High-altitude Balloon Flights Research Articles

FIGARO IV: Large-area balloon-borne telescope to study rapid time variabilities in the gamma-ray sources at energies above 50 MeV

We present a new γ-ray telescope based on the Limited Streamer Tube technology, used as tracking chambers to detect photons above 100 MeV. This technique allows to obtain very large sensitive areas (16 m2 in our experiment), together with a good angular resolution for payloads embarcable in high-altitude balloon flights. The capability to collect a large signal in a short exposure time makes the telescope particularly suitable and competitive with respect to satellite-based detectors for studying both periodic and random time variabilities on galactic and extragalactic γ-ray sources.

A ring imaging Cherenkov telescope for observations of high energy cosmic rays

We describe a ring imaging Cherenkov counter for high altitude balloon flights designed to measure the energy spectra of cosmic ray nuclei above 40 GeV/amu. The instrument has a 3 m long nitrogen gas radiator at 1 atm, a spherical and planar mirror system, and ≈ 2.2 m2 of TMAE/ethane photon detecting drift chambers with fused silica windows in the focal plane. The mirror system is designed such that cosmic ray particles which trigger the instrument cannot pass through the photon detectors. Cosmic ray trajectories through the instrument are determined by eight low mass drift chambers, each of 2.2 m2 area, which predict the ring image center to ± 0.76 mm. Ground tests with cosmic ray muons prior to the flight show that the detectors see about two photoelectrons from a high energy singly charged particle. Special efforts were made to ensure stable operation and constant temperatures and pressures under remote control during the balloon flight. In September 1991, this instrument flew for 31 h at an altitude of ∼ 37 km and collected cosmic ray events which were transmitted to a ground station for recording.

Recent results of Gamma-ray imaging observations of the Galactic center and Crab/A0535+26 regions

Imaging observations at hard X-ray and γ-ray energies of the Galactic center and Crab/A0535+26 regions are presented. The measurements were made in a series of high altitude balloon flights of a coded aperture γ-ray telescope developed by Caltech. The first coded aperture images of the Galactic center region above 35 keV reveal a strong γ-ray source located 0.7 ± 0.1° away from the Galactic nucleus, consistent with the known X-ray source 1E1740.7-2942. In addition a second source consistent in position with GX354+0 has been observed. Flux estimates and upper limits from two other known sources are also discussed. Coded aperture observations of the Crab and A0535+26 are presented, demonstrating the ability of coded aperture instruments to observe multiple time variable sources simultaneously.

Activation of BGO crystals with 1.5 GeV protons

A cyclindrical bismuth germanate (BGO) detector (7.5 cm diameter × 7.5 cm long) and a cylindrical bare crystal of BGO (2.5 cm diameter × 2.5 cm long) were exposed to a fluence of 1.1 × 108 protons cm−2 at 1.5 GeV energy, roughly equivalent to that expected on an interplanetary journey to Mars. No degradation in the energy resolution or counting efficiency of the BGO detector was observed, although the background continuum increased significantly. Events emanating from the bare crystal were counted externally with a high-resolution germanium detector. The activation lines identified were compared to a spectrum from an externally counted BGO detector taken on a high-altitude balloon flight over Antarctica.

Imaging spectrometer for high resolution measurements of stratospheric trace constituents in the ultraviolet

A high resolution spectrometer has been developed for studies of minor constituents in the middle atmosphere at ultraviolet wavelengths. In particular, the instrument is intended for observations of upper stratospheric U V bands. The spectrometer has a slit width of 0.08 A obtained by means of an echelle grating and a cross-disperser grating. The image plane detector is an intensified charge coupled device consisting of a high gain proximity focused image intensifier that is fiber optically coupled to a 2-D CCD array. An instantaneous bandwidth of 9.2 A is resolved across 488 pixels at 0.018 A/pixel, permitting simultaneous acquisition of multiple lines of selected OH bands and the neighboring background. The spectrometer and the approach have been successfully demonstrated as a technique for measuring the concentration of OH on two high altitude balloon flights. We report the instrument design and its achieved performance.

