air travel questions

Any limit on batteries (number) that can be taken in carry on luggage, or problems with memory card erasure due to airport x-ray machines??.  I will be flying Alaska Airway from Dallas to Alaska this summer.  Would like to carry five or six batteries for E-30 in backpack which will go into overhead as well as one charger just in case checked bag gets separated from me.  Camera will be personal item in Lowepro case stored under seat  Thanks

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slowbutsteady