Select Assay Capabilities at PNNL

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1 Select Assay Capabilities at PNNL TODD HOSSBACH with contributions from my PNNL colleagues DAMIC-M Collaboration Meeting June 2018 Paris PNNL-SA June 27,

2 Overview of PNNL Assay Capabilities Relevant to DAMIC-M PNNL has employed or developed a large number of assay capabilities to support fundamental physics, environmental science, and applied research programs Some of these capabilities (e.g. ICP-MS for U/Th/K) have world-leading sensitivity others have competitive sensitivity. All of these capabilities are available for DAMIC-M needs. Relevant assay technologies: ICP-MS (Modified commercial instruments HP/Agilent and PNNL-developed methods) HPGe spectrometers (Canberra, Ortec, and PNNL-built ultra-low-background) Radon Emanation (PNNL-developed emanation bench and ULB proportional counters) Surface Assay (XIA UltraLo-1800) Additional Assay Capabilities ULB liquid scintillation counter High-efficiency beta counters DAMIC-M Collaboration Meeting June 11-13, 2018 Paris June 27,

Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) Requires small amounts of material (<1 gram) Destructive technique Directly measures the 232 Th and 238 U atoms in materials Relatively fast,

3 Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) Requires small amounts of material (<1 gram) Destructive technique Directly measures the 232 Th and 238 U atoms in materials Relatively fast, high throughput Depending on the material, samples take 1-3 days to process, can run samples/day PNNL Detection limits are in the part-per-trillion (pg/g) to partsper-quadrillion range (fg/g) for U and Th for most all materials (see next Table) We have two ICP-MS instruments dedicated to ultralow background measurements Isaac Arnquist DAMIC-M Collaboration Meeting June 11-13, 2018 Paris June 27,

PNNL ICP-MS Detection Limits for Different Materials

Th, U Detection Limits mbq/kg ppt <0.1 <0.

) <1 <0.1 Linear Alkyl Benzene (LAB) <0.1 <0.01 Quartz, Fused Silica <1 <0.

D. LaFerriere, T.C. Maiti, I.J. Arnquist, E.W. Hoppe.

4 PNNL ICP-MS Detection Limits for Different Materials Material Copper (Electroformed or commercial OFHC) Th, U Detection Limits mbq/kg ppt <0.1 <0.01 Lead <1 <0.1 Titanium <1 <0.1 Stainless Steel <1 <0.1 Polymers (PTFE, Acrylic, Kapton, Cirlex, etc.) <1 <0.1 Linear Alkyl Benzene (LAB) <0.1 <0.01 Quartz, Fused Silica <1 <0.1 Electronic Components (FETs, resistors, thermocouples, etc.) <0.1 pg/piece <1 nanobq/piece Solutions <0.01 <0.001 B.D. LaFerriere, T.C. Maiti, I.J. Arnquist, E.W. Hoppe. NIM A (2015) I.J. Arnquist, J.W. Grate, M. Bliss, E.W. Hoppe. Analytical Chemistry (2017) Isaac Arnquist For Reference 1 ppt Th = 4.1 mbq 232 Th/kg 1 ppt U = 12.4 mbq 238 U/kg DAMIC-M Collaboration Meeting June 11-13, 2018 Paris June 27,

Detector We can also measure K using our new triple quadrupole ICP-MS

isotopic abundance of K: 39 K: 93.3% quantify on the most abundant isotope 40 K: 0.

7% Ar-based plasma adds a considerable background at m/z 36-41 from isobaric

, 38 ArH +, 40 Ar +, 40 ArH + ) Poor(er) detection limits w/ conventional ICP-MS

Octopole Quadrupole 2 m/z=39 reaction cell m/z=39 39 K + 38 ArH + H 3 18 O(H 2 16

5 Detector We can also measure K using our new triple quadrupole ICP-MS Determination of K is a challenge for (conventional, single quad) ICP-MS Natural isotopic abundance of K: 39 K: 93.3% quantify on the most abundant isotope 40 K: 0.012% 41 K: 6.7% Ar-based plasma adds a considerable background at m/z from isobaric interferences (e.g., 38 ArH +, 40 Ar +, 40 ArH + ) Poor(er) detection limits w/ conventional ICP-MS however triple quad ICP-MS works well Cool Plasma Isaac Arnquist Quadrupole 1 Octopole Quadrupole 2 m/z=39 reaction cell m/z=39 39 K + 38 ArH + H 3 18 O(H 2 16 O) + 38 ArH + H 3 18 O(H 2 16 O) + 10%NH 3 90% He 39 K + Detection Limits for K: 10 ppq in water Can reach <ppb nat K determinations in most any material (<30 mbq 40 K/kg) DAMIC-M Collaboration Meeting June 11-13, 2018 Paris June 27,

