G.F. Dell

Detection of x-ray transition radiation with multiwire proportional chambers

Abstract The X-ray component of the transition radiation generated by the traversal of high energy electrons through various radiators has been studied with multiwire proportional chambers in the electron beam of the Cornell 10 GeV Synchrotron. Radiators used include stacks of thin aluminium foils, stacks of thin sheets of Mylar and blocks of styrofoam. A chamber-radiator sandwich configuration (primarily to optimize the capture of low energy transition X-rays) is used. Results on the spectrum of the detected X-ray transition radiation in the presence of electron ionization are presented. The design of a detector for detection and identification of ultrarelativistic charged particles is discussed.

Single direct photon production in pp collisions at √s = 53.2 GeV in the pt interval 2.3 to 5.7 GeV/c

Abstract We report the results of an experiment made at the CERN ISR to investigate the possible diret production of single photons in pp collisions at √ s = 53.2 GeV at 90° and in the p t interval 2.3 to 5.7 GeV/ c . The value of the ratio R = n γ / n π 0 is compatible with zero for low p t ⪅ 3 GeV/ c but, in spite of the large error, shows a trend to increase for larger p t .

Transition radiation detector for relativistic particles at accelerator energies

Abstract Transition radiation (TR) has been investigated by using the arithmetic mean and the geometric mean of the pulses from 10 multiwire proportional chambers. The discrimination factor for different kinds of particles has been determined. Also the dependence of the intensity of TR on the Lorentz factor γ has been measured and compared with theoretical calculations.

Search for single photon direct production in p + p collisions at s=53.2 GeV

Abstract From measurements at the ISR of CERN with a lead glass counter matrix we establish an upper limit of 6% (at 95% C.L.) for the ratio of the directly produced photons to the produced π0 at 90° and s = 53.2 GeV in the p ∗ T region 2.3–3.7 GeV/c.

Transition radiation from lithium foils

Abstract The yield of transition radiation is expected to be higher for a low- Z material because of low absorption. Yields of transition radiation from lithium foils have been measured using multiwire proportional chambers and using a thin NaI counter in a beam of electrons and pions from 0.5 to 3.5 GeV/ c . The transition radiator consisted of 1000 foils of 2 mil lithium spaced at 20 mils. Results from a lithium radiator are compared with those of Mylar-foil radiators, and the advantages of lithium radiators in applications are discussed.

COMPARISON OF DIRECT PHOTON PRODUCTION IN P P COLLISIONS AT S**(1/2) = 30.6-GEV AND 53.2-GEV

Abstract We present data obtained at the ISR, on the determination of the ratio R = γ π 0 at s = 30.6 GeV and we compare the results with our previous measurement at s = 53.2 GeV. The ratio R = γ π 0 integrated over the interval 0.1 ⩽ χ T ⩽ 0.2 is (1.6 ± 0.5) × 10 −2 and we obtain an indication of a universal χ T dependence.

Comparison of direct photon production in pp collisions at s= 30.6 GeV and 53.2 GeV

Abstract We present data obtained at the ISR, on the determination of the ratio R = γ π 0 at s = 30.6 GeV and we compare the results with our previous measurement at s = 53.2 GeV. The ratio R = γ π 0 integrated over the interval 0.1 ⩽ χ T ⩽ 0.2 is (1.6 ± 0.5) × 10 −2 and we obtain an indication of a universal χ T dependence.

Observation of transition radiation from pions at 100–250 GeV

Abstract We report on the observation of transition radiation from pions at 100–250 GeV using a transition radiation detector (TRD). The detector consisted of multiwire proportional chambers and foil radiators. The observed spectra and efficiencies for separating pions from protons in this energy region are presented.

RELATIVISTIC PARTICLE SEPARATION BY MEANS OF TRANSITION RADIATION UTILIZING MULTIWIRE PROPORTIONAL CHAMBERS.

Abstract Investigations have been made on a transition radiation detection system consisting of a series of radiator-wire proportional chamber sandwiches and its feasibility for particle separation. A method for eliminating the “Landau” tail in the ionization distribution of a charged particle is described.

Multigamma-ray events at the CERN ISR

Abstract Results of a search for multigamma-ray events at √s = 52 GeV in pp collision are reported. The results are compared with a Monte Carlo simulation of the decay of pairs of heavy mass particles by gamma-ray emission, and upper limits for the production cross section are determined.