SU1220464A1 - Fission fragments spectrometer - Google Patents

Description

one

The invention relates to ion neutron spectrometers and can be used to study fission fragments of heavy nuclei by neutrons, especially when registering rare events under conditions of a significant background of reactor radiation.

The aim of the invention is to improve the resolution of the fission fragment spectrometer by reducing the background load of the fission fragment detector.

The drawing shows a diagram of the spectrometer of fission fragments.

The fission fragment spectrometer contains a source of .1 fission fragments located at one end of the vacuum passage duct 2, made in the form of a cylindrical coaxial section, a capacitor whose internal electrode consists of two separate sections 3 and 4, a negative voltage source 5, the input of which is connected to section 3, two time markers 6 and 7, located successively along the axis of channel 2 in the region of section 3, block 8 for selecting events for speed, pulse generator 9 and fission fragment detector 10 located at the other end of channel 2. The inputs of the markers 6 and 7 are connected to the inputs of the obor block 8, the output of which is connected to the starting input of the generator 9, the output of the generator 9 is connected to section 4 of the internal electrode.

The distance L between the markers and 7 must satisfy the condition

. V. bt L, - -g-,

where V is the speed of the fission fragment; t - time resolution of the system of two markers;

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VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Lrozekna, 4

8 - relative width of the time window.

L from marker 7 to 4 must satisfy

(t

8 + t9) V,

where tg is the response time of selection unit 8;

t is the rise time of the pulse at the output of the generator 9.

The proposed device works as follows.

Negative potential -U,, is supplied to section 3 from source 5, and positive constant potential + U to section 4. from the generator 9 output. Part of the fission fragment ions, captured by the field in the steady motion mode, propagates along channel 2 and causes the signals at the outputs of markers 6 and 7 to appear. If the ion velocity satisfies the selection condition fixed by block 8 selection, the signal from the output of block 8 will cause. the start of the generator 9 and the supply of a negative pulse with amplitude - (U, +. + and) to section 4, which will ensure the passage of the ion and its entry into the detector 10. The fission fragment ions and particles, whose speed does not satisfy the selection condition, will fall into the region of section 4, with a positive potential on the inner electrode, will be deflected by the electric field and scattered on the walls of channel 2 before entering the detector, thus will not cause signal overlaps and radiation damage to the detector, worsening the resolution of the fission fragment spectrometer.

Claims (1)

+ and _d ) to section 4, which will ensure the passage of the ion and its entry into the detector 10. Fission fragment ions and collision particles, whose speed does not satisfy the selection condition, will fall into the region of section 4 with a positive potential on the internal electrode, will be rejected electric field and scattered on the walls of channel 2 before entering the detector, thus will not cause imposition of signals and radiation damage to the detector, worsening ^- resolution of the spectrometer of fission fragments.