Amendment Solicitation 1333ND24QNB610474 Hexapod.docx

Amendment 2 to Solicitation 1333ND24QNB610474 Hexapod Alignment System

Vendor Question 1:

In the requirements, are talking about individual travels or cumulative travels ( meaning all travels need to be applied simultaneously ? ) : +/- 13 mm for Z and Y and +/- 3° for Rz and Ry (assuming X is the optical axis).

NIST Response 1: The travel requirements are individual rather than cumulative. For example, we require that the Y travel be the full ±13 mm when Z = 0, but we expect it to be reduced when Z ≠ 0. The assumption that X is the optical axis is correct in the formulation of the question.

Vendor Question 2:

What is the center of gravity and center of rotation locations? (Position of the center of gravity of Rot-02 and CryoRad III and the center of rotation (is it at the interface with the monochromator? This would allow us to optimize the positions of the hexapod.

NIST Response 2: Please also see attached drawings for more clarification.

Center of Rotation: The point of rotation should be the entrance aperture of the CryoRad III radiometer. This point is located between the front of the CryoRad III (the tall cylinder in the Load Drawing document) and the vacuum valve in front of the CryoRad III. It is nominally on the center line of the tube connecting the CryoRad III and the valve. An additional note about the Load Drawing document: the point marked “Axis of Rotation” on the drawing refers to an internal rotation within the load, not to the point about which the hexapod should rotate the load.

Center of Gravity: The center of gravity can move within the load by a motion that is internal to the load. The hexapod should remain still when this internal motion occurs. In one configuration, shown in the “CoG CryoRad III.pdf” drawing, the center of mass is 71.1 mm (2.80 in) starboard of the optic axis. In the other, shown in the “CoG Test Chamber III.pdf” drawing, it is 141.9 mm (5.59 in)to port of the optic axis. In both configurations, the center of gravity is 285.9 mm (11.26 in) above the base of the load. The load can be mounted so that the midpoint between these configurations is located over the center of the hexapod so that the center of mass should always be within ±15.25 cm (±6 inches) of the center of the hexapod.

Vendor Question 3:

Is it acceptable if the hexapod is backdriven when the power is cut off?

NIST Response 3:

It is not acceptable that the hexapod be backdriven when the power is cut off.

Vendor Question 4:

Do you have any information on where the center of gravity is located for the load? In addition, is it safe to assume that the load's center of gravity will be centered on the Hexapod's table top?

NIST Response 4: Please also see attached drawings for more clarification.

The center of gravity can move within the load by a motion that is internal to the load. The hexapod should remain still when this internal motion occurs. In one configuration, shown in the “CoG CryoRad III.pdf” drawing, the center of mass is 71.1 mm (2.80 in) starboard of the optic axis. In the other, shown in the “CoG Test Chamber III.pdf” drawing, it is 141.9 mm (5.59 in)to port of the optic axis. In both configurations, the center of gravity is 285.9 mm (11.26 in) above the base of the load. The load can be mounted so that the midpoint between these configurations is located over the center of the hexapod so that the center of mass should always be within ±15.25 cm (±6 inches) of the center of the hexapod.