'Jupiter has the scariest radiation environment of any planet in the solar system' says Heidi Becker, leader of Juno's radiation-monitoring team. 'It's like a spray of radiation bullets.'  Juno must endure this potentially damaging barrage for the next 18 months and NASA has taken a number of steps to minimise the probe's radiation exposure.  An extremely elliptical orbit will allow the spacecraft to dip under and get beyond Jupiter's intense radiation belts but it will still be exposed to a radiation dose equivalent to more than 100 million dental X rays over the course of its mission.  To counter this the NASA team has given Juno a 'suit of armour' to lower the dose.  The core of the suit is a 180kg titanium vault with 1.75 cm walls which houses the main computer and sensitive electonic components of its scientific instruments.  Radiation doses inside the vault should be 800 times lower than those experienced outside.  As well as this, the outer parts of Juno's scientific instruments are wearing 'bulletproof vests' and the probe's star-tracking camera (used to navigate) is heavily protected as well.  

See here for short NASA video clips on different aspects of the Juno mission; the 10th clip in the list is Heidi Becker describing the radiation issues for the mission.