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Ambient-Pressure X-Ray Photoelectron Spectroscopy (APXPS) Program

The Ambient-Pressure X-Ray Photoelectron Spectroscopy (APXPS) & Chemical Sciences Program comprises various beamlines and endstations to probe interfacial elemental, chemical, and potential information at solid/gas, solid/liquid, solid/solid, and liquid/vapor interfaces under in situ and operando conditions.

Beamline 11.0.2.1 has an insertion device and 9.3.2 has a bend magnet providing our program’s soft x-ray energies (90–2000 eV and 200–900 eV, respectively), an ideal energy range for probing solid/gas and liquid/vapor interfaces. While 9.3.2 is best suited for conventional solid/gas measurements, 11.0.2.1 supports two multimodal endstations, LARaXS and APPEXS to probe interfaces using APXPS and RIXS, and APXPS and scattering, respectively.

Beamline 9.3.1 is a tender x-ray bend-magnet beamline providing tender x-ray energies between 2100–6000 eV and has an ideal energy range for probing solid/liquid and solid/solid interfaces.

Beamlines 9.0.1 and 9.0.2 share the same insertion device. Beamline 9.0.1 provides soft x-ray radiation (20–800 eV) and accommodates mobile endstations and has a new multimodal solid/gas interface endstation for time-resolved measurements under development. Beamline 9.0.2 delivers vacuum ultraviolet (VUV) radiation (7.4–25 eV), making it ideal for investigating gas-phase species.

Collectively, this program is looking to reveal interfacial chemical properties to provide insight into a wide range of sciences, including energy science, earth and environmental science, materials science, chemical science, applied science, and physical science.

Beamlines

Personnel

ALS Staff

Ethan Crumlin

Staff Scientist, Program Lead

Monika Blum

Staff Scientist

Oleg Kostko

Research Scientist

Slavomir Nemsak

Staff Scientist

Michael Nguyen

Scientific Engineering Associate

Doctoral Researchers

Postdoctoral Researchers

  • Shane Devlin
    ALS Collaborative Postdoctoral Fellow (2023-2025), Berkeley Lab

  • Nureshan Diaz
    Postdoctoral Researcher (2022-2026), Chemical Sciences Division, Berkeley Lab
    VUV photoionization mass spectrometry of gas-phase clusters and hot nozzle experiment

  • Rebecca Hamlyn
    Postdoctoral Researcher (2021-2025), ALS and Chemical Sciences Division, Berkeley Lab

  • Aaron Kaufman
    Postdoctoral Researcher (2025- ), ALS and Chemical Sciences Division, Berkeley Lab
    DOE SCGSR Doctoral Fellow (2023-2024)

  • Dongwoo Kim
    ALS Collaborative Posdoctoral Fellow (2024-2025), Berkeley Lab

  • Pyeongeun Kim
    Postdoctoral Researcher (2022-2025), Chemical Sciences Division, Berkeley Lab
    Heterogeneous reactions on organic aerosols

  • Sander Lemmens
    Postdoctoral Researcher (2022-2026), Chemical Sciences Division, Berkeley Lab
    VUV photoionization mass spectrometry of gas-phase clusters and hot nozzle experiment

  • Haoyi Li
    Postdoctoral Researcher (2023-2025), ALS and Chemical Sciences Division, Berkeley Lab

  • Jay Paudel
    Postdoctoral Researcher (2024-2026), ALS and Chemical Sciences Division, Berkeley Lab

  • Alexander Prophet
    Postdoctoral Researcher (2024-2025), ALS and Chemical Sciences Division, Berkeley Lab

  • Andreas Siebert
    Postdoctoral Researcher (2021-2025), ALS Chemical Sciences Division, Berkeley Lab

  • Sorren Warkander
    Postdoctoral Researcher (2023-2027), Chemical Sciences Division, Berkeley Lab
    Soft x-ray spectroscopy of aerosols