Misc physics properties

New physics files and changes to existing physics files in PS6 must be authenticated by a responsible user (e.g. a medical physicist).

Every time a physics file is loaded a checksum is calculated and compared to the authenticated checksum recorded in PSdatabase.sqlite for that file. If the checksums do not match the file is flagged and cannot be used for dose calculations until it has been authenticated.

Physics files should be initially authenticated the first time PS6 is run following the initial installation of the software by unlocking physics access (using the physics password) and clicking Delete All Checksums followed by the Authenticate All Files button near the lower right corner.

To authenticate a single file click the Authenticate button next to the source menu.

In the Manufacturing calibration binning control group:

  • Enter the standard source strength binning uncertainty range (defaults to 2%). This parameter was added at PS version 6.9.4.
  • Enter a table of manufacturer's standard binning midpoints.

You can add an optional comment to the physics file in this panel.

Any errors detected when loading a physics file are listed in this panel.

If the physics file for the radionuclide source you want to use is not enabled in the inventory window or elsewhere in PS6 (probably because it is not an IsoAid product) you will need to enable all sources in the basic preferences pane.


Authenticating a physics file

When an .iphys file is imported, if any errors are detected (e.g. required data fields are missing) or the current and database checksums do not match, the file will be flagged as defective and MUST be authenticated before it can used for dosimetry calculations. A listing of the problems and authentication tools are found in this Misc panel of the Physics window. In menu listings of physics files, files available for dosimetry calculations are indicated by the Ball-go-16 icon and defective files are indicated by the Ball-stop-16 icon. Note: the screen capture on the right is from an older version of PS6 but is fundamentally the same as the current version as regards file authentication.


Physics files may only be authenticated when the Physics window has been unlocked as described here and here.

  • Authenticate - Authenticates the file of the selected item of the source menu.
  • Delete All Checksums - Clears the checksums database, simulating the conditions of a new installation or application upgrade.
  • Authenticate All Files - Simultaneously authenticates all files listed in the source menu. Use this button to quickly authenticate everything following a new installation or upgrade of Plaque Simulator.

File sharing and permissions

Note: MacOS enforces many levels (sometimes Draconian) of file security. Sometimes access to physics files can be blocked by the underlying Unix file security and permissions layer of MacOS.

This can happen if the software was installed by an administrator other than the currently logged-in MacOS user.

To fix this you will need to:

  1. Close the PS6 application

  2. If you do not have MacOS admin privileges, log-out of MacOS (via the Apple icon menu) and log-in to MacOS as a user that does have MacOS "admin" privileges.

  3. Use the MacOS Finder application to open a File/Get Info window for the Plaque Simulator Folder (usually located in your root Applications folder).

  4. Unlock the Get Info window by clicking the lock icon near the lower right corner of the window. You will need your MacOS user log-in password.

  5. UnlockGetInfo

  6. Set Sharing and Permissions for the Plaque Simulator Folder's username (e.g. melvinastrahan), admin and everyone entries to Read & Write.

  7. Apply those setting to all enclosed items using the "gear" icon and popup menu found near the bottom of the Get Info window. This will assure low-level access for all users to all applications, support files and folders enclosed within the Plaque Simulator folder.

  8. ApplyToEnclosed
  9. Relock the Plaque Simulator Folder's Sharing and Permissions by clicking the lock icon.

  10. Close the Get Info window.

  11. If necessary, log-out (as the admin) and then log-in as whichever user you have designated to run PS6 and launch the PS6 application.


Physics Files