o signal formation for energy, time and position measurements o segmented detectors; - advanced fee...

o Signal formation for energy, time and position measurementso Segmented detectors; - advanced FEE for Ge Detectorso Briefly, some specific issues and cases: ◦ MINIBALL & AGATA (& GRETINA) FEE for gamma rays

(CERN-Isolde & EU Tracking Array -LNL; GSI; Ganil) ◦ LYCCA & TASISpec FEE for particles

(GSI -Calorimeter & Superheavy Element Spectroscopy)

G. Pascovici , Carpathian Summer School of Physics, Sinaia 2012Institute of Nuclear Physics, Univ. of Cologne and NIPNE-HH, Bucharest

Advanced FEE solutions for large arrays of semiconductor detectors

2

a) Signal formation for energy, time and position measurements, (we’ll limit our attention to capacitive & segmented detectors)

b) Related issues in segmented detectors - dynamic range - high counting rates - induced signals & crosstalk - pros vs. contsc) AGATA & MINIBALL – advanced FEE solutions - Dual Gain CSP - for the central contact - ToT method ( - combined dynamic range ~100 dB, up to 170 MeV)

- Transfer function, Induced signals, Crosstalk - Applications: - Impurities concentration measurement; - Cosmic ray direct measurement up to 170MeV equiv. gamma

d) LYCCA & TASISpec - FEE for DSSSD


A typical structure of a segmented, tapered and encapsulated, HP-Ge Detector

Central contact (Core)

Exterior contacts (N Segments)

• Standard n-type• Intrinsic HP-Ge (P-I-N)• Closed end• Coaxial structure• Io ~ < 100 [pA]

(-)

(+)

+ HV

[- HV] (GND)

Ci

• Cdet ~ 30 - 45 pF• Collection time ~ 30 - 1000 ns

(- e ~ mm)

Parameter Ge

Dielectric 16

Electron-hole pair

E

2.96 [eV]

Mobility e / hole(+)

3,900 / 1,900

@ o 300 K

e / hole(+)

[cm2 /V.s]

Vd=μE

40,000 / 50,000

@ o80 K

N = 6; 12; 18; 28; 36- Qi

(~ kV/cm)Rp

Qd - delta

UCSP – exponential

UFA ~ Gaussian

t

t

t

Pile-up of pulses

Baseline restorer

Collected charge pulses (+ & -)

Digital Filters (Fast, Slow)

Fast Pipe line ADC [DGF]

FFEFEE

Fast pipeline ADC [DGF]

Analog E+T Filter Amplifier Chain

FEE

[HP-Ge + CSP] + Analog Nuclear Electronics Spectroscopic Chain is used in order to extract the:

E, t, position (r, azimuth)

t

t

t

Pile-up of pulses

Baseline restorer

Digital Filters (Fast, Slow)

Fast pipeline ADC + PSA

Fast pipeline ADC & [DGF]

Collected charge pulses (+ & -)

UCSP – exponential

UFA ~ Gaussian

Qd - delta

Digital Filters [for Trigger, Timing, Energy, Position]

FEE

[HP-Ge + CSP] + Digital Nuclear Electronics Spectroscopic Chain is used in order to extract the:

E, t, position (r, azimuth)

Detector Signal Collection

+

-

Detector

Rp

• a gamma ray crossing the Ge

detector generates electron-hole pairs

• charges are collected on electrode

plates (as a capacitor) building up

a voltage or a current pulse

Final objectives:• amplitude measurement (E)

• time measurement (t)

• position (radius, azimuth)Electronic Circuit

Z(ω)

Which kind of electronic circuit ; Z(ω) ?

