Bunch-by-Bunch Analyses of CESR Optics
Jim Crittenden/March 2007
The consequences of the beam-beam interaction at the parasitic crossings and at the IP have been calculated in the weak-strong approximation using BMAD-based
CESR simulation software. The crossings are inserted as fixed elements into
the ring simulating the effect of the strong beam (here the positron beam)
on the weak beam (electrons). Since the parasitic crossing positions are
electron-bunch specific, the ring must be regenerated for each electron
bunch.
Full six-dimensional tracking including synchrotron oscillations has
been implemented, as has custom tune setting and pretzel amplitude
choice (PRZ1 and PRZ13).
The results listed below include tune shift and beam function dependence
on positron bunch current, as well as changes in the closed orbit for
each of electron bunches. Dynamic aperture calculations have also
been performed.
- CESR-c Lattices
- Dynamic Aperture Improvement by Use BBI Compensation Knobs in the Present 3770 Operating Lattice 30 March 2007
- 3686 Lattice 14 August 2006
- Dynamic Aperture: Global Tune Correction versus BBI Compensation Knobs for Off-Energy Particles 14 June 2006
- IP Modelling for the BBI Compensation Knobs 6 June 2006
- BBI Effects on e- Sync Light Source Point 17 May 2006
- BBI Compensation Knob Studies 3 May 2006
- Beta Max and B Parameter Comparison of the 4260_092605_v1 nd 4160_113005 Lattices 6 December2005
- Three Suggestions to Improve Luminosity 21 November 2005
- Alpha*/Beam Waist Comparison of the 4260_min_v1 and 4260_092605_v1 Lattices 31 October 2005
- Effects of BBI on alpha* and Electron Beam Waist 21 October 2005
- Comparison of the 4260_min_v1 and 4260_092605_v1 Lattices 3 October 2005
- Orbit Distortions due to BBI
Machine studies measurements of orbit distortions caused by long-range beam-beam interactions were made on 12 August 2005.
These calculations show an analysis of those measurements. Plans for future measurements are also discussed.
The following calculations in March, 2005, compare the
properties of a lattice designs with the new anti-solenoid compensation
scheme described here.
- Lattice c_020305.
9x4 positron bunches, uniformly filled. Design pretzel. Tunes set to 0.518/0.584 and held constant independent of positron bunch current. Sync tune 35 kHz.
This lattice does not include the effect of modifying the rotation of the permanent quads Q0.
BBI at the IP turned off: Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
BBI at the IP turned on: Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
- Lattice c_040305.
9x4 positron bunches, uniformly filled. Design pretzel. Tunes set to 0.518/0.584 and held constant independent of positron bunch current. Sync tune 35 kHz.
This lattice DOES include the effect of modifying the rotation of the permanent quads Q0.
BBI at the IP turned off: Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
BBI at the IP turned on: Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
- Lattice: hibetainj_20040628_v01_flm.
9x4 positron bunches, uniformly filled.
The tunes are set to 0.518/0.584, the present operating tunes,
and are held constant
Sync tune 41 kHz.
This calculation serves as the baseline operating condition
to which the anti-solenoid compensation calculations
can be compared.
BBI at the IP turned off: Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
BBI at the IP turned on: Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
- Lattice: L9A18A000._MOVEREC
9x4 positron bunches, uniformly filled. Design pretzel. Tunes set to 0.518/0.577 and held constant independent of positron bunch current. Sync tune 41 kHz.
The beam-beam interaction at the IP is not included.
This is the Phase II 5.3 GeV lattice which had the best tune shift parameter,
as described
here.
Log file
BBI at the IP turned off: Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
The following calculations in February, 2005, compare the
properties of a lattice design with the wigglers at a peak field of 14 kG and another with wigglers 15E and 15W turned off
to the present operating lattice. The beam-beam interaction at the IP has been turned off for purposes of this comparison.
- Lattice 14kg_021505.
9x4 positron bunches, uniformly filled. Design pretzel. Tunes set to 0.518/0.577 and held constant independent of positron bunch current. Sync tune 41 kHz.
The beam-beam interaction at the IP has been turned off.
This is the first attempt at a lattice with the wigglers at 1.4 T peak field.
Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
- Lattice 10wig_no15s_v00.
9x4 positron bunches, uniformly filled.
The tunes are set to 0.518/0.577, the present operating tunes,
and are held constant
independent of positron bunch current. Sync tune 41 kHz.
This lattice was designed to have wigglers 15 E/W off. It was studied
during machine studies on 1-2 Feb 05.
Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
- Lattice: hibetainj_20040628_v01_flm.
9x4 positron bunches, uniformly filled.
The tunes are set to 0.518/0.577, the present operating tunes,
and are held constant
Sync tune 41 kHz.
