Transcript G0 Project Coordinator Report Joe Grames • “Big Picture” Schedule • Preparations Polarized Source Injector Accelerator Hall C • Accelerator Plans for 687 MeV Run.

G0 Project Coordinator Report
Joe Grames
• “Big Picture” Schedule
• Preparations
Polarized Source
Injector
Accelerator
Hall C
• Accelerator Plans for 687 MeV Run
Scope of Work
Firm Pre-G0 Schedule
Today – Jan. 26, Winter Shutdown Tasks
Jan. 27 – Feb. 5, Restore & G0 Setup for 687 MeV & 362 MeV
Feb. 6 – March 14, Physics Program for Hall B & A
Firm G0 Running Schedule
Mar. 15 – Apr. 2, Commissioning Period
(following long down)
Apr. 3 - Apr. 29, High Q2 Run (687 MeV)
(3-halls, all polarized)
Tentative G0 Running Schedule
Jul. 21 - Sep. 1, Low Q2 Run (362 MeV)
(1-pass, 1-linac, 2-halls)
Sep. 22 - Dec. 22, High Q2 Run (687 MeV)
Polarized Electron Source Layout
Photocathode
Gun 2
Anodized Superlattice
P > 80% @ 780 nm
QE ~ 0.5-1.0 %
Ibeam ~ 80 mA
Laser
Ti:Sapphire (780 nm)
f ~ 499 MHz
Parity Quality Laser Setup
G0 Helicity Sequence
Pockels cell alignment
IA intensity FB
Rotatable ½-waveplate
Insertable ½-waveplate
Superlattice Polarization & Gun2 Lifetime
Polarization ~86%
Lifetime ~130 C
A = 20 mA
B = 5 mA
C = 80 mA
~10 C/day
Laser Table Layout for 3 Halls High Polarization
(courtesy, J. Hansknecht)
Injector Matching
• HC position differences are generated at the source.
• “Matching” the beam emittance to the accelerator acceptance realizes damping,
• Well matched beam => position differences reduced.
• Poorly matched beam => reduced damping (or even growth).
• Accelerator matching (linacs & arcs) routinely demonstrated.
• Injector matching has been arduous, long (~2 year) process.
X-BPM (mm)
without
X-PZT
(Source)
Y-BPM (mm)
1C-Line
1C-Line
with
X-BPM (mm)
Y-PZT
(Source)
Y-BPM (mm)
1C-Line
1C-Line
Superlattice Photocathode for Parity Experiment
Experiment
HAPPEX-I
HAPPEX-He
HAPPEX-H
HAPPEX-He
(2005)
HAPPEX-H
(2005)
Photocathode
Charge Asymmetry at Target
Position Difference at Target
Spec
Achieved
Spec
Achieved
Strained
1 ppm
0.4 ppm
10 nm
10 nm
Superlattice
0.6 ppm
0.08 ppm
3 nm
3 nm
Superlattice
&
Strained
0.6 ppm
2.6 ppm
2 nm
8 nm
Superlattice
0.6 ppm
?
3 nm
4 nm (x)
17 nm (y)
Superlattice
&
Injector Match
0.6 ppm
0.2 ppm
2 nm
1 nm (x)
1 nm (y)
G0 requirements
=>
<2 ppm
<40 nm
Injector HC Position Feedback
Helicity Magnets
HM (electron beam) replace
PZT (laser beam)
4 magnets =>
• position (x,y) & angle (x’,y’)
• linear over desired region
• independent
• electrically Isolated
• orbit correction in each state
• corrleated charge asymmetry 100x better than PZT
• resolution 100 nm => 10 nm (at 5 MeV)
PZTBooster Concept Matching
“Standard” injector matching process
• Time consuming (1 shift + 2 days + 1 shift)
• 30 Hz PZT at source yields small signal
Helicity Magnets in new “Optics Mode”
• Synchronous with 30 Hz BPM acquisition system
• Mimic small signal to deliver large signal
Goal:
• Streamline injector matching
• Improve accuracy of result
• Allow for rapid confirmation
• Direct comparison between Accelerator & Physics results for
damping and response matrix for feedback.
Hall C
Acclerator resources are largely allocated to the accelerator
for the winter shutdown, with the exception of:
• Install Moller kicker to allow high current polarimetry
Accelerator resources re-allocated in February for final 3C line work:
• move Moller quad => low energy polarimetry
• arrange quadruplet optics +> spot size (halo?) control
• install shielded beam pipe => HKS stray field independence
• install Halo & G0 girders w/ improved mating to G0 spectrometer
687 MeV Run
Jan 2 – Jan 16
: Source & Laser Table setup
Jan 17 – Jan 21
: G0 Laser Table setup
Jan 22 – Jan 26
: Machine checkout & PSS Certifications
Jan 27 – Feb 5
: Machine restoration & G0 Tasks
(9) - 56 MeV Injector Restore (Dec.’05)
(1) – PQB source checkout 100 keV, possibly higher
(6) – Setup T=5.0 MeV & 36.6 MeV injector & “lock-in”
(1) – Injector Match Part 1 (PZT acquisition)
(2) – 5-pass machine beam checkout @ 650 MeV/pass
(1) – Machine repair on DAY
(2) – 1-pass 687 MeV to BSY & ½-pass 362 MeV => SAVE
(1) - Injector Match Part 2 to BSY 687 MeV => SAVE
(2) – Full PQB, Source to BSY
(2) – 5-pass machine setup 738 MeV/pass
Feb 6 – Mar 14
: Physics Program resumes (B 6th and A 24th)
Mar 15 - Apr 29
: G0 (commissioning & production) at 650 MeV/pass
Efforts shift to “hot checkout”, commissioning plans & safe operations.