Z(ω)

+-

Detector Electronic Circuit

Rp

if Z(ω) is high,

• charge is kept on capacitor nodes and a voltage builds up (until capacitor is discharged)

• Advantages:

• Disadvantages:

Detector Signal

Collection

if Z(ω) is low,• charge flows as a current through the impedance in a short time.• Advantages:

• Disadvantages:

• limited signal pile up (easy BLR)• limited channel-to-channel crosstalk• low sensitivity to EMI• good time and position resolution

• signal/noise ratio to low worse resolution

• excellent energy resolution• friendly pulse shape analysis position

• channel-to-channel crosstalk• pile up above 40 k c.p.s.• larger sensitivity to EMI

Charge Sensitive Preamplifier

Active Integrator (Charge Sensitive Preamplifier -CSP)• Input impedance very high ( i.e. ~ no signal current flows into amplifier),• Cf /Rf feedback capacitor /resistor between output and input,• very large equivalent input dynamic capacitance,• sensitivity or ~ (conversion factor) A(q) ~ - Qi / Cf

• large open loop gain Ao ~ 10,000 - 150,000• clean transfer function (no over-shoots, no under-shoots, no ringing)

Ci ~ “dynamic” input capacitance

R fStep function

Ci ~ 10 - 20,000 pF ( up to 100,000)

- Invert ing

- Qi

GND

(Rf.Cf ~ 1ms)tr ~ 30-1000ns)

jFET

+ Ao

Charge Sensitive Stage(it is a converter not an amplifier)

“GND” Non- Inv.

o

Pole - Zero cancellation technique

Rf . Cf ~ 1 ms

Rd . Cd ~ 50 µs simple differentiation

if (Rf Cf ) = (Rpz .Cd) and

Rd Cd ~ 50 µs

differentiation with P/Z adj. no baseline shifts

Baseline shifts

Baseline restored

Cf ~ 1pF (0.5pF-1.5pF), Rf ~ 1GOhm

Cd~ 47 nF, Rd~1.1 kOhm

Rpz~ 20 k Ohm

without

Rpz

with

Rpz

Pole - Zero cancellation technique

Rf . Cf ~ 1 ms

Rd . Cd ~ 50 µs simple differentiation

if (Rf Cf ) = (Rpz .Cd) and

Rd Cd ~ 50 µs - clean

differentiation with P/Z adj. no baseline shifts

Baseline shifts

Baseline restored

Cf ~ 1pF (0.5pF-1.5pF), Rf ~ 1GOhm

Cd ~ 47 nF, Rd ~1.1 kOhm

R pz ~ 21 k Ohm

without

Rpz

with

Rpz

CSP

This is only the ‘hard core’ of the CSP stage (Charge Sensitive Preamplifier) but the FEE must provide additional features:

a P/Z cancellation (moderate and high counting rate) a local drive stage (to be able to drive even an unfriendly

detector wiring !) (opt.) an additional amplifier (but with Gmax.~ 5)

(N.B. a “free advice”: … never install an additional gain in front of the ADC ! -namely, after the transmission cable !)

a cable driver (either single ended –coax. cable or differential output - twisted pair cable)

Any free advice is very suspicious ( anonymous quote )


Block diagram of a standard CSP (discrete components and integrated solution… - what they have in common )

Cold part(cryostat)

Warm part(outside cryostat)

(alternatives)

(alternatives)

(alternatives)

Optionally with cold jFET


(+)

(-)

Block diagram of a standard CSP (discrete components and integrated solution… - what they have in common )

Cold part(cryostat)

Warm part(outside cryostat)

(alternatives)

(alternatives)

(alternatives)

Optionally with cold jFET


(+)

(-)

• tr 25 ns ( 1 - 200 ) ns

• tf 50 μs ( 10 - 100 ) μs

• CSP- ‘gain’ 50 mV / MeV (Ge) (10-500 mV / MeV)

15

IF1320 (IF1331) (5V; 10mA)& 1pF; 1 GΩ

tr ~ 30-40 ns Ch.1 @ 800 mV - no over & under_shoot

warm

• Warm & cold jFET• DGF-4C(Rev.C) G. Pascovici , Carpathian Summer School of Physics, Sinaia 2012

Institute of Nuclear Physics, Univ. of Cologne and NIPNE-HH, Bucharest

alsoGRETINA Eurysis

• the equivalent noise charges Qn assumes a minimum when the current and voltage contributions are equal

• current noise ~ (RC)• voltage noise ~ 1/(RC) ~ Cd

2

• 1 / f noise ~ Cd 2

J.-F. Loude, Energy Resolution in Nuclear Spectroscopy, PHE 2000-22, Univ. of Lausanne

AGATA τopt~ 3-6 µs

Dynamic range issue (DC - coupled)

