Plastic Scintillating Fibers Research Articles

Response to electrons and pions of the calorimeter for the CHORUS experiment

We built and tested on charged particle beams the high energy-resolution calorimeter for the CHORUS experiment, which searches for ν μ - ν τ oscillations in the CERN Wide Band Neutrino Beam. This calorimeter is longitudinally divided into three sectors: one electromagnetic and two hadronic. The first two upstream sectors are made of lead and plastic scintillating fibers in the volume ratio of 4 1 , and they represent the first large scale application of this technique for combined electromagnetic and hadronic calorimetry. The third sector is made of a sandwich of lead plates and scintillator strips and complements the measurement of the hadronic energy flow. In this paper, we briefly describe the calorimeter design and we show results on its response to electrons and pions, obtained from tests performed at the CERN SPS and PS. An energy resolution of σ(E)/E=(32.3±2.4)%/ E(GeV) + (1.4±0.7)% was achieved for pions, and σ(E)/E=(13.8±0.9)%/ E(GeV) + (−0.2±0.4)% for electrons.

Neutron radiation distribution sensor using flexible plastic scintillating fiber combined with the time-of-flight technique

As a promising neutron radiation distribution sensor, a long fiber system has been made using two silica fibers connected to both ends of the plastic scintillating fiber (PSF). Its basic properties were investigated to detect the position of neutron incidence with the time-of-flight (TOF) method. From the experimental results for the fission neutron source, the two linear relations were confirmed (1) between the incident position of the neutrons and the time difference and (2) between the neutron flux level and the counting rate. The spatial resolution and the counting efficiency of this system were about 60 cm (FWHM) and about 1.0/spl times/10/sup -4/ [counts/incident neutron] respectively using 1 mm diameter fiber of 100 m length. A neutron dose distribution measured by this system was compared with the mapping result using a conventional neutron Sievert(Sv) counter. After some correction for the spatial resolution by an unfolding method, both results showed good agreement.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The CHORUS calorimeter: test results

In the framework of the CHORUS experiment for the search of vμ ↔ vτ oscillations at CERN, we have built the high resolution calorimeter, intended for the measurement of the energy of hadronic showers produced in neutrino interactions. The calorimeter consists of three parts. The first two are made of lead and plastic scintillating fibers in the volume ratio 4 : 1, such as to achieve compensation. The third is a sandwich of lead plates and scintillator strips in the same volume ratio. The techniques used for the construction of the calorimeter are described, as well as its performance in shower and muon detection. We used electron, pion and muon beams in the energy range 2–100 GeV for this purpose.

Folate receptor imaging with 125I labeled folic acid with a whole body small animal imaging device built with plastic scintillating optical fibers

A small animal whole body imaging cylindrical device was built with plastic scintillating fibers and position sensitive photomultipliers (Hamamatsu) and digitized using flash ADCs. A co-axial brass mesh collimator (septum thickness 1 mm) was used in combination with an electronic collimation scheme to enhance spatial resolution. Imaging studies with 125I labeled folic acid were performed in mice bearing folate receptor +ve (IGROV) tumor and receptor −ve (Meth-A) tumor. In-situ imaging of animals sacrificed at 15–30 min post injection of the tracer showed the localization of the tumor in animals with the folate receptor +ve tumors. Our initial studies demonstrate the utility of a device built with plastic scintillating fibers in small animal imaging studies with low energy photons (25–35 keV).

