Cryogenic Target System:(JLab, CalStLa, Kent, UMD, ODU, W&M)

• Three loops for liquid H₂, D₂ and one gasous target (³He or ⁴He)
  
  
• LH2 and LD2 targets have been in stable operation since 9/29/97
  
• Each Target can handle rastered beam up to 120 microAmps,
  Beam heating up to 700 Watts. A World Record!
  
• LH₂, LD₂: each has 2 cells (15 cm, 4 cm): operation conditions: 20 K, 1.5 atm.
  
  
• Helium target has been in stable operation since 1/2000
  
• ³He, ⁴He: one cell, 10 cm, 5K, 15 atm.
  
  
• Each of the three targets can be remotely moved in and out of beam.
  
• Solid targets attached: Dummy targets (10cm, 15cm and 4 cm), ¹²C, Al, BeO, Empty.

Polarized ³He Target: (Caltech, JLab, Kentucky, MIT, Temple, UVa and William and Mary)

• Based on the principle of spin exchange between optically pumped Rb vapor and ³He gas.
• 40 cm long sealed glass cell containing 10 atm ³He gas.
• Polarization 40-50%, thickness 10²² atoms/cm².
• With 15 microA beam, the polarized luminorsity reaches 10³⁶particles/cm²/s. Another World Record! .
• With no free polarized neutron target available, polarized ³He target provides a target close to a polarized neutron target since the spin of the two protons in ³He are almost all paired in opposite directions.

Solid Target Ladder:

• Attached at the bottom of the cryotarget. Can hold 5 different targets; each can be remotely moved in and out of beam;
  

Waterfall Target Assembly: (INFN)

• Three parallel waterfall H₂O targets each 200mg/cm²;
  Used for spectrometer calibration and ¹⁶O experiments.
• Hydrogen in water provides a precision calibration.

This page is maintained by J. P. Chen. Last Update: Sept.24/2003.
Email: jpchen@jlab.org, Phone: (757)269-7413.