Magnet Specifications

Oxford Instruments
Split pair Helmholtz coil
20 cm bore and a 10 cm split

Along the split the magnet coils formed an opening cone of 100 degrees Along the split the magnet has an opening angle of plus/minus 25 degrees in the vertical and plus/minus 17 degrees in the horizontal.

• Maximum Field = 5.1 Tesla (Temp = 4.2 Kelvin)
• Maximum Current = 78.79 Amps
• Current/Field Ratio = 15.449 Amps/Tesla
• Field Homogeneity = 1.42 x 10-4 over 20 mm diameter
• Shimmed Field Homogeneity = 1.22 x 10-4 over 20 mm diameter
• Magnet Persistence: 5 in 10⁸ per hour
• Magnet Inductance: 232 Henries
• Lead Resistance: 0.058 ohms
• Liquid Helium Boil Off: 290 cc/hour @ 30% full
• Liquid Nitrogen Boil Off: 700 cc/hour @ 70% full

LHe 85 liters
LN2 57 liters
In E143
Field 4.872 Tesla
Current 75.33

Shims
Z₀ = 0 (NA)
Z₁= 0
Z₂ = 0.78

Refrigerator Specifications

Pumps
12000 m³/hr Balzers followed by an Alcatel set consisting of two blowers, a 3000 m³/hr, a 1000 m³/hr. Last stage consisted of 3 mechanical pumps each of capacity 60 m³/hr.

Helium consumption
7 -9 l/hr with earthquake bracing

Magnet should be less 1 l/hr
(15 SLM (vapor) = 1 l/hr liquid)
Separator ran at ~20 SLM
Refrigerator ran at 15 -20 SLM

Microwave Specifications

Varian VKT 2438 series CW EIO
Oldest Tube with central frequency 136.5 GHz
20 Watts

Power Supply

• Varian VPW 2889 Series
• Beam Voltage = - 8903
• Anode Voltage = - 5588
• Mechanical tuning range (bellows) about 1 % -> about plus/minus 0.7 GHz
• Electronic tuning range 600 kHz/volt

Function generator ( 1kHz sawtooth) to audio amplifier to the primary of a isolation transformer. Secondary was HV from Varian supply.
100 volts peak to peak generated 80V on HV -> generated plus/minus 250 MHz modulation

Circuit

• F band out of tube
• Transition Piece to D band
• 40 db coupler to 10 db coupler. Coupled power to EIP frequency counter, through went to power thermistor.
• 4 inches of D band
• Switch
• 2 inch piece of D band
• Elbow of D band
• Transition pieces D band to V band rectangular
• Transition from V band rectangular to V band circular
• 1 inch V band circular
• 5 feet of circular waveguide to horn

NH3+ 136.500 136.430
NH3- 136.900 136.850
ND3+ 136.550 136.470
ND3- 136.830 136.856

Insert Specifications

• NMR Coils: 70/30 CuproNickel, 0.5 mm diameter, 7 ml walls
• LHe: 50 liters
• LN2: 30 liters
• Pumps 12000 m³/hr Balzers followed by an Alcatel set consisting of two blowers,a 3000, a 1000 .