Some emission characteristics of scintillating fibers for low energy X and /spl gamma/-rays

The characteristics of plastic scintillating fibers (PSF) are measured for X and /spl gamma/ photons in the energy range 5 keV to 1.5 MeV. It is shown that a very thin (50 /spl mu/m) slit can be recorded with an array of very thin fibers having 50 /spl mu/m diameter so that the main interaction mechanism is photoelectric absorption, instead of Compton scattering for low energy X-rays. The optical light attenuation, global efficiency and energy resolution have been measured for a system composed of 1 mm diameter fibers and a photomultiplier. An X-ray beam position detector is realized, using an intensified camera, allowing a 4% precision on the position. The effect of bending the fiber is also evaluated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The feasibility of using plastic scintillation fibers for fast neutron spectrometry

The response functions of a plastic scintillation fiber for a fast neutron beam have been studied in detail using Monte Carlo technique. The study shows that a bundle of plastic scintillation fibers can be used as a simple and high efficiency fast neutron spectrometer when high energy resolution is not required. The efficiency and resolution, for 14 MeV incident neutrons, of a bundle of 100 square fibers at thickness of 0.25 mm are estimated at (4.2±0.2)×10 −5 cm 2 and (8.7±0.1)%, respectively, for extra mural absorber (EMA) coated fiber (4.7% for a fiber without EMA).

Radiation position-sensitive detector based on plastic scintillating fibers

The applicability of plastic scintillation fibers as a radiation position detector is evaluated for low-energy x-ray irradiation. A continuous x-ray generator with a copper anode is used as a source radiating very intense lines: Kα2=8.02 keV, Kα1=8.04 keV, Kβ1=8.9 keV. A microchannel intensified tube followed by a vidicon camera is used as the photodetector for scintillation light guided to both extremities of a fiber detector. A one-dimensional position-sensitive radiation detector is constructed as an application. The irradiation position is derived independently of the system operating conditions (gain, sensitivity, efficiency) with a relative error smaller than 4%. Using this device, the optical attenuation length is measured with a relative error less than 10%. The differences in the photon distribution at fiber terminating faces are discussed for light and for x-ray excitations with respect to their incidence angles.

Preliminary results from a low dose rate irradiation of selected plastic scintillating fibers

A series of high dose rate (20 kGy/hr) and low dose rate (<10 Gy/hr) irradiation of a large sample of plastic scintillating fibers (1 mm φ, 150 cm length) has been completed. Measurements of the transmission characteristics of the fibers have been completed and the results are presented in this report. The transmission measurements show striking features: (1) those fibers irradiated slowly in air (i.e., in the presence of oxygen) suffer the greatest level of damage, while (2) the fibers irradiated rapidly, and then allowed to recover, display the least amount of damage, and (3) fibers irradiated slowly in argon display a level of damage intermediate between the other two. One fiber, the green-emitting SCSF-Y8, is the only exception, and shows no difference in the level of damage observed in the three modes of irradiation.

Preliminary results from a low dose rate irradiation of selected plastic scintillating fibers

A series of high dose rate (20 kGy/hr) and low dose rate (<10 Gy/hr) irradiations of a large sample of plastic scintillating fibers (1 mm ø, 150 cm length) has been completed. Measurement of the transmission characteristics of the fibers have been completed and the results are presented in this report. Measurements of the loss to intrinsic scintillation output will be completed at a later date. The transmission measurements show striking features: (1) those fibers irradiated slowly in air (i.e., in the presence of oxygen) suffer the greatest level of damage, while (2) the fibers irradiated rapidly, and then allowed to recover, display the least amount of damage, and (3) fibers irradiated slowly in argon display a level of damage intermediate between the other two. One fiber, the green-emitting SCSF-Y8, is the only exception, and shows no difference in the level of damage observed in the three modes of irradiation.

L3 central tracking system

The L3 central tracking system at LEP consists of a high resolution drift chamber (time expansion chamber) and two outer layers of cylindrical proportional chambers (Z-chamber) with a single layer of plastic scintillation fibers in between for calibration purpose. A short description of the system is presented.

