| 1. |
- Al-Adili, Ali, et al.
(author)
-
Comparison of digital and analogue data acquisition systems for nuclear spectroscopy
- 2010
-
In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 624:3, s. 684-690
-
Journal article (peer-reviewed)abstract
- In the present investigation the performance of digital data acquisition (DA) and analogue data acquisition (AA) systems are compared in neutron-induced fission experiments. The DA results are practically identical to the AA results in terms of angular-, energy- and mass-resolution, and both compare very well with literature data. However, major advantages were found with the digital techniques. DA allows for a very efficient αparticle pile-up correction. This is important when considering the accurate measurement of fission-fragment characteristics of highly αactive actinide isotopes relevant for the safe operation of Generation IV reactors and the successful reduction of long-lived radioactive nuclear waste. In case of a strong αemitter, when applying the αparticle pile-up correction, the peak-to-valley ratio of the energy distribution was significantly improved. In addition, DA offers a very flexible expanded off-line analysis and reduces the number of electronic modules drastically, leading to an increased stability against electronic drifts when long measurement times are required.
|
|
| 2. |
- Al-Adili, Ali, et al.
(author)
-
On the Frisch–Grid signal in ionization chambers
- 2012
-
In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 671, s. 103-107
-
Journal article (peer-reviewed)abstract
- A recent theoretical approach concerning the grid-inefficiency (GI) problem in Twin Frisch–Grid Ionization Chambers was validated experimentally. The experimental verification focused on the induced signal on the anode plate. In this work the investigation was extended by studying the grid signal. The aim was to verify the grid-signal dependency on the grid inefficiency σ. The measurements were made with fission fragments from 252Cf(sf), using two different grids, with 1 and 2 mm wire distances, leading to the GI values: σ=0.031 and σ=0.083, respectively. The theoretical grid signal was confirmed because the detected grid pulse-height distribution was smaller for the larger σ. By applying the additive GI correction approach, the two grid pulse heights were consistent. In the second part of the work, the corrected grid signal was used to deduce emission angles of the fission fragments. It is inconvenient to treat the grid signal by means of conventional analogue electronics, because of its bipolarity. Therefore, the anode and grid signals were summed to create a unipolar, angle-dependent pulse height. Until now the so-called summing method has been the well-established approach to deduce the angle from the grid signal. However, this operation relies strongly on an accurate and stable calibration between the two summed signals. By application of digital-signal processing, the grid signal's bipolarity is no longer an issue. Hence one can bypass the intermediate summation step of the two different pre-amplifier signals, which leads to higher stability. In this work the grid approach was compared to the summing method in three cases: 252Cf(sf), 235U(n,f) and 234U(n,f). By using the grid directly, the angular resolution was found equally good in the first case but gave 7% and 20% improvements, respectively, in the latter cases.
|
|
