Table 3.

Measured activities of radioactive isotopes in the neutron veto, purification, and calibration subsystems. Measured values are given with $\pm 1\sigma$ uncertainties, and upper limits are set at 95% C.L. The facility, sample mass, and lifetime are provided for each measurement (as applicable)

Sample	Component	Manufacturer	Facility	Mass [kg]	Livetime [d]	Units	${}^{238}$U	${}^{235}$U	${}^{226}$Ra	${}^{228}$Ra (${}^{232}$Th)	${}^{228}$Th	${}^{40}$K	${}^{60}$Co	${}^{137}$Cs
Neutron Veto
41	R5912 PMT Body	Hamamatsu	GeMPI	0.2	6.9	mBq/kg	70(30)	$<6.4$	52(4)	37(4)	30(3)	360(40)	$<1.8$	$<1.3$
42	R5912 PMT low radioactivity Glass	Hamamatsu	GeCris	0.4	3.9	mBq/kg	700(200)	40(10)	700(30)	740(50)	670(45)	1000(100)	$<3.0$	$<9.7$
43	Polyethylene PMT Holders	Plastotecnica emiliana	GeMPI	0.1	13.8	mBq/kg	$<19$	$<2.2$	2.1(8)	$<2.2$	$<2.1$	$<22$	–	$<0.6$
44	SS Support Structure	Galli and Morelli	GeMPI	0.5	27.5	mBq/kg	$<25$	$<0.55$	0.8(2)	1.1(4)	2.3(4)	$<4.9$	4.1(4)	$<0.2$
45	ePTFE Reflectors	Applitecno Service	ICP-MS	–	–	mBq/kg	0.3(1)	–	–	0.12(4)	–	–	–	–
46	Gadolinium Sulfate	NYC	GeMPI	1.0	20.7	mBq/kg	$<14$	$<0.5$	0.9(2)	0.4(2)	1.2(2)	$<4.1$	–	$<0.06$
47	Gadolinium Sulfate	Treibacher	GeMPI	1.0	6.6	mBq/kg	$<43$	$<3.6$	3.4(7)	23(2)	190(10)	9(4)	–	$<0.8$
Purifying Getter Materials
48	LXe Filter 2${}_a$	BASF	Corrado	0.3	23.8	mBq/kg	3200(700)	–	145(10)	70(20)	86(9)	920(90)	$<6$	$<7$
49	LXe Filter 2${}_b$	BASF	Corrado	0.4	10.4	mBq/kg	2900(760)	–	150(10)	70(20)	84(16)	720(90)	$<6$	$<6$
50	LXe Filter 2${}_c$	BASF	Corrado	0.1	7.2	mBq/kg	3600(1300)	–	1050(40)	460(60)	560(50)	1500(200)	$<11$	$<8$
Calibration
51	Polyurethane Belt	BRECOFlex	GeMPI	0.6	9.5	mBq/kg	46(19)	$<2.5$	13(1)	5(1)	4(1)	93(17)	1.9(6)	$<0.7$
52	Source Box	–	Giove	7.3	13.8	mBq/kg	$<26.4$	$<1.7$	$<0.9$	1.0(6)	1.7(4)	$<1.2$	6.2(4)	$<0.2$
53	Source Box Clamp	McMaster	Corrado	0.9	24.5	mBq/kg	$<395$	$<44$	46(4)	$<15.5$	15(5)	$<32$	12(2)	$<2$
54	SS316 Tube	Swagelok	GSOr	2.9	7.1	mBq/kg	$<33$	$<2.8$	5.3(7)	6.2(9)	14(1)	$<7.5$	2.5(3)	$<0.8$
55	SS304 Beam Pipe	Weizmann	GeMPI	3.1	16.7	mBq/kg	$<63$	$<1.8$	1.7(5)	6(1)	6(1)	$<10$	6.8(7)	$<0.5$
56	SS304 Support Pipe	Weizmann	GeMPI	0.5	27.6	mBq/kg	36(18)	$<0.9$	0.6(3)	1.9(8)	6.8(8)	$<15$	6.5(8)	$<0.9$
57	SS316 Clamps	McMaster	GeMPI	2.2	5.6	mBq/kg	150(60)	$<8.8$	102(5)	19(2)	18(2)	7(3)	12(1)	–
58	SS304 Bellow	MDC	GeMPI	3.5	13.7	mBq/kg	$<47$	$<1.3$	2.0(4)	5.3(9)	9.8(9)	$<3.6$	7.1(7)	$<0.5$
59	SS304 Flanges	MDC	GeMPI	12.0	20.6	mBq/kg	24(12)	1.0(4)	0.4(1)	1.6(4)	5.0(4)	1.6(6)	11.2(8)	$<0.2$
60	SS304 U-Tube	CG	GeMPI	0.6	16.2	mBq/kg	$<150$	$<5.8$	$<1.9$	$<6.6$	4(1)	15(8)	45(4)	$<1.5$