He3 Target Test Items

Cell Characterization

Density

• Filling density
• Broadening of Alkali absorption

Wall Thickness

• Laser interference measurement: wall and window

Optical Pumping System

Laser Optics

• Laser power measurement
• Laser spectrum measurement/Absorption adjustment
• Calibrations of optics orientations, e.g. λ/4 plates
• Laser polarization measurement
• Optics alignment
• Power consumption at laser connectors (if there is any)

Oven

• RTD calibration
• Condition optimization: oven temperature as a function of gas flow and heater power

Calorimetry

NMR

• System Q-curve measurement of all pickup coils to prevent resonance
• Minimize pickup coil background with maximum RF power
• Linearity check of amplifiers: preamplifier, lock-in amplifier
• Flux calibration: pickup coil survey and flux calculation
• He³ NMRs: frequency and field sweeps (including NMRs during EPR calibration)
• AFP loss measurement
• Internal temperature measurement in pumping chamber using NMR
• NMR cross calibration: frequency vs. field, different locations
• Water NMR calibration: field sweep (frequency sweep as well if possible)

EPR

• Characterization of feedback system: proportional and integration gains
• EPR calibration
• Cross check with water calibrated NMRs

MISC Studies

• Spin up time
• Relaxation time: room temperature, high temperature
• Optimization of pumping condition: laser power, oven temperature
• Polarization gradient