L.C.L. Yuan

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.

Energy dependence of X-ray transition radiation from ultrarelativistic charged particles

Abstract Measurements have been made on the γ (Lorentz factor) dependence of the transition radiation intensity in the x-ray region caused by positrons with γ ranging from 1000 to 8000. Our results show that the intensity of the X-ray transition is linearly proportional to γ as predicted by theory. Because of such a linear dependence as well as a reasonable intensity available the X-ray transition radiation can be feasibly used for the determination of the γ value of ultrarelativistic particles.

A search for dynamic radiation from crystals

Abstract A search for dynamic radiation from mica, LiF and NaI has been made at electron energies from 2.7 to 11.5 GeV/c. No evidence of dynamic radiation has been found.

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 .

Superheated Superconducting Suspension as Transition Radiation Detector

We describe a new particle detector which utilizes a suspension of superheated superconducting granules. When irradiated with relativistic electrons with energy Ee<2 GeV, the detector shows a linear rise of the signal with particle energy. However, for electrons with energies 2<Ee<6 GeV the signal is shown to increase quadratically with energy. The possibilities of using such a transition radiation detector for particle identification and electron energy measurement are discussed.

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.

Investigations on lithium-drift solid-state detectors for high-energy particle detection

Lithium-drift solid-state detectors with depletion layers of several millimeters were developed. A lithium-drift detector, 1 cm in diameter and 2.3 mm thick, was placed in a momentum-analyzed beam consisting of pions and protons with momenta of 3 and 4 Bev/c. Energy spectra at different bias voltages are shown. Good resolution was obtained operating at room temperature. (A.G.W.)

A counter hodoscope digital data handling and on-line computer system used in high energy scattering experiments☆

Abstract This paper describes a counter hodoscope system with automatic digital data handling and on-line computer developed for and used in a series of high energy scattering experiments at the Brookhaven 33 GeV Alternate Gradient Synchrotron. These new techniques resulted in two orders of magnitude increase in data accumulation rate and the highest systematic accuracy. These techniques are also applicable to a broad class of counter and digitized spark chamber multi-particle production experiments.

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.