- 47 Views
- Uploaded on
- Presentation posted in: General

Preliminary Results of (n,f) Measurements at CERN n_TOF with FIC0 and FIC1 Detectors

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Preliminary Results of (n,f) Measurements at CERN n_TOF with FIC0 and FIC1 Detectors

P.Cennini1,

A.Goverdovski2,

W.Furman3,

V.Ketlerov2,1,

V.Konovalov3,1,

V.Vlachoudis1

1CERN, 2IPPE, 3JINR

and n_TOF Collaboration

A.Doroshenko2

S.Girod1

D.Kolokolov2

V.Mitrofanov2

B.Samylin2

M.Sedysheva3

1CERN, 2IPPE, 3JINR

n_TOF Collaboration scientific program

Nuclear data for ADS:

fission cross-section measurements

Fundamental nuclear physics:

study of vibrational fission resonances

- Gas – Ar 90%+CF4 10%
- Pressure – 600 mbar
- Distance – 5 mm
- HV – 300 V
- 17 targets in the beam
- “noise” electrode
- 2 targets out of the beam

For single channel i of given isotope X

TDC data

Flash ADC data

If there is some impurity nucleus Y

Flash ADC data

Kiis obtained from MC simulation

is calculated with accounting for dead time and

from an analysis of pulse-height histogram

is really measured (see below for more detail)

From reference 235U channel one can extract F(E(t))

So it is possible to extract fission cross-section

from counting rate of each (X,i) channel

Definitions:

m5 , m6 – masses of 235U and 236U targets

- content of 235U in 236U target

5, 6 – fission cross-sections

5, 6– registration efficiencies of FF

(6 is valid for FF from 235U admixture to 236U target!)

n5, n6 – count rates

- Master equation

U-235, 0.047%

----FIC0----

235U- 47mg (3 targets)

238U- 110mg (3 targets)

232Th- 80mg (2 targets)

236U- 20mg (2 targets)

237Np- 10mg (1 target)

234U- 34mg (6 targets)

----FIC1----

235U- 30mg (1 targets)

238U- 90mg (2 targets)

241Am- 2mg (4 targets)

243Am- 10mg (4 targets)

245Cm- 2mg (2 target)

233U- 20mg (2 targets)

Backing - 100 microns aluminum foil

Substance is painted on both sides

Spot diameter is 80mm

Thickness from 5mkg/cm2 to 450mkg/cm2

Number of painted layers 100-200

Uniformity is 5% - 10%

For mass, impurities, uniformity with

Ionization chamber with Frisch grid

For low radioactive targets

232Th, 238U, 235U, 237Np, 236U

Si detector

For high radioactive targets

233U, 245Cm, 243Am, 241Am

S = 1 cm2

(2.6%)

Even impurity of 10e-5 – 10e-4

which is impossible to determine by a-analysis

is essential for neutron induced fission experiments

1e-5 of 235U

238U

236U

4e-4 of 235U

235U

234U, 236U

237Np, 245Cm

present

ENDF pointwise

Flash ADC raw data analysis with neural network

TDC and FADC data comparison and adjustment

T-E calibration for En>0.5MeV

Completion of full MC simulation

Neutron flux determination

Extraction of neutron induced fission cross-sections

Good luck!