10 CFR § 35.61 - Calibration of survey instruments.

---
identifier: "/us/cfr/t10/s35.61"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "10 CFR § 35.61 - Calibration of survey instruments."
title_number: 10
title_name: "Energy"
section_number: "35.61"
section_name: "Calibration of survey instruments."
chapter_name: "NUCLEAR REGULATORY COMMISSION"
part_number: "35"
part_name: "MEDICAL USE OF BYPRODUCT MATERIAL"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Atomic Energy Act of 1954, secs. 81, 161, 181, 182, 183, 223, 234, 274 (42 U.S.C. 2111, 2201, 2231, 2232, 2233, 2273, 2282, 2021); Energy Reorganization Act of 1974, secs. 201, 206 (42 U.S.C. 5841, 5846); 44 U.S.C. 3504 note."
regulatory_source: "67 FR 20370, Apr. 24, 2002, unless otherwise noted."
cfr_part: "35"
---


# 35.61 Calibration of survey instruments.

(a) A licensee shall calibrate the survey instruments used to show compliance with this part and 10 CFR Part 20 before first use, annually, and following a repair that affects the calibration. A licensee shall—

(1) Calibrate all scales with readings up to 10 mSv (1000 mrem) per hour with a radiation source;

(2) Calibrate two separated readings on each scale or decade that will be used to show compliance; and

(3) Conspicuously note on the instrument the date of calibration.

(b) A licensee may not use survey instruments if the difference between the indicated exposure rate and the calculated exposure rate is more than 20 percent.

(c) A licensee shall retain a record of each survey instrument calibration in accordance with § 35.2061.