This calculation serves as the baseline operating condition
to which the 1.4 T
lattice 14kg_021505 calculation
and the
wiggler-15e/w-off
lattice 10wig_no15s_v00 calculation
can be compared.
Tune, beta, orbit, emittance, beta* plots
Log file
The following calculations in February, 2005, investigate the
properties of a lattice design with wigglers 15E and 15W turned off.
- Lattice 10wig_no15s_v00.
8x5 positron bunches, uniformly filled.
The tunes are set to 0.525/0.60 as
used on 1-2 Feb 05 during machine studies and held constant
independent of positron bunch current. Sync tune 41 kHz.
This lattice was designed to have wigglers 15 E/W off. It was studied
during machine studies on 1-2 Feb 05.
Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
- Lattice: hibetainj_20040628_v01_flm.
8x5 positron bunches, uniformly filled.
The tunes are set to 0.525/0.60 as
used on 1-2 Feb 05 during wiggler-15-off machine studies and held constant
independent of positron bunch current. Sync tune 41 kHz.
This calculation serves as the baseline operating condition
to which the wiggler-15e/w-off lattice 10wig_no15s_v00
calculation
can be compared.
Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns)
Log file
The following calculations in February, 2005 investigate the
effects of the knob designed by DLR in a 9x4 configuration
to compensate beta* in train 1 bunch 3
for the parasitic BBI with 2 mA per positron bunch.
The knob was studied during the machines studies of 1/17/05.
- 9x4 positron bunches, uniformly filled. Design pretzel and betatron tunes. Sync tune 41 kHz.
These are the baseline conditions of this lattice with betasing 10 set at 1000 cu. The beam-beam interaction at the IP has been turned off.
Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns) and
Log file
- 8x5 positron bunches, uniformly filled. Design pretzel and betatron tunes. Sync tune 41 kHz.
These are the baseline conditions of this lattice with betasing 10 set at 1000 cu. The beam-beam interaction at the IP has been turned off.
Tune, beta, orbit, emittance, beta* plots
Dynamic aperture plots (500 turns) and
Log file
The following calculations in January, 2005 investigate the
effects of the knob designed by DLR in a 9x4 configuration
to compensate beta* in train 1 bunch 1
for the parasitic BBI with 2 mA per positron bunch.
The knob was studied during the machines studies of 1/10/05.
- 9x4 positron bunches, uniformly filled. Design pretzel and betatron tunes. Sync tune 41 kHz.
These are the baseline conditions of this lattice. The beam-beam interaction at the IP has been turned off. This job serves as the baseline for comparing
the intended effect of betasing 10, which was designed to compensate
the effect of the parasitic BBI on beta*.
Tune, beta, orbit, emittance, beta* plots
Log file
- 9x4 positron bunches, uniformly filled. Tunes now set to betasing-10-off design tunes of 0.518/0.577 and held constant independent of positron bunch current. Sync tune 41 kHz.
Comparing these plots to those where the tunes are allowed to change with
positron bunch current (job 595 above) and to those where betasing 10 is on at 1000 cu and the tunes are held fixed (job 599 below) allows to identify which effects
are due to betasing 10 and which are due to allowing the tunes to vary.
Tune, beta, orbit, emittance, beta* plots
Log file
Dynamic aperture plots (500 turns) and
Log file
- 9x4 positron bunches, uniformly filled. Design pretzel and betatron tunes. Sync tune 41 kHz.
These are the baseline conditions of this lattice, with betasing 10 set to 1000 cu. The beam-beam interaction at the IP has been turned off. These results
show the effect of betasing 10 when subtracting the results of job 595 as
the baseline. The design criterion was to restore the value of the horizontal
beta* for train 1 bunch 1 at a positron current of 2 mA/bunch.
Tune, beta, orbit, emittance, beta* plots
Log file
- 9x4 positron bunches, uniformly filled. Design pretzel. Tunes now set to betasing-10-off design tunes of 0.518/0.577 and held constant independent of positron bunch current. This is the intended operational implementation. Sync tune 41 kHz.
These are the baseline conditions of this lattice, with betasing 10 set to 1000 cu. The beam-beam interaction at the IP has been turned off. These results
show the effect of betasing 10 when subtracting the results of job 595 as
the baseline. The design criterion was to restore the value of the horizontal
beta* for train 1 bunch 1 at a positron current of 2 mA/bunch.
Tune, beta, orbit, emittance, beta* plots
Log file
Dynamic aperture plots (500 turns) and
Log file
- 8x5 positron bunches, uniformly filled. Design pretzel and betatron tunes. Sync tune 41 kHz.
