[PPT] - A gamma calorimeter for the monitoring of the ELI-NP beam Michele PowerPoint Presentation

SLIDE 1

A gamma calorimeter for the monitoring of the ELI-NP beam

Michele Veltri

University of Urbino and INFN Firenze

PM2018 - 14th Pisa Meeting on Advanced Detectors

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 1 / 18

SLIDE 2

The ELI Project

ELI: Extreme Light Infrastructure
It is a large scale european project part of the ESFRI roadmap
It will be devoted to the investigation of light–matter interactions
Under construction, it will be implemented as a distributed

facility over 3 sites

ELI–NP – Romania
Photonuclear physics and its applications
ELI Beamlines – Czech Republic
Production of short–pulse secondary

sources driven by ultra intense lasers

ELI Attoseconds – Hungary
Production of laser driven secondary

sources (extreme UV and X–rays) of ultra–short time duration

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 2 / 18

SLIDE 3

ELI–NP: Extreme Light Infrastructure–Nuclear Physics

ELI–NP will hosts two systems:
A very high intensity laser system with two

10 PW sources that combined can reach an intensity of 1023 W/cm2

The Gamma Beam System (GBS)

A very intense and monochromatic γ beam

btained by inverse Compton scattering of laser

light off a high energy pulsed electron beam

The expected performances will push the present limits and
pen a new field of investigation the ”Nuclear Photonics”
The GBS is being realized by the EuroGammaS

Association lead by INFN

Two energy lines are foreseen
Low energy: 0.2→3 MeV
High energy: 5→20 MeV

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 3 / 18

SLIDE 4

The ELI–NP γ beam

The GBS will be operated in multibunches train mode at 100 Hz
The single laser pulse will

be recirculated 32 times to interact with the 32 e- bunches from the LINAC

The γ energy is tunable by

adjusting the e− beam energy

In Compton backscattering the laser photons are scattered in a narrow cone

around the e− direction and the energy is amplified from eV→MeV

The radiation produced by Compton backscattering is not intrinsically

monochromatic ➜ The γ energy is function of the emission angle

The bandwidth can be controlled with proper collimation of the beam

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 4 / 18

SLIDE 5

The ELI–NP γ beam monitoring system

CSPEC – Compton spectrometer (INFN–FI) ➜ Energy distribution
NRSS – Nuclear Resonant Scattering Spectrometer (INFN–CT)

➜ Absolute energy calibration

GPI – Gamma beam Profile Imager (INFN–FE) ➜ Spatial distribution
GCAL – Gamma CALorimeter (INFN–FI) ➜ Average energy and intensity

γ beam CSPEC NRSS GPI GCAL CSPEC #136 NRSS #338 GPI #214

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 5 / 18

SLIDE 6

GCAL: Working principle

The calorimeter has to provide a fast (➜ i.e. within a macro–pulse)

measurement of the beam average energy and intensity

Destructive measurement ➜ Cannot be used during normal data taking

It is placed on a moveable platform

GCAL is a sampling calorimeter with a low–Z absorber
Low–Z absorber ➜ Dominated by Compton scattering at ELI energies
High–Z absorber ➜ Pair production
The Compton cross–section decreases rapidly with energy
The longitudinal profile of the energy deposition retains the dependence
n the beam energy

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 6 / 18

SLIDE 7

GCAL: Working principle

The expected longitudinal profile of

the energy distribution is parametrized by detailed Monte–Carlo simulations done with Geant4

The average energy of the beam is

determined by fitting the measured profiles against the simulated ones

Low beam BW ➜ The beam intensity

can be inferred from the measured total energy release Nγ = 21

i=0 E meas i

f (Eγ)Eγ

High beam intensity

➜ Low statistical error At nominal intensity in few seconds of

perations the resolution is ≃ 0.1%

layer # 5 10 15 20 MeV 200 400 600 800 1000 1200 1400

1 MeV 3 MeV 5 MeV 10 MeV 20 MeV 1 MeV 3 MeV 5 MeV 10 MeV 20 MeV 1 MeV 3 MeV 5 MeV 10 MeV 20 MeV 1 MeV 3 MeV 5 MeV 10 MeV 20 MeV 1 MeV 3 MeV 5 MeV 10 MeV 20 MeV

