I found electrical scheme that describing geiger muller counter. source
All necessary electrical parts described here.
Main mystery for me what should be the nominal voltage of the capacitors С1, C2,C3,...,C7. 100v,400v,1000v?
Parts:
Part Value Device Package Description MF MPN OC_FARNELL OC_NEWARK
C1 32n C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C2 100n C-EUC3216 C3216 CAPACITOR, European symbol
C3 10n C-EU050-025X075 C050-025X075 CAPACITOR, European symbol
C4 100n/630V C-EU102-064X133 C102-064X133 CAPACITOR, European symbol
C5 100n C-EUC3216 C3216 CAPACITOR, European symbol
C6 330u CPOL-USA/3216-18W A/3216-18W POLARIZED CAPACITOR, American symbol
C7 330u CPOL-USA/3216-18W A/3216-18W POLARIZED CAPACITOR, American symbol
D1 1n4007 1N4004 DO41-10 DIODE
D2 BAS40 BAS40 SOT23 Silicon Schottky Diodes
IC1 LM358D LM358D SO08 OP AMP also LM158; LM258; LM2904
IC2 MC34063 DIL8 DIL08 Dual In Line / Socket
L1 680m L-EU0207/5V 0207/5V INDUCTOR, European symbol
LED1 LEDSFH482 SFH482 LED
R1 R22/0.5W R-EU_0207/5V 0207/5V RESISTOR, European symbol
R2 10k R-EU_R1206 R1206 RESISTOR, European symbol
R3 30k+1k R-EU_0207/5V 0207/5V RESISTOR, European symbol
R4 10M R-EU_0207/5V 0207/5V RESISTOR, European symbol
R5 6M8 R-EU_0207/12 0207/12 RESISTOR, European symbol
R6 10k R-EU_0207/5V 0207/5V RESISTOR, European symbol
R7 470R R-EU_0207/5V 0207/5V RESISTOR, European symbol
R8 R-EU_R1206 R1206 RESISTOR, European symbol
R9 1k R-EU_M1206 M1206 RESISTOR, European symbol
R10 1k R-EU_M1206 M1206 RESISTOR, European symbol
R11 1k R-EU_M1206 M1206 RESISTOR, European symbol
R12 510R R-EU_M1206 M1206 RESISTOR, European symbol
R13 R-EU_M1206 M1206 RESISTOR, European symbol
SP1 8R KSS1201 KSS1201 SPEAKER unknown unknown
SV2(GM) MA03-1 MA03-1 PIN HEADER unknown unknown
SV3(OUT) MA03-1 MA03-1 PIN HEADER unknown unknown
SV4(POWER) MA03-1 MA03-1 PIN HEADER unknown unknown
T1 BC807-40-PNP-SOT23-BEC SOT23-BEC PNP Transistror
T2 BC848ALT1SMD SOT23 NPN Transistor
T3 IRF840 BUZ11BV TO220BV N-CHANNEL MOS FET
T6 BC848ALT1SMD SOT23 NPN Transistor
T7 BC848ALT1SMD SOT23 NPN Transistor