Factors contributing to saturation:

- Conversion factor – ( step amplitude / energy unit [mV/MeV] );- Counting rate [c. p. s.] and fall time;

- The allowed Rail-to-Rail area [LV-PS] {(+Vc - Vc ) – 2xΔf -2δFilt.}

Saturation (+Vc)

Saturation (-Vc)

+Vc

(+ Rail )

-Vc

(- Rail)

Linear range

Δf-

Δf+( forbidden region )


DC coupled channel

DC – unipolar (+)

DC - bipolar

A(q) ~ - Qi / Cf

DC – unipolar (-)

δFilter

δFilter

Dynamic range issue (AC - coupled)

Factors contributing to saturation:

- Conversion factor – ( step amplitude / energy unit [mV/MeV] );- Counting rate [c. p. s.] and fall time;

- The allowed Rail-to-Rail area [LV-PS] {(+Vc - Vc ) – 2xΔf -2δFilt.}

Saturation (+Vc)

Saturation (-Vc)

+Vc

(+ Rail )

-Vc

(- Rail)

Linear range

A(q) ~ - Qi / Cf

Δf-

Δf+( forbidden region )


AC coupled channel

AC -Unipolar (positive)

BL shift

δFilt

AC -Unipolar (negative)

What to do to avoid saturation? Conts (“price”)

• to reduce the “gain” Resolution ( Cf larger )• to fix the base line asymmetric if DC coupled (expand: F ~ 2),

but for AC ? (expand only: F ~ 1.5)!• to reduce the fall time Resolution ( Rf smaller )

(OK only for high counting rate limitation)

• to reduce the fall time, how ?• passively (smaller tf) Resolution ( Rf smaller ) • linear active fast reset

• in the 2. stage ToT 2.nd stage ( <10 -3) (GP et al, AGATA- FEE solution)

• in the first stage ToT 1.st stage ( <10 -3 ??)

(not yet tested for high spectroscopy) (G. De Geronimo et al, FEE for imaging detectors solution A. Pullia, F. Zocca, Proposal for HP-Ge detectors)


G. De Geronimo, P. O’Connor, V. Radeka, B.Yu; FEE for imaging detectors, BNL-67700

a) & b) for sequential reset c) through g) for continuous reset

Potential solutions for active reset @ 1st stage


a) Custom designed vs. Commercial FEE ? b) Discrete components vs. ASIC FEE ? (Application Specific Integrated Circuits)

- Pros vs. Cons - (price, performance, size, quantity, price/performance ratio, R&D and production time, maintenance manpower … but generally, it is more a project management problem ! ) - personally, I am trying to avoid generalization !

ANALOGUE CIRCUITS TECHNIQUES, April , 2002; F. ANGHINOLFI ; CERN

- the dominant pole compensation technique

NINO, an ultra-fast, low-power, front-end amplifier discriminator for the Time-Of-Flight detector in ALICE experiment F. Anghinolfi et al, ALICE Collab.

GDC ~ 30,000

Zo ~ 66 Ohm

“ A Large Ion Collider Experiment, ALICE-TPC -TDR”, ISBN 92-9083-153-3, (1999), CERN

24

C. Chaplin, Modern Times (1936)

crosstalk between participants transfer function issue

1. Charge Sensitive Preamplifier ( Low Noise, Fast, Single & Dual Gain ~ 100 dB extended range with ToT )

2. Programmable Spectroscopic Pulser (as a tool for self-calibrating)

3. Updated frequency compensations to reduce the crosstalk between participants (-from adverse cryostat wiring and up to - electronic crosstalk in the trans. line)

8 Clusters (Hole 11.5cm, beam line 11cm)


GSI-2012

25

Best performance: Majorana dedicated FEE (PTFE~0.4mm; Cu~0.2mm;C~0.6pF; R ~2GΩ Amorphous Ge (Mini Systems) ~ 55 eV (FWHM) @ ~ 50 µs (FWHM)

BF862 (2V; 10mA)1pF; 1 GΩ

BAT17 diode(GERDA)

Test Pulser ?-yes-not & how ?


