Irradiation test on the nSYNC ASIC using X-Ray and protons ... · nSYNC architecture 20/09/18 - Davide Brundu nSYNC irradiation test - TWEPP 2018 5 48 LVDS Input channels: • Fully

Irradiation test on the nSYNC ASIC using

X-Ray and protons beam

Antwerpen – TWEPP 201820 Sep 2018

Davide Brundu1, S. Cadeddu1, A. Cardini1, L. Casu1

1INFN Cagliari

Outline• Introduction

• LHCb upgrade

• The nSYNC chip architecture

• Protons irradiation test at Catana facility• Facility description

• Experimental setup• Results

• X-Ray irradiation test in Cagliari• Experimental setup and Calibration• Results

• Conclusions

20/09/18- DavideBrundu nSYNC irradiation test - TWEPP 20182


Introduction

LHCb upgrade


BUT…• The current Level-0 trigger (1 MHz, 4 𝜇𝑠)

becomes a limitation (hadronic lines saturation)

• nSYNC is the new fundamental component of the upgradedmuon detector readout, developed in UMC 130 nm.

• TID expected : 130&'𝐺𝑦, (𝑚𝑎𝑥 < 200𝐺𝑦)• Hadrons with Energy > 20 MeV = 2 3 1044/𝑐𝑚7

• 1 MeV Neutrons equivalent = 2 3 1047/𝑐𝑚7 , (NIEL: 0.65 Gy)

• Expected dose for nSYNC chip (10 years of upgrade operations):

• LHCb need more data: statistical improvementwith increased luminosity to 𝓛 = 𝟐 3 𝟏𝟎𝟑𝟑𝒄𝒎@𝟐𝒔@𝟏

• Remove Level-0 hardware trigger.• Readout directly at 40 MHz (p-p collisions rate)

SOLUTION:

nSYNC architecture


48 LVDS Input channels: • Fully digital TDC (with Giordano-DCO[1,2] + dithering correction)

with programmable resolution (8-32 slices; 3.125 – 0.78 ns) @ 40MHz, • Nominal resolution: 16 slices, • Programmable pipeline to synchronize different channels,• Histogram block for each channel.

Bunch-Crossing (BX) tagging: • 12 bits BX counter.

Frame builder and TDC Zero Suppression (ZS): • Frame fixed will be implemented, • Header will be 16 bits wide, • Full Hit-Map (not-ZS) + TDC data ZS.

Output GBTx interface via e-LINK (SLVS, LVDS-compatible) @ 320MHz,

Interface for synchronous signals from LHCbTiming and Fast Control (TFC) system,

I2C Interface for slow control signals.

nSYNC is the fundamental component of the upgraded muon detector readout, developed in UMC 130 nm.

nSYNC is the fundamental component of the upgraded muon detector readout, developed in UMC 130 nm

48 LVDS Input channels: • Fully digital TDC with programmable resolution

(8-32 slices; 3.125 – 0.78 ns) @ 40MHz. • Nominal resolution: 16 slices• Programmable pipeline to synchronize different channels. • Histogram block for each channel

Bunch-Crossing (BX) tagging: • 12 bits BX counter

Frame builder and TDC Zero Suppression (ZS): • Frame fixed will be implemented• Header will be 16 bits wide • Full Hit-Map (not-ZS) + TDC data ZS

Output GBTx interface via e-LINK,

Interface for synchronous signals from LHCbTiming and Fast Control system,

I2C Interface for slow control signals.

nSYNC architecture


Not protectedTDC status and histograms (90 B + 2.3 kB)

Protected with TMRConfiguration registers and TFC (~65 B)

Protected with Hamming code + EDACInternal counters, prog. output buffer

and TDC FSM states

nSYNC architecture


• Size: about 4.4 x 3.8 mm2

• Technology: UMC 130 nm • Voltage Supply:

• I/O ring: 3.3 V • Core: 1.2 V

• Pin count: 125 • Package: QFP 160


Protons Irradiation Test

Protons irradiation at Catana facility

20/09/18- DavideBrundu

Test room

Injection and acceleration

CatanaControl room

• Catana facility (LNS - CT)*,• TID collected : 1.2 kGy[Si] (120 kRad[Si]),• Fluence collected : 1.1・1012 prot./cm2,

NIEL equivalent: 0.72 Gy (2.2・1012 1MeV neutr. eq./cm2),• 3 chips tested.

