Transcript PIXE-TES results from Jyväskylä

LARGE AREA TRANSITION-EDGE SENSOR
ARRAY FOR PARTICLE INDUCED X-RAY
EMISSION SPECTROSCOPY
M Palosaari1, K Kinnunen1, I Maasilta1, C Reintsema2, D Schmidt2, J Fowler2, R
Doriese2, J Ullom2, M Käyhkö1, J Julin1, Mikko Laitinen1, T Sajavaara1
1Department
2National
of Physics, University of Jyväskylä, P.O. Box 35, Jyväskylä 40014, Finland
Institute of Standards and Technology, Boulder CO 80305, United States
email: [email protected]
INTRODUCTION to TES
Superconducting Transition-Edge Sensor
Transition-Edge Sensor (TES)
 TES as a calorimeter
– Measures the energy of incident radiation
Typical pulse from a calorimeter
Schematics of a calorimeter
TES Operation

Operates between superconducting and normal state

Extremely sensitive R(T)

Excellent energy resolution

Wide energy range

Detects radiation,
in our case X-rays

Particles also possible
Normal
state
Superconducting
state
Typical transition of a TES
TES basics

TES thin film device is made of normal metal superconducting metal bilayer.

The absorber details depend on the desired energy range.

TESs are usually fabricated on thin SiN membranes to limit the
thermal conductivity G.
Photograph of a 256 pixel
TES array made in VTT, Finland.
In typical TES array, all pixels different
-> automated calibration essential
PIXE-TES SETUP IN JYVÄSKYLÄ
PIXE-TES Setup in Jyväskylä
Details inside the instrument
~15 mm
~300 mm
Jyväskylä TES specifications

160 pixels from NIST, upgradable to 256 (from VTT)

Total area with 160 pixels ~16 mm2

Single pixel count rate limited to <20 Hz, typical value 10 Hz

2 mm thick Bi absorber with Mo/Cu superconducting juction

Detection efficiencies
with 100 um of Be:
80 % at 5 keV,
20 % at 10 keV,
5 % at 30 keV

Low energies limited by
MeV particle absorber,
probably not needed
PIXE-TES MEASUREMENTS
From a single pixel to many…
PIXE-TES results from Jyväskylä
Roughly one year ago: 12 pixels
Mn Kα from Fe-55 source
Best pixel
Instrumental resolution for the best pixel
with 55Fe source was 3.06 eV
PIXE-TES results from Jyväskylä
Now: 160 pixels…
• But, Computer interface and I/O cards
cannot handle all pixels simultaneously
• I/O card + PC update coming from NIST
to finally secure the function of all 256
possible channels, simultaneously.
This month: data with Fe-55 source
Resolution around 5 eV
for combined 40 pixels,
Improvement seen by
better data
analysis
PIXE-TES results from Jyväskylä
SRM-611, trace elements in glass
All TES data shown was analyzed last week, 1 eV / bin
Analysis resolution for all of these plots ~10 eV
PIXE-TES results from Jyväskylä
SRM-611, trace elements in glass
PIXE-TES results from Jyväskylä
SRM-611, trace elements in glass
Differences between pixels which are not only statistics
PIXE-TES results from Jyväskylä
SRM-1157, speciality tool steel
No Si escape peak
Bi escape peaks
Single measurement, wide energy range
PIXE-TES results from Jyväskylä
SRM-1157, speciality tool steel
V, Cr, Mn, Fe separated
In the Near Future

Read-out upgraded to full scale.

Modification of PIXE setup to be able to measure samples
in atmosphere.

Study art samples in a project that just started

X-ray measurements with our own detector array
fabricated by VTT.

Study the satellite peaks with different ions and energies.

