Recover iPhone backup file from SSD
Assuming you can see the contents on the file system, the backups are located at /Users/yourusername/Library/Application Support/MobileSync/Backup/ in relation to the root of the drive.

Heads up that the Library folder located in your user's directory is hidden. You can use shortcut Shift + Command + G in Finder to bring up the 'Go To' dialog so you can copy + paste that location to get to the file. Just be aware that if you're mounting the drive, you will need to append /Volumes/DriveNameHere to the beginning of the path.