γ

5

Simulated energy release for 10

(MeV)

γ

E 2 4 6 8 10 12 14 16 18 20 /E (%)

E

σ Resolution 1.5 2 2.5 3 3.5 4 4.5 5

Energy resolution N resolution

γ

5

Expected resolution for 10 Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 7 / 18

SLIDE 8

GCAL for the ELI–NP low energy line

GCAL for the low energy ELI–NP beam is ready
22 layers:
7 SiStrip pads with 128 strip each
FE board with 7 channels + SUM
PE target block with O-ring
Frame+spacers (and positioning bars)
Ventilation system (dry air)
LV/HV distribution systems
Crate to hold and carry the device

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 8 / 18

SLIDE 9

Active layer

Si Strip technology for the active layer
Fast response time
Radiation hardness
Linearity
Detectors developed by Hamamatsu
Test structures of the CMS tracker
Can sustain up to 100 kGy irradiation
128 strips all bonded together
Depletion voltage: 200 V
Operation voltage: 600 V

➜ Saturate the drift velocity and reduce the response time

Large area but low capacitance (≃ 300 pF)
Cutting
Cleaning
Visual inspection
C–V characterization
Gluing 7 pads onto

the read–out board

The 7 pads have ∆C <1 pF

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 9 / 18

SLIDE 10

FE electronics

Custom FE electronics
Specifically designed to be very fast
Individual read–out and analog sum
The first two boards have connected

the five central pads and the sum

For the boards from 3 to 22 only the

sum is acquired

Typical noise is 5 ADC ch for the single channel and the 12 for the sum

hNoise0__1

Entries 778000 Mean

0.009277

RMS 4.928

50
40
30
20
10

10 20 30 40 50 10000 20000 30000 40000 50000 60000

hNoise0__1

Entries 778000 Mean

0.009277

RMS 4.928 hNoise1__2 Entries 778000 Mean -0.0107 RMS 4.87

50
40
30
20
10

10 20 30 40 50 10000 20000 30000 40000 50000 60000

hNoise1__2 Entries 778000 Mean -0.0107 RMS 4.87 hNoise2__3

Entries 778000 Mean -0.007135 RMS 4.858

50
40
30
20
10

10 20 30 40 50 10000 20000 30000 40000 50000 60000

hNoise2__3

Entries 778000 Mean -0.007135 RMS 4.858

hNoise3__4 Entries 778000 Mean

0.01005

RMS 4.923

50
40
30
20
10

10 20 30 40 50 10000 20000 30000 40000 50000 60000

hNoise3__4 Entries 778000 Mean

0.01005

RMS 4.923

hNoise4__5

Entries 778000 Mean -0.005559 RMS 4.888

50
40
30
20
10

10 20 30 40 50 10000 20000 30000 40000 50000 60000

hNoise4__5

Entries 778000 Mean -0.005559 RMS 4.888 hNoise5__6 Entries 778000 Mean -0.006276 RMS 11.19

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise5__6 Entries 778000 Mean -0.006276 RMS 11.19 hNoise6__7 Entries 778000 Mean -0.009536 RMS 4.729

50
40
30
20
10

10 20 30 40 50 10000 20000 30000 40000 50000 60000

hNoise6__7

Entries 778000 Mean -0.009536 RMS 4.729

hNoise7__8 Entries 778000 Mean

0.006676

RMS 4.685

50
40
30
20
10

10 20 30 40 50 10000 20000 30000 40000 50000 60000 70000

hNoise7__8 Entries 778000 Mean

0.006676

RMS 4.685 hNoise9__9 Entries 778000 Mean

0.01413

RMS 4.962

50
40
30
20
10

10 20 30 40 50 10000 20000 30000 40000 50000 60000

hNoise9__9 Entries 778000 Mean

0.01413

RMS 4.962 hNoise10__10 Entries 778000 Mean

0.01334

RMS 4.993

50
40
30
20
10

10 20 30 40 50 10000 20000 30000 40000 50000 60000 hNoise10__10 Entries 778000 Mean

