The AC current

It is produced by the EIN RF Power Amplifier located at the bottom of the same rack. When it is running, the manual switch is set to the ON position, the red LED is steady and the needle on the display is above zero. The AC current comes out from the BNC OUTPUT plug, goes through a current monitor (looks like a small toroid) and finally goes to the RF coils. In the hall, the cable is connected to the RF coils along the RF mounting using simple connectors with screws. Those are protected by electrical black tape. They should never be touched when the RF Power Amplifier is running. The grounding of the system is provided by the RF Power Amplifier.

How to turn the RF Power Amplifier off in an emergency ?

1. Turn the Function Generator HP 33120A connected to the RF Power Amplifier off.

2. Turn the RF Power Amplifier off by setting the manual ON/OFF switch to the OFF position. The red LED should turn off and the needle should go back to the zero position.

Table: KEPCO settings

Orientation	KEPCO 3 Voltage	KEPCO 3 Current	KEPCO 4 Voltage	KEPCO 4 Current
0 deg	38.0 V	7.1 A	0.0 V	0.0 A
90 deg	0.0 V	0.0 A	38.2 V	7.2 A

Detailed description of the NMR system is contained in the following technical note by S. Incerti: The NMR system of the Hall A polarized Helium 3 target, JLab-TN-98-049. A copy of this note is included in the target binder in the Hall A counting house.