Astroparticules et Cosmologie, Cosmology

5639 27549
Position ID:Astroparticules et Cosmologie-Cosmology-POSTDOC [#27549]
Position Title: Contributions to the end-to-end development and characterization of the CMB-S4 detection and data processing chain
Position Type:Postdoctoral
Position Location:Paris, Paris 75013, France [map] sort by distance
Subject Areas: Astrophysics / Instrumentation/Observation/Experiment
Cosmology / Cosmic Microwave Background
Appl Deadline:2024/08/01 11:59PMhelp popup (posted 2024/04/24)
Position Description:    


This position will assist the global characterization and modeling effort of the detection and data analysis chain of the future CMB-S4 ground-based Cosmic Microwave Background observatory. 


The precise measurement of polarized fluctuations of the Cosmic Microwave Background (CMB) emission is a major objective of modern observational cosmology. So-called primordial B modes of CMB polarization, thought to have been generated in an early phase of cosmic inflation, would provide unique information about the origin of the Universe and fundamental laws of physics at very high energies. The faint amplitude of the expected signals, of order of a few nK, requires highly sensitive observations together with exquisite control of instrumental systematic errors that can be higher by a few orders of magnitude. 

CMB-S4 (stage 4) is a 4th generation ground-based instrument aiming at observing these signals with ultimate sensitivity. To that effect, the experiment will deploy about 500 000 cryogenic detectors distributed over 85 optics tubes distributed in a few small (SAT) and large (LAT) aperture telescopes, which will observe from Chile and Antarctica. This will make it the largest and most advanced CMB observatory ever constructed. CMB-S4 has recently been ranked as the top priority for the next decade by the US Particle Physics Project Prioritization Panel (P5). 

The unprecedented sensitivity, precision and accuracy of the observations requires precise understanding of the instrument and optimization of the data analysis pipeline. The postdoctoral scholar will work on one or more of the following topics: 
  1. Design and characterization of readout electronics using Application Specific Integrated Circuit (ASIC) and S4 sample detectors. A prototype of this detection chain will be installed and tested at APC in a dilution fridge.
  2. Development of an optical test bench to measure the response and the bandpass of detectors. An external Fourier Transform Spectrometer will be used together with a dilution fridge equipped with a window and optical filters. The precision of this testbench will have to be consistent with the requirements of CMB-S4.
  3. CMB-S4 simulation and data analysis to evaluate the scientific impact of instrumental and pipeline design choices and optimize the instrumental efficiency of CMB-S4.
The post-doc will work with the CMB-S4 project and collaboration, and in particular with Aritoki Suzuki, John Groh, Jacques Delabrouille and Reijo Keskitalo at LBNL in Berkeley, Adrian Lee at UCB, Damien Prêle and Michel Piat at the APC laboratory in Paris. The postdoc will be based at Centre Pierre Binetruy in Berkeley for 2 years.detection chain readout development and modeling





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email address
Université Paris Cité
10, rue Alice Domon et Léonie Duquet
75013 Paris