The Advanced Photon Source
a U.S. Department of Energy Office of Science User Facility

Magnetic Measurement Facility

The Magnetic Measurement Facility (MMF) is used to meet, maintain, and verify Insertion Device (ID) magnetic and mechanical performance. This is essential for maintaining uninterrupted high-quality x-ray beam with the desired specified brightness and high level of spatial stability at the APS. The MMF consists of three parts: The measurement benches, magnetic calibration system, and magnetic moment measurement system. 

ID Magnetic Measurement Benches

As of now, the MMF consists of two measurement benches, 3 meters and 6 meteres long. Each bench is equipped with a set of interchangeable magnetic sensors. Mechanical systems installed on both benches provide for highly accurate motion of the magnetic sensors, three linear and one angular. The control system synchronizes the readings of the sensor's signal with the encoder readings during the process of continuous sensor motion. A data acquisition system collects and processes measurement data, and a graphic user interface presents it on the computer screen as plots and tables. These systems have been partially described in technical reports and conference presentations [1].

Fig. 1. General view of the 3 meter bench with an Insertion Device ready to be measured
Fig. 2. General view of the 6 meter bench with an Insertion Device ready to be measured
Magnetic Calibration System

This system consists of the calibration electromagnet and a set of Nuclear Magnetic Resonance (NMR) probes. These are used to precisely calibrate the Hall probes used during undulator tuning

Fig. 3. Calibration Electromagnet

The MM1 Controls Documentation describes the operation of the control system used to measure and tune undulators before they are installed in the APS storage ring.