Jul 22 – 26, 2019
Europe/Rome timezone

Cold readout technology development for the LCLS - II soft x-ray spectrometer

Jul 26, 2019, 9:15 AM
Auditorium G. Testori (Milano)

Auditorium G. Testori


Piazza Città di Lombardia, 1, 20124 Milano MI
Oral Presentation Detector readout, signal processing, and related technologies Orals LM 002


Abigail Wessels (University of Colorado Boulder)


The combination of good energy resolution, high dynamic range, and large solid angle coverage has made arrays of transition-edge sensors (TES) an attractive option for x-ray spectral analysis. Because of these unique properties, we are developing a soft x-ray spectrometer that will become one of the first instruments available to scientists at the upgraded Linac Coherent Light Source (LCLS-II), an x-ray free electron laser at SLAC. The requirements for this ambitious instrument include maintaining an energy resolution of 0.5 eV across 1,000 pixels in a compact and expandable geometry that enables future upgrades. In this presentation, we will discuss the cold readout technology we are developing to meet these stringent. A key challenge is to increase the packing efficiency relative to our existing 250-pixel detector packages without degrading the performance of the detector and its associated microwave SQUID multiplexing readout. To this end, we have developed the concept of the “micro-snout” detector package. Each micro-snout will hold a 250-pixel TES array on the top of a box shaped structure, with the microwave readout chips placed on the 4 adjacent sides. To minimize the footprint, the sensors and microwave readout chips are connected via around-the-corner wire bonds, and 4 micro-snouts are tiled to produce a 1,000-pixel focal plane assembly. We will present the design of this compact 1,000-pixel detector assembly, and discuss challenges associated with maintaining undegraded high-frequency signals in this tight geometry. We will show electrical measurements from multiplexer chips installed on our prototype micro-snout, including successfully routing the microwave transmission line to all 4 sides of the micro-snout without major unwanted reflections. Finally, we will discuss progress in developing a suitable TES array that is compatible with this geometry and meets the resolution requirement of the instrument.

Student (Ph.D., M.Sc. or B.Sc.) Y
Less than 5 years of experience since completion of Ph.D Y

Primary author

Abigail Wessels (University of Colorado Boulder)


Douglas Bennett (National Institute of Standards and Technology) Daniel Becker (National Institute of Standards and Technology) Dr Johnathon Gard (NIST) Joel Ullom (NIST/University of Colorado) Kent Irwin (Stanford) Daniel Swetz (National Institute of Standards and Technology) Dr William Doriese (National Institute of Standards and Technology) Joel Weber (NIST) John Mates (National Institute of Standards and Technology) Kelsey Morgan (National Institute of Standards and Technology) Daniel Schmidt (NIST) Nathan Ortiz (National Institute of Standards and Technology) Sang-Jun Lee (SLAC) Dale Li (SLAC) Charles Titus (Stanford University)

Presentation materials