بسم الله الرحمن الرحيم قـــــل إن صلاتــى ونكسى ومحيـــــاى وممـاتـى لله رب العالميـــن $لا شريك له و بذلك أمـــرت وأنـا أول المسلميـــن $ سورة الأنعام (الآية 163،162)

B.Sc. Physics, Zagazig University, 1999 Study of physical properties of polymeric NTD’s using α-particles with medium energy By Saad Ahmed Abd-Elaal B.Sc. Physics, Zagazig University, 1999 Under the Supervision Prof. Dr Ahmed Elfalaky El-sayed Abd El-Rehiem Physics department, Faculty of Science Zagazig University Prof. Dr Abd El-Fatah Abd ElHaliem Mahmoud Nuclear Physics Department, Nuclear Research Centre, Atomic Energy Authority Ass. Prof. Dr. Usama Seddik Abd El-ghafar Nuclear Physics Department, Nuclear Research Centre, Atomic Energy Authority

دراسة الخواص الفيزيائية لبعض كواشف الأثر النووى بجسيمات ألفا ذات الطاقة المتوسطة رسالة مقدمة من سعد أحمد عبد العال للحصول على درجة الماجستير فى الفيزياء قسم الفيزياء كلية العلوم – جامعة الزقازيق 2006

2- Volume and areal track for present detectors 58 cm 20 cm 2.5 cm Am-BeSources CR-39 sample Borated paraffin 7 cm Experimental set-up of the Am-Be neutron sources assembly.

The ATD for the front surface of the TASTRAK type versus the etching time.

The ATD for the front surface of the INTERCAST type versus the etching time.

For etching times less than 10 hours the volume track density (Dm) in gm-1 could be deduced from the slope of the linear part n/cm2. hr, the bulk etching rate (VB) where: VB = 0.791×10-4µm/hr and the density (ρ) of CR-39 (ρ =1.32 g/cm3) the following equation is used two calculate Dm values

ATD versus etching time for TASTACK

ATD versus etching time for INTERCAST

Dm (gm-1) x 109 Exposure time TASTRAK INTERCAST The volume track density is defined as the etchable track density in unit mass of CR-39 detector. Volume track density Dm of both CR-39 types at two different exposure time. Dm (gm-1) x 109   288 (hr) 96 (hr) Exposure time 1.719 0. 513 TASTRAK 1. 693 0. 507 INTERCAST

The image of registered tracks using TASTRAK type that was exposed to neutrons passing through (Al) for a time period of 96 hours. The sample is etched for a time period of 4 hours in 6.25 N NaOH at 70ºC

Note: We note that for an etching time longer than 10 hours, the ATD values reach asymptotic values (Ds) for both types of CR-39 detectors.

Asymptotic areal track density (Ds) of both CR-39 types at two different exposures times. Ds (cm-2) x 10 5   288 (hrs) 96 (hrs) Exposure time 21.04 6.16 TASTRAK 21.00 6.14 INTERCAST The table demonstrates the good agreement for the same irradiation times and they are consistent for different irradiation times. It also shows that both types of CR-39 have nearly the same sensitivity.

The Mask 0.05 mm 0.15 mm a 0.05 mm 0.15 mm 0.15 mm b The two types of stainless steel used masks: (a) Hole matrix 2x4. (b) Hole matrix 3x3.

The Timer Unit

LIECA Q500/IW IMAGE ANALYSER

The Gaussian fit of the α-energy spectrum at a gap shift of 1 The Gaussian fit of the α-energy spectrum at a gap shift of 1.5 mm for the FLGwith a diameter of 2.2mm

The relation of the distance between two neighbors vs The relation of the distance between two neighbors vs. number of count for 9 holes mask

The relation of the distance between two neighbors vs The relation of the distance between two neighbors vs. number of count for 8 holes mask

Live photo of the 3X3 image matrix on CR-39 which exposed to alpha-particles for 3 minutes at energy 5.48 MeV

The total area of the 2x4 image matrix as a function of the incident alpha-particles energy for exposure time 3, 4 and 5 minuets.

The total area of the 3x3 image matrix as a function of the incident alpha-particles energy for exposure time 3, 4 and 5 minuets.

1-The two techniques were applied to compare the sensitivities of TASTRAK and INTERCAST types of CR-39 detectors. According to the present measurements we conclude that both detectors have nearly the same sensitivity to detect neutrons. It can be inferred that the two types of CR-39 detectors have nearly equal sensitivities for detecting heavy charged particles since the tracks are produced from recoil nuclei C, H, O and other heavy charged particle reaction products. The present data show that the used techniques could also be used to compare and calibrate the sensitivities for other track detectors of different types.

2- The proposition regarding the use of masked detectors with a matrix of narrow holes for alpha-particles energy spectrometry is experimentally verified. It is found that the total area AT(μm2) of the image matrix on CR-39 detector can be used as a measure of alpha-particle energy, provided that the track density of alpha-particles is high. On the other hand, this technique is expected to fail to account the cases of extremely low ion intensity. It is not necessary to etch the detector for a long etching time where a relatively short time is enough to determine the location of the track. Measurements of AT factor, for a wider energy range of the incident charged particles, is needed using accelerated ions to improve this technique, where it is likely to be a suitable technique to detect the energy of plasma-ion streams.

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