SciPost Submission Page

UCN, the ultracold neutron source -- neutrons for particle physics

by Bernhard Lauss, Bertrand Blau

This is not the current version.

Submission summary

As Contributors: Bernhard Lauss
Arxiv Link: (pdf)
Date submitted: 2021-04-13 14:37
Submitted by: Lauss, Bernhard
Submitted to: SciPost Physics Proceedings
Proceedings issue: PSI Particle Physics
Academic field: Physics
  • Nuclear Physics - Experiment
Approach: Experimental


Ultracold neutrons provide a unique tool for the study of neutron properties. An overview is given of the ultracold neutron (UCN) source at PSI, which produces the highest UCN intensities to fundamental physics experiments by exploiting the high intensity proton beam in combination with the high UCN yield in solid deuterium at a temperature of 5K. We briefly list important fundamental physics results based on measurements with neutrons at PSI.

Current status:
Has been resubmitted

Submission & Refereeing History

Resubmission 2104.02457v2 on 8 June 2021

Reports on this Submission

Anonymous Report 2 on 2021-5-16 (Invited Report)


The manuscript by B. Blau, "UCN, the ultracold neutron source - neutrons for particle physics," provides an excellent description and overview of the PSI UCN source. As this source is one of the most intense and productive UCN sources in the world the paper will serve as valuable resource for those in the field of neutron research. Particularly noteworthy the very complete set of references describing the extensive literature that emerged during the development of the PSI source.

I have only two minor questions, neither of which raises to the level of a significant concern. In the otherwise complete description of the properties of the target, the isotopic purity of the the D_2 was described only as being “isotopically pure.” It might be helpful to include the actual purity as that is a quantity of considerable interest similar to the ortho-para fraction.

The second comment concerns the inclusion of section 4.5 which appears to be almost an afterthought. While its inclusion does not diminish the overall value of the article, I believe the paper would be improved by either dropping this section, and limiting the discussion to UCN or expanding it to the point where it include technical details comparable to those in the discussion of the UCN source.

I include these comments only as suggestions. Whether or not they are accepted does not affect my recommendation that this this article be published.

  • validity: high
  • significance: high
  • originality: good
  • clarity: high
  • formatting: excellent
  • grammar: excellent

Author:  Bernhard Lauss  on 2021-06-06

(in reply to Report 2 on 2021-05-16)
answer to question

Thank you for the comments. The value of the isotopic purity (0.09%)was added. Section 4.5 is kept. This was part of teh original request to show that neutron particle physics at PSI is not limited to UCN.

Report 1 by Adrian Signer on 2021-4-22 (Invited Report)


We (the editors Cy Hoffman, Klaus Kirch, Adrian Signer) had the
opportunity to review an earlier draft of the article and were in
communication with the authors before the submission. All our comments
and suggestions have been taken into account. Hence, we think the
paper can now be published in the current form.

  • validity: -
  • significance: -
  • originality: -
  • clarity: -
  • formatting: -
  • grammar: -

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