26

Pole /Zero Adj. Fast Reset (Ch2)

Pole /Zero Adj. Fast Reset (Ch1)

Differential Buffer (Ch1)

Ch1 ( tr ~ 25.5 ns)

Ch2 ( tr ~ 27.0 ns)

CommonCharge

SensitiveLoop +

Pulser +

Wiring

Differential Buffer (Ch2)

Ch 1 ~200 mV / MeV

Ch 2 ~ 50mV / MeV

Programmable Spectroscopic Pulser

Pulser CNTRL

C-Ch1/C-Ch1INH1SDHN1

C-Ch2/C-Ch2INH2SDHN2

oneMDR10mcable

Ch1 (fast reset)-Pulser @ ~19 MeV

Ch2 (linear mode)

Segments (linear mode)

Dual Gain Core Structure

2keV -170 MeV @ +/- 12V in two modes & four sub-ranges of operations: a) Amplitude and b) TOT

36_fold segmentedHP-Ge detector + cold jFET

27

R1

R1

R1

SegmentNon-Inverting

Segment CSP Negative Output

Core Inverting

AGATA CSPs – the versions with large open loop gain

( INFN-Milan – IKP-Cologne )

P/Z cancellation

fromActiveReset

why large Ao > 100,000 ? frequency compensation, slope & crosstalk

Cv

Cv

* (Cv) stability adj.

DC coupled

AC coupled

Core CSP Positive Output

28

Fast Reset as tool to implement the “TOT” method

Core Active Reset OFF

Fast Reset circuitry

Core -recovery from saturation (but base line …)

one of the segments


29


Core Active Reset – OFF

Active Reset – ON

- very fast recovery from TOT mode of operation - fast comparator LT1719 (+/- 6V)- factory adj. threshold + zero crossing- LV-CMOS (opt)- LVDS by default

ToTNormal analog spectroscopy


Core -recovery from saturation

one of the segments

one of the segments


> 220 MeV @ +/-15V

30


Core Active Reset – OFF

Active Reset – ON

ToTNormal analog spectroscopy


Core -recovery from saturation

one of the segments

one of the segments

INH-C

- very fast recovery from TOT mode of operation - fast comparator LT1719 (+/- 6V)- factory adj. threshold + zero crossing- LV-CMOS (opt)- LVDS by default


> 220 MeV @ +/-15V

31

see Francesca Zocca PhD Thesis, INFN, Milan A. Pullia at al, Extending the dynamic range of nuclear pulse spectrometers, Rev. Sci. Instr. 79, 036105 (2008)


32

Comparison between “reset” mode (ToT) vs. “pulse-height” mode (ADC)

A. Pullia at al, Extending the dynamic range of nuclear pulse spectrometers, Rev. Sci. Instr. 79, 036105 (2008)

33

10 MeV

Due to FADC; G=3

range !

X-talk !with CMOS

34

AGATA Dual Core crosstalk test measurements Ch2 (analog signal) vs. LVDS-INH-C1 (bellow & above threshold)

Ch1 @ INH_Threshold - (~ 4mV)

Ch2 @ INH_Threshold + (- 1mV)

INH_Ch1/+/

INH_Ch1/-/

INH_Ch1/-/

INH_Ch1/+/

LV_CMOS

Core amplitude just below the INH threshold Core amplitude just above the INH threshold

tf ~ 2.45 ns

tr ~ 1.65 ns

Ch2 @ INH_Threshold Vp-Vp (~ 1mV)

Ch1 @ INH_Threshold + (~ 4mV)

LV_CMOS

AGATA Dual-Core LVDS transmission of digital signals: - INH-C1 and INH-C2 (Out) and Pulser Trigger (In) signals

(1) Core_Ch1, (2) Core_Ch2, (3) INH_Ch1(LVDS/-/, (4) INH_Ch1(LVDS/+/)


If we have developed a FEE solution with:

• Dual gain for the central contact (Core);• ToT for both Core channels and all Segments;• Saturation of the CSP at 170 MeV @ +/-12V … ( and ~ 220 MeV @ +/- 15V )

… then why not to perform a direct spectroscopic measurement up to 170 MeV equivalent gammas ?

… were to find them ? … in cosmic rays!


