- Part I is 150 questions in 3 hours; the cut score has typically landed near 95 correct.
- Domain 1 (Measurements and Instrumentation) carries the heaviest weight at 25% of Part I.
- Part II demands six core questions plus four of eight specialty problems, closed-reference, in 6 hours.
- Part I and Part II require passing within seven years of each other, so plan sequencing early.
Understanding the CHP Exam Structure
The Certified Health Physicist credential, administered by the American Board of Health Physics (ABHP) under the American Academy of Health Physics (AAHP), is not a single test but a two-part gate. Part I is a Pearson VUE computer-based exam: 150 five-option multiple-choice questions delivered in 3 hours, with a statistically set cut score that has typically required roughly 95 correct answers. Part II is an entirely different animal - a 6-hour closed-reference written exam requiring six core questions plus four of eight specialty problems, scored out of 700 points with 469 needed to pass.
Because the two parts test different skills - recognition and recall versus applied problem-solving under time pressure - your preparation strategy has to change depending on which part you're targeting. If you haven't already mapped out exactly how difficult each stage is relative to the other, the How Hard Is the CHP Exam? Complete Difficulty Guide 2026 breaks down where most candidates actually lose points.
Part I: The Five Domains in Depth
Part I content is organized into five weighted domains. Knowing the weighting tells you exactly where to spend your limited study hours. For a full domain-by-domain walkthrough with sample topics, see the CHP Exam Domains 2026: Complete Guide to All 5 Content Areas.
Domain 1: Measurements and Instrumentation (25%)
This is the single largest domain on Part I and deserves proportionally more of your review time. Candidates must understand detector physics, counting statistics, and instrument response under real field conditions.
- Gas-filled detectors (ionization chambers, GM, proportional counters) and their operating regions
- Scintillation and semiconductor detector efficiency and energy response
- Counting statistics, minimum detectable activity, and dead-time corrections
- Calibration sources, geometry corrections, and instrument response curves
Domain 2: Standards and Requirements (20%)
This domain tests familiarity with the regulatory and consensus-standard framework health physicists operate within daily.
- NRC and Agreement State regulations (10 CFR Parts 20, 35, 61)
- DOE orders and OSHA overlap in occupational radiation protection
- ICRP and NCRP recommendations and how they've shaped dose limits
- Transportation regulations (49 CFR) for radioactive material shipments
Domain 3: Hazards Analysis and Controls (20%)
Candidates must be able to identify radiological hazards and apply appropriate engineering and administrative controls.
- External and internal dose assessment methodologies
- ALARA program design and shielding calculations
- Criticality safety fundamentals and contamination control
- Emergency response planning and dose reconstruction basics
Domain 4: Operations and Procedures (20%)
This domain focuses on the day-to-day operational judgment expected of a working health physicist.
- Radioactive waste management and disposal pathway selection
- Respiratory protection and personal protective equipment selection
- Dosimetry program administration and recordkeeping
- Decommissioning and decontamination procedures
Domain 5: Fundamentals and Education (15%)
The smallest domain by weight but foundational to everything else - expect questions on core physics and biological effects.
- Atomic and nuclear structure, decay modes, and half-life calculations
- Interaction of radiation with matter
- Radiobiology and stochastic versus deterministic effects
- Basic dosimetry quantities (absorbed dose, equivalent dose, effective dose)
Part II: Applied Practice Problems
Part II is not multiple choice - it's a closed-reference exam where you bring your own references and calculator and work through six core questions covering broad health physics practice, plus four of eight specialty problems you select based on your professional background. This format rewards candidates who have actually applied health physics concepts on the job, not just memorized them.
Because scoring requires 469 of 700 points, partial credit on multi-part quantitative problems matters enormously. Practicing full problem write-ups - showing assumptions, units, and intermediate steps - is more valuable than passively reading references. If you're still unsure exactly what score threshold you're working toward on either part, the CHP Passing Score 2026: Exactly What You Need to Pass article lays out both scoring systems side by side.
| Feature | Part I | Part II |
|---|---|---|
| Format | 150 five-option multiple choice | 6 core + 4 of 8 specialty problems, closed-reference |
| Duration | 3 hours | 6 hours |
| Passing Standard | ~95 correct (statistically set) | 469 of 700 points |
| Apply + Register Fees | $100 + $150 | $250 + $500 |
| 2024 Pass Rate | 30.99% | 45.83% |
Eligibility and Registration Mechanics
Part II eligibility isn't automatic. It generally requires six years of professional health physics experience, including three years of applied experience, along with qualifying education, professional references, and a submitted radiation protection report demonstrating independent technical work. This means most candidates sit for Part I well before they're eligible for Part II - and both parts must be passed within seven years of each other.
