More Like this

1. U–Pb ID-TIMS geochronology using ATONA amplifiers

   https://doi.org/10.1039/d0ja00135j  

   Szymanowski, Dawid; Schoene, Blair (June 2020, Journal of Analytical Atomic Spectrometry)

   We document the performance of new ATONA (‘aA to nA’) amplifiers installed on an Isotopx Phoenix thermal ionisation mass spectrometer (TIMS) at Princeton University and evaluate their suitability for high-precision analyses of Pb and U isotopes in pg- to ng-size samples characteristic for U–Pb geochronology. The new amplifiers are characterised by low and stable noise levels comparable to 10 12 to 10 13 ohm resistors, response time <0.5 s, exceptional gain stability <1 ppm and a vast dynamic range theoretically allowing to quantify signals from aA (10 −18 A) to nA (10 −9 A) level. We measured a set of Pb standards, synthetic U–Pb solutions and natural zircons at currents of 2 × 10 −16 to 2 × 10 −12 A (corresponding to intensities of 20 μV to 200 mV relative to a 10 11 ohm amplifier) to assess the utility of ATONA in replacing ion counting for the smallest samples. The results show a clear precision benefit of using ATONA-Faraday detection over Daly ion counting for ion currents of >10 −14 A (1 mV relative to a 10 11 ohm amplifier or ca. 60 kcps). As such currents are routinely achievable for major Pb peaks of interest ( 205–208 Pb) in natural samples containing more than ca. 10 pg Pb* (radiogenic Pb), we expect ATONA-Faraday detection to find broad applications in U–Pb geochronology. Its practical use for low-blank, radiogenic samples continues to require ion counting for 204 Pb, either with a fixed Faraday–ion counter gain or using a dynamic two-step ( e.g. FaraDaly) method. Routine adoption of ATONA-Faraday collection in place of ion counting for most major Pb and U isotopes has the potential to increase sample throughput and precision, both improving the accessibility of isotope dilution (ID)-TIMS geochronology and pushing this technique towards better reproducibility. 

   more » « less
2. Serpentine Integrated Grating Spectrometer

   https://doi.org/10.1364/COSI.2021.CF2B.2  

   Brand, M.; Zhang, B.; Popović, M.; Dostart, N.; Wagner, K.H. (July 2021, OSA Computational Optical Sensing and Imaging)

   The serpentine integrated grating spectrometer uses a meandering delay line and outcoupling grating rows to implement a crossed-dispersion wide-bandwidth integrated spectrometer with resolving power of 10 5 and 10 4 spectral bins in a few cm 3 volume. 

   more » « less
3. The SeaQuest spectrometer at Fermilab

   https://doi.org/10.1016/j.nima.2019.03.039  

   Aidala, C.A.; Arrington, J.R.; Ayuso, C.; Bowen, B.M.; Bowen, M.L.; Bowling, K.L.; Brown, A.W.; Brown, C.N.; Byrd, R.; Carlisle, R.E.; et al (June 2019, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment)
4. Channel dispersed Fourier transform spectrometer

   https://doi.org/10.1038/s42005-018-0036-1  

   Hong, Brandon; Monifi, Faraz; Fainman, Yeshaiahu (December 2018, Communications Physics)
5. Pair Spectrometer for FACET-II

   https://doi.org/10.18429/JACoW-IPAC2021-THPAB270  

   Naranjo, B.; Andonian, G.; Cavanagh, N.; Di Piazza, A.; Fukasawa, A.; Gerstmayr, E.; Holtzapple, R.; Keitel, C.; Majernik, N.; Meuren, S.; et al (August 2021, IPAC)

   We present the design of a pair spectrometer for use at FACET-II, where there is a need for spectroscopy of photons having energies up to 10 GeV. Incoming gammas are converted to high-energy positron-electron pairs, which are then subsequently analyzed in a dipole magnet. These charged particles are then recorded in arrays of acrylic Cherenkov counters, which are significantly less sensitive to background x-rays than scintillator counters in this case. To reconstruct energies of single high-energy photons, the spectrometer has a sensitivity to single positron-electron pairs. Even in this single-photon limit, there is always some low-energy continuum present, so spectral deconvolution is not trivial, for which we demonstrate a maximum likelihood reconstruction. Finally, end-to-end simulations of experimental scenarios, together with anticipated backgrounds, are presented. 

   more » « less