• Protons energy: 60 MeV,• Flux: 5.69・108 prot./cm2 sec,• Beam collimated (not squeezed),

used collimator of 15 mm diameter,• Omogeneus lateral profile.*

nSYNC irradiation test - TWEPP 2018

*G.Cuttone et al., CATANA protontherapy facility - DOI: 10.1140/epjp/i2011-11065-19


Catana room and collimator



10


I2C

Power 3.3V

Power 1.2V

Alignementand cabling



PLLandone LVDSdriver

11


We have developed a complete custom DAQ system, to automatize I2C communication, control and monitoring operationsduring the irradiation test:

• Send I2C commands, set/read configuration;• Monitor internal error counters, current consumptions,

PLL jitter;• Calibrate TDCs, read TDCs status;

PCCustom

DAQSoftwarenSYNC

Supply1.2V

Supply3.3V

Oscilloscope Switch

I2C-tools

RemotePC

~20m

Testroom Controlroom

beam BeamControl

Tomaincontrolroom

I2C USB

GPIBEth.


Protons irradiation – DAQ system

12


Protons irradiation - Runs

Run details: Integrated Dose Overall fluence values• 5 runs of 80 Gy/run @ ~0.08 Gy/sec 400 Gy 3.6531011 prot./cm2

• 6th run of 400 Gy @ ~0.08 Gy/sec 800 Gy 7.2931011 prot./cm2

• 7th run of 400 Gy @ ~0.8 Gy/sec 1200 Gy 1.0931012 prot./cm2

We will show results separately for the different chip blocks:• Current consumption and PLL jitter• TDC performance• SEU cross sections for TDC, histograms and protected blocks• Final summary

Three chips tested: - one for dose rate calibration / SW debugging, - two for analysis and results (named chip 13 and chip 14).

13


Chipcore(1.2V)

Current consumption

I/O(3.3V)

14

• Monitored the current consumption for the chip core (@ 1.2 V) and I/O (@ 3.3 V)• Expected increase due to change of the frame pattern in output interface (LVDS

driver) [from CCCC to AAAA] • Current stable at low dose rate, increase at higher dose rate, no failure behavior or

SEL seen.

change of the frame pattern to output LVDS drivers

change of the frame pattern to output LVDS drivers

Higher doserate:0.8Gy/sec


Current consumptionComparison in I/O current consumption , at low and high dose rate.

15

Run 1 @ 0.08 Gy/sec Run 7 @ 0.8 Gy/sec

Current increase @ 0.08 Gy/sec:~1.2% with 400 Gy (~3 LHCb upgrades)~0.8% with 130 Gy (~1 LHCb upgrade)

130 Gy à TID in 10 years of LHCb upgrade operation (named “1 upgrade”)

Current increase @ 0.8 Gy/sec:~4% with 400 Gy (~3 LHCb upgrades)~1.3% with 130 Gy (~1 LHCb upgrade)


PLL and LVDS driver

• Monitored the jitter of PLL (@ 40 MHz) and of one LVDS driver Controlling the oscilloscope remotely (measuring the period in statistics mode).

• Seen no unexpected instability during the full runs. • PLL jitter increase with beam ≲ 5%.• LVDS jitter fluctuations of the order of ∼ 4%.

0 50 100 150 200

Time (min)

136

138

140

142

144

146

LVD

S jit

ter (

ps) @

80M

Hz

0 50 100 150 200 250Time (min)

38

39

40

41

42

43

44

45

46

PLL

jitte

r (ps

)

Begin RunBegin Run

EndRun– 1.2kGyEndRun– 1.2kGy

16


TDC performance

• Check for unexpected trend in TDC performance w.r.t. TID, reading TDC-DCO ctrl word immediately after the DCO calibration.

