A new instrument for use in astronomical research has been developed. This is the differential video photometer, a device for detecting differences in light intensity between two television pictures. With a suitable source of video, the device is capable of detecting intensity differences of the order of one part in one thousand. It should be useful in many applications, such as colorimetry, polarimetry, motion detection, and doppler shift measurements. It has been used thus far primarily as a videomagnetograph which measures the line-of-sight component of the solar magnetic field in the photosphere. Sensitivity to magnetic field strength is on the order of 5 to 10 gauss.
\r\n\r\nA study has been made of the characteristics of magnetic flux diffusion in weak plage regions. Points of enhanced magnetic field have been found to exist which have lifetimes of about 3 to 4 days, and which move in a random walk with a step time short compared to 24 hours. The random walk of these points considered as discrete entities is not, however, responsible for much of the flux diffusion in the weak plage regions. The R.M.S. displacement of the points is about 7800 km in 24 hours. A second form of flux transport has been found in which in a period of a few hours, a previously stable point will become unstable, and either shoot out a tongue of flux, or begin to move as a unit. This process can move flux over distances of the order of 10,000 km at apparent velocities of 1 to 2 km/sec. This process may be responsible for most of the flux transport in weak plage regions.
", "doi": "10.7907/QGBD-XQ45", "publication_date": "1972", "thesis_type": "phd", "thesis_year": "1972" }, { "id": "thesis:3263", "collection": "thesis", "collection_id": "3263", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08282008-095104", "primary_object_url": { "basename": "Roberts_ph_1970.pdf", "content": "final", "filesize": 13638538, "license": "other", "mime_type": "application/pdf", "url": "/3263/1/Roberts_ph_1970.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Velocity Fields in Magnetically Disturbed Regions of the H\u03b1 Chromosphere", "author": [ { "family_name": "Roberts", "given_name": "Phillip Howard, Jr.", "clpid": "Roberts-Phillip-Howard" } ], "thesis_advisor": [ { "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\nA cancellation machine has been constructed to automatically produce the cancellation required by the method of Leighton in making Doppler movies. Various adaptations of the machine allow rapid data reduction to the 16 mm print required for cinema viewing. The preliminary data gathered in 1966 and 1967 has been reduced. These data consist mostly of He Doppler movie pairs, and some Zeeman movie pairs, of sunspot regions. A new calibration technique for inferring Doppler velocities from cancellation densities has been developed. This technique extends the calibration to large Doppler shifts with no less in accuracy.
\r\n\r\nDoppler movies taken in H\u03b1,.070 nm from the core, show a long lived flow region connecting spots of opposite magnetic polarity in newly developing sunspot regions. The flow regions consist of a series of parallel arched filaments about 2 Mm thick by 23 \u00b1 8 Mm long which are found also in the H\u03b1 core superimposed upon bright plage. The material in the arches is shown to flow downward along the legs of the arch from its center. The average height of the arches is 2 to 4 Mm depending upon the method of calculation. Velocities of 35 km/s inferred in the arches are consistent with those expected from frictionless descent from the top of the arch. An ascent velocity of about 5 km/s of the arch center is also consistent with the data. The material flow is not a mass flow from one leg of the arch to another as previously reported by other observers. A discussion of other minor discrepancies of this work with that of previous observers points out certain possible sources of error in both their work and this.
\r\n\r\nA physical model for the arches is proposed, whereby they consist of material trapped by magnetic lines of force which are emerging from the photosphere in the forming sunspot region. This material then flows downward along the arched lines of force as they rise. The subsurface magnetic field energy is shown to be sufficient to raise the material to the heights inferred for the arches, but insufficient to raise the temperature of the photosphere at the feet of the arches by more than about 7\u00b0 K. The average lifetime of an arch is about thirty minutes yet the rise and decay times indicated by the data are shown to be about five minutes. Two possible explanations are offered for this discrepancy, one involving a great optical depth and the other a series of arches superimposed. Several suggestions are made for further persuing this phenomenon.
