Science Anxiety Questionnaire (see page 2 of document), from a United Nations meeting contains a science anxiety questionnaire that can be given to students.
Articles with practical information about science anxiety:
Mallow, J. (2006) Science anxiety: Research and action. National Science Teacher Association. Focuses on college students but is also especially relevant for upper division HS and AP teachers.
Britner, S. (2010). Science anxiety: Relationships to achievement, self-efficacy and pedagogical factors. In J. Cassady (Ed.) Anxiety in Schools: The Causes, Consequences, and Solutions for Academic Anxieties (pp 80-95). New York: Peter Lang.