These are the baseline conditions of this lattice. The beam-beam interaction at the IP has been turned off. BETASING 10 set to zero.
This job serves as the baseline for comparing
the intended effect of betasing 10, which was designed to compensate
the effect of the parasitic BBI on beta*.
Tune, beta, orbit, emittance, beta* plots
Log file
- 8x5 positron bunches, uniformly filled. Design pretzel. Tunes now set to betasing-10-off design tunes of 0.518/0.577 and held constant independent of positron bunch current. This is the intended operational implementation. Sync tune 41 kHz.
This job serves to answer the question of how well betasing 10 works
for our operating conditions of 8x5. It was designed for 9x4.
These are the baseline conditions of this lattice, with betasing 10 set to 1000 cu. The beam-beam interaction at the IP has been turned off. These results
show the effect of betasing 10 when subtracting the results of job 60 as
the baseline. The design criterion was to restore the value of the horizontal
beta* for train 1 bunch 1 at a positron current of 2 mA/bunch.
Tune, beta, orbit, emittance, beta* plots
Log file
The following calculations in December, 2004 use the tunes measured
in HEP conditions for electrons during the characterization
measurements of 20 Dec 2004: Qh=213.5 Qv=230.6 fs=40.4 kHz.
- HIBETAINJ_2004_0628_V01_FLM 8x5 Positrons PRZ13=design (No separation)
Tunes compensated for positron current. (22 December 2004)
Tune, beta, orbit, emittance, beta* plots and
Phase, beta and orbit difference plots
Log file
- HIBETAINJ_2004_0628_V01_FLM 8x5 Positrons PRZ13=design (No separation)
Positron t1.b1 empty. (21 December 2004)
Tune, beta, orbit, emittance, beta* plots and
Phase, beta and orbit difference plots
Log file
- HIBETAINJ_2004_0628_V01_FLM 8x5 Positrons PRZ13=design (No separation)
Positron t1.b1-5 empty. (21 December 2004)
Tune, beta, orbit, emittance, beta* plots and
Phase, beta and orbit difference plots
Log file
- HIBETAINJ_2004_0628_V01_FLM 1x5 Positrons PRZ13=design (No separation)
Only t1.b1-5. (21 December 2004)
This calculation was made in preparation for machine studies
on December 22, 2004. It shows large changes in the beta function
around the ring due to the beam-beam interactions around the
north and south IP.
Tune, beta, orbit, emittance, beta* plots and
Phase, beta and orbit difference plots
Log file
- HIBETAINJ_2004_0628_V01_FLM 2x5 Positrons PRZ13=design (No separation)
2x5 positron bunches, only train 2 filled. (21 December 2004)
This study isolates the effects of the parasitic crossings in the
arcs for electron t1.b1. This non-colliding train has a very small effect
on the beta function for e- t1.b1.
Tune, beta, orbit, emittance, beta* plots and
Phase, beta and orbit difference plots
Log file
- HIBETAINJ_2004_0628_V01_FLM 8x10 Positrons PRZ13=design (No separation)
Intercalary bunches are inserted into the normal 8x5 configuration,
space by 2 ns and 12 ns from the original bunches. This calculation
was done because of a recent machine study in which 2 ns bunch spacing
was tested. (21 December 2004)
Tune, beta, orbit, emittance, beta* plots and
Phase, beta and orbit difference plots
Log file
- HIBETAINJ_2004_0628_V01_FLM 8x5 Positrons PRZ13=design
These are the baseline operating conditions. (21 December 2004)
Tune, beta, orbit, emittance, beta* plots and
Phase, beta and orbit difference plots
Log file
- HIBETAINJ_2004_0628_V01_FLM 1x1 Positrons PRZ13=design
This calculation shows how much of the effects are due to the colliding bunch. (21 December 2004)
Tune, beta, orbit, emittance, beta* plots and
Phase, beta and orbit difference plots
Log file
The following studies in November, 2004 used the operating tunes of October, 2004: Qh=207 kHz Qv=226 kHz fs=38 kHz. This is not quite right, since the
operating tunes were measured for single-beam t1.b1. positrons, while
they are used as the electron tunes in the calculation.
