1. email: mikko.i.laitinen@jyu.fi
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 of Physics, University of Jyväskylä, P.O. Box 35, Jyväskylä 40014, Finland
2National Institute of Standards and Technology, Boulder CO 80305, United States

2. INTRODUCTION to TES Superconducting Transition-Edge Sensor

3. Transition-Edge Sensor (TES)
TES as a calorimeter
Measures the energy of incident radiation
Schematics of a calorimeter
Typical pulse from a calorimeter

4. Superconducting state
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
transition edge
Superconducting state
Typical transition of a TES

5. 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.
In typical TES array, all pixels different
-> automated calibration essential
Photograph of a 256 pixel TES array made in VTT, Finland.

6. PIXE-TES SETUP IN JYVÄSKYLÄ

7. PIXE-TES Setup in Jyväskylä

8. Details inside the instrument
~15 mm
~300 mm

9. 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

10. PIXE-TES MEASUREMENTS From a single pixel to many…

11. 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

12. 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

13. 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

14. PIXE-TES results from Jyväskylä
SRM-611, trace elements in glass

15. PIXE-TES results from Jyväskylä
SRM-611, trace elements in glass
Differences between pixels which are not only statistics

16. PIXE-TES results from Jyväskylä
SRM-1157, speciality tool steel
No Si escape peak
Bi escape peaks
Single measurement, wide energy range

17. PIXE-TES results from Jyväskylä
SRM-1157, speciality tool steel
V, Cr, Mn, Fe separated

18. 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 ???

19. 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 ?

20. Acknowledgements

21. t
3-8. July, 2016, in Jyväskylä, Finland

22. Pixel calibration
Single pixel shows Si peaks nicely but without good calibration, sum spectrum useless
Sample: SRM-611
No/bad calibration regime
good calibration

23. TES-PIXE data calibration
Raw pulse height data where sample was changed.
Sample 1
Sample 2
Eenergy scale
Substrate was Si for both samples
Measurement time/duration

24. TES-PIXE data Making selection to single (example) emission line
Before liner fit
Straight line to guide the eye

25. Straight line to guide the eye
TES-PIXE data
After linear fit Si Si
Straight line to guide the eye

26. Nitride hits

27. PIXE Mn vs. 55Fe What is the origin of the hump?
Mn Kα from Fe55 source
same pixel
What is the origin of the hump?

28. 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 /s

29. PIXE applications Traditional PIXE applications
Archaeology
Geology
Filters in industry
Old paintings
Rev. Sci. Instrum. 78, (2007)
J. Hasegawa et. al
With better detectors one could see the chemical environment of the sample.

30. TES vs. SDD
Impurities in the Cu sample resolved better with TES detector

31. Stainless steel example

32. PIXE Mn vs. 55Fe FWHM broadens less than 1eV. Mn Kα from Fe55 source
same pixel
FWHM broadens less than 1eV.

33. TES vs. SDD

34. TES circuit diagram

35. 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
Metallic films have traditionally been difficult to deposit with ALD. This is one example of ongoing analysis of these Ru thin films. Scattered 35Cl is used for Ru depth profile, recoiled Ru suffers too much from multiple scattering.
Poor E resolution
Low energy heavy ion ERDA – See posters!

36. 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.%)
Menetelmä soveltuu bulk-näytteiden mittaamiseen.
Low energy heavy ion ERDA

37. 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.%
Parhaimmillaan menetelmä on ohutkalvotutkimuksessa. hiili eroaa pinnassa ja rajapinnassa (surface and interface).

38. 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
Tavalliset jorinat, kehutaan syvyysresoluutiota. Mainitaan kalvossa näkyvän aikaismman kasvatuksen jäljiltä fluoria sekä kromia + sputteroinnista johtuen argonia. 38

39. Effect of stripper gas pressure
13.6 MeV 63Cu7+ CaPO (hydroxyapatite)

40. Gas ionization detector
Thin (~100 nm) SiN window
Electrons for T2 timing signal emitted from the membrane
Myös etusironneita elektroneja: paikkaherkkään anodiin 40

41. Future improvements: Gas ionization detector
30 mm
Massaerotuskyky raskaammille massoille paranee huomattavasti, huomaa mm Si:n isotoopit
TOF-E results from ETH Zürich
Incident ion 12 MeV 127I and borosilicate glass target
200 nm thick SiN membrane from Aalto University, Finland, on 100 mm wafer
Nucl. Instr. and Meth. B 248 (2006)

42. 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!