• No trend found: calibration curves superimposable, TDC very stable.

10 15 20 25 30TDC resolution

0

2

4

6

8

10

12

TDC

Sta

tus

num

ber (

for c

h. 0

)

0 Gy80 Gy160 Gy240 Gy320 Gy400 Gy800 Gy1200 Gy

0 10 20 30 40Channel number

3.4

3.5

3.6

3.7

3.8

3.9

4

4.1

TDC

Sta

tus

num

ber @

res.

16


(plots only for chip 14, similar for chip 13 in backup slides)

Calibration curves for ch. 0 Calibration curves for resolution 16.

17

Very smalltrend,but completelyinsidethedithering correction

DCO

ctr

lwor

d (f

or c

h. 0

)

DCO

ctr

lwor

d

Nominalresolution =16


SEU cross section – TDC

2 4 6 8 10)2 protons/cm11Fluence (x 10

0

10

20

30

40

50n.SE

U

1 2 3 4 5 6 7)2 protons/cm11Fluence (x 10

5

10

15

20

25

30

35

40

45

n.SE

U

• Counted the number of SEU w.r.t. fluence, periodically reading TDC status for all channels.

• SEU widespread over all channels.• Cross section [𝜎 = 𝑛. 𝑆𝐸𝑈/𝑓𝑙𝑢𝑒𝑛𝑐𝑒] quite stable at

different fluence values. (Note: linear fit constraint at the origin)

Chip 14: 6.7 ± 0.3 ⋅ 10@44𝑐𝑚7Chip 13: 4.9 ± 0.2 ⋅ 10@44𝑐𝑚7

Seu exampleReading

continuosly

TDCstatusfori-th channel

18

TDC status: 2 bytes per channel(DCO control word, TDC enable etc)


SEU cross section – time histograms

• Counted the number of SEU w.r.t. fluence, periodically downloading 2.3 kB of histograms for all channels, in order to compare each bits.

• Cross section stable at different fluence values.


100

200

300

400

500

600

700

n.SE

U


100

200

300

400

500

600

700

800

900

n.SE

U

Chip 14: 10.4 ± 0.3 ⋅ 10@4X𝑐𝑚7Chip 13: 8.7 ± 0.1 ⋅ 10@4X𝑐𝑚7

19


Error Detection in Conf.Regs. and Internal Logic• Counted the number of:

• TMR activaction in configuration registers (using the internal counter),• Error detection for Hamming and EDAC (using internal counters).

• SEU in conf.regs. are always corrected by TMR Upper limit to cross section: <8310-13 @95%CL

• SEU in internal logic not corrected only if double errors (<3% of errors detected, dose rate dependent).



5

10

15

20

25

30

35

40

45

n.SE

U


10

20

30

40

50

60

70

80

90

n.SE

U

TMRHamm.+EDAC

n.SEU

detected

n.SEU

detected

Cross section:13⋅ 10@44𝑐𝑚7 Cross section:8⋅ 10@44𝑐𝑚7

20

Protons Irradiation SummarySEUestimationsfordifferentblocks

MethodofSEUcounting

Cross Section𝜎:events/(part3cm-2)

Cross Section𝝈 persinglebit:cm2/n.bits

Internallogic(allerrorsdetected)

Internal counters 13⋅ 10@44 -

Internallogic (doubleerrorsnotcorrected)

Internalcounters 4 310-12 -

TDC Readperiodically(~1s) 5.8310-11 0.8 310-13

Histograms Readperiodically(~2min) 0.9310-9 0.5310-13

Conf.Regs.+TFC(TMRcorrected)

Internalcounters 8310-11 0.6310-13


• Stable SEU cross section at different fluence values (LET: 0.0086 MeV cm2 /mg), single bit cross section ≃ (0.5 − 0.8) ⋅ 10@4`cm7 ,

• No Single Event Latch-up seen (maybe too low LET to induce it),• No TMR failure,• Stability of current consumption, increase < 5% in 1 eq.LHCb upgrade (0.8 Gy/sec),• Stability of PLL and LVDS jitter and TDC performance.

