Why is this important

1
Defining a Golden Closed Orbit (smoothed n
centered)
beams doc 1540

• Why is this important?
• We want average corrector current to be zero (not
  contribute to central trajectory)
• Reduce feed down from quad and sextupole in
  gradient magnet
• Determine true tune/chromaticity/coupling from
  Recycler permanent magnets
• Match complex to true Recycler energy (w/o
  corrector contribution to average dipole field)
• Reduce/eliminate dependency on DC magnetic
  elements, use magnet moves to reduce corrector
  strength (0.2A max) and install PM quad trims in
  phase trombone
• Some statements
• The Recycler central trajectory should be as
  defined by the design lattice.
• The BPMs were specified to lay on the central
  trajectory with dp/p as zero
• The BPMs/beam pipe were installed to centered on
  this central trajectory
• The gradient magnets were installed with a
  specific sagatti (and longitudinal offset)
  correction to minimize feeddown and maximize
  aperture.

2
Recycler BPMs (do we trust them?)

• Factors in absolute BPM readings
• Data for individual channels
• Survey offset
• Electrical center of plates
• Electronic offset (cableselectronics)
• Data for BPM type
• Gain (mm/volt)
• In process of verifying gains/offsets installed
  in front end
• Rechecked lattice specification and survey
  technique
• Magnets survey w/ Laser tracker (not shown)
• Radial m 0.001mm , s 0.041 mm
• V m 0.002 mm, s 0.022 mm
• Roll m -0.024mr , s 0.201 mr
• BPM/beam pipe optical survey
• PLOTS to the right -gt
• Parallel offset to mini straight as defined by
  up/down stream gradient magnets/quads (using
  sagatti corrected offsets)

Results of global BPM survey 2001
/- 1.6 mm
Horizontal
/- 1 mm
Vertical
BPM Survey Offsets installed in front end
O
3
Our Current Operational Orbit
rms 7.3 mm dp/p 0.0013 Xmax 16 mm
rms 1.38 mm aveg -.174mm Xmax 16 mm
After Stans vertical aperture scan
Centering in physical aperture
4
Corrector Settings for Current Operational Orbit
-.30573 ur/A lt22.3 urgt down
.157117 ur/A lt18.4 urgt inside Q corr / q
dipole 0.001
5
Smoothed and Centered Orbit

• Centered Orbit by Rfreq
• Smoothed using R50
• to select dipole/region for smooth
• Not smoothed MI30 or MI60
• Avoided LEP corr (for now)
• Fixed positions thru known apertures

S
Known Offsets

• Closed injection to same eff

rms 3.7 mm dp/p 0.0002 Xmax 2 mm

• First pass at adj tunes

• Admittance gt 90 p

• Coupling/chromaticity
• NOT adjusted

First pass
6
Recycler frequency change

• RF freq 52809500 -gt 52809000 (only approximate
  now)
• Revolution freq reduced by 0.85 Hz (89812.0748
  Hz -gt 89811.2244 Hz)
• Revolution period reduced by 105 ps
• dp/p (RR) -0.0011 (h -0.00851)
• Impact on MI and complex
• MI/complex energy reduced by 8 Mev
• Impact on RR BPM
• only 89 kHz and narrow band
• Minor impact
• Schottkies
• Mixdown frequencies
• Stochastic Cooling
• delay times between pickup and kicker change by
  20 ps
• Electron Cooling
• RF (low level wave forms)

7
Corrector Currents for Smoothed Orbit
.027117 ur/A lt3.1 urgt inside
8
Dynamic Aperture
Working point (.425, .415) for this calculation
Chromaticity -2 units
D
dp/p 0.003
25.5 mm
Current central orbit dp/p .0014 Typical
dp/p(90) /-.0015
38.25 mm
TM-2134 Meiqin, et.al.
9
Working point
Current Operating Point Qh .414-.415 Qv .412
For x -10, And dp/p .0015 Dv /-0.015 each
plane (into 5th and 7th)
x
For x -2, And dp/p .0015 Dv /-0.003 each
plane (into 12th)
Approx. tune spread for x -10 shown on plot
For dp/p of .0015 maximum x to avoid 5th and 7th
order resonances
10
Current Momentum Aperture
12/3/04
52809500
52810250
52808750
1250 Hz
2500 hz
3000hz
dp/pgt0 dn lt 0
dp/pgt0 dn gt 0
Data taken by Stan Extinguish points are
52805750 and 52813300 for momentum aperture of
/- about 3800 Hz. MI is not ramping for this
data, H and V chromaticity is about -2.5 unit.
11
Tunes
Qh .414 Qv .415
Current Orbit
Smoothed Orbit
Currents 0.427, 0.040, 0.489, -0.679,
0.172
Currents 0.808, -0.239, 0.919, 0.016,
0.395
No attempt to adjust coupling or chromaticity
Trims 2/half-cell _at_ 0.027 T/A PM quad
4/half-cell _at_ .85 T ? trims contribute 1.6 of
focusing at 1 amp
12
Bare Machine Tunes
Design .425/.415
Measured Harm .4269 / .4022
Nov 30, 2004
Qh .4099 Qv .4310
January 11, 2005
VSA (uncorrected)
Qh .4131 Qv .4393
Schottky
Qh .4216 Qv .4349
13
Horizontal Admittance
A 0.022329.52/52 A gt 90 p-mm-mr
21.7 mm
22.3 mm
Operational orbit
Smoothed orbit
14
Our Current Operational Orbit
gtr 19.968

• Smoothed orbit with freq at 52809000 Hz
• Increased freq back to 52809500 Hz
• Orbit difference shows dp/p 0.0014
• Contribution 0.0011 from freq change

Dp/p -(1/h)Df/f
Dp
h(1/gtr2 1/g2) h -0.00851
15
What Needs to be Done

• Include all offsets in BPM front end (in
  progress)
• Smooth orbit (reduce average corrector strength)
• Determine quad moves to reduce largest correctors
  (MI30 and MI60)
• Adjust freq to get a zero dp/p with average corr
  current zero.
• Investigate apertures in MI60 and MI30
• Center beam in phase trombone quads
• (H V rms lt .1mm / 5A) - Jan 11
• Adjust coupling (whats the source)
• Adjust chromaticity
• Determine momentum aperture
• Determine source of bare machine tune shift
  (DnX -.0034 , Dny .02)
• Measure sensitivity of lifetime due to tunes
• Re-tune injection/extraction (may require
  adjustments to closed orbit/counter-wave in MI)
• Re-adjust cooling/instrumentation to centered
  Recycler frequency
• Match MI (and eventually the complex) to this
  new frequency/energy
• Revisit MI ramp compensation