• Topic ID: id_2002056
  • Version: 5.1
  • Date: Mar 3, 2020 10:19:12 AM

Calibrating RF Amplifier and UPM

Calibrate the maximum power for the RF amplifier. Also, calibrate and check the Universal Power Monitor (UPM) for each channel.

Prerequisites

Personnel requirements
Required persons Preliminary requirements Procedure Finalization
1 - 45 minutes 5 minutes
Tools and test equipment
Item Quantity Part number Manufacturer
RF Power Measurement Kit 1 Either 5307511-2 or 5307511-3 (Bird wattmeter) -
Digital Voltmeter (DVM) 1 46-194427P284 -
Required conditions
Before beginning this procedure, make sure that the exciter has been on for at least 20 minutes.
Safety

Before working in any GE Healthcare MR suite or performing any GE Healthcare service procedure, you must:

  • Have read and understood all hazard conditions and safety requirements in the latest revision of the GE Healthcare MR Service Safety Manual (5452735).
  • Have successfully completed all relevant GE Healthcare Environmental Health and Safety (EHS) courses (or for non-GE employees, equivalent workplace training courses).
  • Comply with all site-specific training and workplace safety requirements.

If you have any safety concerns at any time, do not begin work or immediately stop work and move to a safe location. Immediately contact your supervisor or site safety officer for instructions on how to proceed.
Notice Image
  • notice
  • Possible equipment damage
  • Operating the RF amplifier with an improper load can cause permanent damage to the amplifier.
  • Do not operate the RF amplifier with an improper load connected to its output.
Notice Image
  • notice
  • Possible component damage
  • Hardware and phantoms left in the magnet bore can cause component damage.
  • Prevent coil and associated switch damage by removing all phantoms and hardware (such as head coil or surface coil) from the magnet bore.
Notice Image
  • notice
  • Possible component damage
  • If you connect or disconnect the wattmeter sensor while the meter is ON, component damage can occur.
  • Do not connect or disconnect the wattmeter sensor while the meter is ON. Always turn the meter OFF before plugging in or unplugging the sensor.
This procedure provides instructions to setup and calibrate the maximum power for the RF amplifier. The procedure also includes the calibration and functional check of the Universal Power Monitor (UPM) for each channel.

Use the UPM tool to process each channel. For example, when you select head mode, the tool executes the RF amplifier calibration and, if the amplifier passes, it proceeds to the UPM calibration and then to the functional check. The process is order-dependent.

For RF amplifier calibration, process the following in order:
  1. Body channel 1.
  2. Head channel.

For each channel, adjust the RF amplifier output power first, then calibrate UPM forward and reflected power, and finally run a UPM functional check.