A sample container for NMR measurements, the sample container being closed on one side thereof, the NMR measurements performed by disposing the sample container in an environment, having a magnetic susceptibility χ1, within an external homogeneous magnetic field B0, the external homogeneous magnetic field B0 extending parallel to a z axis, the sample container being structured to hold a sample substance occupying a volume V within the sample container and having a magnetic susceptibility χ3, the sample container comprising:
- a first wall structure defining an upper partial volume V2b of the sample substance;
- a second wall structure defining a lower partial volume V2a of the sample substance;
- a third wall structure defining a center partial volume V1 of the sample substance, said first second and third wall structures being made from a material having a magnetic susceptibility of χ2, the center partial volume having an origin SZ of a spherical coordinate system having the z-axis, wherein the upper, lower and center partial volumes adjoin one another;
- a fourth wall structure defining a first interface G1 facing the environment, the first interface having a first susceptibility jump generating a first location-dependent disturbance field BG1;
- and
- a fifth wall structure defining a second interface G2 facing the sample substance, the second interface having a second susceptibility jump generating a second location-dependent disturbance field BG2, wherein the sample substance defines a third interface G3 between the sample substance and the environment, the third interface having a third magnetic susceptibility jump generating a third location-dependent disturbance field BG3, wherein the second susceptibility jump is sufficiently large that a maximum value of |B′G2/B0| within the volume V is at least 0.5 ppm, a first residual field R1 being present in the center partial volume V1 and a second residual field R2a in the lower partial volume V2a, wherein a geometry of the sample container is thereby selected in such a fashion that a location-dependent relative field change F is present in the volume V due to the first, second and third susceptibility jumps, wherein, at least at one point in the center partial volume V1, a relative field change F is larger than 20 ppb, the first residual field R1 being smaller than 1.6 ppb and the second residual field R2a being smaller than 30 ppb, wherein:
- BG1:
- is a location-dependent z component of the magnetic field that is generated in the volume V due to the first susceptibility jump from χ1 to χ2 at the first interface G1;
- BG2:
- is a location-dependent z component of the magnetic field that is generated in the volume V due to the second susceptibility jump from χ2 to χ3 at the second interface G2;
- BG3:
- is a location-dependent z component of the magnetic field that is generated in the volume V due to the third susceptibility jump from χ3 to χ1 at the third interface G3;
- F:=(B′G1+B′G2+B′G3)/B0:
- is a location-dependent relative field change due to the first, second and third susceptibility jumps;
- B′j:=Bj−Bj:
- is a location-dependent deviation of a field Bj from an average value Bj
- Bj:
- is an average value of the z component of the field Bj, wherein j=G1, G2, G3;
- R
- 1
- :=
- (
- 1
- V
- 1
-
- ∫
- V
- 1
-
- (
- F
- -
- F
- N
- )
- 2
-
-
- ⅆ
- V
- )
- 1
- /
- 2
- ,
- is the first residual field in the center partial volume V1;
- R
- 2
-
- a
- :=
- (
- 1
- V
- 2
-
- a
-
- ∫
- V
- 2
-
- a
-
- (
- F
- -
- F
- N
- )
- 2
-
-
- ⅆ
- V
- )
- 1
- /
- 2
- ,
- is the second residual field in the lower partial volume V2a;
- and
- FN:
- is an expansion of the relative field change F about the origin SZ in rotationally symmetrical spherical functions up to order N, wherein N=4 to 10;
- with
- 〈
- A
- 〉
- :=
- 1
- V
-
- ∫
- V
-
- A
- ·
- ⅆ
- V
-
- :
- being an average value of any magnetic field A in the sample volume V;
- and
- A
- N
- :=
- ∑
- n
- =
- 0
- N
-
- a
- n
-
- K
- n
-
- (
- r
- ,
- θ
- )
-
-
- :
- an expansion of A in rotationally symmetrical spherical functions up to order N, wherein
- an:
- are expansion coefficients
- Kn(r,θ)=rnPn(cos θ):
- are rotationally symmetrical spherical functions and
- Pn(cos θ):
- are Legendre polynomials.