Cosmic-ray elemental abundances from 1 to 10 GeV per AMU for boron through nickel

The relative abundances of cosmic-ray nuclei in the charge range boron through nickel over the energy range 1-10 GeV per amu were measured with a balloon-borne detector. The instrument consists of a scintillation and Cerenkov counter telescope with a multiwire proportional chamber hodoscope and has been flown in four high-altitude balloon flights. Good charge resolution (sigma = 0.2 charge units at iron) and high statistical accuracy have been achieved. These data are used to derive the energy dependence of the leakage path length using the leaky box model of propagation and confinement in the galaxy. This energy dependence is found to be best fit by lambda = E(tot) exp -n, where n = 0.49 + or - 0.06 over 1-10 GeV per amu. Relative abundances at the source are consistent with an energy-independent composition.

Summary of the Symposium

S. CURTIS: I have the pleasure of introducing Dr. Tobias. It is very fitting for Toby to be giving the summary of this symposium. If there is anyone who deserves to be called the father of heavy charged particle biophysics, I believe it is he. From the very early days, just after heavy galactic cosmic rays were discovered, he predicted that these might be detected by astronauts who would see flashes of light-which did turn out to be the case. All through his career he has shown an insight into the field of heavy charged particle biophysics that is truly remarkable. And in characteristic style he told me yesterday that he would not be able to come on the cruise last night because he felt he had to work on today's talk. I take great pleasure in introducing the honorary chairman of this symposium, Dr. Cornelius Tobias, to give the summary. C. A. TOBIAS: Let me first summarize some general thoughts about the field of heavy ions. Heavy charged particles are part of our universe. This has been known only since 1948 when Phyllis Freier and group first discovered galactic heavy ions in high-altitude balloon flights. Low-energy accelerated heavy ions (7 MeV/u) became available at the HILAC in the early 1950s, and the Bevalac has been used to accelerate particles up to krypton since 1975. The entire spectrum of heavy ions became available only in 1982 when GSI and LBL successfully accelerated any of the nuclei in the periodic table, including uranium. I believe it is good for us all to remember that this was only 3 years ago, and unless we plan wisely for the future of biomedical heavy ion research, the heavy-ion accelerators might shut down when they have served their purpose for physics and chemistry research. Second, we may state that we have no surefire method to predict what heavy particles can do without actually performing experiments using heavy beams. It is not possible to reproduce or calculate accurately either the spatial pattern of ionization or the temporal complexity of early chemical events in particle tracks. With present-day techniques one could not put a heavy ion track together from a beam of electrons: practically this is not feasible because one would need such a fantastically intense electron beam that the electrons would repulse each other and scatter away. Temporally if you try to put two electrons next to one another, these particles would have to follow within 10-16 s. Dr. Paretzke mentioned that one would need an extremely high electron beam intensity to achieve this. Third, as was shown during the symposium, it is important to have heavy particle beams to be able to explore what they can contribute to medicine. Our entry into space and the eventual colonization of space by man requires the understanding of the magnitude and nature of the deleterious effects of heavy ions. Dr. Lett and Dr. van der Kogel demonstrated that cataractogenesis and the effects of

Spectroscopic measurements of atmospheric HCN at northern and southern latitudes

A number of lines belonging to the ν3 fundamental vibration‐rotation band of hydrogen cyanide (HCN) have been identified in atmospheric infrared absorption spectra obtained on high‐altitude balloon flights at 32°N in 1976 and at 30°S in 1977. Quantitative analysis of these spectral features has resulted in the first determination of atmospheric HCN concentrations in the southern hemisphere, as well as an independent estimate of stratospheric HCN abundance in the northern hemisphere. Within the uncertainties of our own and previous measurements, our northern‐hemisphere result is consistent with those of other investigators, and southern‐hemisphere HCN concentrations appear to be similar to those in the northern hemisphere.

The dependence of track response on registration temperature in Lexan and CR-39

ABSTRACT The track response of Lexan polycarbonate and CR-39 track detectors has been found to vary significantly with the polymer temperature during registration. This temperature effect may cause errors in cosmic ray composition experiments employing detector arrays exposed by means of high altitude balloon flights or earth orbiting spacecraft with passive temperature control. Outline results are presented for a series of exposures to high energy Fe beams at the LBL Bevalac during 1980 covering registration temperatures from −189°C to +48°C and using detector stacks sealed in an environment of dry air. Comparison is made with results from unsealed stacks and from detectors exposed in vacua.

