Large Bubble Chamber Research Articles

A direct test of Auger cascade induced nucleation from heavy element contamination in C3F8 bubble chambers

Understanding and quantifying the gamma-induced bubble nucleation background in clean nuclear recoil detection bubble chambers is of utmost importance to bubble chamber based dark matter searches. We present data confirming the hypothesis that large Auger cascades from high-Z elements such as iodine and xenon dramatically increase the response of C3F8 bubble chambers to gamma rays. These tests, performed with a small calibration bubble chamber filled with C3F8+\U0001d4aa(10) ppm xenon, show that the probability of bubble nucleation scales with the rate of xenon inner-shell vacancies, reaching values >10% per K-Shell vacancy for Seitz thresholds of interest to future dark matter searches in bubble chambers. We also place an upper limit on bubble nucleation probability for argon Auger events, relevant to large future bubble chambers which may contain some residual atmospheric argon after the active fluid fill.

A measurement of the holographic minimum-observable beam branching ratio in the FERMILAB 15-ft bubble chamber

Holography has been used successfully in combination with conventional optics for the first time in a large cryogenic bubble chamber, the 15-foot bubble chamber at Fermilab, during a physics run. The innovative system combined the reference beam with the object beam, irradiating a conical volume of ∼1.4 m 3. Bubble tracks from neutrino interactions with a width of ∼120 μm have been recorded with good contrast. The ratio of intensities of the object light to the reference light striking the film is called the beam branching ratio. We obtained in our experiment an exceedingly small minimum-observable ratio of (0.54±0.21)×10 −7. The technology has the potential for a wide range of applications.

Materials for holographic recording of tracks in a bubble chamber

The noise and diffraction characteristics of a number of silver halide photographic materials were investigated to help with the selection of a material suitable for holographic recording of tracks in a large bubble chamber. Calculations were made of the best possible parameters for the recording of coherent and partly coherent holograms, based on experimental characteristics such as the energy spectrum of the noise and the diffraction efficiency of a plane grating. The noise energy spectrum and the exposure dependence of the diffraction efficiency were determined for various silver halide materials. A study was made of the influence of glass and film substrates on the noise characteristics of a material labelled IAE-630. The study demonstrated the advantages of IAE-630 and IAE-690 photographic materials developed at the Russian Scientific Centre 'Kurchatov Institute' in respect of the noise [noise energy spectrum (1–3)×10-9 mm2 in the angular range 20°—30° and the sensitivity (5 μJ cm-2) at the diffraction efficiency maximum. Holographic results obtained for a large bubble chamber indicated that IAE, with the highest sensitivity and the lowest noise level, was the best material.

Holography in big bubble chambers

The development of holography for large cryogenic bubble chambers, which extended over almost one decade, is described. It culminated in the successful application of this ambitious technique to the 15-foot Bubble Chamber at Fermilab. During an exposure to the neutrino beam, produced by 800 GeV/c protons on the production target, over 110'000 good holograms were taken simultaneously with conventional photographs. Bubble tracks with sizes as small as 100 μm within a volume of ∼1.5 m 3 could be recorded with good contrast, improving the resolution over the standard optics by a factor of four.

HOLRED — A machine for the replay of holograms made in a large Bubble Chamber

The Fermilab 15′ Bubble Chamber, exposed to a beam of neutrinos generated at the Fermilab Tevatron, has been equipped with holographic optics in order to provide a high resolution view of particle interactions over a volume of several m 3. A mahine, “HOLRED”, has been constructed to replay the holograms recorded. The principles of the machine and aspects of its construction and operation are described. Results are presented comparing holographic and conventional recordings of neutrino interactions.

Invitation to chemistry through a large soap bubble chamber

This article describes the preparation and use of a bubble changer in which students can view a bubble from the inside.

Detection Of Short-Lived Particles Using Holography

Vertex detectors with good spatial resolution are ideal devices for the detection of short-lived particles (mean lifetime > 10-13 s; mean distance traveled before decay- um) produced in high energy interactions. The bubble chamber equipped with high resolution photography is one such vertex detector. However, improving the resolution in photography results in a very rapid decrease of the depth of field, thereby rendering most of the chamber optically inaccessible. Using holography instead of photography remedies this problem by decoupling resolution and depth of field. This paper reports on our recent work in the use of a two-beam holographic technique for a large Freon bubble chamber (80 cm in diameter and 100 cm deep). The results reported here are for a full-scale setup in air with test targets to simulate bubble chamber tracks and in some cases a full-scale 28 cm thick glass plate to simulate chamber windows. This bubble chamber is the vertex detector for a hybrid spectrometer system that will be used for two of our forthcoming experiments at the Fermi National Accelerator Laboratory: the first to search for the short-lived charmed particles and the second to establish the existence of the T neutrino by observing the decay of the T lepton. We demonstrate that a 30 resolution can be achieved throughout the entire volume of the chamber. Specific details pertinent to achieving this resolution are also discussed. We also report on the construction of a semiautomated high precision measuring apparatus that will be used to scan and measure bubble chamber holograms.

