Solar Physics: Ulysses and ACE

Solar Physics: HI-SCALE & EPAM

The HISCALE and EPAM instruments, carried by Ulysses and ACE respectively, have been designed to measure the intensities of 38-315 keV electrons and 56-4752 keV protons in the interplanetary medium. There is also an ion composition detector on board both instruments. EPAM was the HI-SCALE flight spare which was adapted for use on the ACE spacecraft. Consequently both instruments are functionally identical, although they look quite different in the pictures below.


HI-SCALE		EPAM

The HI-SCALE and EPAM instruments consist of 2 separate telescope assemblies (seen best in the picture of HI-SCALE above). When combined these detector-telescope combinations provide almost full angular coverage of the entire sky as the spacecraft spins (right). This means that not only can these instruments measure the intensities of low energy ions and electrons, but they can also determine their angular distribution. Click the image on the right for a larger version.

By dividing a single spacecraft spin into sectors (right) we can record the electron and ion intensities in each of these sectors and derive the angular distributions. Clicking on the image on the right shows the sector configurations for both the HI-SCALE and the EPAM instruments.

This page is maintained by James Tappin, was written by Ian M. Robinson, and last updated on 27th October 2003. If you have any comments, please contact web@star.sr.bham.ac.uk