Position sensitive scintillation detectors for the trigger system in the space experiment NUCLEON

Supervisors: Anatoliy I. Kalinin a Students: Irina Cioara b

Alexandra Chilug b

a Joint Institute for Nuclear Research, Dubna,Russiab University of Bucharest, Romania

Dzhelepov Laboratory of Nuclear Problems

Were discovered by Victor Hess in 1912 They are energetic charged subatomic

particles, originating from outer space. They

may produce secondary particles that

penetrate the Earth's atmosphere and surface. The NUCLEON experiment is aimed at

studying cosmic rays that have energies

between 1011- 1014 eV. The TUS experiment is aimed at studying

cosmic rays that have ultra high energy,

above 5*1019 eV. The used method is an

indirect one, that does not remember the

primary particle.

Cosmic rays

NUCLEON The main idea of the NUCLEON project is to design

and to create a scientific device with large aperture and

a relatively light weight for measure elemental spectra

of cosmic rays in a wide energy range E ~ 1011- 1014 eV. The method is based on event by event measurement of

spatial distribution of the charged and neutral secondary

particles which were produced in the inelastic nuclear

interaction in the target of the detector and have passed

through layers of silicon micro strip detectors and thin

converters to produce e- e+ pairs of the secondary

gammas. This technique is known as KLEM (Kinematic

Lightweight Energy Meter).

KLEM [Kinematic Lightweight Energy Meter]

The main objective of the KLEM instrument is direct measurement of the

elemental energy spectra of high-energy (1011-1016eV ) cosmic ray in

space. The basis of the KLEM method is energy determination by measuring the

number and the angular distribution of secondary particles produced in a

target. The energy of a primary particle is calculated using the following

function:

Ni= number of secondary particles registered in strip i

ηi= pseudorapidity

xi= distance of strip i from the point of intersection of the extrapolated

primary particle trajectory with the detector plane

h= the distance between the detector plane and the midle of the target

i

iES 2iN)(

))2/(tan( hxLn ii

Advantages of KLEM method:

a large aperture a lightweight device (it does not need a

thick absorber) has easy read out of information (thanks

to the use of silicon microstrip detectors) long duration exposures in orbit measurement of an individual energy

spectra with single technique over a very

wide energy range

KLEM

NUCLEON Structure

COMPARATOR

MPMT XPMT+ IVN A

PMT + IVN A

MPMT YPMT + IVN A

PMT + IVN

A

P1

P1

Fibers

P-16

P-16

P-32

Block diagram of the plane

Trigger systemThe goal of the trigger system is the selection and rejection of data flux to a limited volume that can be

transferred to the ground data acquisition and control center for further offline analysis.

• Scintillator detectors - basic instruments for registration of cosmic rays and other radiations.

The scintillator converts the falling radiation into a short pulse of visible light.

The photomultiplier converts the collected light from the scintillator into electrical signal and amplifies it

as much as possible.

In the NUCLEON project vacuum photomultipliers are used.

A

Amplifier

ScintillatorFiber

PMT CC COMPARATOR

0 500 1000 1500 2000-200

0

200

400

600

800

1000

1200

1400

1600

1800

2000

D19600

Channels

NN

E= 60V430nmS= 6,6V

Spectrum of Light Diod

SiPM S60

PMT and SiPMVacuum Photomultiplier Silicon PhotoMultiplier

Advantages for Silicon Photomultipliers:

Applicability in many different fields (high energy physics calorimetry, astrophysics, medical imaging)Low voltage supply (<100 V)Insensitivity to magnetic fieldHigh gain ~ 106 Better one-electron resolution

The general equivalent circuit of the SiPM

Thank you for your attention!