\r\n\r\nThe study of Tile of velocity features in the Ha chromosphere of the quiet sun has been extended to active regions. The results for network regions near the sunspots corroborate those of Title. A mean lifetime of 215 \u00b1 9 s was found for upflow events and 371 \u00b1 30 s for downflow. In the regions covered by bright plage in the H[alpha] core photographs the mean lifetime in a majority of both upflow and downflow events was 217\u00b171 s and 211 \u00b1 91 s respectively.
", "doi": "10.7907/BVQF-BY60", "publication_date": "1970", "thesis_type": "phd", "thesis_year": "1970" }, { "id": "thesis:3258", "collection": "thesis", "collection_id": "3258", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08282008-085815", "primary_object_url": { "basename": "Title_am_1966.pdf", "content": "final", "filesize": 14288888, "license": "other", "mime_type": "application/pdf", "url": "/3258/1/Title_am_1966.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "A Study of Velocity Fields in the H\u03b1 Chromosphere by Means of Time-Lapse Doppler Movies", "author": [ { "family_name": "Title", "given_name": "Alan Morton", "clpid": "Title-Alan-Morton" } ], "thesis_advisor": [ { "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\nThe technique of Leighton for making Doppler spectroheliograms has been extended to movies. Doppler movies made in H [alpha] from the core show a class of upgoing features with a 113 \u00b1 3.4 second mean lifetime and a definite velocity history. The velocity reaches its maximum in less than 30 seconds, then declines for the next 90 seconds. In the case of 27 percent of these features a similar upflow event occurred soon after the first had died away. The average lifetime of these \"double\" events is 236 \u00b1 8 seconds, approximately twice the lifetime of a single event. No region has been observed to repeat more than twice in the time a region could be followed (about 15 m), nor has any showed a tendency to repeat after a lapse of more than 60 seconds. Moreover, the region on the sun where an upflow event has occurred tendsto show no downflow for at least fifteen minutes afterward.\r\n\r\nThe prominent upgoing features occur in the rosette structure seen in the H [alpha] wings. Further, they are often visible as absorbing features in the red as well as the violet wing. This suggests that their profiles are broadened with respect to the mean profile. A statistical study of a time series of high dispersion H [alpha] spectra has shown that there is a positive correlation between the average speed of upgoing features and their profile width. The measured increase in width is sufficient to cause features with speeds greater than 1.5 km/second to appear in absorption on both sides of the line.\r\n\r\nLifetimes of upflow features have been measured using the time series of spectra and the Doppler movies. The results of these measurements are consistent with there being a single predominate form of upflow that is visible in the H [alpha] wings further than .4 [\u2026] from the core with an average lifetime of a few minutes.\r\n\r\nThe mean lifetime of downflow regions is six to nine minutes. However, about 20 percent of the downflow regions are observed to persist for fifteen minutes or more. A few downflow regions have lasted the entire length of a Doppler movie, which is about forty minutes.\r\n\r\nDownflow typically occurs in the central regions of rosettes. As with upflow features, downflow features often are visible as absorbing features in both wings of H [alpha]. However, the statistical study of spectra has shown that although the average profile width increases with average speed for downflow features, approximately 50 percent of the downflow features have profiles that do not tend to increase with feature speed.