Ahmed S.N. Physics and Engineering of Radiation Detection

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746 Appendix-A A. Essential Electronic Measuring Devices

A typical passive probe is shown in Fig.A.2.3. This is the so called high impedance

compensated probe. Due to its high dynamic range, it can be used in a variety of

circuits. In fact, due to its versatility, most oscilloscope manufactures include this

in the standard oscilloscope package. The most problematic thing about this probe

is its very low bandwidth, which does not allow it to be used for highly sensitive

measurements. As shown in Fig.A.2.3, this probe has a variable capacitor. This

allows the user to match the capacitance to the input capacitance of the oscilloscope.

The compensation unit of the probe is provided in the termination box, which is

usually at the other end of the probe, that is, at the oscilloscope side. The input

impedance of the probe is very high, on the order of a few mega ohms. However

probes having input impedances of about 1 MΩ are also not uncommon. For typical

probes the input resistance is chosen such that the probe provides a 10:1 attenuation.

Probes with other attenuation factors are also available.

Cable

Tip

To Scop

Termination Box

Figure A.2.3: A shigh impedance compensative passive probe.

The probe shown in Fig.A.2.3 does not have high bandwidth. This shortcoming

does not allow it to be used in highly sensitive measurements, specially when the

signal has a high or wide bandwidth. A much simpler probe, as the one shown

in Fig.A.2.4 can solve this problem. Such a probe consists of a resistor in series

with a 50 Ω signal carrying cable. Typically the value of the resistor is chosen such

that it ensures a signal attenuation of 10:1. However higher attenuation probes

are also available. This kind of probe is good for probing low level voltage signals

specially when timing information is important. Such probes oﬀer excellent time

measurements due to their very wide bandwidths.

Cable (50 )

Resistor (usually < 1k )

Ω

Tip

cop

Ω

Figure A.2.4: A simple low impedance passive divider probe.

The two probes we just discussed are not the only passive probes available in the

market. There is a variety of probes available and the user should carefully chose

one according to the requirements.

C.2 Active Probes

A simple active probe is shown in Fig.A.2.5. As the name suggests this probe has an

active electronic component, which is usually an operational ampliﬁer. Such a probe

oﬀers excellent resistive and capacitive loading together with wide bandwidth. The

A.2. Oscilloscope 747

dynamic range of such a probe is usually limited by the speciﬁcations of its active

circuitry, which for typical probes is fairly low.

Tip

To Scop

Cable (50 )

Ω

Figure A.2.5: A simple passive probe.

All of the probes we have visited so far measure signals with ground as reference.

If we wanted to measure a signal that has some other reference point, we can not

use such probes. In such a situation we need the so called diﬀerential probe.A

diﬀerential probe has two tips to probe the two points on the circuit. A simple

active diﬀerential probe is shown in Fig.A.2.6.

Cable (50 )

Ω

−

Tip

To Scop

Figure A.2.6: A simple diﬀerential probe.

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749

Appendix B

Constants and Conversion Factors

B.1 Constants

Constant Symbol Value Units

Atomic mass constant m

1.660 × 10

−27

Atomic mass constant (energy equivalent) m

1.492 × 10

−10

931.49 MeV

Avogadro’s number N

6.022 × 10

mole

−1

Boltzmann’s constant k

1.380 × 10

−23

−1

8.617 × 10

−5

eV K

−1

Elementary charge e 1.602 × 10

−19

Plank’s constant h 6.626 × 10

−34

4.135 × 10

−15

eV s

Speed of light in vacuum c 2.99 × 10

−1

Thomson cross section σ

6.652 × 10

−29

750 Appendix-B B. Constants and Conversion Factors

B.2 MassesandElectricalChargesofParticles

Particle Symbol Charge (multiples of e) Mass

alpha α,

+2 6.644 ×10

−27

3727.379 MeV

deuteron d,

+1 3.343 ×10

−27

1875.612 MeV

electron, beta e, β -1 9.109 × 10

−31

0.511 MeV

neutron n 0 1.675 × 10

−27

939.565 MeV

positron e

, β

+1 9.109 ×10

−31

0.511 MeV

proton p,

+1 1.672 ×10

−27

938.171 MeV

B.3. Conversion Preﬁxes 751

B.3 Conversion Preﬁxes

Preﬁx Symbol Factor

peta P 10

tera T 10

giga G 10

mega M 10

kilo k 10

hecto h 10

deka da 10

deci d 10

−1

centi c 10

−2

milli m 10

−3

micro µ 10

−6

nano n 10

−9

pico p 10

−12

femto f 10

−15

atto a 10

−18

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753

Appendix C

VME Connector Pin Assignments

Table C.0.1: Pin assignments of standard VME32 P1 and P2 connectors. UD stands

for user deﬁned. The asterisk (*) speciﬁes the opposite state of the logic: high is 0

and low is 1.

