Antiproton Acceptance

1
Antiproton Acceptance

• Steve Werkema
• Temple Review
• January 20, 2004

2
Scope

• Two Projects
• AP2 Beamline and Debuncher Acceptance
  Improvements
• Project Leader Keith Gollwitzer
• High Gradient Lithium Lens Upgrades
• Project Leader Jim Morgan

3
Layout

• Layout of Antiproton Acceptance projects
• Target station downstream of target (Li Lens,
  Pulsed Magnet, Target Dump)
• AP2 beamline
• Debuncher ring

4
WBS Overview
5
Motivation

• Increase the number of antiprotons collected from
  the target by
• increasing the gradient of the collection lens
• increasing the admittance of the AP2 beamline
  and the Debuncher

6
AP2 Debuncher Acceptance Admittance
Measurement

• Improved Measurement of AP2 Debuncher
  Horizontal Admittance
• Figures at the right plot various measures of
  beam loss and intensity as a function of
  Debuncher horizontal scraper position.
• Measurement performed while stacking.
• Top scan Scraper touch point
• Bunch Rotation ON, All Cooling OFF
• Loss Monitors downstream of scraper monitored as
  scraper moved into beam at the end of a 30 sec
  stacking cycle
• Bottom scan Beam extinction point
• Bunch Rotation OFF, All Cooling OFF
• Monitor integrated power spectral density (log
  scale) on longitudinal schottky at the end of a 6
  sec stacking cycle as scraper extinguishes the
  beam
• Can determine extinction point to within 0.2 mm
  by observing change in schottky power above noise
  floor

7
AP2 Debuncher Acceptance Momentum Acceptance

• Longitudinal Schottky profile ofps filling the
  momentum aperture of the Debuncher.
• Bunch rotation and stochastic cooling are off.

NOTE An earlier (11/2002) measurement gives
Dp/p 4.6
8
AP2 Debuncher Acceptance -- Parameters

• AP2 Debuncher admittances reported at the
  July 2003 review were
• Horizontal 20 p mm-mrad, Vertical 12 p mm-mrad

Debuncher admittances reported at the July 2003
review were Horizontal 25 p mm-mrad,
Vertical 20 p mm-mrad
Design Goal is 40 p horizontal and vertical
admittance everywhere within a 2.00 momentum
acceptance
9
AP2 Debuncher Acceptance -- Plan

• Identify Limiting Apertures
• Assemble Documentation and Drawings (FNAL Tech.
  Div.) (WBS 26.2.2.1)
• Optical Survey and Alignment (WBS 26.2.2.2)
• Beam based determination of limiting apertures
  (WBS 26.2.2.9.2)
• Improve AP2 and Debuncher Lattice models (WBS
  26.2.2.8)
• Required for Beam Based alignment
• Required for evaluation of chromatic errors
• Mitigate aperture restrictions
• Redesign/modify/rebuild/relocate beamline
  elements (WBS 26.2.2.5)
• Implement Beam Based Alignment
• Instrumentation upgrades (WBS 26.2.2.3)
• AP2 BPMs
• Debuncher BPMs
• Orbit control (WBS 26.2.2.6)
• Install additional dipole trims in AP2
• Motorized quad stands in the Debuncher
• Beam Based Alignment (WBS 26.2.2.4)
• Develop procedures
• Software development

10
AP2 Debuncher Acceptance Beam Based Alignment

• Beam Based Alignment
• Excite quad ? Measure Response ? Correct Orbit
• We will be able to accomplish this because
• Most quads have shunts installed
• Upgraded BPMs in AP2 and the Debuncher
• Greatly increased orbit correction capability in
  AP2 and the Debuncher

11
AP2 Debuncher Acceptance Limiting Apertures
The numbers in this column were calculated
using b-functions at Dp/p 0
DRF3 was moved during the Fall 2003 shutdown
and is no longer an aperture restriction. Table
gives pre-move admittances.
12
AP2 Debuncher Acceptance Status (1)

• Identification of limiting Apertures
• Documentation and Drawings
• Debuncher injection region drawing complete
• AP2 Physical Aperture table complete. Apertures
  have been incorporated into the AP2 lattice
  model.
• Debuncher Physical Aperture table was recently
  completed (still requires final error checking)
• Optical Survey
• Tunnel work is 90 complete
• Survey data are being compiled
• Mitigate Aperture Restrictions
• Recent developments
• DRF3 move completed during the Fall 2003 shutdown
• Horizontal Debuncher aperture has improved from
  25 p before the shutdown to present value of 28 p