\r\n\r\nIndividual upflow or downflow features did not have a periodic nature on a time scale longer than a few minutes. However, plots of the total upflow or total downflow areas as a function of time in regions 30 x 10[\u2026] km square did show systematic variations. The auto-correlation functions made from the plots of up and downflow area versus time had secondary peaks spaced by about 550 seconds thus indicating a periodicity in both the total upflow and total downflow with a period of 550 seconds. Cross-correlation of the plots of upflow and downflow areas for six different regions indicated that the phase relation between upflow and downflow is random.", "doi": "10.7907/7FCG-0448", "publication_date": "1966", "thesis_type": "phd", "thesis_year": "1966" }, { "id": "thesis:352", "collection": "thesis", "collection_id": "352", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01262004-142433", "type": "thesis", "title": "Measurements of Solar Magnetic Fields", "author": [ { "family_name": "Sheeley", "given_name": "Neil Rolfson, Jr.", "orcid": "0000-0002-6612-3498", "clpid": "Sheeley-Neil-Rolfson" } ], "thesis_advisor": [ { "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": "The photographic technique of Leighton (1) has been used to obtain high resolution measurements of photospheric magnetic fields with the following chief results:
\r\n\r\n1. \"Source fluxes\", \u03a6(defined as the average of the absolute values of the total fluxes of positive and negative polarity in a bipolar magnetic region on the day when this\taverage is largest), of bipolar magnetic regions (BMRs) have been measured as a function of the \"size\", Am, of the associated sunspot activity. [Am is defined to be the area covered by all of the sunspots of a group (umbras plus penumbras of both leading and following parts) on the day when this area is largest.] The source fluxes were found to satisfy \u03a6 = 1.2 Am within about \u00b1 50%, where \u03a6 is in \"solar flux units\" (1 SFU = 1021 maxwells) and Am is in units of 1018 cm2. Within measurement accuracy\tthere was no imbalance of flux of positive and negative magnetic polarity in the BMRs observed, provided that the photographically-obtained fluxes were supplemented by the fluxes in the umbras of sunspots, as calculated from Mount Wilson observations.
\r\n\r\n2. Two BMRs were traced for the first few months following their birth. The development of each was semi-quantitatively what one would expect if the random-walk (2) plus solar differential rotation were the only means of flux transport on the solar surface.
\r\n\r\n3. In quiet regions of the solar surface, magnetic flux is distributed in small bits and fragments, and in the quietest regions, in tiny points less than 3000 km in diameter. Measurements for eight small features yielded fluxes ranging from 0.05 SFU for the very small points to 0.4 SFU for typical network fragments. The corresponding magnetic fields\tranged from 200 gauss for the points to 700 gauss for the network fragments, showing that magnetic fields of a few hundred gauss are not at all uncommon for small magnetic features.
\r\n\r\n4. Polar faculae curves (3) have been calibrated to give magnetic flux on the polar caps of the sun as a function of time during the period 1905-1964. The fluxes vary cyclicly with time approximately 90\u00b0 out of phase with the variation of the sunspot number for the whole solar disk with time during this same period (provided the sunspot number is given a polarity corresponding to the magnetic polarity of the following sunspots of the relevant hemisphere). The maxima of the polar fluxes vary considerably from cycle to cycle (just as the maxima of the sunspot number vary considerably from cycle to cycle), maximum fluxes ranging from 6 SFU to 21 SFU with 12 SFU being a typical maximum polar flux during the 1905-1964 period.
\r\n\r\nThe principal conclusion is that these measurements are consistent with the hypothesis that all of the magnetism on the sun's surface originates in BMRs, and that it is gradually spread about the surface by the random-walk (2, 4) and differential rotation, eventually causing the cancellation and reversal of the polar fields.