Interaction of muons with matter

• Low energy correction: excitation and ionization ‘density effect’• High energy corrections: bremsstrahlung, pair production and photo-nuclear interaction

To extend the comparison between active “reset” mode (ToT) vs. “pulse-height” mode (ADC) well above 100 MeV measuring directly cosmic rays (i.e. equivalent with interaction of gamma rays above 100 MeV)

MUON STOPPING POWER AND RANGE TABLES - 10 MeV|100 TeVD. E. GROOM, N. V. MOKHOV, and S. STRIGANOV

David Schneiders, Cosmic radiation analysis by a segmented HPGe detector, IKP-Cologne, Bachelor thesis, 03.11.2011

Two set-up have been used:

a) LeCroy Oscilloscope with only Core signals: Ch1; Ch2, INH-Ch1; INH-Ch2 from Core Diff-to-Single Converter Box

b) 10x DGF-4C-(Rev.E) standard DAQ - complete 36x segments and 4x core signals from Diff-to-Single Converter Boxes (segments & core)


Determination of the High Gain Core Inhibit width directly fromthe trace while the low gain coreoperates still in linear mode upto ~22 MeV ( deviation ~0.5%)

Calibrated energy sum of all segments vs. both low & high-gain core signals (linear & ToT )

Calibrated energy sum of all segments vs. both low & high-gain core signals (both in ToTmode of operation)


Experimental results for cosmic ray measurement

R.Breier et al., Applied Radiation and Isotopes, 68, 1231-1235, 2010

• Averaged calibrated segments sum +++• Averaged calibrated Low gain Core xxx• Scaled pulser calibration (int. & ext.) ----

Combined spectroscopy up to ~170 MeV

Direct measurement of cosmic rays with a HP-Ge AGATA detector, encapsulated and 36 fold segmented


Transfer Function & Crosstalk

Transfer function - calculation (Frequency domain, Laplace transf., time domain)

- measurement spectroscopic pulser - applications: - bulk capacities measurement - crosstalk measurements and corrections

Detector

The AC coupled Pulser - classical approach !

In standard way the pulser input signal is injected AC (1pF) in the gate electrode of the jFET

1pF

50 Ω

δq(t)


δq(t)

43

AGATA HP-Ge Detector

Front-End Electronics

AGATA – 3D Dummy detector


Cold part Warm part

Cold part Warm part

44

Cold part Warm part

Cold part Warm part




Simple current dividing rule

Rewritten as a Laplace transform of an exp. decaying function

with

If τ1 is sufficiently small, the exponential function can be “δ(t)“ and than the transfer function becomes:

equivalent input impedance of the preamplifier

Miller part Cold resistance


• to be able to measure the transfer function, we need to build and incorporate also a clean pulser with spectroscopic properties and rectangular pulse form …

!

48

Incorporated Programmable Spectroscopic Pulser (PSP)

• why is needed? self-calibration purposes

• brief description• Specifications, measurements and application: - Transfer function; - Charge distribution; - Impurities concentration measurements


49

Parameter Potential Use / Applications

• Pulse amplitude Energy, Calibration, Stability• Pulse Form Transfer Function in time (rise time, fall time, structure) domain, ringing (PSA)• Pulse C/S amplitude ratio Crosstalk input data (Detector Bulk Capacities) (Detector characterization) • Pulse Form TOT Method (PSA)• Repetition Rate (c.p.s.) Dead Time (Efficiency) (periodical or random distribution)• Time alignment Correlated time spectra (DAQ)• Segments calibration Low energy and very high energy calibration• Detector characterization Impurity concentration, passivation (Detector characterization)

The use of PSP for self-calibrating


50

Mode

In4

S2 D 7

38

GND

VDD

Shown forIn = 1

V12

In4

S2 D 7

38

GND

VDD

Shown forIn = 1

V13

R79

R80

8

2

34

6

1

GND

VDD

V15

C94

R75

GND_D

GND_D

GND_D

GND_D

GND_D

R81

+V13 +V13

-V13

+V13

+V13

-V13

C53

GND_D

+V13D6

C59

3

4

2

1

6

U13

3

4

2

1

6

U11

R31

R30

-V13

-V13

R107

R94

R90

C86

GND_D

C101

GND_D

C120

Vref

Chopper Out

Trigger

• Analog Switches:

- t on / t off , - Qi, - dynamic range (+/- 5V)• Op Amp: - ~ R to R - bandwidth• Coarse attenuation (4x 10 dB) (zo~150 Ohm)• transmission line to S_ jFET and its return GND!

