A large multiplate cloud chamber, 5 feet x 5 feet x 2 feet, was built\r\nfor the purpose of investigating high energy nuclear interactions. The\r\nchamber contained eleven (11) steel plates of absorbing material, totaling\r\ntwo hundred fifty-four (254) grams/(centimeter)^2.
\r\n\r\nThe cross-section for the transfer of small amounts of energy by\r\nincident primary particles of high energy was obtained by direct mensuration\r\non the stereoscopic photographic negatives. The tracks of high energy\r\ncosmic ray particles were identified by observation of events in which\r\nat least 50 Bev was observed in a high energy nuclear interaction. These\r\nsame tracks were searched for nuclear interactions of less than 10 Bev.
\r\n\r\nThe analysis of six hundred thirty-six (636) cases yielded a mean\r\nfree path in iron for the primary particles in producing the small interactions of (4.37 \u00b1 1.46) x 10^3 grams/(centimeter)^2. The primary particle-nucleus\r\ncross-section was 21.1 \u00b1 7.1 millibarns, which corresponded to\r\na primary particle-nucleon cross-section of 0.38 \u00b1 0.13 millibarns.\r\nThese events were interpreted as resulting from peripheral collisions of\r\nthe primary particles with the nucleons of the iron nuclei.
\r\n\r\nAn independent part of the analysis was the effect of the geiger\r\ncounter efficiency. Results indicated an absence of bias in high energy\r\ncross-section measurements which were based on the assumption that the\r\nselection of events for measuring the cross-section was independent of\r\nthe counter efficiency. However, analysis also showed that the establishment of symmetric errors in such a cross-section is probably misleading.
", "doi": "10.7907/R9C6-XA46", "publication_date": "1963", "thesis_type": "phd", "thesis_year": "1963" }, { "id": "thesis:1278", "collection": "thesis", "collection_id": "1278", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-04062006-140126", "primary_object_url": { "basename": "Jacobs_ed_1961.pdf", "content": "final", "filesize": 5555842, "license": "other", "mime_type": "application/pdf", "url": "/1278/1/Jacobs_ed_1961.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "A Cloud Chamber Investigation of Interactions at Energies Greater than 50 BEV", "author": [ { "family_name": "Jacobs", "given_name": "Earl Donald", "clpid": "Jacobs-Earl-Donald" } ], "thesis_advisor": [ { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" }, { "family_name": "Cowan", "given_name": "Eugene W.", "clpid": "Cowan-E-W" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.\r\n\r\nAn experiment to measure the inelastic scattering cross-section for nucleons with energies greater than 50 BEV on Iron has been carried out using a large multiplate cloud chamber as the detector and the cosmic-ray flux at Pasadena as the source of nucleons. This cross-section has been found to be 0.56 \u00b1 .07 barns and the corresponding nucleon-nucleon cross-section (averaged over protons and neutrons) to be 18 \u00b1 5 mb. The average energy of the events included in the measurement is estimated at 250 BEV. These results have been compared with the inelastic scattering cross-section data available for energies above the [...] meson threshold.\r\n\r\nAn analysis has been made of the angular distribution of N-rays having energy greater than 50 BEV to determine the absorption mean free path in the atmosphere. Also it is shown that the neutral to charged particle ratio at a known depth in the atmosphere and the ratio of the mean free path for absorption to the mean free path for interaction are related to the average elasticity in nucleon-nucleon collisions, the former setting a lower limit and the latter, an upper limit. The absorption mean free path in the atmosphere is found to be 115 \u00b1 15 gm/cm2 and the elasticity is estimated at (0.27 \u00b1 .06) [...] 0.45.", "doi": "10.7907/0Q79-KG30", "publication_date": "1961", "thesis_type": "phd", "thesis_year": "1961" }, { "id": "thesis:2714", "collection": "thesis", "collection_id": "2714", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06242004-144822", "type": "thesis", "title": "Proportional-Counter Selection of Cloud-Chamber Events", "author": [ { "family_name": "Rouse", "given_name": "Carl Albert", "clpid": "Rouse-Carl-Albert" } ], "thesis_advisor": [ { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" }, { "family_name": "Cowan", "given_name": "Eugene W.", "clpid": "Cowan-E-W" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "The 48\" magnet-cloud chamber has been controlled by a gated proportional counter and photographs taken of 5313 expansions have been analyzed.