", "doi": "10.7907/MFD2-WY70", "publication_date": "1965", "thesis_type": "phd", "thesis_year": "1965" }, { "id": "thesis:6078", "collection": "thesis", "collection_id": "6078", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:09302010-103625645", "primary_object_url": { "basename": "Noyes_rw_1963.pdf", "content": "final", "filesize": 7252062, "license": "other", "mime_type": "application/pdf", "url": "/6078/1/Noyes_rw_1963.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Observations of Oscillatory Motions in the Solar Atmosphere", "author": [ { "family_name": "Noyes", "given_name": "Robert Wilson", "clpid": "Noyes-Robert-Wilson" } ], "thesis_advisor": [ { "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": " This thesis presents observations of the macroscopic line-of-sight velocity field in the solar atmosphere. The observations were made at Mt. Wilson Observatory, primarily in 1960 and 1961. A quasi-periodic vertical oscillatory motion has been detected in the upper photosphere and low chromosphere. The \"average period\" of this oscillation has been determined with some accuracy to be about 300 sec.; there appears to be a slight decrease of period with increasing altitude. The mean life of a single oscillation is about 400 sec. The \u201cvelocity elements\" which partake of the oscillation have an appearance very similar to the photospheric granulation of low levels, and are probably identical to it. The vertical velocity amplitude is about 1/2 km/sec at these levels, and increases with altitude. The horizontal component of velocity is nearly as large as the vertical at low levels, but decreases with altitude, until at higher levels the velocities are substantially vertical only. The mean diameter of the velocity elements is only slightly larger than the photospheric granulation at low levels, but increases to many times that size at higher levels.\r\n\r\n We also report in this thesis on observations of macroscopic intensity fields, made concurrently with the velocity observations. A correlation coefficient between intensity and velocity has been found which appears to decrease monotonically with altitude, from about +0.5 at the lowest elevations observed to about -0.2 at the highest observed elevations. An oscillatory behavior of the intensity field is found in the chromosphere, with roughly the same period as the velocity oscillation, and evidently coupled to it. This oscillation may be followed to considerable altitudes in the chromosphere. It is apparently absent in the upper photosphere, however, even though the velocity oscillation is quite strong there.\r\n\r\n Also discussed are some possible interpretations of the observations and what they might imply about the structure of the solar atmosphere. We find that the observed period is close to the \"critical period\" separating propagating and standing acoustic waves in a gravitating atmosphere with the solar values for temperature and gravitational field. Several possible explanations for the decrease of period with altitude are suggested. The amplitude and phase of the temperature fluctuations accompanying a wave propagating in an atmosphere with radiative leakage are discussed; this leads to a possible explanation of the presence of an intensity oscillation at high levels and its absence at low levels, and of the reversal with altitude of the sign of the correlation coefficient between intensity and velocity.\r\n\r\n Some observational problems are also discussed, both in the body of the thesis (Parts I and II) and in appendices.", "doi": "10.7907/31J4-0X44", "publication_date": "1963", "thesis_type": "phd", "thesis_year": "1963" }, { "id": "thesis:4292", "collection": "thesis", "collection_id": "4292", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-10282008-150608", "primary_object_url": { "basename": "Simon_gw_1963.pdf", "content": "final", "filesize": 11296553, "license": "other", "mime_type": "application/pdf", "url": "/4292/1/Simon_gw_1963.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Correlations Between Large-Scale Solar Photospheric and Chromospheric Motions, Ca II (K) Emission, and Magnetic Fields", "author": [ { "family_name": "Simon", "given_name": "George Warren", "clpid": "Simon-George-Warren" } ], "thesis_advisor": [ { "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\nAs previously reported (2,3), large-scale, principally horizontal, motions have been Observed in the solar photosphere. These motions have a cellular appearance, with the flow proceeding from the center of each \"cell\" toward the outer boundary, with velocities of 0.3 - 0.5 km/sec. These cells are arranged in a more-or-less regular pattern over the solar surface, with an average cell diameter of 30000 - 35000 km. Cross-correlation measurements Obtained by superposition of velocity plates and Ca II (\u03bb3933) plates show that the K[subscript 232]emission network occurs directly above the boundaries of the velocity cells. Downward velocities of 1.0 - 2.0 km/sec are observed in the wings of H\u03b1 ([...]