Table 4 Comparison of the final radiopurity levels achieved in custom cables produced as part of this work (highlighted in bold) with other commercial and custom cables used in low background rare event experiments. The commercial (abbreviated as Com.) cables listed near the top of the table are the same design as our custom cables and can be compared directly. The cables listed at the bottom of the table have different construction and fabrication options—see text for details
Cable | Copper layers [μm] | Polyimide layers [μm] | Coverlay | Surface finish | 238U [pg/g] | 232Th [pg/g] | natK [ng/g] |
|---|---|---|---|---|---|---|---|
nEXO SiPM | 18 (x2) | 50.8 (x1) | No | No | 20 ± 2 | <12.3 | 40 ± 12 |
nEXO SiPM [Com.] | 18 (x2) | 50.8 (x1) | No | No | 1300-6200 | 16-63 | |
DAMIC-M CCD | 18 (x2) | 50.8 (x1) | x2 | ENIG | 31 ± 2 | 13 ± 3 | 550 ± 20 |
DAMIC-M CCD [Com.] | 18 (x2) | 50.8 (x1) | x2 | ENIG | 2600 ± 40 | 261 ± 12 | 170 ± 50 |
18 (x1) | 25.4 (x1) | No | No | 412 ± 47 | <117 | ||
18 (x4) | 25/125 (x3/x4) | No | No | 650 ± 490 | 3700 ± 2500 | 2100 ± 840 | |
DAMIC at SNOLAB [4] | 18 (x5) | 25.4 (x4) | x2 | ENIG | 4700 ± 400 | 790 ± 120 | 940 ± 60 |