Electron microprobe dating of lunar zirconolite

Journal of Analytical Science and Technology

Table 1 Configuration of electron microprobe analysis for 31 elements in zirconolite at 15 kV and 100 nA

Element	Si Kα	Ti Kα	Al Kα	Cr Kα	Fe Kα	Mn Kα	Mg Kα	Ca Kα	Zr Lα	La Lα
Channel #	2	5	2	5	4	4	1	3	3	4
Crystal	TAP	LIFH	TAP	LIFH	LIF	LIF	TAPH	PETL	PETL	LIF
Peak (mm)	77.344	191.361	90.608	159.491	134.680	146.211	107.476	107.616	194.414	185.407
Counting time¹	100	20	100	200	40	200	200	40	20	700
Background	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN
Standard	Zircon	Rutile	Corundum	Eskolaite	Fayalite	Manganosite	Periclase	Wollastonite	Zircon	LaPO₄
Interference			Ti Kα III
Blank (ppm)²
Detection limit³	69	85	55	28	109	46	82	21	199	76

Element	Ce Lα	Pr Lβ	Nd Lα	Sm Lβ	Eu Lα⁴	Gd Lβ	Tb Lα	Dy Lα	Ho Lβ	Er Lα
Channel #	4	4	4	4	5	4	4	5	5	5
Crystal	LIF	LIF	LIF	LIF	LIFH	LIF	LIF	LIFH	LIFH	LIFH
Peak (mm)	178.165	157.100	164.856	139.000	147.756	128.468	137.448	133.007	114.821	124.367
Counting time	200	600	200	200	800	300	300	200	200	200
Background	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN
Standard	CePO₄	PrPO₄	NdPO₄	SmPO₄	EuPO₄	GdPO₄	TbPO₄	DyPO₄	HoPO₄	ErPO₄
Interference					Nd Lβ3 Pr Lβ2 Mn Kα	Ho Lα		Mn Kβ
Blank (ppm)						2.21			4.84	24.6
Detection limit	122	132	116	226	46	212	108	94	237	107

Element	Tm Lα	Y Lα	Th Mα	U Mβ	Pb Mα⁴	Yb Mα⁴	Lu Mα⁴	Hf Mα⁴	Sc Kα	Ta Mα⁴	Nb Lα
Channel #	5	3	3	3	3	2	2	2	5	2	3
Crystal	LIFH	PETL	PETL	PETL	PETL	TAP	TAP	TAP	LIFH	TAP	PETL
Peak (mm)	120.360	206.526	132.542	119.020	169.274	88.401	85.128	81.846	210.954	78.761	183.330
Counting time	600	100	400	1000	1000	200	1000	200	400	1000	200
Background	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN	MAN
Standard	TmPO₄	YPO₄	Thorium Oxide	U-Glass	PbVGe-oxide	YbPO₄	LuPO₄	Hafnium metal	ScPO₄	Tantalum metal	Potassium Niobate
Interference				(Th M3-N4)⁵ (K Kα)⁵	(Th Mζ)⁵ (Y Lγ2,3)⁵	Ti Kα III Tm Mβ	Yb Mβ, Th Mβ II, U Mα II	Lu Mβ, Ti Kβ III		Hf Mβ, Y Lι
Blank (ppm)	6.89	140	29.9	80	17.85
Detection limit	83	106	34	35	34	333	151	204	17	189	61

¹Counting times (s) on the X-ray peak. Background intensities were not measured but determined by the MAN method.
²Blank correction with the 91500 zircon standard. Data are working values from Wiedenbeck et al. (2004).
³Detection limits (3σ) for individual elements are reported in ppm.
⁴Measurement of Eu Lβ, Pb Mβ, Yb Lα, Lu Lα, Hf Lα, and Ta Lα is recommended for zirconolite analysis (Additional file 4: Table S3).
⁵Interference corrections for K Kα and Th on U Mβ and Th Mζ and Y Lγ2,3 on Pb Mα are estimated from Jercinovic & Williams (2005).