\u03bb = 0.74) and H\u03b2 ([...]\u03bb = 0.4A). These localized motions exist in a network pattern which coincides with the position of the K[subscript 232] emission and the velocity cell boundaries. The lifetime of the K[subscript 232] network has been measured by cross-correlating plates taken at various time intervals, and has a mean life of 17 - 21 hours, in excellent agreement with the findings of Macris (4, 5). Using magnetograph measurements obtained by Howard (6), we find a very high degree of correlation between the positions of weak magnetic fields (1.5 - 15 gauss) and the K[subscript 232] network, the correlation increasing as the field strength increases.\r\n\r\nThese observations suggest that the average solar magnetic field (0.5 - 1.0 gauss) is swept to the cell boundaries by the horizontal currents, and concentrates there in strengths several times greater than the average field. These narrow regions of enhanced field strength could then account for the presence of the K[subscript 232] emission at the cell boundaries, and perhaps also indirectly for the downflow of chromospheric material in this region, as well as the small \"dots\u201d of rising material seen at the edges of the downward flowing network which may be spicules seen on the disc. The origin of the \"supergranulation\" may be related to helium ionization which occurs at a depth of 0.5 - 1.5 10[superscript 4] km in the sun. Most of these results have already been reported (7).", "doi": "10.7907/MH5M-9152", "publication_date": "1963", "thesis_type": "phd", "thesis_year": "1963" }, { "id": "thesis:1441", "collection": "thesis", "collection_id": "1441", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-04212006-170658", "primary_object_url": { "basename": "Moffet_at_1961.pdf", "content": "final", "filesize": 8442064, "license": "other", "mime_type": "application/pdf", "url": "/1441/1/Moffet_at_1961.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Interferometric Measurement of Brightness Distributions in Discrete Radio Sources", "author": [ { "family_name": "Moffet", "given_name": "Alan Theodore", "clpid": "Moffet-Alan-Theodore" } ], "thesis_advisor": [ { "family_name": "Bolton", "given_name": "John G.", "clpid": "Bolton-J-G" }, { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Stanley", "given_name": "Gordon J.", "clpid": "Stanley-G-J" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "Owens Valley Radio Observatory (OVRO)" }, { "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\nInformation about the brightness distributions in 110 extragalactic and 17 galactic radio sources has been obtained from observations with the Caltech variable spacing interferometer at a wavelength of 31.3 cm. In these observations, the amplitude and phase of the complex visibility function were measured at transit with antenna spacings of 195[...], 389[...], 779[...], and 1557[...] along an east-west baseline. Using these same basic spacings, and by observing at large hour angles, the visibility amplitude was measured at ten other effective spacings between 126[...] and 1363[...]. Not all sources were observed at all spacings.\r\n\r\nOf the 110 extragalactic sources, 47 are found to have angular diameters greater than [...]. Only 4 of these 47 appear to have smooth, simple structure, while the remaining 43 show some form of complexity, many having two fairly well separated components. It is suggested that the majority of all extragalactic sources have complex structure. For three extragalactic sources (M 87, NGC 5128, and Cygnus A) comparable measurements at other wavelengths have been published, and in each case, significant changes in structure with wavelength are noted.\r\n\r\nThe theory of interferometric investigation of discrete sources is developed in some detail, and previous work in the field is reviewed. Calculations on a number of model sources are described.", "doi": "10.7907/QCM3-7524", "publication_date": "1961", "thesis_type": "phd", "thesis_year": "1961" }, { "id": "thesis:2770", "collection": "thesis", "collection_id": "2770", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06292004-152135", "primary_object_url": { "basename": "Sorrels_jd_1956.pdf", "content": "final", "filesize": 4129935, "license": "other", "mime_type": "application/pdf", "url": "/2770/1/Sorrels_jd_1956.