nSYNC irradiation test - TWEPP 2018 21


X-Ray Irradiation Test

X-Ray facility


X-Ray irradiation system in Cagliari, used in the past to check uniformity on triple-GEM detectors. • X-ray tube with Fe anode, 20kV, max. current 40mA,

water cooled, 250 μm Be exit window;• Smallest X-ray spot: 7 mm diameter;• XY moving system with 50 μm accuracy available,

alignement with radiochromic film; • Same DAQ used at protons facility;• nSYNC with silicon exposed (bare die).

nSYNC irradiation test - TWEPP 2018 23

X-Ray irradiation – Calibration


• Used an Amptek XR-100 CR (300 𝜇𝑚 tick) to study X-Ray spectrum (corrected by det. efficiency and air absorption);

• Added Al filter to harden the spectrum and get more uniform absorption in the silicon (100÷300 𝜇𝑚 Al filter)

• Used a Si PIN (300 𝜇𝑚 tick) to estimate dose rate → Estimate of ~200av Gy/min (100 𝜇𝑚 Al filter).

• A posteriori correction for the dose reduction due to distance from the source.

RelativeDo

se[S

i] Dose VS SI depth weighted with spectrum


0 5 10 15 20 25 30 35 40X-ray tube current (mA)

0

50

100

150

200

250

300

Aver

age

dose

rate

(Gy[

Si] /

min

)

No filter100um Al filter200um Al filter300um Al filter

PIN detector response

24

X-Ray irradiation – Consumption


0 2 4 6 8 10Time (min)

120

130

140

150

160

170

180

Cur

rent

(mA)

Current Consumption (chip decap. @ 3.3V)

0 2 4 6 8 10Time (min)

30

35

40

45

50

55

60

Cur

rent

(mA)

Current Consumption (chip decap. @ 1.2V)

I/O(3.3V) Chipcore(1.2V)

• Not failure behaviour found after several (~12) upgrades,• Current increase in ~1LHCb upgrade compatible with protons beam test:

• ~1-2 % @ low TID, first minutes after irradition start;• ~10% @ higher TID.

Tubecurrent:40mA~100𝜇𝑚 Alfilterd~25mm



First test with one chip decapped, TID collected (16 mins at ~1.7Gy/sec): 1.6 kGy

1upgrade=130Gy 1upgrade=130Gy

25

• Compatible results for the other chips.• Monitored annealing (~1 week). Possibility to continue to irradiate the same chip.

X-Ray irradiation – Consumption


I/O(3.3V) Chipcore(1.2V)

Current increase in 1 LHCb upgrade:• 4% (3.3V) ÷ 7% (1.2V)




- Second test with a previously irradiated chip, after annealing, with different conditions(distance reduced, added Al filters up to 300 𝜇𝑚).- Lower dose rate: ~0.03Gy/sec. Total: 220 Gy (120 minutes)

1upgrade=130Gy 1upgrade=130Gy

• Not failure behaviour after continuing to irradiate the same chip (>3 kGy total),• Even after the annealing and lower dose rate, the consumption increasing is higher,

cumulative (permanent?) effect.26

Conclusions


nSYNC continue to work after several equivalent LHCb upgrades, tested with a TID of 1.2 kGy using protons beam, and up to 3 kGy using X-Ray.


• SEU cross section per single bit ≃ (0.5 − 0.8) ⋅ 10@4`cm7

• Fully digital TDC very stable, small trends within the DCO-dithering correction. • No unexptected effects seen (asymmetries or more vulnerable registers than others);• PLL and LVDS jitter increase ≲ 4%;• Current increase due to TID ~5% in one equivalent LHCb upgrade (130 Gy), with

evidence of cumulative effects (less evident with protons test);• No SEL or micro-SEL found.

Test done to validate the radiation hardening for LHCb upgrade operations, but it isinteresting to further test UMC 130 nm with different LET for cross section and SEL studies.

