Thin Shell, Segmented X-Ray Mirrors

Table 3

Multilayer coated foil mirrors.

	InFOCμS	HEFT	SUMIT	NuSTAR
Diameter (cm)	40	24	36	38
Focal length (m)	8	6	8	10
Number of shells	255	72	90	130
Number of modules per mirror	4	1*	3	1*
Segment length (cm)	10	2×10^∗∗	13	22.5
Total number of segments	2040	700	540	2340
Substrate material	aluminum	glass	aluminum	glass
Substrate thickness (mm)	0.17	0.3	0.22	0.21
Surface production method	replication	thermal forming	replication	thermal forming
Multilayer coating	Pt/C	W/Si	Pt/C	Pt/C, W/Si
Effective area (cm^2)	51	50@40		150
Angular resolution (arcmin)	2.7	1.3	2.06	<60
Year of launch	2001, 2004	2005	2006	2012

*HEFT and NuSTAR mirrors consist of one module, but shells are composed of multiple segments.
**Each reflecting stage consists of a pair of segments.