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "I. A \u039b\u1d52-Fragment Decay in a Cloud Chamber. II. Example of the Associated Production of a \u039e\u207b and Two \u03b8\u1d52 Particles. III. A Study of Multiple V-Events", "author": [ { "family_name": "Sorrels", "given_name": "John David", "clpid": "Sorrels-John-David" } ], "thesis_advisor": [ { "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\nA cloud chamber photograph of the decay in flight of a heavy nuclear fragment is described. The event is most reasonably interpreted as the decay of a [lambda] particle bound to a He3 nucleus, and is similar to examples previously observed in nuclear emulsions. Under this interpretation, the lifetime of the excited fragment in this single example is [...] sec and the binding energy of the [lambda] to He3 is probably less than 2 Mev.\r\n\r\nIn another cloud chamber event, a negative cascade particle and two neutral heavy mesons appear to be produced in a single nuclear interaction above a cloud chamber. It is suggested that this event may be an example of the associated production of [...] particle with two [...] particles according to the scheme of Gell-Mann.\r\n\r\nAll of the 48-inch magnet cloud chamber events where two or more V-particles appear to come from a single origin and decay in a single chamber are described. These V-events are analyzed for origin coplanarity and associated production. In the case of [...] production, a search for angular relationships between decay planes and the plane containing the lines of flight of the two [...] detects no strong correlations. Origin coplanarity tests do not indicate three body decay except in two cases of anomalous [...]. The data is consistent with the assumption of associated production of [...]. The role of the anomalous [...] in multiple production events is discussed.", "doi": "10.7907/72KQ-XZ56", "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:476", "collection": "thesis", "collection_id": "476", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02032004-111841", "primary_object_url": { "basename": "Strassenburg_aa_1955.pdf", "content": "final", "filesize": 2241700, "license": "other", "mime_type": "application/pdf", "url": "/476/1/Strassenburg_aa_1955.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "The Lifetimes of the Neutral \u039b\u00b0 and \u03b8\u00b0 Particles", "author": [ { "family_name": "Strassenburg", "given_name": "Arnold Adolph", "clpid": "Strassenburg-Arnold-Adolph" } ], "thesis_advisor": [ { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" }, { "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\nThe maximum likelihood procedure for determining mean lifetimes of unstable particles is applied to cloud chamber photographs of [...] and [...] particles. Selection methods designed to select pure, unbiased samples are discussed in detail. A formulation of selection criteria which enables optimum use of the data without introducing bias is outlined. The techniques which were employed to make the necessary momentum and distance measurements are described.\r\n\r\nThe mean lifetime of the [...] based on 93 cases is [...] sec. The mean Q-value for 82 cases which permit a Q-value calculation is [...] Mev. The errors in these results are briefly discussed.\r\n\r\nThe mean lifetime of the [...] is computed using two independent selection techniques. Biases resulting from anomalous [...] contamination are discussed and a \"best value\" of [...] sec, based on 60 cases, is given. The errors due to momentum measurements and sample contamination are discussed qualitatively. The mean Q-value for 58 cases is [...] Mev.", "doi": "10.7907/VBNF-MG96", "publication_date": "1955", "thesis_type": "phd", "thesis_year": "1955" }, { "id": "thesis:4889", "collection": "thesis", "collection_id": "4889", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-12092003-113707", "primary_object_url": { "basename": "Bjornerud_ek_1955.pdf", "content": "final", "filesize": 4637577, "license": "other", "mime_type": "application/pdf", "url": "/4889/1/Bjornerud_ek_1955.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "I. Photometric Determination of Ionization of Cloud Chamber Tracks. II. Cloud Chamber Study of Charged V-Particles", "author": [ { "family_name": "Bj\u00f6rnerud", "given_name": "Egil Kristoffer", "clpid": "Bj\u00f6rnerud-Egil-Kristoffer" } ], "thesis_advisor": [ { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" }, { "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\nA photoelectric method for the measurement of ionization of cloud chamber tracks has been developed. The principal feature of the method is the use of a comparison track of known ionization in the same part of the chamber. A microphotometer slit is made to scan the track perpendicular to its direction and a tracing of the transmission of the track relative to the background transmission is obtained. A calibration curve is established and the method is used to measure the ionization of various tracks. The error of measurement is of the order of 10 per cent. A theoretical treatment of the problem is carried out to show the effects of various physical parameters not easily ascertained experimentally.