- HIBETAINJ_2004_0628_V01_FLM 9x9 Positrons PRZ13=design
Horizontal tune fixed at 0.545 for all positron current values (19 November 2004)
Dynamic aperture plots (500 turns),
Tune, beta, orbit, emittance, beta* plots
and Log file
- HIBETAINJ_2004_0628_V01_FLM 9x9 Positrons PRZ13=design
Zero-current horizontal tune raised from 0.53 to 0.545
and number of turns for dynamic aperture raised from 500 to 2000 (19 November 2004)
Dynamic aperture plots (2000 turns),
Tune, beta, orbit, emittance, beta* plots
and Log file
- HIBETAINJ_2004_0628_V01_FLM 9x9 Positrons PRZ13=design
Zero-current horizontal tune raised from 0.53 to 0.545 (19 November 2004)
Dynamic aperture plots (500 turns),
Tune, beta, orbit, emittance, beta* plots
and Log file
- HIBETAINJ_2004_0628_V01_FLM 9x9 Positrons PRZ13=design (15 November 2004)
Dynamic aperture plots (500 turns),
Tune, beta, orbit, emittance, beta* plots,
Energy orbit plots
and Log file
- HIBETAINJ_2004_0628_V01_FLM 9x10 Positrons PRZ13=design (9 November 2004)
Tune, beta, orbit, emittance, beta* plots and Log file
These are studies of the effect of "interbunches", bunches
added between the bunches in each train in the 9x5 configuration.
The distances between bunches are thus 3/4 buckets rather than 7.
- HIBETAINJ_2004_0628_V01_FLM 1x1 Positrons PRZ13=design (22 October 2004)
Dynamic aperture plots (500 turns),
Tune, beta, orbit, emittance plots, Energy orbit plots and Log file
- HIBETAINJ_2004_0628_V01_FLM 8x4 Positrons PRZ13=design (5 and 24 November 2004)
Dynamic aperture plots (mm and sigma) (500 turns)
Dynamic aperture plots (mm) (500 turns)
Tune, beta, orbit, emittance plots, Energy orbit plots
Log files
5 Nov
and
24 Nov
- CESR Lattice at 5.3 GeV in use as of June, 2001
- CHESS Lattices
- CHESS_20060617 Compare 8x5 5 mA/bunch with 4x5 on 5x5 non-colliding 10 mA/bunch (15 May 2006)
Report on lattice parameters and dynamic aperture
- CHESS_040928_0800 8x5 Positrons PRZ13=design (No e+/e- separation at IP) (9 November 2004)
Tune, beta, orbit, emittance, beta* plots and Log file
- CHESS_040928_0800 8x5 Positrons PRZ13=800cu (1.5 mm e+/e- separation at IP) (10 November 2004)
Dynamic aperture plots (500 turns),
Tune, beta, orbit, emittance, beta* plots and Log file
- CHESS_040928_0800 8x4 Positrons PRZ13=design (No e+/e- separation at IP) (5 November 2004)
Dynamic aperture plots (500 turns),
Tune, beta, orbit, emittance plots, Energy orbit plots and Log file
- CHESS_040928_0800 8x4 Positrons PRZ13=800cu (1.5 mm e+/e- separation at IP) (5 November 2004)
Dynamic aperture plots (500 turns),
Tune, beta, orbit, emittance plots, Energy orbit plots and Log file
- CHESS_040928_0800 1x1 Positrons PRZ13=design (No e+/e- separation at IP) (25 October 2004)
Tune, beta, orbit, emittance plots, Energy orbit plots and Log file
As of October, 2004 it was realized that the BMAD closed-orbit calculation is appropriate
only for positrons when synchrotron oscillations are included. In order to get the
longitudinal oscillation correctly calculated for electrons, the ring elements must
be reversed and electrons must be tracked in the forward direction. Prior to this
realization, electron tracking had been done backwards in the un-reversed ring.
Therefore, the results below are superceded by those above.
The correct treatment of the electron energy evolution during one revolution
in the CHESS and CESRc optics can be seen here.
- CESRc Lattices
- CHESS Lattices
- CHESS_20040820_1445 8x4 Positrons PRZ13=design (2.6 mm sep) (8 September 2004)
Tune, beta, orbit plots and Log file
Dynamic aperture plots (Only 100 turns) and Log file
These plots conform to the running conditions reported in the elog here
Electron bunches 8x4 are included and the plots vs e+ current stop at 5 mA.
Bad lifetimes were reported for currents greater than 4.2 mA.
Tunes have been set to the observed values:
Qx = 0.59 (229 kHz)
Qx = 0.64 (250 kHz)
Qs = -0.49 (19 kHz)
- CHESS_20040820_1445 9x5 Positrons PRZ13=design (2.6 mm sep) (3 September 2004) Tune, beta, orbit plots and Log file
- CHESS_20040820_1445 8x4 Positrons PRZ13=design (2.6 mm sep) (3 September 2004) Tune, beta, orbit plots and Log file
These analyses were done with the design Qx, Qy settings for this lattice.
Qs was set to -0.54.
critten@lns.cornell.edu
Jim Crittenden
Wilson Synchrotron Laboratory
Room 212
Phone:(607) 255-4882
FAX:(607) 255-8062
Last modified 30 March 2007