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Cyclotron trap

by D. Gotta and L.M. Simons

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Submission summary

Authors (as registered SciPost users): Detlev Gotta
Submission information
Preprint Link: scipost_202102_00017v1  (pdf)
Date submitted: 2021-02-11 12:41
Submitted by: Gotta, Detlev
Submitted to: SciPost Physics Proceedings
Proceedings issue: Review of Particle Physics at PSI (PSI2020)
Ontological classification
Academic field: Physics
Specialties:
  • Nuclear Physics - Experiment
Approach: Experimental

Abstract

The cyclotron trap was developed at SIN/PSI to increase the stopping density of nega- tively charged particle beams for the formation of exotic atoms in low pressure gases. A weak focusing magnetic field, produced by superconducting solenoids, is used. Particles are injected radially through the fringe field to a moderator, which decelerates them into orbits bound by the field. Further deceleration by moderators and/or low-pressure gases leads the particles to the center of the device, where they can be stopped or eventually extracted. Experiments became feasible with this technique, such as those dealing with pionic hydrogen/deuteriumat SIN/PSI.Muonic hydrogen laser experiments also became possible with the extraction of muons from the cyclotron trap. The formation of antipro- tonic hydrogen in low pressure targets led to successful experiments at LEAR/CERN.

Current status:
Has been resubmitted

Reports on this Submission

Report #2 by Anonymous (Referee 2) on 2021-3-9 (Invited Report)

  • Cite as: Anonymous, Report on arXiv:scipost_202102_00017v1, delivered 2021-03-09, doi: 10.21468/SciPost.Report.2671

Report

The report is nicely written and describes a fantastic instrument that has been crucial in several important measurements. I recommend its publication.
I only have a few minor points that the authors might consider (see below).

Requested changes

1) Line 31: Please add a reference to the effect mentioned in this sentence.
2) Line 35: “self-absorption in high Z gases”. Is high Z here really correct or was the intention to write “high pressure” or “higher Z” (compared to hydrogen) as at the beginning of this paragraph?
3) Line 104: It might be worth mentioning at that point that the extraction of the particles through an axial electric field was, e.g., done for the lamb shift experiment.
4) Line 136: It is a bit confusing to mention the radius of 29.5 cm explicitly as there are no other dimensions given as context. It might help the reader to see a cut through the cyclotron trap as a separate figure that shows the position of the coils, the yoke, and the soft iron pieces etc.

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

Author:  Detlev Gotta  on 2021-03-13  [id 1303]

(in reply to Report 2 on 2021-03-09)
Category:
correction

The referee comments have been included in the following way:

1) Line 31: Please add a reference to the effect mentioned in this sentence. *We add as ref. [2]: E. Borie and M. Leon, X-ray yields in protonium and mesic hydrogen, Phys. Rev. A 21, 1460 (1980).

2) Line 35: “self-absorption in high Z gases”. Is high Z here really correct or was the intention to write “high pressure” or “higher Z” (compared to hydrogen) as at the beginning of this paragraph? * We change: of higher Z formed in low-pressure gases. - > of higher Z gases.

3) Line 104: It might be worth mentioning at that point that the extraction of the particles through an axial electric field was, e.g., done for the lamb shift experiment. *We add the sentence: This approach was used to provide a low-energy muon beam for an experiment to determine the proton radius mentioned in Section 13.6.2. In addition, the last sentence of 13.6.2 has been adapted accordingly to: This opened a path for important experiments to determine the proton radius via the Lamb shift in muonic hydrogen [16] (Section 21 [17]).

4) Line 136: It is a bit confusing to mention the radius of 29.5 cm explicitly as there are no other dimensions given as context. It might help the reader to see a cut through the cyclotron trap as a separate figure that shows the position of the coils, the yoke, and the soft iron pieces etc. *We change: to reduce the field at a radius of 29.5 cm. - to reduce the fringe field.

An updated version is communicated to the editor as optional remark (file cycl_corr_2021_03_11.pdf)

Attachment:

cycl_corr_2021_03_11.pdf

Report #1 by Adrian Signer (Referee 1) on 2021-2-26 (Invited Report)

  • Cite as: Adrian Signer, Report on arXiv:scipost_202102_00017v1, delivered 2021-02-26, doi: 10.21468/SciPost.Report.2619

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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