
• Issues
{With protons
Dedicated Variable Event
A new TCLK event E6 is allotted for this purpose for future usage
WCM data of Pbar stacking(AR MIRR Transfer 2, January 10, 2003)
Four Different Timing during Stacking
l =13eVsl =64eVsE/E=0.29%
l =64eVs E/E=0.29%
l =14.5eVs E/E=0.27%
l =81eVsE/E=0.23%
l =88eVsE/E=0.13%
l =77eVs
l =78.5eVs
RR WCM data of Pbar Un-stacking (RRMI Transfer 4, January 8, 2003)
Three Different Timing during Un-stacking
l = 46eVs E/E=0.33%
l = 29eVs E/E=0.31%
l = 15eVs E/E=0.1%
l = 29eVs E/E=0.31%
l > 13.7eVs
(52bkts)
(85bkts)
(26bkts)
(26bkts)
(85bkts)
l = 44eVs
l >42.7eVs
Pbar Un-stacking (RRMI Transfer 5, January 8, 2003)
l = 29eVs E/E=0.31%
l = 11.5eVs E/E=0.26%
l >13.7eVs
l = 17eVs E/E=0.30% l >30.7eVs
l =28.5eVs
Pbar Un-stacking (RRMI Transfer 6, January 8, 2003)
l = 17eVs E/E=0.30%
l = 19eVs E/E=0.13%
l > 13.6eVs
De-bunching and Re-bunching in 2.5 MHz rf buckets
= 85bkts
= 48bkts
V=2kV
Before de-bunching
After re-bunching
De-bunched
De-bunching time = 20 secHold off time = 8 secRe-bunching time = 20 sec
De-bunching and Re-bunching in 2.5 MHz rf buckets(continued)
= 85bkts
= 48bkts
V=1.4kV
Before de-bunching ; l = 4.8eVs
After re-bunching ; l = 6.2eVs
De-bunched
De-bunching time = 3 secHold off time = 8 secRe-bunching time = 3 sec
V=2kV
Conclusions : Emittance Growth ~30%
De-bunching and Re-bunching in 2.5 MHz rf buckets(continued)
= 85bkts
= 48bkts
V=1.4kV
Before de-bunching ; l = 5.5 eVs
After re-bunching ; l = 8.0 eVs
De-bunched
De-bunching time = 20 secHold off time = 8 secRe-bunching time = 20 sec
V=2kV
Conclusions : Emittance Growth ~ 45%
ESME Simulations of De-bunching and Re-bunching in 2.5 MHz rf buckets
At Injection After Re-bunching
De-bunching time = 3 secHold of time = 2secRe-bunching time = 3 sec
Some Issues
• The data have been analyzed using a primitive (but accurate) method. We need to automatize this. We need this information on every transfer This is a lots of work (we are working on it)
• By integrating the area and calibrating it with I:RBEAM we can measure beam intensity on each transfer
• We see systematic difference in emittance from sequence to sequence during stacking and un-stacking of pbars, which is indicative of emittance dilution. This needs more study. This can be done using protons
• At present the stacking and un-stacking sequences are about 100 sec long. This has impact on collider operation. We should revisit them and optimize.
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