Ultra Heavy Cosmic Rays

The existence in the cosmic rays of ultra-heavy (UH) nuclei with Z ≥ 30 was established by two separate experiments in 1966. Fleischer et al. first demonstrated the fossil tracks of such nuclei in certain meteoritic crystals and shortly afterwards Fowler established their existence in present-day cosmic rays with the detection of their tracks in photographic emulsion which had been exposed during a high altitude balloon flight. The fluxes of such nuclei are very low, only ~ 10−4 of that of iron, and the most suitable method of detection to date has been the analysis of the tracks formed by these particles in very large(several m2) arrays of plastic detector material, notably Lexan polycarbonate. Such exposures on balloons and on Skylab have provided practically all present knowledge of the UH cosmic rays. Unfortunately, the charge resolution obtained was disappointing, even though scrupulous care was taken in the handling and etching of the material, and the charge scale itself of necessity had to be based on a considerable extrapolation from the iron peak and could not be used with great confidence. The situation now, however, is in the process of being transformed. We have two satellite experiments devoted to the study of UH cosmic rays and in operation at the moment. These are the Bristol University experiment on Ariel 6 launched on 3rd June 1979 and the joint group under Israel, Waddington and Stone on HEAO-C launched in September 1979. It is therefore appropriate, I believe, if I devote this review to the new preliminary results and a comparison of this material with the published data.

The isotopic composition of cosmic-ray helium from 123 to 279 MeV per nucleon - A new measurement and analysis

A description is given of an experiment which was designed to measure the spectra and composition of cosmic-ray hydrogen and helium isotopes in the interval 120-280 MeV per nucleon to compare with the recent values observed at low energies and also with the only earlier measurement in this high-energy regime. The results presented were obtained during a high-altitude balloon flight from Thompson, Manitoba, in 1973 August. This flight occurred during the period in which the presence of the anomalous component in the helium spectrum became apparent, and provides the opportunity of determining whether this component extends to higher energies than those studied by satellite experiments. The results place an upper limit on the flux of 'anomalous' He-4 (which appeared at low energy in 1972) of at most 15% in the energy range of this experiment, and combined with the low-energy observations of the Chicago group, show an energy dependence of the average ratio of the helium isotopes in the modulated cosmic rays which is difficult to reconcile with current modulation models.

Construction and performance of a large-area multiwire ionization hodoscope for use in a cosmic-ray detector

The mechanical construction and electronics of a large-area multiwire ionization hodoscope are described. Each chamber is 0.83 m by 1.65 m with wire spacing of 2.5 cm. The chambers are assembled to compose a hodoscope for a 6.6 m 2·sr cosmic ray detector. Operating characteristics and in-flight performance from two 30 h high-altitude balloon flights are presented.

Further observations of geomagnetically forbidden cosmic ray nuclei

Cosmic-ray particles with kinetic energies well below cutoff values were detected during a high-altitude balloon flight at 41 deg N geomagnetic latitude. These particles had kinetic energies up to 400 MeV/amu and charges in the range from 6 to 30. They are probably reentrant albedo particles and are of interest primarily because they can be confused with fast ultraheavy primary particles in some experiments.

The isotopic composition of cosmic rays with Z between 5 and 26

Results are reported for a high-altitude balloon flight which measured the isotopic composition of cosmic rays by using a Cerenkov-range technique to determine the masses of arriving cosmic rays with charges between 5 and 26 for kinetic energies around 450 MeV/amu. Event-selection criteria are discussed, and the mass-determination technique is outlined. Some of the mass histograms resulting from the analysis are presented along with the mean masses calculated from the data, and the derived isotopic compositions. It is found that: (1) C, N, and O are consistent with pure C-12, N-14, and O-16 sources; (2) Mg seems to require some neutron-rich component at the source; (3) Ne appears to require a source isotopic composition that is even more neutron-rich than the universal abundances; and (4) the source may be somewhat enriched in Fe-54. It is suggested that the fundamental nuclear physics which governed the synthesis of solar-system material may also be responsible for cosmic rays, implying that the solar system is probably an average sample of galactic matter.

Detection of new celestial objects at far-infrared wavelengths

During a high-altitude balloon flight, sources of far-infrared radiation have been detected with apparent fluxes greater than or about equal to 3 pW/sq cm in the spectral band from 50 to 500 microns. While the sources are not uniquely identifiable with any well-known class of celestial objects, two associations should be noted. Many of the objects lie close to local stars; there is also a tendency to cluster around the ecliptic plane. Alternatively, a new class of celestial objects may have been observed.