->> Chemical information from wide energy/elemental range ???
Conclusions

Instrumental resolution of 3 eV demonstrated

Combined pixel resolution of ~5 eV looks realistic

Wide energy scale (“0” to tens of keV)

Reasonable count rates available (10 Hz/pixel, 256 pixels)

Active detector area about 16 mm2

No liquid He needed for ADR cryo cooler

Largish instrument: ~5 cm sample-to-detector

Data handling and analysis: automation necessary

Is the chemical information achievable, after all ?
Acknowledgements
t
3-8. July, 2016, in Jyväskylä, Finland
Pixel calibration
Single pixel shows Si peaks nicely but without good calibration, sum spectrum useless
Sample: SRM-611
No/bad calibration regime
good calibration
TES-PIXE data calibration
Raw pulse height data
where sample was changed.
Sample 2
Eenergy scale
Sample 1
Substrate was Si for both samples
Measurement time/duration
TES-PIXE data
Making selection to single (example) emission line
• Before liner fit
Straight line to guide the eye
TES-PIXE data
• After linear fit
Si
Straight line to guide the eye
Si
Nitride hits
PIXE Mn vs. 55Fe
Mn Kα from Fe55 source
same pixel
What is the origin of the hump?
Detector performance: PIXE Mn vs. 55Fe source
Instrumental resolution for the best pixel with 55Fe source was 3.06 eV.
For 2 MeV protons and Mn sample resolution was 4.20 eV.
M. Palosaari et. al J. Low Temp.
DOI 201310.1007/s10909-013-1004-5
PIXE applications
Traditional PIXE applications
–
–
–
–
Archaeology
Geology
Filters in industry
Old paintings
With better detectors
one could see the
chemical environment
of the sample.
Rev. Sci. Instrum. 78, 073105 (2007)
J. Hasegawa et. al
TES vs. SDD
Impurities in the Cu sample resolved better with TES detector
Stainless steel example
PIXE Mn vs. 55Fe
Mn Kα from Fe55 source
same pixel
FWHM broadens less than 1eV.
TES vs. SDD
TES circuit diagram
Example: Thin film with high mass element

Atomic layer deposited Ru film on HF cleaned Si

Scattered beam, 35Cl, used for Ru deph profile

Monte Carlo simulations needed for getting reliable
values for light impurities at the middle of the film
Ru
SiO2
Si
Poor E resolution
Low energy heavy ion ERDA – See posters!
Example: Diamond-like carbon films

2.3 µm thick diamond-like-carbon film on Si, measured with 9 MeV 35Cl

All isotopes can be determined for light masses

Light elements can be well quantified (N content 0.05±0.02 at.%)
Low energy heavy ion ERDA
ALD 8.6 nm Al2O3/Si

Atomic layer deposited Al2O3 film on silicon (Prof. Ritala, U. of Helsinki)

Density of 2.9 g/cm3 and thickness of 8.6 nm determined with XRR (Ritala)

Elemental concentrations in the film bulk as determined with TOF ERDA
are O 60±3 at.%, Al 35±2 at.%, H 4±1 at.%. and C 0.5±0.2 at.%
10 nm CNx on silicon

TOF-ERDA results from sputter deposited 10 nm thick CNx hard coating on
Si. Measured with 6 MeV 35Cl beam and extreme glancing angle of 3°

A density of 2.0 g/cm3 was used in converting areal densities to nm
Effect of stripper gas pressure

13.6 MeV 63Cu7+ CaPO (hydroxyapatite)
Gas ionization detector

Thin (~100 nm) SiN
window

Electrons for T2
timing signal
emitted from the
membrane
Future improvements: Gas ionization detector
TOF-E results from ETH Zürich
Incident ion 12 MeV 127I and borosilicate glass target
Nucl. Instr. and Meth. B 248 (2006) 155-162
200 nm thick SiN membrane from Aalto
University, Finland, on 100 mm wafer
Gas ionization detector to replace
Si-energy detector

Why try to fix a well working system?



Greatly improved energy resolution for low energy heavy ions →
heavier masses can be resolved
Gas detector is 1D position sensitive by nature → possibility for
kinematic correction and therefore larger solid angles possible
Gas detector does not suffer from ion bombardment
Recoil ranges in isobutane
10.2 MeV 79Br
8.5 MeV 35Cl
Gas ionization detector develoment – See posters!