• +/- 1ppm• 16 bit +/- 1bit• fast R-R driver

return GND

CSP


51

Cold part Warm part

Cold part Warm part




Uncorrected for individual segment gain

Pulser Ratio Core / Segments

Corrected for each individual segment gain

C0-X4 = 1.19 pF

C0-X5 = 1.16 pF

C0-X6 = 0.98 pF

C0-X1 = 0.943 pF

C0-X2 = 0.666 pFC0-X3 = 0.980 pF

Agata measured capacities:

Core and Segment crosstalk

T020102012,

T2

T0201011,

T1

1202

1201

0201

1)1(1 v

11 :doubles

11 v

011 :singles

1

1

1

1

v

acacfbout

acacfbout

fbac

fbac

fbfb

fbout

CCxCCxACCxxC

xxi

CCCCACC

i

i

ACCCC

ACCCC

ACCACC

sC

Core normalization

Segment normalization

Observed shift in segments

acac CCCC 0201 1sumSegment

• The reconstruction of the three dimensional space charge distribution inside highly segmented large volume HP-Ge Detector from C-V measurement was investigated

• A computer program was developed to understand the impact of impurity concentrations on the resulting capacities between core contact and outer contact for HP-Ge detectors biased at different high voltages The code is intended as a tool for the reconstruction of the doping profile within irregularly shaped detector crystals.

• The results are validated by comparison with the exact solution of a true coaxial detector.

• Existing methods for space charge parameter extraction are shortly revised.

• The space charge reconstruction under cylindrical symmetry is derived.

3D Space charge reconstruction in highly segmented HP-Ge detectors through CV measurements, using PSP


Influence of the space charge on the core signal rise time (in the coaxial part of the AGATA detector )

The example indicates the need for characterization of each individualdetector, including detailed investigationof space charge distribution and theexact geometry of the sensitive material

simple planar capacitor

from charge neutrality condition of the device ( N(d) being the remaining net charge at the boundary of the depletion region) to the variations in capacity with the bias voltage and as function of the changing bias voltage a scan through the depletion depth of the sample is obtained only the relationship between measured bulk capacity and applied bias voltage is sufficient to reconstruct the doping profile

N.B. - one dimensional reconstruction planar approximation, where the space charge depending only on “d”

N(d) = [ND -NA ]

where ND ; NA donator, acceptor concentration levels of the crystal

• The novel approach is a full 3D reconstruction of the impurity profile throughout the bulk of the HP-Ge crystal. • The technique should be applicable for any detector geometry, not only for planar detectors. G. Pascovici , Carpathian Summer School of Physics, Sinaia 2012

Institute of Nuclear Physics, Univ. of Cologne and NIPNE-HH, Bucharest

Electrical model of 36-fold segmented detector

Coreelectrode Curre

nt [

pA]

Bias [V]


Impurities concentration of last four rings of AGATA detector S002

B. Birkenbach at al, Determination of space charge distributions in highly segmented large volume HP-Ge detectors from capacitance-voltage measurements Nucl. Instr. Meth. A 640 (2011) 176-184

59

Pulser peak position for different voltages of det. C006

[10

10 /c

m 3

]

Crystal Height [mm]

o Variation of the Am (59.5keV) peak position with detector bias voltage (the error bars indicate the FWHM of the energy peak – they do not represent an uncertainty)

o The core energy position is strongly varying with bias voltage, while segments are nearly unaffected. The FWHM width is drastically growing due to the increased detector capacity


Energy vs. Applied Voltage

Detector Capacity vs. Applied Voltage

Crosstalk and signal induction in segmented detectors

Segmented detector show mutual capacitive coupling of the: - segments & -core crosstalk and worsening the energy resolutiono The crosstalk has to be measured experimentally and to be corrected while due to crosstalk effect the segment sum peak energy value (“add-back”) is reduced

o The radiation leave a trail of ionization in the detector and the movement of these charges in an electric field induces signals on the detector electrodes.• In the case of a detector with ideal segmentation and ideal distributed

capacitors one can calculate the signal with an electrostatic approximation using the so called “Ramo theorem” (HP-Ge Det.; MWPC; DSSSD).