6 HPGe Spectrometers for Gamma Assay 30+ surface-level shielded commercial HPGe spectrometers 14-crystal ULB HPGe array, coincidence LB BEGe system, HPGe-well at 35mwe overburden Sum of Outer Crystals Total energy 1173 kev Total energy 1332 kev 1173 kev center 1332 kev outer 1332 kev center 1173 kev outer Center Crystal DAMIC-M Collaboration Meeting June 11-13, 2018 Paris June 27,

7 Carrier gas Detection Gas Radon Emanation Emanation Chamber (vacuum vessel) Radon Trap Liquid Nitrogen Detector Vacuum Pump Ray Bunker Step 1: Rinse sample with low-radon gas & evacuate to low pressure Step 2: Emanate for 1 week until radon level nears equilibrium Step 3: Transfer emanated radon to cryogenic trap Step 4: Load radon into detector & detect decays DAMIC-M Collaboration Meeting June 11-13, 2018 Paris June 27,

lowest-background ROI Radon Emanation 1 High-sensitivity Radon

for dark matter direct detection experiments Leverages PNNL

low-background proportional counters 2 222 218 Po 214 Po

2% Ray Bunker Ultra-low-background proportional counter technology

8 lowest-background ROI Radon Emanation 1 High-sensitivity Radon Emanation Capability Important materials radiopurity assay method for dark matter direct detection experiments Leverages PNNL expertise: 1. noble gas systems 2. low-background proportional counters Po 214 Po well-calibrated overall efficiency 9.1±0.2% Ray Bunker Ultra-low-background proportional counter technology Seifert et al., Radioanal. Nucl. Chem. 296 (2013) 915 Loaded activity 2.10±0.06 Bq DAMIC-M Collaboration Meeting June 11-13, 2018 Paris June 27,

9 Radon Emanation High-sensitivity Radon Emanation Capability Demonstrated with prototype proportional counter operated in surface lab Already sufficiently sensitive for assay needs of G2 projects (SuperCDMS & LZ) PNNL radon emanation system sensitivity paper in preparation results presented at TAUP2107 conference by SCGSR student: Mr. Dan Jardin (SMU) Stacked histogram magenta part rejected by pulse-shape analysis 210 Po peak from 210 Pb internal contamination (prototype detector exposed to lots of!) Cosmic- & gamma-ray background in surface lab w/o shield 214 Po ROI Low ~9% efficiency is sensitivity-limiting factor for capability demonstration w/ prototype Operation of new counters in PNNL underground lab shows potential for significant improvement Efficiency & background characterization in progress New counter operated in low-background shield in underground lab Single event in 214 Po ROI blank rate <100 μbq ~50 atoms of Calibration sample = 50 mbq LZ operates four emanation systems with typical blank rates μbq (LZ TDR Table 9.5.1; arxiv: ) Ray Bunker Higher-efficiency ROI Possible Background run < 10 μbq June 27,

radioassay w/smu XIA spectrometer 210 Po ROI Background Sample Example of

10 Surface Assay XIA UltraLo-1800 Acquired an XIA UltraLo-1800 in September 2017 Preparing to install in PNNL s Shallow Underground Laboratory Surface radioassay w/smu XIA spectrometer 210 Po ROI Background Sample Example of surface assay for SuperCDMS DAMIC-M Collaboration Meeting June 11-13, 2018 Paris June 27,

11 Additional ULB Assay Capabilities Liquid Scintillation Counter 3 counting cells in a common shield Employs unique methods to mitigate PMT backgrounds Beta Spectrometer Gas flow-through proportional counter Produced from OFHC copper and lowbackground polymers High-efficiency ~100% Low background 35mwe DAMIC-M Collaboration Meeting June 11-13, 2018 Paris June 27,

12 Questions? Walla Walla Valley Wheat Fields Typical Eastern Washington May June 27,

Low Background Counting At SNOLAB

Low Background Counting At SNOLAB Ian Lawson Collaboration Meeting Minneapolis, Minnesota, June 22-23, 212 1 Outline SNOLAB and description of the SNOLAB Low Background Gamma Counting System Other material