\r\n\r\nThe proportional counter was found to (1) select events of lower energy than penetrating shower detectors; and (2) select at a much lower hourly rate interactions in which V-particles were produced. However, the V-particles detected appeared on the average to be of lower energy, hence, could be measured with maximum cloud-chamber accuracy.
\r\n\r\nThe \u00b5-meson-induced electron showers detected by the proportional counter have been analyzed. Experimental and theoretical frequencies were obtained for the production of showers with a minimum of 40, 100, and 200 electrons. The frequencies for showers of 100 and 200 electrons were found to be the most reliable. These experimental frequencies are 1.6+0.8-0.4 x 10-6 per second and 0.44 \u00b1 0.21 x 10-6 per second, respectively. The corresponding theoretical values computed from collision and bremsstrahlung probabilities for spin \u00bd \u00b5-mesons of 10 x 10-6 per second and 3.5 x 10-6 per second reflect the uncertainties of cascade shower theory.
\r\n\r\nTwo V-particles of particular interest were photographed. One, event 47202, appears to be strong evidence for the existence of the neutral \u03c4-particle with the decay scheme, \u03c4\u00b0 \u2192 \u03c0\u207a + \u03c0\u207b + \u03c0\u00b0 + Q ~ 78 Mev.
\r\n\r\nThe second V-particle, event 46944, was a negatively charged K-particle that is consistent -- from ionization momentum measurements and decay dynamics -- with the decay scheme, \u03b8\u207b \u2192 \u03c0\u207b + \u03c0\u00b0, P* = 206 Mev/c. The measured P* for the event is 207 \u00b1 10 Mev/c. With other events that could be consistent with the \u03b8\u207b, this event helps to establish the existence of this K-particle.
", "doi": "10.7907/8D6S-QT11", "publication_date": "1956", "thesis_type": "phd", "thesis_year": "1956" }, { "id": "thesis:2668", "collection": "thesis", "collection_id": "2668", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06212004-155258", "primary_object_url": { "basename": "Pickrell,jr_dh_1956.pdf", "content": "final", "filesize": 1341846, "license": "other", "mime_type": "application/pdf", "url": "/2668/1/Pickrell,jr_dh_1956.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "A Study of Distortions in a Cloud Chamber", "author": [ { "family_name": "Pickrell", "given_name": "Don H. Jr.", "clpid": "Pickrell-Don-H" } ], "thesis_advisor": [ { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" }, { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Cowan", "given_name": "Eugene W.", "clpid": "Cowan-E-W" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "Measurements of the distortions of the tracks in a cloud chamber were made using a multiple exposure technique. It was determined that the chamber, when used in a magnetic field of 8000 gauss, was capable of yielding measurements of the momentum of ionizing particles up to approximately 5 Bev/c. This corresponds to an uncertainty in the motion of the droplets forming a track of 0.005 cm. The operation of the chamber in different thermal conditions was studied, and it was concluded that the chamber should be operated with a top temperature several hundredths of a degree C higher than that of the bottom. An analysis of the motion of the gas in the chamber was made and compared with the experimental values. The behavior of tracks near the chamber walls was studied.", "doi": "10.7907/24TZ-SW47", "publication_date": "1956", "thesis_type": "phd", "thesis_year": "1956" }, { "id": "thesis:3000", "collection": "thesis", "collection_id": "3000", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08032004-143918", "primary_object_url": { "basename": "Trilling_gh_1955.pdf", "content": "final", "filesize": 2957356, "license": "other", "mime_type": "application/pdf", "url": "/3000/1/Trilling_gh_1955.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "A Cloud-Chamber Investigation of Charged V Particles", "author": [ { "family_name": "Trilling", "given_name": "George Henry", "clpid": "Trilling-George-Henry" } ], "thesis_advisor": [ { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" }, { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Cowan", "given_name": "Eugene W.", "clpid": "Cowan-E-W" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.