Test of high resolution two-beam holography in a model of the Big European Bubble Chamber, BEBC

We describe a method used to take holograms of test objects in a configuration where a large volume, simulating the BEBC bubble chamber, was viewed through a single viewing port containing aberrating optical elements and where illumination is achieved using “Scotchlite” retroreflectors. Using a simple method of speckle averaging in replaying the holograms, wires with diameters ⩾ 20 μm, situated at ∼ 2 m from the limiting optical aperture, were reconstrucwith an effective resolution of ∼ 40 μm. The application of the technique to the conditions of an operating bubble chamber is discussed. We conclude that the method provides a viable means of recording with high resolution the interactions of particles in large bubble chambers and hence of studying the properties of short-lived particles.

Scintillation light from liquid argon and its use in a new hybrid detector

Scintillation light, produced by 200 MeV/c pions in a liquid argon bubble chamber/calorimeter was measured. Results from the test device show that this signal could be used in future large bubble chambers to trigger the flash on the occurrence of an interesting event. Furthermore, this signal give rough information about total track lengths, hence energy contained in massive electromagnetic and hadronic showers, and could complement measurements obtained by charge collection.

A particle detector using solid neon frozen from a neon-hydrogen mixture

Abstract In developing an electromagnetic calorimeter to improve the analysis of neutrino events in large bubble chambers, the possibility of using a sandwich structure of lead and solid neon has been discussed. The tests reported here demonstrate that when neon-hydrogen mixtures, available in large quantities at CERN and Fermilab, are frozen in a small ionization counter the pulses produced by high energy muons are comparable to those seen previously with pure neon. It has also been demonstrated that contaminated and thus insensitive liquid argon yields clear particle pulses after it has been frozen solid.

Limits on neutrino-antineutrino transitions from a study of high-energy neutrino interactions

We distinguish electron and positron tracks from ν e and ν e charged-current interactions in a large bubble chamber f ed with a neon-hydrogen mixture. No evidence is seen for an excess of ν e interactions from primary ν e sources secondary ν μ → ν e or ν e → ν e oscillations. Upper limits on oscillation parameters, majoron sion and lepton-number violating π and K decays are presented.

Measurement of thef+form factor inK0L→π±e∓νdecays using a large hydrogen bubble chamber

The decay K/sup 0//sub L/ ..-->.. ..pi..e..nu.. was studied in an experiment using the Argonne 12-ft bubble chamber exposed to a K/sup 0//sub L/ beam of momentum 550 +- 35 MeV/c. Use of the monochromatic beam and the large chamber volume allowed the selection of about 12 000 K/sup 0//sub e/3 events, containing a small ((5.3 +- 0.5) %) and well understood background from K/sup 0//sub mu3/ decay. The main feature of this experiment is the good acceptance over the Dalitz plot which minimizes possible systematic errors in the determination of the vector form factor f/sub +/(q/sup 2/). We find that the data are adequately described by a linear q/sup 2/ parameterization, f/sub +/(q/sup 2/) = f/sub +/(0)(1 + lambda/sub +/q/sup 2// m/sub ..pi..//sup 2/), with the slope parameter lambda/sub +/ = 0.028 +- 0.004 before radiative corrections are made. Direct application of radiative corrections, as calculated by Ginsberg, yields lambda/sub +/ = 0.025 +- 0.005. Our result is in good agreement with other recent experiments and with the assumption of K* (890) dominance.

Experimental limits on the mass and decay lifetime of νμ

The nonobservation of photon-induced e +e − pairs pointing in the neutrino beam direction in large bubble chambers would allow one to set an upper limit on the product m ν μ λ CM for muon-type neutrinos, where m ν μ is the mass and λ CM is the intrinsic partial decay width in sec −1 for ν μ → γ+ X. In the theory of Eliezer and Ross where λ LAB ∼ 0.8 × 10 −19 (m 2 ν μ − m 2 ν e )/ h ̵ E ν , this implies an upper limit on m ν μ considerably smaller than the present upper limit, and a large lower limit on the lifetime τ ν μ .

