Polarized 3He ion source development for RHIC.

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Polarized 3He ion source development for RHIC.
A.Zelenski. J.Alessi, E.Beebe, A.Pikin, A.Kponou,
D.Steski

• Check the Bjorken Spin Sum Rule (the difference
  between the 1st moments of the proton and neutron
  spin structure  function). Violation of that
  would be a very big deal. If we find the rule to
  be CONFIRMED, i.e. no violations, then these
  evaluation will give the BEST value of the strong
  coupling constantAlpha-S and its running.
  A.Deshpande
• Polarized 3He ions can be accelerated in RHIC
  with the present siberian snakes.
• Electron Beam Ion Source is being constructed at
  CAD.

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EBIS ionizer for polarized 3He gas .
He-3 metastability-exchange polarized cell P -
80-90.
2.51011 He/pulse
He(2S)? He(1S)
RFQ
EBIS-ionizer, B 50 kG
Pumping laser 1083 nm.
He-transfer line. Valve. 501011 , 3He /pulse.
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EBIS ionizer for polarized 3He gas.

• Polarized 3He gas is produced by a metastability
  exchange technique. P 70-80 (pressure 1
  torr).
• 3He gas is injected in the EBIS ionizer. Pulsed
  valve?
• The ionization in EBIS is produced in a 50 kG
  field.
• This field will greatly suppress the
  depolarization in the intermediate He single
  charge state, Bc(He) 3.1 kG
• The charge ratio He/He gtgt 1.
• The number of He ions is limited to maximum
  charge which can be confined in EBIS (about 2.5
  1011 of 3He/store).
• It is sufficient to obtain 1011 He/bunch in
  RHIC.

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Electron Beam Ion Source at RHIC
Acceleration Tube
What intensity is expected? Capacity will be
1012 charges/pulse ? 2-3 x 1011 3He ions
per pulse ?
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EBIS Preinjector Layout in lower equipment bay of
200 MeV Linac
Polarimeter
17 keV/u 300 keV/u 2 MeV/u
100 MHz
Ion He - U
Q/m 1/6
Current gt 1.5 emA (for 1 turn inj)
Pulse Length 10 ?s
Rep. Rate 5 Hz
Time to switch species 1 second
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SUMMARY

• Expected Results.
• Building of the He 3 polarizing setup.
• Study the limitation on the maximum attainable
  nuclear polarization in the metastability-exchange
  technique.
• Study the possible depolarization effects during
  polarized 3He gas injection to EBIS and
  multi-step ionization process.
• 3He beam polarimeter development for
  polarization measurements and optimization.
•  Requested budget 545 k/ 3 years (2 years
  postdoc is included).