Version 0: An Educational Package for Helium Atom Scattering Studies
Ethan L. Arnold, Ming-Shau Liu, Rohit Prabhu, Connor S. Richards, David Ward, Nadav Avidor
aa r X i v : . [ phy s i c s . e d - ph ] S e p Version 0: An Educational Package forHelium Atom Scattering Studies
E.L. Arnold, M-S. Liu, R. Prabhu, C.S. Richards, D. Ward, N. Avidor ∗ Cavendish Laboratory, University of Cambridge
Helium atom scattering studies have the potential for making numerous breakthroughs inthe study of processes on surfaces. As this field remains active, there will frequently benew young researchers entering the field. The transition from student to researcher is oftenmet with difficulty, consequently wasting limited time available for a PhD or master’s levelresearch. Addressing this issue, we present an educational package for emerging researchstudents in the field of helium atom scattering. We hope that this package serves as sufficientmaterial to significantly accelerate the progress made by new postgraduate students.
Helium atom scattering has remained a fruit-ful field throughout the time from its inceptionin the 1980s [1–3] to the present day. Conse-quently, there has been significant interest in theimprovement of existing techniques during thistime period, and the development of novel ma-chines; this promotes the encouragement of in-creasingly more sensitive measurements to bemade of surface processes on solids. One exam-ple of this is the development of a sophisticatedhelium-3 spin-echo ( HeSE) spectrometer [4] bythe Cambridge group, building on a prototypefrom [5] in the 1990s. This machine has beenone of the main research focusses for the Cam-bridge group for over a decade; thus it is highlyimportant new research students have access tohigh quality resources to introduce its use. Inthe light of the importance of spin-echo to thegroup, a significant proportion of the resourcespresented in this article are oriented towards building an understanding of the spin echo ma-chine.In this document, we discuss a package cre-ated for a Summer internship programme at theSurfaces group in Cambridge. In section 2, wediscuss the Educational Package itself (whichconstitutes a significant bulk of the programme);section 3 focusses on the additional activities un-dertook by the students; section 4 discusses thefuture ambitions in expanding the EducationalPackage to serve an even greater selection of top-ics, and section 5 briefly concludes the contentof the current article.
The educational package [6] presented in thisarticle contains two main features. The focusof this package is 15 so-called "assignments",which are computational investigations into aparticular area of relevance in surface physics. ∗ Correspondance to all authors to [email protected] E D U CAT I O NA L PAC K AG E FO R H E L I U M ATO M S CAT T E R I NG
These are designed in such a way to partiallybridge the gap from typical British undergradu-ate teaching to research. A list of these is givenin the appendices. These "assignments" are ac-companied by a handbook of the theory neededto complete them. We believe this handbookis written in such a way to promote the devel-opment of intuition early in the study of therelevant physics, especially the less rigorous in-tuition that is difficult to promote in ordinaryresearch papers. It is styled to mimic typicalundergraduate texts, while still being orientedtowards research students. The package furthermimics the convenient style of reading lecturenotes followed by attempting a problem, whichshould be particularly familiar to most under-graduates.
In the Summer of 2020, the Surfaces, Microstruc-ture and Fracture group at Cambridge organiseda (remote) set of computational research projectsfor undergraduates at the University of Cam-bridge. These were an ambitious set of projectsrelated to the research output of the group andcollaborators from Wales, Austria, Australia andthe Open University; most of the projects expandon published work from both students and fac-ulty.At the time of writing, only the pilot year ofthe projects had been run, under the name of theUndergraduate Summer Research Program inSurface Nanophysics and Atom-Surface Scatter-ing. What did the projects in the pilot year con-sist of? The students completed research-styletasks from the prototype assignments, withoutabandoning the teaching style familiar to them.During the same time frame, regular seminarswere held, allowing the relevant theory to be in-troduced in a more passive format. Once thesehad been completed, the students regularly metwith an assigned project supervisor to plan andsolve a research activity. Overall, the pilot yearprogramme took most students 10 weeks to com-plete, of which two weeks were assigned to solv-ing the prototype assignments.We hope that future years of the projectscan rely heavily on the Educational Package pre-sented as the main product of this article, which should greatly ease the first month’s work in theprojects. This package is designed to be flexible;thus we hope that it can be easily extended tosupport the progress of postgraduate students;we further anticipate that it can support thoseoutside of the surfaces group at Cambridge. Thepackage does not require the support of the au-thors, or the faculty members running the pro-gramme, to be effective.
The package presented in this document hasbeen labelled as "version 0" rather than "ver-sion 1". This is because the process for inter-nally checking and updating the package is an-ticipated to take a significant length of time (asit is approximately 300 pages in length!), so thepackage we present to date cannot be assured tobe free of errors. We hope that the package willbe rereleased in the future as a higher qualityset of documents. The authors aim to submit anupdated publication during late 2021.Furthermore, we hope that documents per-taining to helium atom microscopy and time-of-flight methods can be added to the package,along with documents aimed to serve more gen-eral surface science.
The package we have written is aimed to easethe transition from lectured courses in physicsto research-oriented studies in helium scattering.Elements of this package may find use in otherfields, especially those related to atom scatteringor surface diffusion. We hope that, in the future,this package may be expanded by other Summerinterns in the surfaces group at the CavendishLaboratory.
ACKNOWLEDGEMENTS
The authors declare they have no financial in-terests related to the resources discussed in thisarticle.E.L.A., M.-S.L., R.P., and C.S.R. issue specialthanks to N.A. for organising the summer pro-gramme.
E D U CAT I O NA L PAC K AG E FO R H E L I U M ATO M S CAT T E R I NG
REFERENCES [1] Brusdeylins, G., Doak, R. B. & Toennies, J. P. Observation ofsurface phonons in inelastic scattering of he atoms from lif(001)crystal surfaces.
Phys. Rev. Lett. , 1417–1420 (1980).[2] Brusdeylins, G., Doak, R. B. & Toennies, J. P. Measurement ofthe dispersion relation for rayleigh surface phonons of lif(001)by inelastic scattering of he atoms. Phys. Rev. Lett. , 437–439(1981).[3] Brusdeylins, G., Doak, R. B. & Toennies, J. P. High-resolution he-lium time-of-flight studies of rayleigh surface-phonon dispersioncurves of lif, naf, and kcl. Phys. Rev. B , 3662–3685 (1983).[4] Jardine, A., Hedgeland, H., Alexandrowicz, G., Allison, W. &Ellis, J. Helium-3 spin-echo: Principles and application to dy-namics at surfaces. Prog. Surf. Sci. , 323 – 379 (2009).[5] DeKieviet, M., Dubbers, D., Schmidt, C., Scholz, D. & Spinola,U. He spin echo: New atomic beam technique for probingphenomena in the nev range. Phys. Rev. Lett. , 1919–1922(1995).[6] Arnold, E., Liu, M.-S., Prabhu, R., Richards, C. & Avidor, N.An educational package for helium atom scattering (2020). DOI:10.5281/zenodo.4047967. APPENDICES
Appendix A: Location of Resources
The resources discussed in this document arefreely available at [6].
Appendix B: List of Resources (Educa-tional Package)
There are four categories of documents in the ed-ucational package. Summarily, these are the 15assignments, their accompanying handbook, a readme file ( i.e.i.e.