mercoledì 22 luglio 2009

NTPD LINUX

Come sincronizzare il demone ntpd su Linux (REDHAT) ....

http://www.brennan.id.au/09-Network_Time_Protocol.html

mercoledì 15 luglio 2009

SPIREA OLMARIA - ASPIRINA NATURALE

Si fà l'alcolatura con ALCOL a 90%, altrimenti l'estrazione del principio attivo non avviene.
20 grammi di fiori secchi, ogni 100 grammi di alcol.

Da prendere 20 gocce alla volta, come aspirina.

lunedì 6 luglio 2009

ERRORE % dovuto alla lunghezza del segnale nei contatori geiger

considerando un periodo di 1 sec.

num=100 = numero di impulsi contati nel periodo
dur = 1/1000 (durata di ogni impulso)

l'errore % in difetto sulla lettura sarà:

perc=100*exp(-dur*num/2)

ad esempio x
num=100
e dur =1/100

vale =63 %

per num =100
e dur = 1/1000

vale = 95 %



vedi seguente codice:

list
3 NUM=1000:DUR=1/10000
5 DIM A(NUM):DIM B(1/DUR)
10 RANDOMIZE TIMER
15 FOR Z=1 TO 100
20 FOR I=1 TO NUM
30 A(I)=RND
40 NEXT I
200 FOR I=1 TO NUM
210 B(INT(A(I)*1/DUR))=B(INT(A(I)*1/DUR))+1
220 NEXT I
300 FOR I=0 TO 1/DUR-1
320 X=X+B(I):IF B(I)>0 THEN Y=Y+1
325 B(I)=0
330 NEXT I
340 YAVG=YAVG+Y:Y=0:X=0
350 NEXT Z
360 YAVG=YAVG/100
370 PRINT YAVG/NUM
400 REM PRINT 1/LOG(YAVG/NUM)/2
420 PRINT EXP(-DUR*NUM/2)
Ok

PANCAKE GEIGER TUBE RUSSO N.2









This pancake geiger tube has been made in Russia. It is from old stock but brand new in box. It is unused and checked with source.

The counter is designed to be operated in various dosimetric and radiometric devices.

Besides beta-particles, the counter can register alpha-particles and gamma radiation. To register alpha-and beta-particles the counter #2 is provided with a thin mica window.

The other design peculiarity is a minimal possible cathode surface (in comparison with cylindrical end-window beta-counters) that allows registering alpha-and beta-radiation.

The counter is produced in a baseless modification.

MAIN DATA:

Work. Voltage, V 400
Plateau Length/Inclination, V / %/V 200 / 0.25
Own Background, Pulses/s 1
Sensitiv. to Gamma Radiation 60Co or 137Cs, not less, Pulses/?R 160
Sensitiv. to Gamma Radiation 60Co or 137Cs, not more, Pulses/?R 240
Efficiency to Beta-Radiation 90Sr-90Y, not less, % 60
Efficiency to Beta-Radiation 204Tl, not less, % 45
Efficiency to Alpha-Radiation 239Pu,not less, % 20
Window Area, cm2 13.8-15.2
Mica Thickness, ?m 10-14
Operating temprerature range, 0C +60...-50
Service Life , Pulses

1x1010

Weight, gram 27.5