27

1

2


Backup Slides

Dose expected


• TID expected : 130&' 𝐺𝑦, (𝑚𝑎𝑥 < 200𝐺𝑦)• Hadrons with energy > 20 MeV = 2 3 1044/𝑐𝑚7

• 1 MeV Neutrons equivalent = 2 3 1047/𝑐𝑚7, NIEL dose: 0.65 Gy

FLUKA simulation of Radiation Levels

Considerations:• Muon towers structure not represented in the

simulation geometry;• In general, simulation values for dose tend to

be lower than measurements. The missingtower structures partially compensate for that;

• Measurements took during Run1 suggest thatthe simulation was rather accurate in thesepositions;

• Reccomandation anyway of a safety factor 2.

X=5-1<Y<+1Z=15.2meters

Hotregions


Radiation not so critical in ODE positions (~20÷ 40 times smaller than very FE).Values in hottest regions (M2 – ODE-IB racks) for 10 years of LHCb upgrade:

All values with safety factor 2

Y,cm

[Rate:~6 3 10@f𝐺𝑦/𝑠𝑒𝑐]

30

Dose expected in other regions


Station IB-ODE position (x,y,z in meters)

Dose (Gy) Hadrons fluence(cm-2) (>20MeV)

1 MeV neutr. eq. fluence (cm-2)

M3 (5.5, ±1, 16.4) av. 60 Gymax. 73 Gy

av. 6.631010

max. 8.631010av. 1.731011

max. 231011

M4 (6, ±1, 17.6) av. 53 Gymax. 62 Gy

av. 6.331010

max. 7.531010av. 1.431011

max. 1.631011

M5 (6.5, ±1, 18.8) av. 48 Gymax. 61 Gy

av. 7.431010

max. 7.931010av. 231011

max. 2.131011

All values with safety factor 2.

31

Dose expected in other regions


Fluence little bit bigger in M5 wrt M4

X=500

X=650

X=550

X=600

1 MeV neutrons eq. fluence

32

Experimental setup at Catana

20/09/18- DavideBrundu nSYNC irradiation test - TWEPP 2018 33

Experimental setup at Catana

20/09/18- DavideBrundu nSYNC irradiation test - TWEPP 2018 34

DAQ system used at Catana - FSM


The DAQ software is based on a FSM with 5 states in order to:• Switch easier from/to different functionalities,• Perform a smart error handling, since different kinds of errors are present: Hw from

oscilloscope or I2C dongle, soft radiation-induced errors from the chip, I2C communication errors, such as address not ack. etc.

35

DAQ system used at Catana


Communication between the two domains is possibile sending notifiers (LabVIEW tool for tasks synchronization), wihout interfere with the parallelism.

The DAQ software architecture is based on: • a first fast-loop that expects user actions from the front panel in real time,• a second (above) asynchronous loop that performs measurements and r/w operations

on the nSYNC.

36


Current consumption• Monitored the current consumption for the chip core (@ 1.2 V) and I/O (@ 3.3 V)

Note: complete power cycle after every run → small fluctuactions exptected.• Current very stable at low dose rate, small instability/increase at higher dose rate;

→ Instability of the beam current and changing of the frame pattern in output interface(from CCCC to AAAA) → no failure behavior seen.


Chipcore(1.2V)I/O(3.3V)

37


Current consumption for chip 13Small increase in the current in the 3.3V supply also in the first runs. Not observedin chip 14.

Only run 1 and 2 (@ 0.08 Gy/sec)

Current increase:~1.2% with 400 Gy (~3 upgrades)~1.6% with 800 Gy (~6 upgrades)

0 200 400 600 800 1000Time (sec)

128.8

129

129.2

129.4

129.6

129.8

Curren

t (mA)

Current Consumption (chip 13 @ 3.3V)

0 200 400 600 800 1000 1200Time (sec)

126.5

127

127.5

128

128.5

129

129.5

Cur

rent

(mA)

Current Consumption (chip 13 @ 3.3V)

400 Gy

Run1

Run2

38


Channels vulnerability – TDC

• Check for channels vulnerability: histogram of SEU per channel number;

• Low statistics to perform deeper studies, but no particular trend seen.SEU widespread over all channels.

