Is there a place to check-in my backpack ?

Backpacks can be checked in at the front desk

There were lockers inside the west entrance. I haven't been through that door for a while, so I don't remember whether or not they're still there. If you have a backpack when go to enter the galleries, the security desk attendant will ask that you leave your bag there at the desk.

I think you leave them at the desk

Im not for sure i did not have one when i visited