Experimental flight of a large spherical gas scintillator

A spherical argon-nitrogen gas scintillation detector of diameter 119 cm has been constructed and operated successfully during a six-hour high-altitude balloon flight. Primary cosmic-ray nuclei in the charge range 14 ≤ Z ≤ 26 were detected. The number of iron-group nuclei detected was consistent with previous results. This large detector, with a geometrical factor of 7 m2sr, was designed as a simple engineering test on which to base the construction of larger, more versatile instruments.

The Spectrum of Galactic Electrons with Energies Between 10 and 900 GEV

view Abstract Citations (38) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Spectrum of Galactic Electrons with Energies Between 10 and 900 GEV Muller, Dietrich ; Meyer, Peter Abstract A cosmic-ray electron detector has been designed which consists of a counter telescope with 1060 cm2 sterad geometry factor and a lead scintillator sandwich of about 19 radiation lengths thickness. In order to identify electron showers efficiently, multiple pulse-height analysis of many counters and time-of-flight techniques have been used. This instrument has been exposed during 1970 in three high-altitude balloon flights from Palestine, Texas. The data analysis is based on results from accelerator calibrations with electrons and pions at SLAC. Discrimination against a contamination of the electron data due to interacting protons has been achieved by statistical methods. The resulting differential energy spectrum of cosmic-ray electrons can be well described by a single power law with spectral index 2.66 i 0.1 up to energies around 250 GeV. Within the experimental uncertainty, no change in this spectral slope up to almost 1000 GeV can be detected. Some implications of these results are discussed. Subject heading: cosmic rays Publication: The Astrophysical Journal Pub Date: December 1973 DOI: 10.1086/152551 Bibcode: 1973ApJ...186..841M full text sources ADS |

New radiometric techniques and solar constant measurements

A series of absolute cavity radiometers, designed to measure solar irradiance, has been developed at the Jet Propulsion Laboratory. Analysis indicates the absolute uncertainty of irradiance measurements made by the most recent devices to be less than ±0·5 mW/cm 2. In a series of experiments the radiometric scale defined by the JPL instruments has been compared with the International Pyrheliometric Scale (IPS). A systematic 2·2 per cent difference has been observed with the IPS producing consistently lower measurements. The solar constant and spectral distribution have been derived from high-altitude balloon flight measurements made by two types of JPL cavity radiometers. Measurements at 25 km in 1968 produced a solar constant value of 137·0 mW/cm 2. From 1969 measurements at 36 km, a value of 136·6 mW/cm 2 was derived, with an estimated absolute uncertainty of ±0·5 per cent. The solar spectrum information from these experiments agrees most closely with the solar spectrum model of Labs and Neckel.

Physical sciences: New Point γ-ray Source Lib γ-1: Evidence for Time Variation and Possible Identification with PKS 1514-24

DURING the past 2 yr evidence has been presented for the existence of four point sources of high energy γ-radiation (Eγ > 50 MeV). Three were found by the Case-Melbourne (C-M) collaboration using high altitude balloon flights from Australia (Fig. 1) and two of these sources, Gγ 2 + 3 and Gγ 341 + 1, coincided closely with known high energy X-ray sources1,2. A group from the Moscow Physical Engineering Institute detected a source with a counter telescope on Cosmos 2513. Three aspects of the Russian source are particularly noteworthy: (1) the source position, 54° 100 MeV), a factor of 30 greater than any of the C-M sources; and (3) most of the detected γ-ray flux must have been due to photons above 500 MeV, because inserted between the counters of the Cosmos counter telescope were 3.7 radiation lengths of lead in which multiple scattering and energy loss greatly reduce the efficiency between 100 and 500 MeV. The Russian group's claim for time variability of 3C 120 as a γ-ray source, because it was not observed on earlier surveys, is not valid. The surveys in this energy range which were cited (refs. 8 and 9) did not cover this region of the sky. The OSO-3 detector (ref. 10), which did cover this area, has a sensitivity to point sources which is about the same as the reported flux from 3C 120.

Large-area pulse ionization chamber for measurement of extremely heavy cosmic rays

Parallel-plate ionization chambers with nearly 1 m 2 active area have been constructed and successfully operated in a series of high-altitude balloon flights. The chambers are used for identification of relativistic cosmic-ray nuclei with charge greater than or equal to 20. For relativistic iron nuclei (charge 26) the charge resolution (fwhm) achieved is 5.5 percent (i.e., less than 1.5 charge units).