13
AP2 Debuncher Acceptance Status (2)

• Implement Beam Based Alignment
• Instrumentation
• AP2 BPMs
• Presently trying to mitigate Deb. Extraction
  kicker noise
• Est. Completion SD 2004
• DAQ hardware software upgrade Est.
  completion Jan. 2005
• Debuncher BPM upgrade
• All 6 sectors installed and operational
• Console software is functional and in routine use
  some improvements are still being made.
• Orbit Control
• AP2 line trim dipoles
• 4 NDB dipole trims have been installed in the AP2
  line 1 in Jan. 2002, 1 in June 2002, and 2 in
  Jan. 2003.
• Install moveable stands for selected Debuncher
  quads.
• 10 stands installed during the Fall 2003 shutdown
• Install an additional 20 stands during the Summer
  2004 shutdown

14
AP2 Debuncher Acceptance Status (3)

• AP2 and Debuncher Lattice modeling
• Working OptiM models of the AP2 line and the
  Debuncher exist
• AP2 model has been updated with physical aperture
  information
• Debuncher and AP2 models will be updated with
  physical aperture and survey information as the
  data becomes available
• LBNL has developed a MAD model that includes
  chromatic effects
• Beam Studies
• Recently completed studies (Sept. 2003 Jan.
  2004)
• Reverse proton studies
• Observation of beam signal on all AP2 BPM cables
• Commissioned the new Debuncher BPM electronics
• Commissioned bumps with new moveable quads (in
  progress)
• Aperture measurements
• Stacking studies
• Measure AP2 Debuncher admittance
• (development of measurement techniques)
• Development of AP2 BBA using Debuncher TBT
• p bumps in AP2

15
AP2 Debuncher Acceptance Chromatic Correction

• New Task added since July 2003
• Chromatic Correction of the AP2 Beamline
• Work being done by LBNL
• Model chromatic effects
• Beam studies to test model
• Propose correction scheme (August 2004)

AP2 line chromatic b-functions
16
High Gradient Li Lens Goals Plan

• Goal Operate a Lithium lens --
• at a gradient of at least 1000 T/m (34 ?)
• for at least 10 million pulses
• Action Plan
• New solid Li Lens design (began 2000) (WBS
  26.2.1.2)
• General Li Lens RD (WBS 26.2.1.3)
• Autopsies of failed lenses
• FEA model of present design
• RD of various Lens technologies
• Improve present Li Lens design (WBS 26.2.1.1)
• Fabricate New Lenses (WBS 26.2.1.5)

17
High Gradient Li Lens -- Parameters
18
High Gradient Lithium Lens Present Li Lens
19
High Gradient Lithium Lens New Design

• Features
• Diffusion bonded titanium body
• Improved cooling
• Li buffer volumes eliminated

• Diffusion Bonding
• Better, more uniform cooling of lens body
• Allows use of new Ti alloy (Ti 10V-2Fe-3Al has a
  15 40 better fatigue endurance limit)
• Simplified lens fabrication
• Elimination of weld joints on septum

20
High Gradient Li Lens -- Status

• New Lens design (diffusion bonded lens)
• Complete and test new lens design prototype 1
• Presently on test stand
• Intend to pulse to failure
• Construction on prototype 2 expected to begin in
  March 2004
• General Lens RD
• Lens 22 autopsy in process
• 2nd longest lived lens (9.2 million pulses). Did
  not fail during pulsing.
• Weld failure
• Continue to refine and expand FEA model
• Ti 10-2-3 testing in process
• Modifications to existing lens design
• Presently operating a lens constructed with
  improved quality control procedures (Lens 28)
• Original intention operate 28 for 1 month at 745
  T/m then increase to 820 T/m.
• Will not do because of too few operational spares
• Fabrication of new lenses
• Go into regular production of lenses with the new
  design
• Construction of lenses of new design scheduled to
  start in early 2005

21
Milestones
22
Major Shutdown Work

• Shutdown 2004
• Replace D4Q4
• Wider Band 4 cooling arrays
• DRF2 Move
• Install additional 20 motorized quad stands
• Shutdown 2005
• Upgraded Debuncher Injection Septum
• Motorized stands for Debuncher injection
  extraction kickers
• Possible modifications to Debuncher extraction
  kicker
• Possible implementation of AP2 chromatic
  correction
• Shutdown 2006
• New Debuncher extraction kicker (if not modified
  during SD2005)
• Implement of AP2 chromatic correction (if not
  implemented during SD 2005)

23
Conclusion The Bottom Line

• Presentp yield
• 16?10-6p/POT
• Expectedp yield
• 36?10-6p/POT
• ? 52 ?1010p/hr
• Delivered to the Accumulator for stacking
• For
• 8?1012 POT/pulse
• (slip stacking)
• 2.0 sec cycle time