Nuclear Instrumentation

Nuclear Instrumentation

CEU 2014 Waikoloa Resort Hawaii

Nuclear Instrumentation & Signal Processing

Mohammad W. Ahmed

TUNL REU Lecture

What is all this mess ?

Closer Look

Seems to be some organization in this mess

Instrumentation

InstrumentationDetectors

Electronic Modules

Computers

Instrumentation

Signal Processing & Logic

Event Reconstruction

Signal

10010011010010111

Interaction Picture

Signal

Signal Processing

Event Reconstruction

Positive

TTLNIM

LongShortNegative

Bi-polarDC

ECL

• Amplitudes (Pulse Height = Peak Voltage);• Time (Duration = dt, Start time, t0; • Charge Q

iR + Q/C = Vo

dQ/dT + Q/RC = Qo/RC

…

Q = (V0/R e – t/RC) t

Gamma-Ray of 1.46 MeV Gamma-Ray of 2.61 MeV

V

T

V

T

VV

V

Example 1

Cou

nts

Energy (MeV)1.46 2.61

Energy = Constant X V Acquiring the Constant is calledEnergy calibration

d1

d2

Example 2

d0

T

Time-of-Flight (TOF) is differnt

Example 3 Pulse Shape

Gamma-Ray neutron

Start Time is the same, Amplitude is also same

Charge (Q) is different (Pulse Shape Discrimination PSD)

T

V

Making Copies

Passive Splitting Active Splitting

Simple “T”

ElectronicModule

Linear/LogicFan In/Out

Linear Fan In/Out Modules

Logic Creation (Yes/No)

Presence of a signal

Define the condition for a signal to be valid

e.g., If the absolute amplitude is greater than 0.5 V than the signal is good

= - 0.5 V

Test Result

YES !

INOut

YES NO

Discriminator

the

Logic Modules

Gain

INCG

FG

T

Out

Spectroscopy Amplifier “SpecAmp”

Amplifiers

Coincidence

Did the two gamma-rays originate from the same source at the same time ?

A B

A

B

A+B

A

B

FalseTrue

A+B

Coincidence

IN

Outputs

ABCD

Logic InputsLogic Output

Coincidence Unit

Analog to Digital Convt (ADC) / DAC

0110010100111101ADC

0110010100111101

(to computer)(From device)

(From computer)DAC

(To device)

ADC

Mask the signal by Bits

0 bit

8 bit

Amplitude (0 to 10 V) is ranged from 0 to 8192 ADC Counts(for the case of 13 bits)

0 bit

13 bit

More bits means better resolution !!!

Logic Gate

ADC

Linear Inputs

ADC

• Scalers;•Gate & Delay Generators;•Pulse Generators;•Filters;•High Voltage Generators;•Level Adaptors• etc.

Fan IN/OUT, Disc., Amplifiers, etc

ADCs, TDC, Scalers, etc

BNC “T” BNC Term.LEMO “T” LEMO Term.

BNC Barrel BNC to LEMOLEMO Barrel

Where are all the cables and connectors in the Control Room ?

Acquire and process data

DAQ and Analyzer

DAQ is responsible of taking data from the electronics