ConstantID

Neutron gyromagnetic ratio

Atomic & nuclearMeasured

γn = 1.832 471 74(43) × 108 s−1 T−1

Value
1.832 471 74 × 108 s−1 T−1
Standard uncertainty
43 s−1 T−1
Relative uncertainty
2.3 × 10−7 (235 parts per billion)
Status
Measured
Symbol
γn
Source
CODATA 2022 via NIST · NIST entry

Use in a calculation

# neutron gyromagnetic ratio, CODATA 2022 (NIST)
neutron_gyromagnetic_ratio = 1.83247174e8  # s^-1 T^-1, standard uncertainty 43

# SciPy: scipy.constants.physical_constants['neutron gyromag. ratio']

What it is

The ratio of magnetic moment to angular momentum for the neutron, the electrically neutral nucleon. In a magnetic field B the spin precesses at angular frequency γB; this is the basis of magnetic resonance.

How the value changed, 1998–2022

Each point is one CODATA adjustment, plotted as its difference from the 2022 value; the bars show one standard uncertainty (an arrowhead means the bar runs off the chart).

neutron gyromagnetic ratio: CODATA values 1998–2022 relative to the 2022 value, in parts per billion, with one-standard-uncertainty bars−600−400−2000+200+400+600parts per billion1998200220062010201420182022

Relative uncertainty

neutron gyromagnetic ratio: relative standard uncertainty in each CODATA adjustment, logarithmic scale10⁻⁸10⁻⁷10⁻⁶1998200220062010201420182022
CODATAValue (uncertainty)Relative uncertaintyChange from previous
20221.832 471 74(43) × 1082.3 × 10−7 +0.1 σ of 2018
20181.832 471 71(43) × 1082.3 × 10−7 −0.0 σ of 2014
20141.832 471 72(43) × 1082.3 × 10−7 −0.2 σ of 2010
20101.832 471 79(43) × 1082.3 × 10−7 −0.1 σ of 2006
20061.832 471 85(43) × 1082.3 × 10−7 +0.0 σ of 2002
20021.832 471 83(46) × 1082.5 × 10−7 −0.1 σ of 1998
19981.832 471 88(44) × 1082.4 × 10−7

“Change from previous” is the shift in the value divided by the standard uncertainty of the previous adjustment. Earlier values are converted into the current unit where NIST changed it (for example J s to J Hz⁻¹).

Related constants

Atomic & nuclear λC,n Neutron Compton wavelength 1.319 590 903 82(67) × 10−15 m Atomic & nuclear μn/μe Neutron-electron magnetic moment ratio 1.040 668 84(24) × 10−3 Atomic & nuclear mn/me Neutron-electron mass ratio 1838.683 662 00(74) Atomic & nuclear gn Neutron g factor −3.826 085 52(90) Atomic & nuclear γn/2π Neutron gyromagnetic ratio in MHz/T 29.164 6935(69) MHz T−1 Atomic & nuclear μn Neutron magnetic moment −9.662 3653(23) × 10−27 J T−1 Atomic & nuclear μn/μB Neutron magnetic moment to Bohr magneton ratio −1.041 875 65(25) × 10−3 Atomic & nuclear μn/μN Neutron magnetic moment to nuclear magneton ratio −1.913 042 76(45)