The Principles of Cloud-Chamber Technique

Wilson, J. G.; Hazen, W. E.

doi:10.1119/1.1933015

Cited by 17 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The resultant ions act as a centre for nucleation, forming charged clusters. 9,10 In the second case, clusters are formed first and these clusters undergo surface ionisation on a heated surface. 11,12 The TCC was developed while studying the growth mechanism of CVD diamond.…”

Section: Introductionmentioning

confidence: 99%

Charged clusters in thin film growth

Hwang¹,

Kim²

2004

International Materials Reviews

View full text Add to dashboard Cite

A cauliflower structure is a granular film composed of spherical particles similar in size, each with numerous nanoscale nodules on its surface. The structure is produced during certain chemical vapour deposition (CVD) processes for diamond and silicon thin film growth. A classical account in terms of atomic unit deposition fails to explain the growth of such a cauliflower structure, as it requires a gas phase of much higher supersaturation than for onset of diffusion controlled growth. Another interesting and somewhat puzzling phenomenon encountered during a diamond CVD process is that while diamond is depositing on a graphite substrate, carbon atoms in the graphite itself are etched away into the vapour phase; that is, experience evaporation. Again, an elementary kinetic barrier mechanism fails to explain such CVD deposition of a less stable diamond phase combined with simultaneous evaporation of a stable graphite phase. In order to account for such puzzling CVD phenomena and others, a theory of charged clusters has been developed over the past decade as a new paradigm for thin film growth. The theory and its applications are reviewed in this work.

show abstract

Section: Introductionmentioning

confidence: 99%

Charged clusters in thin film growth

Hwang¹,

Kim²

2004

International Materials Reviews

View full text Add to dashboard Cite

show abstract

“…where D is the diffusion coefficient of the ions and τ is the time after the passage of the ray. Since the mean value of D for the positive and negative ions in air at ntp conditions is 0.034 cm 2 s −1 [29], we have x = 0.86 √ D cm at ntp. So 'if we demand that the tracks shall not be more than 1 mm broad, then we must have τ not more than 1/70 s' ( [25], p 282).…”

Section: The Counter-controlled Cloud Chambermentioning

confidence: 98%

P M S Blackett, G Occhialini and the invention of the counter-controlled cloud chamber (1931–32)

Leone¹,

Robotti²

2008

Eur. J. Phys.

View full text Add to dashboard Cite

Among the most important detecting devices in the 1930s, cosmic-ray experimental physics figures the so-called ‘counter controlled cloud chamber’. This apparatus was jointly developed in 1932 by P M S Blackett, the cloud chamber expert at the Cavendish Laboratory in Cambridge and by G Occhialini, who mastered the counting coincidence technique following his work under the guidance of B Rossi in Florence. In this paper we address the original technical description of the apparatus and place its development within the historical and scientific framework of 1930s physics.

show abstract

“…Since Wilson invented the expansion cloud chamber [1], these chambers have frequently been used to find new particles [2,3]. In 1939, Langsdorf developed the diffusion cloud chamber [4].…”

Section: Past Studies On Track Formation In Cloud Chambersmentioning

confidence: 99%

“…Equation (2) gives the velocity v for an alpha-particle with initial energy E 0 . From the minute travelling distance x, we can derive the minute travelling time t (= x/v).…”

Section: Travel Time Of Alpha-particlesmentioning

confidence: 99%

Visibility of the growth direction of an alpha-particle track in a diffusion cloud chamber

Mori

2013

Journal of Nuclear Science and Technology

View full text Add to dashboard Cite

The growth direction of an alpha-particle track in a diffusion cloud chamber can be observed with the naked eye. Unlike the track of a beta-particle, an alpha-particle track appears first at the beginning of its path and proceeds to the end of the path. However, the alpha-particle covers the path in less than 10 ns, which is inconsistent with the visibility of the track-growth direction. This inconsistency was attributed to the following reasons: the number of ion pairs per unit length in the path is very large compared with that of a beta particle, the ion density near the end of the path is larger than that near the beginning, and alcohol droplets have to grow to a diameter of about 3 μm for being able to be seen. The alcohol molecules have to diffuse from a distant place to the region where the ions are created by the alpha-particle and the diffusion time near the end of the path is longer than that near the beginning of the path. This phenomenon was examined by diffusion theory.

show abstract

The Principles of Cloud-Chamber Technique

Cited by 17 publications

References 0 publications

Charged clusters in thin film growth

Charged clusters in thin film growth

P M S Blackett, G Occhialini and the invention of the counter-controlled cloud chamber (1931–32)

Visibility of the growth direction of an alpha-particle track in a diffusion cloud chamber

Contact Info

Product

Resources

About