Energy resolution with ParyleneN

1
Evaluation of the IR-UV blocking filters for
ADR With a TES microcalorimeter
A. Hoshino, K. Shinozaki, Y. Ishisaki, T. Ohashi,
K. Tanaka1), T. Mihara2), Y. Tawara3) Tokyo
Metropolitan university, 1) SII Nanotechnology,
2) RIKEN, 3) Nagoya University
IR to UV blocking filters are indispensable for
refrigerators of space missions, hence material
and design of the filters determine overall X-ray
detection efficiency. We have tested
Toray-Lumirror (C10H8O4) and Parylene-N (C8H8)
films with thin Al coating, installed in a
portable ADR system with a TES microcalorimeter.
Aperture cone structures are attached surrounding
the films to protect them from adhesion of
contaminant. The system was connected to the
Manson X-ray generator with a vacuum duct, and
the X-ray spectrum from the electron beam target
was obtained by cooling down to 100 mK. We
observed bremsstrahlung continuum and
fluorescence lines from the electron target
modified with C- and O-edges of the filters and
strong C-/O-Ka lines. We fitted the depth of
each edge and determined the quantities of both
elements in line of sight. The fit result is
consistent with the expected values for C and Al,
while suggesting 1.0-1.6 µm built-up of ice for
O. We may need to contrive the way to avoid
contaminant, e.g., introducing heaters.
1. Purpose
Designed X-ray Transmissions
The IR-UV blocking filters are necessary for
observations of soft x-ray spectra with TES
calorimeters. We introduce two experimental
projects in which the filers are essential.
B.L. Henke, E.M. Gullikson, and J.C. Davis.
http//www.cxro.lbl.gov/optical_constants/filter2
.html
I. DIOS mission
Transmission
DIOS is a relatively small Japanese X-ray mission
which will study large-scale distribution of the
warm-hot intergalactic medium (WHIM) using OVII
(566-665 eV) and OVIII (653 eV) emission lines.
Interior structure
DIOS spacecraft
Energy (keV)
Red Parylene-N from filter thickness Blue Toray-
Lumirror from filter thickness Green Suzaku XRS
IR-UV blocking filters (Al-Polymide)
6 m
Including the detection efficiency of the XSA,
gt 50 Assuming the focal length of the FXT, L
70 cm XSA (X-ray Spectrometer Array)
Aperture cones were attached after Toray-Lumirror
measuring experiment.
II. Observation for soft x-ray of Reversed Field
Pinch plasma
3. Experimental setup
With a TES microcalorimeter, investigating the
characteristic soft X-ray lines (C, O, Fe, Mo,
Cr) of impurities to evaluate the contribution of
line intensity to continuum, and then estimate
electron temperature. (L49, K.Shinozeki et al, in
this conference)

• X-ray generator was connected to ADR in vacuum.
• We got the primary X-ray spectrum with a TES
  microcalorimeter bremsstrahlung continuum
  fluorescence lines.

ADR Dewar
2. Introduction of Experimental Instruments
2.1 TES microcalorimeter
Manson X-ray generator model 3B
1616 pixel TES microcalorimeter array
TES microcalorimeter (100 mK)
R
Al target
4. X-ray spectrum
Measured spectra were evaluated with XSPEC
spectrum fitting packages in the energy range 0.2
- 2.5 keV. The best fit model convolved with
detector response is overlaid. Film thickness and
contaminations are evaluated from the absorption
edge depth.
?R
Operating point
T
?T
Spectrum with Toray-Lumirror filters
TES microcalorimeter

• X-ray energy is measured as a rise of
  temperature .
• In DIOS mission, 1616 pixel formatted array of
  TES
• microcalorimeters is planned for the focal
  plane detector.
• FWHM 6.6 eV achieved in our laboratory.
• cool down to 100 mK by ADR
• The theoretical energy resolution of a
  microcalorimeter

HV 3 kV / 583 kcts / 16 ksec
C-Kedge
Au-Medge (TES origin)
O-Kedge

• Energy resolution with TorayLumirror
• C-Ka FWHM 11.5 0.1 eV
• O-Ka FWHM 23.5 0.1 eV

X-ray spectrum at TMU
FWHM 6.6 0.4 eV at Mn-Ka1 (5898 eV) Ka2
(5887 eV)
TES paramaters
Spectrum with Parylene-N filters
HV 3.5 kV / 6.4 kcts / 3.2 ksec
Al-Kedge
O-Kedge
C-Kedge

• Energy resolution with Parylene-N
• C-Ka FWHM 13.1 0.1 eV
• O-Ka FWHM 26.1 0.3 eV

Au-Medge (TES origin)
Measured and designed X-ray Transmissions
5. Evaluation of Transmissions
The obtained thickness of the contaminant H2O is
thicker for the Toray-Lumirror film. Aperture
cone worked as a role to decrease the H2O
contamination.

• The O-Kedge (0.5 keV) in the spectra with
  Parylene-N filters indicate the existence of
  contaminant with outgas or intrinsic components
  of X-ray generator.
• Transmission of Parylene-N filters are degraded
  by 1-10 at 0.6 keV probably due to the
  contamination of H20.
• The thickness of H20 on Parylene-N filters is 1
  µm.
• Al-Kedge were not seen in the spectrum with
  Toray-Lumirror.

Transmission
Energy (keV)
6. Discussion
Pink transmission of Parylene-N filters from
absorption depth Red that of Parylene-N from
filter thickness Cyan that of Toray-Lumirror
from filter absorption depth Blue that of
Toray-Lumirror from filter thickness Green that
of Suzaku XRS IR-UV blocking filters

• The three steps to accomplish the designed
  transmission for DIOS
• Mylar film to work as vapor cooling in the
  refrigerator which is the source of outgas should
  be cut down as possible.
• We should install absorbant material around the
  blocking filters to help the ability of
  absorption.
• Install a heater on each filter, and prevent
  outgas from attaching on it.

• How to derive the film thickness by atomic
  abundance
• abundance from absorption depth (using XSPEC
  parameters) Nabs. abundance (angr) vphabs
  par. (nH) vphabs par. (each atom)
• abundance from film thickness Nthick.
• (atoms/molecular) (number density) (film
  thickness)
• (film numbers) (NA) (atomic weight)
• Measured thickness (Nabs. / Nthick) designed
  film thickness