1. Optical Blocking Filter and Dust-proof Film for HXMT
Tianxiang Chen
IHEP, Beijing, 21 March 2017

2. The overview of Optical Blocking Filter and dust-proof Film

3. The Dimension design of Optical Blocking Filters
The dimension of optical blocking filter is in accordance with collimators

4. The structure of optical blocking filter
100 nm Al
≥65 μm Ni
400 nm PI
100 nm Al PI Ni
The dust-proof Film is composed by 300 nm polyimide film and ≥65 μm Ni frame with no mesh and no aluminum films compared with optical blocking filters

5. The transmittance of optical blocking filters in UV-VIS band
Different thickness Al film coated on 400 nm polyimide
The transmittance is beyond the resolution of the UV-VIS spectrometer for 120 nm and 180 nm Al.

6. The transmittance of filters in soft X-ray band
The transmittance of an optical blocking filter (Al/PI/Al = 100/230/100nm) in soft X-ray band
the soft X-ray transmittance of optical blocking filter (Al/PI/Al=100/246/100nm) before and after irradiation. Irradiated A and Irradiated B curves were the two samples exposed with proton irradiation in the same dose (1010 protons/cm2) and energy (10MeV)

7. Acoustic test of optical blocking filters and dust-proof film
Test condition
The optical blocking filters and dust-proof films are mounted on the top and bottom of the collimators which are assembled in a light shielding structure
Frequency （Hz）
SPL（dB） Reference sound pressure amplitude：2×10-5 Pa
Acceptance level
Appraisal level
Tolerance （dB）
31.5
120
124
-2 ~ +4 63
126
130
125
131
135
250
137
141
500
139
1000
133
2000
4000
122
127
-5 ~ +5
8000
115
119
Total SPL
145
-1 ~ +2
time
1 min
2 min
Sound field
Reverberation field

8. Acoustic test of optical blocking filters and dust-proof film
The light shielding structure are mounted in the reverberation room
Samples with defect in polyimide will be broken.
Samples with no mesh can also survive after acoustic test.
Al/PI/Al=100/400/100 nm sample 4 and 2
Al/PI/Al=100/200/100 nm sample 3

9. Other test of optical blocking filters
Thermal cycling test conditions:
Appraisal level temperature range: -50~+40℃；
Thermal cycling 25.5 times；
average temperature change rate 3~5℃/min；
filled with dry nitrogen；
Avoid direct blow the temperature monitoring point with the circulation wind in the test.
Thermal vacuum test conditions:
1. Tolerance：High temperature（0~+2℃），low temperature（-2~0℃）
2. Appraisal level temperature range :-95~-15℃
3. vacuum level：≤1.3x10-3Pa
4. Thermal circulation 6.5 times，total 13 working conditions.

10. Other test of optical blocking filters
Random vibration test condition
Frequency（Hz）
Power spectral density（g2/Hz）
Appraisal level
Acceptance level
10~100
+3dB/oct
100~600
0.125
0.05
600~2000
-9dB/oct
RMS acceleration
10.14g
6.41g
time
2min
1min
direction
Along X、Y、Z three axis
Sine vibration test condition
axis
Frequency（Hz）
acceleration / Amplitude 0~P
Appraisal level
Acceptance level
X、Y、Z
5-15
13.5mm
9.0mm
15-85
12g 8g
85-100
10g
6.7g
Scan speed
Every axis：2 Oct/min
Every axis：4 Oct/min
Impact test condition
Frequency（Hz）
Appraisal level（g）Q=10
100~500
+6dB/oct
500~4000
200
direction
3 axises
Times every axis 3

11. Thermal filter for LAD in eXTP
Thermal filter photo taken in IAPS
LUXEL Polyimide: 1 micron
Aluminum: 40 nm
From the paper“Baseline design of the filters for the LAD detector on board LOFT”. Marco Barbera etc.

12. The feasibility of manufacturing thermal filters for LAD
1 micron polyimide film is easy to manufacture by spinning;
40 nm aluminum film is easy to prepare by vacuum coating;
Nickel frame is easy to prepare by electroplating.
120mm
80mm
4mm
6 inch

13. Smaller thermal filter prepared for LAD
900nm PI
40nm Al
Electroplating Ni frame with no mesh
More than 100 micron
The wafer supported by our Mask Aligner is 6 inch.
The wafer supported by our magnetron sputtering deposition system is 4 inch.

14. The instruments used for measuring the properties of optical blocking filters
UV-3600Plus UV-VIS-NIR Spectrophotometer is used for measuring the transmittance of the filters in the UV-VIS-NIR band
KLA-Tencor Alpha-Step D-100 profilometer is used for measuring the thickness of films

15. Thank you!