0.01334

RMS 4.993 hNoise11__11 Entries 778000 Mean -0.01611 RMS 4.96

50
40
30
20
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10 20 30 40 50 10000 20000 30000 40000 50000 60000 hNoise11__11 Entries 778000 Mean -0.01611 RMS 4.96 hNoise12__12 Entries 778000 Mean -0.01504 RMS 11.47

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise12__12 Entries 778000 Mean -0.01504 RMS 11.47 hNoise13__13 Entries 778000 Mean

0.01258

RMS 11.17

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise13__13 Entries 778000 Mean

0.01258

RMS 11.17 hNoise14__14 Entries 778000 Mean -0.01221 RMS 11.17

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise14__14 Entries 778000 Mean -0.01221 RMS 11.17 hNoise15__15 Entries 778000 Mean -0.0103 RMS 11.21

50
40
30
20
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10 20 30 40 50 5000 10000 15000 20000 25000 hNoise15__15 Entries 778000 Mean -0.0103 RMS 11.21 hNoise16__16 Entries 778000 Mean -0.01424 RMS 11.17

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise16__16 Entries 778000 Mean -0.01424 RMS 11.17 hNoise18__17 Entries 778000 Mean

0.01652

RMS 11.22

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise18__17 Entries 778000 Mean

0.01652

RMS 11.22 hNoise19__18 Entries 778000 Mean -0.01324 RMS 11.22

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise19__18 Entries 778000 Mean -0.01324 RMS 11.22 hNoise20__19 Entries 778000 Mean -0.01473 RMS 11.11

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise20__19 Entries 778000 Mean -0.01473 RMS 11.11 hNoise21__20 Entries 778000 Mean

0.01508

RMS 11.24

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise21__20 Entries 778000 Mean

0.01508

RMS 11.24 hNoise22__21 Entries 778000 Mean -0.01382 RMS 11.14

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise22__21 Entries 778000 Mean -0.01382 RMS 11.14 hNoise23__22 Entries 778000 Mean -0.01775 RMS 11.18

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise23__22 Entries 778000 Mean -0.01775 RMS 11.18 hNoise24__23 Entries 778000 Mean -0.01496 RMS 11.13

50
40
30
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10 20 30 40 50 5000 10000 15000 20000 25000 hNoise24__23 Entries 778000 Mean -0.01496 RMS 11.13 hNoise25__24 Entries 778000 Mean -0.01504 RMS 11.23

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise25__24 Entries 778000 Mean -0.01504 RMS 11.23 hNoise27__25 Entries 778000 Mean

0.02419

RMS 11.44

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise27__25 Entries 778000 Mean

0.02419

RMS 11.44 hNoise28__26 Entries 778000 Mean

0.02542

RMS 11.36

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise28__26 Entries 778000 Mean

0.02542

RMS 11.36 hNoise29__27 Entries 778000 Mean

0.02393

RMS 11.34

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise29__27 Entries 778000 Mean

0.02393

RMS 11.34 hNoise30__28 Entries 778000 Mean -0.02578 RMS 11.45

50
40
30
20
10

10 20 30 40 50 5000 10000 15000 20000 25000 hNoise30__28 Entries 778000 Mean -0.02578 RMS 11.45 hNoise31__29 Entries 778000 Mean -0.02113 RMS 11.23

50
40
30
20
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10 20 30 40 50 5000 10000 15000 20000 25000 hNoise31__29 Entries 778000 Mean -0.02113 RMS 11.23 hNoise32__30 Entries 778000 Mean -0.0231 RMS 11.23

50
40
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10 20 30 40 50 5000 10000 15000 20000 25000 hNoise32__30 Entries 778000 Mean -0.0231 RMS 11.23 hNoise33__31 Entries 778000 Mean -0.0247 RMS 11.19

50
40
30
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10 20 30 40 50 5000 10000 15000 20000 25000 hNoise33__31 Entries 778000 Mean -0.0247 RMS 11.19 hNoise34__32 Entries 778000 Mean -0.02693 RMS 11.18

50
40
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10 20 30 40 50 5000 10000 15000 20000 25000 hNoise34__32 Entries 778000 Mean -0.02693 RMS 11.18

FE response to 2 ns injection pulse Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 10 / 18