\r\n\r\nAn analysis of 101 charged V-particles decays, observed with a double cloud chamber, is presented. The events in the upper chamber appear to have markedly different properties from those in the lower. The particles in the upper chamber have measured properties which are in every respect consistent with those of the kappa meson: (a) lifetime 5 x 10[^-10] to 2 x 10[^-10] sec; (b) mass 1000m[subscript e], and (c) transverse momentum distribution consistent with a three-body decay scheme. The majority of the particles in the lower chamber, on the other hand, are tentatively identified as charge hyperons with the aid of two cases which appear to have proton secondaries: (a) lifetime 10[^-10] to 3 x 10[^-10] sec; and (b) transverse momentum distribution consistent with a two-body decay scheme.", "doi": "10.7907/JZH8-0240", "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" }, { "id": "thesis:1741", "collection": "thesis", "collection_id": "1741", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05122003-124049", "primary_object_url": { "basename": "Wanlass_sd_1953.pdf", "content": "final", "filesize": 17193498, "license": "other", "mime_type": "application/pdf", "url": "/1741/1/Wanlass_sd_1953.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "The Decay of the Neutral V-Particle", "author": [ { "family_name": "Wanlass", "given_name": "Sylvan Dean", "clpid": "Wanlass-Sylvan- Dean" } ], "thesis_advisor": [ { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" }, { "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\nIn a set of 23,000 cloud chamber photographs taken in a study of penetrating showers, 134 examples of the decay of neutral V-particles were observed. These have been analyzed in an endeavor to determine the properties associated with this phenomenon.\r\n \r\nIt is apparent in the great majority of cases that the two charged decay products are protons and negative [pi]-mesons. There is, however, a significant number of data available to indicate the existence of other charged decay-products; the poor quality of these events has unfortunately prevented an interpretation in terms of a decay scheme.\r\n\r\nNo direct evidence has been observed which indicates the existence of neutral secondary particles, and the statistical data are consistent with a two-body decay scheme.\r\n\r\nQ-values have been calculated under the assumption of a two-body decay into a negative [pi]-meson and a proton; these values range from 10?3 Mev to about 87?15 Mev. It is exceedingly difficult to reconcile the observed results with any unique Q-value.\r\n\r\nOther interesting events which were observed in these experiments included charged V-particles and heavy mesons. A brief analysis of these events has also been included.", "doi": "10.7907/5291-D817", "publication_date": "1953", "thesis_type": "phd", "thesis_year": "1953" }, { "id": "thesis:1698", "collection": "thesis", "collection_id": "1698", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05092003-162924", "primary_object_url": { "basename": "Shelton_fh_1953.pdf", "content": "final", "filesize": 5202168, "license": "other", "mime_type": "application/pdf", "url": "/1698/1/Shelton_fh_1953.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "V-Particle Production", "author": [ { "family_name": "Shelton", "given_name": "Frank Harvey", "clpid": "Shelton-Frank-Harvey" } ], "thesis_advisor": [ { "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\nIn set of about 23,000 cloud chamber photographs, 37 V[...]-particles and 9 charged V-particles were produced in nuclear interactions in a lead plate between two cloud chambers in a magnetic field. An analysis of the circumstances of occurrence of V-particles strongly indicates that the V-particles were produced principally by mesons. Production of V[...]-particles by nucleons is also indicated. By a study of the multiplicity of the stars containing V[...]-particles, the average momentum of the particles producing V[...]-particles is found by several methods to be about 10 Bev/c. At present it appears that all V[...]-particles were produced by particles having momenta in excess of about 2 Bev/c. It is found that the V[...]-particle is produced in the center-of-mass system with about 400 Mev/c momentum.