• In the case of under-depleted DSSD; MRPC-detectors the time dependence of the signal is not only given by the movement of the charges but also by the time-dependent reaction of the detector materials. Using quasi-static approximation of Maxwell’s equations –W. Riegler developed an extended

formalism to allows calculation of induced signals for a larger number of detectors with general materials by time dependent weighting fields

Crosstalk correction is needed for AGATA• Crosstalk is present in any segmented detector• Crosstalk creates energy shifts proportional to fold• crosstalk can be corrected

without X-talk

with X-talk


The segment sum energy for

Eγ = 1332.5 keV plotted for different segment multiplicities (‘fold’ – number of hit segments)

Energy shift and ‘resolution’ vs. segment ‘fold’

The data points in this figure show peak energy shifts of the 1332.5 keV line of 60Co as a function of all possible twofold segment combinations. A refined inspection of the peak position of the twofold events reveals a regular pattern as a function of pair wise segment combinations

Miniball (HeKo) PSC 823 PSC-2008 AGATA like Miniball (Eurysis /Ortec propr. prod.) (differential out.) 2011-2012

Technical Specifications - conversion factor ~ 200 mV/MeV (PSC-2008 opt. 100 mV/MeV)

- open loop gain Ao ~ 20,000 The new series 2008 & 2012

- single ended - reconfigurable as Inv. / Non Inv.); - Ao ~ 100,000

•- adjustments: - Idrain ; - P/Z adj. ; - Offset adj. ; Bandwidth - differential outputs - adjustments: - Idrain ; - P/Z adj. ; - Offset adj. ; Bandwidth - INH-C & SDHN - power supply: +/- 12V ( i.e. ToT mode of operation) - rise time ~ 25 ns / 39 pF det. cap. (terminated)

INH

SH

DN

Either BF862 or IF1320

Advanced solution for FEE: - to extend the dynamic range and counting rate with a combined dual gain and dual ToT method 100dB; - transfer function tools ( from dummy to freq. comp.); - programmable spectroscopic pulser; - applications as: - impurities concentration - up to ~180 MeV equiv. gamma range - crosstalk corrections

69

AGATA Dual Gain Core Final Specs.

• Summary active reset: - active reset @ 2nd stage - active reset @ 1st stage with advantages vs. disadv.


• By design optimized Transfer Function (no over/under-shoots)

• Crosstalk requirements < 10 -3 core-segment

MINIBALLCharge Sensitive

Preamplifier Specifications

Parameter IKP-Cologne(Miniball – jFET IF1320)

Sensitivity( mV / MeV)

~ 175 mV/MeV( single ended )

Resolution(Cd= 0pF; cold FET) ~ 600 eV

Slope( + eV/ pF) [Cd]

< 10 eV / pF (cold FET)

Rise time (Cd= 0pF);

~ 15 ns ( cold FET)

Slope( + ns/ pF) [Cd]

~ 0.3 ns( ~ 25 ns / 33 pF )

U(out) @ [50 Ohm]

/ Power [mW]

~ 4.5V /~ 450 mW ( + /- 12V Op.Amp.LM-6172)

Saturation of

the 1st stage @

equiv. ~100 MeV(@ ~60mW_ jFET)

Open Loop Gain

~ 20,000G. Pascovici , Carpathian Summer School of Physics, Sinaia 2012Institute of Nuclear Physics, Univ. of Cologne and NIPNE-HH, Bucharest

G. Pascovici, Institute of Nuclear Physics, Univ. of Cologne

A. Wendt et al – Der LYCCA-Demonstrator, HK 36.60, DPG, Bonn, 2010

74

TASISpec (TASCA) A new detector Set-up forSuperheavy Element Spectroscopy

LYCCA-0Set-up for DSSSD + CsI

75G. Pascovici , Carpathian Summer School of Physics, Sinaia 2012Institute of Nuclear Physics, Univ. of Cologne and NIPNE-HH, Bucharest

76

~1.25 sq.cm


o signal formation for energy, time and position measurements o segmented detectors; - advanced fee...

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