G. B. Yodh

The experimental identification of individual particles by the observation of transition radiation in the x-ray region

Abstract Transition radiation in the X-ray region produced by 1.3 GeV/c and 3.0 GeV/c electrons has been detected using multi-wire proportional chambers (MWPC). The radiation was generated in eleven stacks of 100 mylar foils (thickness 1 2 mil. or 1 6 mil. ) each preceding one of eleven MWPC placed in line; two inch thick slabs of styrofoam were also used. The incident particles, electrons or π−-mesons, passed through the MWPC as well as the foils. Results are given on the numbers of transition radiation photons detected, the energy deposition in the chambers and the relativistic rise of ionisation loss in argon and krypton. The distribution in total pulse height obtained with krypton shows a good separation of π−-mesons and electrons at 3 GeV/c.

Unaccompanied hadron flux at a depth of 730 g cm-2, 102<E<104 GeV

The energy spectrum of unaccompanied hadrons has been measured at a depth of 730 g cm-2 in the atmosphere. The energy was determined by a deep calorimeter (960 g cm-2) of area 4 m2. For charged hadrons unaccompanied in a 3.3 m2 spark chamber placed above the calorimeter, the observed flux was fitted in the energy range 100

Cosmic rays in the atmosphere and characteristics of high energy interactions

Abstract A detailed examination of the generic relation between the primary all nucleon spectrum and the spectra of hadrons and muons in the atmosphere is carried out. The analysis shows that these spectra are consistent with a continuously increasing cross section and no violation of scaling in the fragmentation region up to several hundred TeV.

Ultra‐high energy cross section from study of longitudinal development of air showers

We present calculations necessary for interpretation of large cosmic ray experiments and argue that both cross section and composition around 1018 eV may be estimated soon.

A new measurement of σp-Feinel and σπ-Feinel at high energies

Abstract Measurements of the inelastic cross sections for hadron-iron nucleus interactions over the hadron energy range of 100–3000 GeV are reported. The cross sections were obtained from the observed attenuation of unaccompanied cosmic ray hadron beams inside an iron calorimeter containing wide-gap spark chambers. A transition radiation detector was used to measure directly the pion content of the hadron beam. The hadron-iron inelastic cross section is seen to increase by (12 ± 4)% over the energy interval 150 GeV to 1250 GeV. Using a value of 1.26 for the ratio σp-Fe/σπ-Fe derived from Glauber theory we deduce that the pion-iron inelastic cross section increases by (7.7 ± 3.4)% over this energy interval.

Hadronic cascade curves in iron between 20 and 8000 GeV

Abstract Cascade curves produced by cosmic ray hadrons in an iron calorimeter with depth 960 g cm−2 have been studied in the energy range 100 e −x L(E) , with x in g cm−2, L(E) = (203±21)+(91±8)log10(E/100 GeV)g cm−2 in the range 20 From this study important conclusions can be drawn concerning the use of thin calorimeters.

Neutral to charged ratio for unaccompanied high-energy cosmic-ray hadrons at mountain altitude

The neutral to charged ratio for unaccompanied high-energy cosmic-ray hadrons has been measured at a mountain altitude of 730 g cm-2 with well-defined geometric selection and good statistical precision. The ratio is found to be independent of energy over the energy range of 100 to 3000 GeV and has an average value of 0.37+or-0.02. Using the directly measured pion to proton ratio with transition radiation detectors for hadrons of energy greater than 400 GeV, this result yields a value for the neutron to proton ratio of 0.67+or-0.08, which is significantly different from the value obtained by Pal and Peters (1964) from phenomenological considerations.

The mass and width of the ξ(1530)

Abstract 286 ξ O (1530) and 185 ξ − (1530) events corresponding to production cross sections of 29 μb and 26 μb respectively are analysed for mass, width and electromagnetic mass difference. The distribution of invariant mass errors and important systematic effects are included in the analysis. A width of 11.0 ± 1.8 MeV for the ξ O (1530) and of 16.2 ± 4.6 for ξ − (1530) are obtained. The former is in some disagreement with the presently accepted value of 7.3 ± 1.7 MeV whilst the latter is the only such reported measurement to date, and these new values bring the world average value into closer agreement with the prediction of unbroken SU(3). Corresponding masses are 1532.3 ± 0.7 MeV and 1536.2 ± 1.6 MeV giving a mass difference of ΔM = 3.9 ± 1.8 MeV and lead to a world average value of ΔM of 4.3 ± 1.3 MeV. Some conclusions regarding measurement of resonant widths are made.

Drift-pots for small angle elastic scattering at the fermilab collider

In order to measure the small angle p-p scattering at the Fermilab Tevatron collider we developed very small drift chambers integrated with thin-wall roman pots. We named them drift-pots. The drift-pots are active 100 μm from the vacuum of the beam with an expected resolution of 60 μm in the drift direction and 250 μm in charge division. They are radiation resistant detectors intrinsically insensitive to the beam pickup pulses and their multiple hit readout capability will allow us to push them into the beam halo where p-p Coulomb elastic scattering dominates. For our application, we belive the drift-pots, are superior to state of the art silicon detectors.

A study of albedo from hadronic calorimeter for energies ≈100–2000 GeV☆

Abstract Characteristics of particles emitted backwards from high energy hadrons interacting in a calorimeter are studied. It is shown that there exists a substantial albedo of charged particles, neutrons and photons. The average yield of this albedo increases logarithmically with energy of the hadrons between 100 and 2000 GeV. This study shows that measurements of the charge of the particle or the number of particles, incident on the calorimeter, with detectors juxtaposed with the calorimeter are of limited value.