\r\n\r\nIn order that the cross-section for V[...]particle production be checked, an interaction length for penetrating shower particles is found to be 340 [plus or minus] 40 gr/[square centimeter], and is a value that is consistent with the results obtained in other cloud chamber experiments. About one in twenty interactions by penetrating-shower particles whose momenta are in excess of 1 Bev/c results in a V[...]-particle being produced. About 2 percent of all of the shower particles produced in penetrating-shower particle interactions are V[...]-particles.\r\n\r\nA measurement which might indicate a high angular momentum in the V[...]-particle is obtained far each V[...]-particle produced in the lead plate. The best examples are recalculated. There is a weak indication that the V[...]-particle has a high angular momentum.", "doi": "10.7907/79GV-BM08", "publication_date": "1953", "thesis_type": "phd", "thesis_year": "1953" }, { "id": "thesis:1429", "collection": "thesis", "collection_id": "1429", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-04212003-085844", "primary_object_url": { "basename": "Alford_wl_1953.pdf", "content": "final", "filesize": 3107442, "license": "other", "mime_type": "application/pdf", "url": "/1429/1/Alford_wl_1953.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "The Mean Lifetime of V-Particles", "author": [ { "family_name": "Alford", "given_name": "William Lumpkin", "clpid": "Alford-William-Lumpkin" } ], "thesis_advisor": [ { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" }, { "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": "A maximum-likelihood procedure for determining mean lifetimes of V-particles from cloud chamber data is discussed and applied to samples taken from a group of 134 neutral V-particle decays. For 74 events which were consistent with a decay into a proton and a negative pi meson, a lifetime of (2.5 \u00b1 0.7) x 10-10 sec is obtained. Dividing the data into \"low-Q\" and \"high-Q\" groups on the basis of the calculated energy release in the decay, a value of \u03a4L = (2.9 \u00b1 0.8) x 10-10 sec is found for those cases with 0 < Q \u2264 50 Mev and a value of \u03a4H = (1.6 \u00b1 0.5) x 10-10 sec is found for those cases with 50 < Q < 150 Mev. While no significant difference exists between these two values, the difference is greater than for other plausible division schemes which are considered.
\r\n\r\nA qualitative discussion of lifetimes is given for the case of 23 charged V-particle decays. For the charged V-particles these data suggest either a lifetime less than that of the neutral V-particles, provided the sample is homogeneous, or a more likely an apparent average lifetime less than that of the neutral V-particles, if the sample is a mixture of two or more types of particles. The possibility of kappa mesons making up a part of these decays is considered and data indicating lifetimes approximately equal to or longer than 10-9 sec for both the kappa and tau mesons are briefly discussed.
\r\n", "doi": "10.7907/7EDY-K211", "publication_date": "1953", "thesis_type": "phd", "thesis_year": "1953" }, { "id": "thesis:17480", "collection": "thesis", "collection_id": "17480", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:06242025-160202494", "primary_object_url": { "basename": "Jopson_RC_1950.pdf", "content": "final", "filesize": 28212805, "license": "other", "mime_type": "application/pdf", "url": "/17480/1/Jopson_RC_1950.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "I. Flux of Low Energy Protons at Sea Level. II. Other Phenomena Involving Particles of Greater than Minimum Ionization", "author": [ { "family_name": "Jopson", "given_name": "Robert Clarke", "clpid": "Jopson-Robert-Clarke" } ], "thesis_advisor": [ { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Anderson", "given_name": "Carl D.", "clpid": "Anderson-C-D" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "A proportional counter has been installed in a six-inch\r\ncloud chamber with a magnetic field of 6400 gauss. By use of the\r\nproportional counter as a selection device, pictures o\u00a3 more than\r\n200 low energy protons have been obtained in a time of somewhat\r\nover a year's duration. From these the absolute intensity of the\r\nlow-energy proton component of cosmic rays has been determined at\r\nsea level. A spectrum of fifty electrons resulting from mu-meson\r\ndecays has been obtained as well as other data on mu-mesons.\r\nPhotographs of typical low-energy protons, mu-meson decays, and\r\nother interesting events are presented. In addition several\r\ninteresting pictures are discussed in detail.", "doi": "10.7907/690h-wm96", "publication_date": "1950", "thesis_type": "phd", "thesis_year": "1950" } ]