These experience and documentation requirements trip up more candidates than the exam content itself, so review them early. The CHP Requirements 2026: Eligibility, Prerequisites & How to Qualify guide walks through exactly what counts as applied experience and how to structure your radiation protection report submission. If you're budgeting for the full path, the CHP Certification Cost 2026: Complete Pricing Breakdown article totals up application, registration, and test-site fees across both parts.
Key Takeaway
Start your Part II eligibility documentation - references, experience logs, and your radiation protection report - years before you plan to sit for the exam, not after passing Part I.
A Domain-Weighted Study Timeline
Generic study techniques like spaced repetition and timed practice blocks only help if you apply them to the right material at the right time. Because Domain 1 carries 25% of Part I's weight, it should anchor the early weeks of any schedule, with the three 20%-weighted domains rotating through the middle stretch and Domain 5 fundamentals reviewed continuously since they underpin every other domain.
Domain 1: Measurements and Instrumentation
- Work detector-response and counting-statistics problems daily
- Build a reference sheet of calibration and efficiency formulas
Domain 2 & Domain 3
- Cross-reference regulatory citations with hazard-control scenarios
- Practice ALARA and shielding calculations under time pressure
Domain 4: Operations and Procedures
- Review waste-pathway decision trees and PPE selection logic
- Take a full timed 150-question practice set
Domain 5 and Weak-Area Review
- Reinforce nuclear fundamentals and radiobiology basics
- Retake missed questions from earlier practice sets
For a deeper, standalone breakdown of this exact approach, see the full CHP Study Guide 2026: How to Pass on Your First Attempt resource, and pair it with the CHP Cheat Sheet 2026: One-Page Review of Must-Know Facts for quick final-week review. Running full-length timed drills on our practice test platform before exam day is one of the most reliable ways to confirm your pacing across all five domains holds up under the real 3-hour limit.
Who Hires Certified Health Physicists
The CHP credential signals applied competence across nuclear power, federal and DOE facilities, academic and medical radiation safety programs, environmental consulting, and regulatory bodies. Employers in these sectors often list CHP status as a preferred or required qualification for senior radiation safety officer and health physicist roles because it verifies both breadth (Part I) and hands-on judgment (Part II).
If you're evaluating whether the credential fits your career trajectory, the CHP Salary Guide 2026: Complete Earnings Analysis and Is the CHP Certification Worth It? Complete ROI Analysis 2026 articles cover compensation trends and return on investment in more depth. For a look at the range of positions the credential opens up, browse the CHP Jobs overview.
Common Mistakes First-Time Candidates Make
Most first-attempt failures on Part I trace back to uneven domain preparation - candidates over-study Domain 5 fundamentals because it feels familiar from academic coursework, then underestimate the volume of instrumentation and standards questions actually on the exam. On Part II, the most common error is running out of time on the specialty problems because too much time was spent perfecting the six core questions.
- Skipping domain weighting entirely: Studying every topic equally instead of prioritizing Domain 1's 25% share.
- Underestimating closed-reference logistics: Not practicing with the actual references you'll bring to Part II until days before the exam.
- Ignoring the seven-year clock: Delaying Part II attempts so long that the seven-year window between passing Part I and Part II becomes a real risk.
- Not tracking eligibility documentation early: Waiting to compile references and the radiation protection report until after deciding to register.
If you want data-backed context on why these mistakes are so common, the CHP Pass Rate 2026: What the Data Shows article examines the 2024 pass rate figures in more detail, and CHP Exam Dates 2026: Testing Windows, Deadlines & Scheduling helps you avoid registration timing mistakes.
Frequently Asked Questions
Part I consists of 150 five-option multiple-choice questions administered via Pearson VUE, with a 3-hour time limit.
Part I uses a statistically set cut score that has typically required around 95 correct answers out of 150, rather than a fixed percentage.
Both parts must be passed within seven years of each other, and Part II eligibility generally requires six years of professional health physics experience, so most candidates complete Part I first.
Part II is a closed-reference exam, meaning you bring your own approved reference materials rather than being provided a standard set, so practicing with your actual references beforehand is essential.
Part I requires a $100 application fee plus $150 registration fee, and Part II requires a $250 application fee plus $500 registration fee, each with an additional separate test-site fee.