0 5 10 15 20 25 30 35 40 45Channels

0

1

2

3

4

5

6

Flip

s / c

hann

el

TDC SEU (chip 14)

0 5 10 15 20 25 30 35 40 45Channels

0

1

2

3

4

5

6

Flip

s / c

hann

el

TDC SEU (chip 13)

39


Channels vulnerability – Histograms

• Check for channels vulnerability: counted number of SEU wrt channel number, grouping together the corresponding 16 counters (3 byte/counter).

• No particular trend seen, SEU widespread over all channels.

0 100 200 300 400 500 600 700Sequential bins

8

10

12

14

16

18

20

22

24

Flips

/ cha

nnel

Histograms SEU (chip 14)

0 100 200 300 400 500 600 700Sequential bins

12

14

16

18

20

22

24

26

28

Flip

s / c

hann

el

Histograms SEU (chip 13)

0 ChannelNumber 47 0 ChannelNumber 47

40


TDC performance for chip 13

• Check for unexpected trend in TDC performance wrt TID, reading TDC status immediately after a calibration, in order to not include SEU.

• No trend found: calibration curves superimposable, TDC very stable.

10 15 20 25 30TDC resolution

0

2

4

6

8

10

12

TDC

Sta

tus

num

ber (

for c

h. 0

)


0 10 20 30 40Channel number

3.4

3.6

3.8

4

4.2

4.4

4.6

TDC

Sta

tus

num

ber @

res.

16


Calibration curves for ch. 0 Calibration curves for resolution 16.

41


TDC performance for chip 14 – ch.31

A very tiny trendfrom 0 Gy to higherdoses, but within the dithering correction(trend not significant)

6 8 10 12 14 16 18 20 22Resolution

2

3

4

5

6

7

8

9

10

TDC

sta

tus

num

ber (

ch.3

1) 0 Gy80 Gy160 Gy240 Gy320 Gy400 Gy800 Gy1200 Gy

42


EDAC and TMR in chip 13• Counting the number of TMR activaction in configuration registers (using internal counter) and error

detection for hamming and EDAC (using internal counters).

• Important points:• SEU in conf.regs. are always corrected by TMR (get an upper limit to cross section)• SEU in internal logic not corrected only if double errors (~3% of errors detected)


10

20

30

40

50

60

70

n.SE

U


10

20

30

40

50

60

70

n.SE

U

Conf.Regs.Hamm.+EDAC

n.SEU

detected

n.SEU

detected

Cross section:13⋅ 10@44𝑐𝑚7 Cross section:8⋅ 10@44𝑐𝑚7

43


All cross sections measured

44

TDCChip 14: 6.7 ± 0.3 ⋅ 10@44𝑐𝑚7

Chip 13: 4.9 ± 0.2 ⋅ 10@44𝑐𝑚7

HistogramsChip 14: 10.4 ± 0.3 ⋅ 10@4X𝑐𝑚7

Chip 13: 8.7 ± 0.1 ⋅ 10@4X𝑐𝑚7

Config. Regs. Chip 14: 8.5 ± 0.1 ⋅ 10@44𝑐𝑚7

Chip 13: 6.9 ± 0.2 ⋅ 10@44𝑐𝑚7

Part of Internal logic(hamming + EDAC)

Chip 14: 16.5 ± 0.2 ⋅ 10@44𝑐𝑚7

Chip 13: 10.3 ± 0.3 ⋅ 10@44𝑐𝑚7

Errors in Config. Regs. without TMR correction (upper limit) < 8 ⋅ 10@4`𝑐𝑚7 @ 95%CL

Part of Internal logic(Hamming + EDAC) double errors

not corrected

Chip 14: 4 ⋅ 10@47𝑐𝑚7

Chip 13: <3 ⋅ 10@47𝑐𝑚7 @ 95%CL


Beam Current @ Catana(InWater)

Chip13(05/07/2017)

45


Beam Current @ Catana(InWater)

Chip14(04/07/2017)

46

X-Ray irradiation – Calibration


• Important: X-Ray spot has an angular semi-aperture of ~3.6° (estimated measuring spot diameter at different distances with radiochromic film),

• Changing the distance from the tube will change the dose:𝐷 𝑧 = 𝐷(0) 3 𝑅jklm7 (0)/𝑅jklm7 (𝑧)

• We have taken into account this dose reduction, based on the nSYNC – X-Ray tube distance.