Superconductivity in technology

Abstract Physics, especially high energy physics and solid state physics waa the first area in which superconducting magnets were used. The field requirements of large bubble chambers can only be met economically by superconducting magnets, and the control of beams of particles by multipole magnetic fields ma be done more effectively with superconducting field windings. Many solid state phenomena have to be investigated in high magnetic fields, for which superconducting magnets offer many advantages, and are in common use today. Their industrial applications in magnetic separation and also for levitated trains are promising. In the long run, the most extensive application of superconductivity will probably be in energy technology. Superconducting power transmission cables, magnets for energy conversion in superconducting electrical machines, MHD-generators and fusion reactors and magnets for energy storage are being investigated. Magnets for fusion reactors will have particularly large physical dimensions, which means that much development effort is still needed, for there is no economic alternative-these, the magnets for fusion reactors, have got to be superconducting. Superconducting surfaces in radio frequency cavities can give Q-vadues up to a factor of 106 higher than those of conventional resonators. Particle accelerators are the important application. And for telecommunication, simple coaxial superconducting radio frequency cables seem promising. The tunnel effect in superconducting junctions is now being developed commercially for sensitive magnetometers and may soon possibly feature in the memory cells of computer devices. Hence superconductivity can play an important role in the technological world, solving physical and technological problems and showing economic advantages as compared with possible conventional techniques, bearing also in mind the importance of reliability and safety.

Observation of the relativistic rise in bubble density in a neon-hydrogen bubble chamber

In a bubble chamber containing a neon-hydrogen mixture surrounding a hydrogen-filled track sensitive target, electrons with momenta above 100 MeV/ c are observed to have (1.25 ± 0.02) times more bubbles per unit length in neon-hydrogen than pions with momenta between 400 and 1500 MeV/ c. We interpret this difference as due to a relativistic rise in bubble density, such as has been observed previously in a freon bubble chamber. The total magnitude of the rise from minimum to plateau is estimated to be (28 ± 2)%. This should provide a method for distinguishing between relativistic pions, kaons and protons of the same momentum. It could in particular be exploited in high energy experiments using the track sensitive target technique in large bubble chambers such as BEBC.

Weak Neutrino‐Lepton Annihilation into Hadrons

AbstractAn exploratory study of weak neutrino‐lepton annihilation into hadrons, v̄l + l → hadrons is presented. Simple cross‐section estimates indicate processes of this type may be observable in a large bubble chamber. We discuss the information one could hope to obtain from such experiments. General formulas for amplitudes and cross sections are given for v̄l + l → hadrons assuming a point‐like V – A interaction. To establish tests of the V – A interaction, we recalculate the annihilation amplitudes assuming a point‐like scalar‐pseudoscalar or tensor‐pseudotensor interaction. The extension to theories with intermediate vector bosons is sketched. We discuss the connection between v̄l + l → hadrons and e+e− → hadrons implied by the conserved vector current hypothesis. We note that in v̄l + l → rH, K⋆(890), A1, B creation (these reactions enjoy comparatively large cross sections) the leptonic as well as hadronic couplings of these J = 1, I = 1/2 or 1 mesons could be determined. A related possibility is the direct creation of new heavy charged J = 1 mesons. The normal J = 1 resonance region could be explored with neutrino energies of the order 500–2000 GeV. For this, and for higher‐energy work, a TeV proton accelerator is clearly necessary.

Design, construction and performance of the Brookhaven National Laboratory 7-foot Bubble Chamber

The BNL 7-foot Bubble Chamber was originally built as a facility to test many of the new concepts involved in the design of very large bubble chambers, and later modified to become a high energy physics research tool. Though there are individual differences, it typifies the design of the newest generation of these devices. It is described with reference to the design of each of its subsystems, and to its operation.

MIR: Scanning and measurement tables for large bubble chambers

The tables MIR described below are scanning and measuring tables built for the projection of film from the big European bubble chambers, Mirabelle and BEBC. The tables stress ease of handling, good optical quality and high precision.

Measuring bubble chamber tracks

Large bubble chambers now exist at a number of high energy laboratories and tracks of fast particles and their secondaries formed in the chamber are being photographed at the rate of many million pictures per year. The analysis of these pictures is a mammoth task and it was inevitable that attempts should be made to automate the process.

Turning Angles of Charged Particle Tracks in Large Bubble Chambers

Low energy separated beams into very large bubble chambers, such as the Argonne National Laboratory 12 ft chamber, will have the consequence that many of the secondary particles will be magnetically trapped within the chamber volume. We show that for a highly uniform magnetic field, the turning angle of the tangent to a track of known mass, taken from production to stopping, provides visual estimates of the range to stopping, the total momentum, and the in-flight decay probability. We also show that these estimates are independent of depth in the chamber and orientation in the magnetic field, and can be obtained for any view projection in the presence of optical distortions.