---
kind: "section"
citation: "10 C.F.R. § 35.61"
title: "10"
number: "35.61"
heading: "Calibration of survey instruments."
url: "https://uscodex.org/cfr/10/35.61"
---

# §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](/cfr/10/part20.md) 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](/cfr/10/35.2061.md).

## Notes

### Authority

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.

### Source

Source: 67 FR 20370, Apr. 24, 2002, unless otherwise noted.