# openmc.model.CylinderSector¶

class openmc.model.CylinderSector(r1, r2, theta1, theta2, center=(0.0, 0.0), axis='z', **kwargs)[source]

Infinite cylindrical sector composite surface.

A cylinder sector is composed of two cylindrical and two planar surfaces. The cylindrical surfaces are concentric, and the planar surfaces intersect the central axis of the cylindrical surfaces.

This class acts as a proper surface, meaning that unary + and - operators applied to it will produce a half-space. The negative side is defined to be the region inside of the cylinder sector.

Parameters
• r1 (float) – Inner radius of sector. Must be less than r2.

• r2 (float) – Outer radius of sector. Must be greater than r1.

• theta1 (float) – Clockwise-most bound of sector in degrees. Assumed to be in the counterclockwise direction with respect to the first basis axis (+y, +z, or +x). Must be less than theta2.

• theta2 (float) – Counterclockwise-most bound of sector in degrees. Assumed to be in the counterclockwise direction with respect to the first basis axis (+y, +z, or +x). Must be greater than theta1.

• center (iterable of float) – Coordinate for central axes of cylinders in the (y, z), (z, x), or (x, y) basis. Defaults to (0,0).

• axis ({'x', 'y', 'z'}) – Central axis of the cylinders defining the inner and outer surfaces of the sector. Defaults to ‘z’.

• **kwargs (dict) – Keyword arguments passed to the Cylinder and Plane constructors.

Variables
classmethod from_theta_alpha(r1, r2, theta, alpha, center=(0.0, 0.0), axis='z', **kwargs)[source]

Alternate constructor for CylinderSector. Returns a CylinderSector object based on a central angle $$\theta$$ and an angular offset $$\alpha$$. Note that $$\theta_1 = \alpha$$ and $$\theta_2 = \alpha + \theta$$.

Parameters
• r1 (float) – Inner radius of sector. Must be less than r2.

• r2 (float) – Outer radius of sector. Must be greater than r1.

• theta (float) – Central angle, $$\theta$$, of the sector in degrees. Must be greater that 0 and less than 360.

• alpha (float) – Angular offset, $$\alpha$$, of sector in degrees. The offset is in the counter-clockwise direction with respect to the first basis axis (+y, +z, or +x). Note that negative values translate to an offset in the clockwise direction.

• center (iterable of float) – Coordinate for central axes of cylinders in the (y, z), (z, x), or (x, y) basis. Defaults to (0,0).

• axis ({'x', 'y', 'z'}) – Central axis of the cylinders defining the inner and outer surfaces of the sector. Defaults to ‘z’.

• **kwargs (dict) – Keyword arguments passed to the Cylinder and Plane constructors.

Returns

CylinderSector with the given central angle at the given offset.

Return type

CylinderSector