P1 P2

Pin Row-A Row-B Row-C Row-A Row-B Row-C

1 D00 BBSY* D08 UD +5 V UD

2 D01 BCLR* D09 UD GND UD

3 D02 ACFAIL* D10 UD RETRY UD

4 D03 BG0IN* D11 UD A24 UD

5 D04 BG0OUT* D12 UD A25 UD

6 D05 BG1IN* D13 UD A26 UD

7 D06 BG1OUT* D14 UD A27 UD

8 D07 BG2IN* D15 UD A28 UD

9 GND BG2OUT* GND UD A29 UD

10 SYSCLK BG3IN* SYSFAIL* UD A30 UD

11 GND BG3OUT* BERR* UD A31 UD

12 DS1* BR0* SYSRESET* UD GND UD

13 DS0* BR1* LWO R D* UD +5 V UD

14 WRITE* BR2* AM5 UD D16 UD

15 GND BR3* A23 UD D17 UD

16 DTACK* AM0 A22 UD D18 UD

17 GND AM1 A21 UD D19 UD

18 AS* AM2 A20 UD D20 UD

19 GND AM3 A19 UD D21 UD

20 IACK* GND A18 UD D22 UD

21 IACKIN* SERCLK A17 UD D23 UD

22 IACKOUT* SERDAT* A16 UD GND UD

23 AM4 GND A15 UD D24 UD

24 A07 IRQ7* A14 UD D25 UD

25 A06 IRQ6* A13 UD D26 UD

26 A05 IRQ5* A12 UD D27 UD

27 A04 IRQ4* A11 UD D28 UD

28 A03 IRQ3* A10 UD D29 UD

29 A02 IRQ2* A09 UD D30 UD

30 A01 IRQ1* A08 UD D31 UD

31 -12 V +5 V SB +12 V UD GND UD

32 +5 V +5 V +5 V UD +5 V UD

754 Appendix-C C. VME Connector Pin Assignments

Table C.0.2: Pin assignments of standard VME64x P1 connector. The asterisk (*)

speciﬁes the opposite state of the logic: high is 0 and low is 1.

Pin Row-z Row-A Row-B Row-C Row-d

1 MPR D00 BBSY* D08 VPC

2 GND D01 BCLR* D09 GND

3 MCLK D02 ACFAIL* D10 +V1

4 GND D03 BG0IN* D11 +V2

5 MSD D04 BG0OUT* D12 RsvU

6 GND D05 BG1IN* D13 -V1

7 MMD D06 BG1OUT* D14 -V2

8 GND D07 BG2IN* D15 RsvU

9 MCTL GND BG2OUT* GND GAP*

10 GND SYSCLK BG3IN* SYSFAIL GA0*

11 RESP* GND BG3OUT* BERR GA1*

12 GND DS1* BR0* SYSREST +3.3 V

13 RsvBus DS0* BR1* LWO RD GA2*

14 GND WRITE* BR2* AM5 +3.3 V

15 RsvBus GND BR3* A23 GA3*

16 GND DTACK* AM0 A22 +3.3 V

17 RsvBus GND AM1 A21 GA4*

18 GND AS* AM2 A20 +3.3 V

19 RsvBus GND AM3 A19 RsvBus

20 GND IACK* GND A18 +3.3 V

21 RsvBus IACKIN* SERCLK A17 RsvBus

22 GND IACKOUT* SERDAT* A16 +3.3 V

23 RsvBus AM4 GND A15 RsvBus

24 GND A07 IRQ7* A14 +3.3 V

25 RsvBus A06 IRQ6* A13 RsvBus

26 GND A05 IRQ5* A12 +3.3 V

27 RsvBus A04 IRQ4* A11 LI/I*

28 GND A03 IRQ3* A10 +3.3 V

29 RsvBus A02 IRQ2* A09 LI/O*

30 GND A01 IRQ1* A08 +3.3 V

31 RsvBus -12 V +5 V Standby +12 V GND

32 GND +5 V +5 V +5 V VPC

755

Table C.0.3: Pin assignments of standard VME64x P2 connector. UD stand for

user deﬁned.

Pin Row-z Row-A Row-B Row-C Row-d

1 UD UD +5 V UD UD

2 GND UD GND UD UD

3 UD UD RETRY UD UD

4 GND UD A24 UD UD

5 UD UD A25 UD UD

6 GND UD A26 UD UD

7 UD UD A27 UD UD

8 GND UD A28 UD UD

9 UD UD A29 UD UD

10 GND UD A30 UD UD

11 UD UD A31 UD UD

12 GND UD GND UD UD

13 UD UD +5 V UD UD

14 GND UD D16 UD UD

15 UD UD D17 UD UD

16 GND UD D18 UD UD

17 UD UD D19 UD UD

18 GND UD D20 UD UD

19 UD UD D21 UD UD

20 GND UD D22 UD UD

21 UD UD D23 UD UD

22 GND UD GND UD UD

23 UD UD D24 UD UD

24 GND UD D25 UD UD

25 UD UD D26 UD UD

26 GND UD D27 UD UD

27 UD UD D28 UD UD

28 GND UD D29 UD UD

29 UD UD D30 UD UD

30 GND UD D31 UD UD

31 UD UD GND UD GND

32 GND UD +5 V UD VPC