0 50 100 150 200 250 300distance from beam (mm)

0

20

40

60

80

100

120

140

160

180

200

Aver

age

dose

rate

(Gy[

Si /

min

])

100um Al filter200um Al filter300um Al filter

fz1

Average dose (in 300 𝜇𝑚Si) wrt distance from the X-Ray tube

Distance fromtube(mm)

At 25 mm → Reduction by a factor 2.100av Gy/min using 100 𝜇𝑚 Al.

47


X-Ray irradiation in Cagliari - spectrum

Kα1 eKα2:~6396eV(2mergedlines)Kβ:7058eV(1line)

Kα Siescapepeak:~4656eV

48



Fittox-raymassattenuationcoefficientμ/ρ (allinteractions)andthemassabsorptioncoefficientμ/ρen(photoelectric)intherange2-30keVusingdatafromhttp://physics.nist.gov/PhysRefData/XrayMassCoef/ElemTab/z14.html

𝜀 𝐸 = 1 − 𝑒@o p q

Correctedspectra →𝑁ks(𝐸t) =uvwxyz{y||(p})

~(p})

d=detectorthickness

49



• Use of aluminum filters of various thickness could be used to reduce the low-energy component

• Effect of approximately 100μm Al filter on the X-Ray spectrum

50


Dose estimation with Si-PIN diode

Used a Si-PIN detector to perform an absolute estimate of the dose rate for the X-Rayradiation.

Supposing 1 W power deposition:

1𝑊 =1𝐽𝑠𝑒𝑐 = 6.242 3 104�𝑒𝑉/𝑠𝑒𝑐

1.734 3 104�𝑒ℎ𝑝𝑎𝑖𝑟/𝑠𝑒𝑐 = 0.2778𝐴

Sensitivity: 0.2778A/W

3.6eV forcreate1ehpair

𝐷𝑜𝑠𝑒𝑅𝑎𝑡𝑒 =𝑃𝑜𝑤𝑒𝑟𝑀𝑎𝑠𝑠 =

𝐶𝑢𝑟𝑟𝑒𝑛𝑡𝑆𝑒𝑛𝑠𝑖𝑡𝑖𝑣𝑖𝑡𝑦 ∗ 𝑀𝑎𝑠𝑠

Where with the mass term we consider the mass corresponding to the volume, in the PIN detector, irradiated by the full spot:

𝑀 = 𝐴�� 3 𝑑��u 3 𝜌�t

• To estimate the max. dose rate, the full spot must be inside the active area of the PIN diode. • This metod provides a lower limit to the dose, because we are neglecting inefficiencies (we are

considering a maximum/ideal sensitivity) and an average dose in the full thickness.• Suppose to have a detector with the same area of the spot and unitary mass: moving it far away

from the X-Ray tube leads to a smaller dose rate, if the beam has a non-vanishing angularaperture (neglecting air attenuation). The dose rate scale with the square of spot radius:𝐷 𝑧 = 𝐷(0) 3 𝑅jklm7 (0)/𝑅jklm7 (𝑧)

51


X-Ray spot aperture

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• Used radiochromic film to measure spot diameter at different distance. Spot shape elliptical with small eccentricity.

• Estimation of angular semiaperture (3.77° horizontal, 3.63° vertical)

mm mm

mm mm


X-Ray radiation test – different distances

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Distance~14𝑚𝑚Distance~25𝑚𝑚

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Irradiation test on the nSYNC ASIC using X-Ray and protons ... · nSYNC architecture 20/09/18 - Davide Brundu nSYNC irradiation test - TWEPP 2018 5 48 LVDS Input channels: • Fully