\r\n\r\nAn analysis of 84 charged V events obtained during two years of operation of a vertical magnetic cloud-chamber array is presented. The particular features of interest which are studied in detail are the distribution of P*, the momentum of [...] charged secondary in the rest system of the primary, and the possible existence of a component of short lifetime (i.e., [...]).\r\n\t\t\r\nThe P* distribution from 19 slow, accurately measurable positive events is shown to imply that the large majority of these events arise from one or more two-body decays from primaries of mass approximately equal to that of the [...] meson. One case turns out to be inconsistent with this interpretation, and is presumed to represent a three-body decay.\r\n\r\nThe P* distribution from six slow, accurately measurable negative events is consistent with a single two-body decay having a P* value of about 200 Mev/c. This suggests the existence of a negative counterpart to the well-known [...] particle, though the statistics are much too poor to permit any strong conclusion.\r\n\r\nThe lifetime analysis provides strong evidence for the existence of a negative component of lifetime equal to or less than (1.3[plus or minus]0.6) x [...]second. The transverse momentum distribution for these short lived events is shown to suggest a two-body decay with a P* value of 201[plus or minus]12 Mev/c.", "doi": "10.7907/1AF7-4Y96", "publication_date": "1955", "thesis_type": "phd", "thesis_year": "1955" }, { "id": "thesis:477", "collection": "thesis", "collection_id": "477", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02032004-140201", "primary_object_url": { "basename": "Van_Lint_vaj_1954.pdf", "content": "final", "filesize": 5852418, "license": "other", "mime_type": "application/pdf", "url": "/477/1/Van_Lint_vaj_1954.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Observations of Neutral V-Particle Decays with the 48\" Magnet Cloud Chambers", "author": [ { "family_name": "van Lint", "given_name": "Victor Anton Jacobus", "clpid": "van-Lint-Victor-Anton-Jacobus" } ], "thesis_advisor": [ { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" }, { "family_name": "Cowan", "given_name": "Eugene W.", "clpid": "Cowan-E-W" }, { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.\r\n\r\nThis thesis is the first to result from operation of the 48\" magnet cloud chambers at the California Institute of Technology. The apparatus is not described here in any detail. The techniques used to measure track curvatures and the positions of points inside the chambers are discussed in detail as is the analysis of the possible errors in these quantities. A formula is derived for computing the momentum of a particle from its measured curvature on the film. It includes corrections for the nonaxial components of the magnetic field and the effect of the conical projection involved in the photography. A method for correcting approximately for the variation of the magnetic field along the track is also presented.\r\n\r\nA summary of the dynamics of the two-body decay of a neutral V-particle is presented. A discussion of the uses of plots of [...] and [...] for a two-body decay is included. The dynamics of some simple three-body decays are discussed. The distribution of the momenta of one of the decay products is derived, including only the effects of the density of states in phase space. An attempt is made to analyze the observable properties of a three-body decay when the two charged products are treated as products of a two-body decay.\r\n\r\nThe results from the analysis of the best cases of [...] and [...] decays observed in the 48\" magnet cloud chambers are summarized. They include a value for the energy release in the [...] decay of [...] Mev, and a preliminary discussion of the coplanarity and transverse momentum balance for those cases in which an origin for the [...] can be located. In addition, an excellent case of the decay of a neutral V-particle into two light secondaries with an energy release much lower than that for the usual [...] decay scheme forms the basis for the discussion of all such \"anomalous [...]\" decays observed in the three Caltech magnet cloud chambers.\r\n", "doi": "10.7907/1GTW-1274", "publication_date": "1954", "thesis_type": "phd", "thesis_year": "1954" } ]