Results of a low dose rate irradiation of selected plastic scintillating fibers

A series of high-dose-rate and low-dose-rate irradiations of a large sample of plastic scintillating fibers has been completed. Measurement results of the transmission characteristics of the fibers are presented. The transmission measurements showed striking features: (1) those fibers irradiated slowly in air suffered the greatest level of damage, (2) the fibers irradiated rapidly, and then allowed to recover, displayed the least amount of damage, and (3) fibers irradiated slowly in argon displayed a level of damage intermediate between the other two. One fiber, the green-emitting SCSF-Y8, was the only exception, and showed no difference in the level of damage observed in the three modes of irradiation. >

New radiation detector of plastic scintillation fiber

Fundamental characteristics of a new plastic scintillation fiber (PSF) has been studied for four kinds of radiations, and the possibility of using the PSF as a radiation detector has been discussed. Irradiation experiments of scintillation output characteristics have been made for γ rays, x rays, fast neutrons, and α particles. Various scintillation pulse height spectra have been obtained, depending on the variations of radiation types, energies, intensities, and scintillating positions on the PSF. Position detection experiments have been also made for γ rays and fast neutrons, and a new position sensitive detector of the PSF has been proposed.

Scintillating optical fiber trajectory detectors

Measurements of attenuation in several types of plastic scintillating optical fibers give attenuation lengths varying from 0.8 to 1.5 m. By comparing attenuation as a function of wavelength in fibers of different thicknesses we infer the contributions to the attenuation from reflection losses and bulk scintillation losses. We find good agreement between these values and calculated estimates of attenuation in scintillator. We have also calculated the effective scintillation efficiency of small fibers relative to that of bulk scintillator (for scintillator with dimethyl POPOP as the waveshifting dye) for the two cases of optically coupled and decoupled fibers. Scintillating fiber ribbons made of 200 μm square cross section fibers were exposed to relativistic iron nuclei at the LBL Bevalac, and positional resolution of 70 μm was obtained. Relativistic neon and carbon were also detected in these ribbons. In a similar exposure of 100 μm fibers to 50 MeV/n nitrogen nuclei at the NSCL cyclotron, Michigan State University, a positional resolution of about 50 μm was obtained.

A simple method for measuring the performance of plastic scintillating materials

The authors propose a method to measure the relative efficiency of scintillating materials based on the fabrication of thin films (10 to 100 mu m) with at least one of the faces roughened. Excitation with a monochromatic beam of ultraviolet light then permits a thorough study of the energy transfer in plastic scintillators and their spectral emission and a comparison of their intrinsic scintillation intensity. The results obtained are reproducible and in satisfactory agreement with direct measurements with alpha radiation. It is shown that the standard ternary scintillator PS+1%butylPBD+dimethylPOPOP cannot be used for the core of a plastic scintillating fiber (PSF) with a diameter smaller then 0.4 mm. Instead, a binary solution, PS+0.6%PBBO, has been studied which makes it possible to consider the production of PSF with a diameter less than 50 mu m, with acceptable crosstalk and good efficiency. >

Development of plastic scintillation fiber

We developed a plastic scintillation fiber (PSF) with a light-attenuation length as long as 2.8 m which was applied for a calorimeter. The performance of a calorimeter made of PSF and lead with a new method of fabrication is presented.

Plastic scintillating fibers for track detection

A particle track detector consisting of plastic scintillating fibers and a gatable image intensifier system has been developed and tested with pion, proton and deuteron beams of 1 GeV/ c. We have observed clear tracks of beams and scattered particles at a beam rate of up to 10 5 particles per second. Tracks have been recorded by using a CCD video camera at a trigger rate of around 30 Hz. The energy and spatial resolutions have been investigated.

Some Considerations on Luminescent Fiber Chambers and Intensifier Screens

Factors affecting the performance of filamentary scintillators are considered. Experimental data on light attenuation for both plastic scintillator filaments and thin-wall glass tubing liquid scintillators are presented. A theoretical interpretation which satisfactorily accounts for the performance of luminescent filaments in terms of bulk properties and surface reflection losses is given and permits quantitative evaluation of surface losses for various materials. While plastic scintillator fibers are mechanically convenient, it is suggested that liquid-filled fibers will prove more consistent and stable in their properties. Comments on the utility of arrays of fibers as particle track imaging devices and as image intensifier screens are included.

Thin Fiber Scintillation Counter for Determining Particle Beam Distributions in Accelerators

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