Dependence Of Energy Resolution Research Articles

A gas ionization electromagnetic calorimeter filled with C3F8

Abstract The performance of a gas ionization electromagnetic calorimeter with planar electrodes and lead absorbers has been investigated using 10– 40 GeV electron beams of the IHEP accelerator. The results of signal and noise spectra measurements vs. electron energy, high voltage and gas pressure are presented. The energy dependence of energy resolution is compared with Monte Carlo simulations.

An optimum digital signal processing for radiation spectroscopy

When resolution is a primary requirement in high performance spectroscopy systems, the signal pulse filtering should approach the theoretical optimum weighting function. This goal, almost impossible to reach with analog filtering especially when 1 ƒ noise is dominant, is achieved by the presented digital signal processor. It synthesizes the optimum weighting function by exploiting experimentally measured noise. The energy resolution dependence on the experimental settings is reported. Those include the number of samples acquired per pulse, the sampling frequency and the bandwidth of the antialiasing filter. An experimental comparison against the best analog filter shows an improvement of more than 10% in energy resolution.

Response of the BaF 2 scintillator to light charged particles

The response of a large BaF 2 scintillator crystal in terms of analog output and energy resolution dependence on the light charged particles kinetic energy in the 4–150 MeV/u range has been investigated. The occurrence of loss mechanisms in the kinetic energy to light yield conversion is observed. A model calculation, based on the electron-hole recombination to trapping competition and the occurrence of ionization quenching, gives results in very good agreement with the experimental data. The detector energy resolution is found to be consistent with the photoelectron statistics as the main contribution. A procedure for reproducible particle energy calibration, based on the cosmic muon energy deposition in the BaF 2 as reference is established.

Dependence of energy resolution on anode diameter in zenon proportional counters

The characteristics of a conventional cylindrical geometry proportional counter with different anode wire diameters from 12.5 μm to 100 μm were investigated for both pure xenon gas and xenon +5% methane gas mixtures at 1 atm. With pure xenon gas the energy resolution with 12.5 μm to 100 μm anodes were 7.0% and 8.1% for 22 keV X-rays, respectively. From calculations of the Townsend ionization coefficient it is shown that proportional counters with thinner anode wires operate at stronger reduced electric fields than those with thicker anode wires. It is suggested that this is the fundamental reason for the improvement in energy resolution observed as the anode diameter is decreased.

Sub-keV X-ray detection with a low-pressure multistep detector

A large-area low-pressure multistep counter designed for the detection and timing of X-rays with energies below 1 keV is described. The dependence of energy resolution on gas pressure was investigated and found to improve at lower pressures. At 7.6 Torr the FWHM resolution was 58% for 279 eV carbon K X-rays. The time resolution is dependent on the gas composition, pressure and detector thickness. At 200 Torr of ArCH 4 (50%-50%), two thirds of the detected carbon X-rays occur within 12 ns for a detector thickness of 4 mm.

Low energy X-ray and γ spectroscopy using silicon pin photodiodes

An energy resolution of 1.43 keV (FWHM) for the 59.55 keV 241Am γ-ray line at 19°C was obtained by using low-cost silicon PIN photodiodes. The dependence of energy resolution on detector and preamplifier temperature was investigated. At −40°C a FWHM of 1.04 keV was reached. Low energy Mn and Ti K X-ray spectra were also taken, and the 5.9 and 4.5 keV peaks were clearly resolved from the noise. Our measurements show that silicon PIN photodiodes are comparable in performance with the best room temperature silicon detectors which are considerably more expensive.

Experimental results of count rate effect studies in some X-ray proportional counters

The experimental results of the investigations of pulse height and energy resolution dependence on the count rate in proportional counters are presented. The measurements were carried out using a fast system of a current mode amplification coupled with a single channel analyzer and a fast scaler. The investigations covered certain single-anode proportional counters as well as the new so-called multicell types of multianode counters. The counters were not only of cylindrical shape with side-window but also with an end-window and of rectangular cathode cross-section. It was found that the measured changes in pulse height and resolution are strongly dependent on the gas filling, counting geometry, shape and dimensions of the cathode and on the operating potential. In addition to this, it was observed that the multicell counters can operate at count rates one order of magnitude higher, on the average, than the conventional single-anode counters.

Pulse-height resolution of thin scintillator foils

Pulse-height resolution of thin scintillator foils prepared from plastic scintillators NE 111 and NE 102A was experimentally tested. Since the intrinsic energy resolution was not observed it was found that the overall resolution of the detector is due to the properties of the photomultiplier only. From the discussion of the dependence of energy resolution on foil thickness and mean number of photoelectrons released per scintillation it was concluded that this phenomenon can be related to the good optical properties of scintillator foils and their unusual optical coupling to the photomultiplier tube face, but not to the mechanism of light generation.

525. Dependence of energy resolution of proportional counters on the coefficient of gas amplication. (USSR): D A Goganov et al,Prib Tekh Eksper, No 2, March–April 1972, 45–46 ( in Russian)

525. Dependence of energy resolution of proportional counters on the coefficient of gas amplication. (USSR): D A Goganov et al,Prib Tekh Eksper, No 2, March–April 1972, 45–46 ( in Russian)

Detector energy resolution corrections for X-ray spectrum measurements

A method was described for measuring the energy resolution dependence of NaI(Tl), Si(Li) and Ge(Li) X- and gamma -ray spectrometer systems. The method is based upon the observed Gaussian response of the spectrometer systems, when exposed to a monoenergetic photon source. A curve was derived relating the observed energy resolution dependence of the spectrometer systems with photon energy. From the energy resolution dependence curve, the normalized Gaussian was derived that describes the spectrometer system's energy resolution dependence as a function of energy. The normalized Gaussian was used to derive a matrix Gij(E), describing the distortions introduced into the incident X- or gamma -ray spectrum by the energy resolution dependence of the spectrometer system as N'j(E)=Gij(E)Nj(E), where N'j(E) and Nj(E) are the observed and true spectra, respectively. The matrix Gij(E) cannot be inverted in normal fashion to obtain Nj(E) and must be solved by an iterative procedure that avoids direct inversion. A digital computer was used in these calculations. A method was described whereby the effects of spectrometer energy resolution upon an incident spectrum can be calculated. Energy resolution distortions of incident X-ray spectra were compared for NaI(Tl), Si(Li) and Ge(Li) detectors.