SLIDE 11

Time Response

Use an IR laser to test the time response of

Si Strip devices

Pulsed laser diode PicoQuant LDH–P
IR Laser ➜ Can penetrate uniformly the

whole depth of Si

High Power ➜ Can reproduce the very large

energy depositions expected at ELI–NP

High Rate ➜ Can reproduce the same time

structure of the ELI–NP beam

Data Acquisition with CAEN digitizer V1742
1024 samples in a circular memory buffer
To acquire the whole ELI–NP

macro–pulse a 1 GHz sampling frequency will be used

λ=1060 nm
MaxPower: 21 mW
Rate: single→80 MHz
FWHM < 100 ps

N misura

10 20 30 40 50

Mean (ADC counts)

500 1000 1500 2000 2500

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 11 / 18

SLIDE 12

Time Response

Very fast response of detector+electronics
Well inside the 16 ns boundary
These tests prove the capability of our system to cope

with the demanding time structure of the ELI–NP beam

Detector response when the laser is driven by a train of pulses mimicking the time structure of the GBS Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 12 / 18

SLIDE 13

Energy Response

The energy deposition in Si detectors

was tested at DEFEL (ELectrostatic DEFlector) at the LABEC facility in Firenze

Electrostatic chopper which produces a pulsed beam:
Particles: p
Short pulses: 0.2→1 ns
Adjustable average number of p/pulse
Energy: Ep=3 MeV
Typical spectra contain equally spaced peaks at energies multiple of Ep

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 13 / 18

SLIDE 14

Energy Response

Fit the spectrum with a Poisson convoluted with n gaussians
Extract λp, meani, σi
System linearity tested up to 200 MeV
Energy calibration using ∆E

ADC counts 50 100 150 200 250 300 350 400 450 500 500 1000 1500 2000 2500 3000

=7

p

λ

Energy (MeV) 20 40 60 80 100 120 140 160 180 200 Mean (ADC counts) 200 400 600 800 1000 1200 1400

/ ndf

2

χ 601.3 / 58 p0 0.02313 ± 19.43 p1 0.0003843 ± 7.327 / ndf

2

χ 601.3 / 58 p0 0.02313 ± 19.43 p1 0.0003843 ± 7.327 Mean 21.95 RMS 0.3338 Integral 59

E (ADC counts) ∆ 20 20.5 21 21.5 22 22.5 23 23.5 24

1 2 3 4 5 6

Mean 21.95 RMS 0.3338 Integral 59

ADC counts 200 400 600 800 1000 1200 1400 1600 1800 500 1000 1500 2000 2500

Adding runs with different intensities Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 14 / 18

SLIDE 15

Summary

A low–Z sampling calorimeter has been realized to meet the

extraordinary properties of the ELI–NP γ beam

It will measure the average energy and intensity of the beam

exploiting the energy dependence of the γ absorption cross–section

The active layer is made by Si detectors read out by a custom

FE electronics

Test performed with an IR laser have shown the capabilty of

the device to cope with the time structure of the ELI–NP beam

Test performed at the LABEC facility in Firenze show the excellent

linearity of the device in the energy range relevant to ELI–NP beam

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 15 / 18

SLIDE 16

Additional Material

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 16 / 18

SLIDE 17

Gamma Beam System

For head–on collisions and

the back–scattered γ in the e− direction Eγ ≃ 4γ2

eEL

γe = 1/
(1 − β2) and EL

energy of the laser photons

The recirculator is needed to match

the time structure of the e− beam with the laser one

Mirror system to provide 32

collisions between the laser light and the e− micro–bunches

The laser pulses are focussed on

the same IP

Same incident angle

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 17 / 18

SLIDE 18

Absolute energy calibration with the NRSS

NRSS is one of the four detectors which form the the monitoring system
f the ELI–NP γ beam
It detects the resonant condition between the beam energy and selected,

well known, nuclear levels of given target nuclei

➜ Can provide an absolute energy calibration for GCAL and CSPEC
External shell of BaF2 crystals for fast counting to detect the

establishment of the resonant condition

Inner core made by a LYSO crystal for precise identification of the resonant

energy (in this configuration the surrounding BaF2 crystals act as Compton shield)

Michele Veltri A gamma calorimeter for the monitoring of the ELI-NP beam 18 / 18