The research on vacuum window of cryogenic receiver

The research on vacuum window of cryogenic receiver Wang kai 2015 -7 -9 中国科学院新疆天文台 XINJIANG ASTRONOMICAL OBSERVATORY, CHINESE ACADEMY OF SCIENCES

目 录 • What is vacuum window？ • the samples of vacuum window • The requirement of vacuum window：Sealing、 wave-transparent、Resistance to pressure • the measurement of vacuum window • the fabrication of vacuum window 2

What is vacuum window? 3

S/X dual-band cryogenic receiver PTFE（聚四氟乙烯） polyimide film（聚酰亚胺） Polystyrene foam（聚苯乙烯） 4

XAO 1. 3 cm band cryogenic receiver PETP(Polyethylene terephthalate)： MYLAR（聚对苯二甲酸乙二醇酯）, tensile strength ：MD 186. 2 MPa，TD 205. 8 MPa，thiceness: 0. 188 mm, Diameter=125 mm, Insertion loss= 0. 05 d. B 5

Broadband cryogenic receiver vacuum window Broadband： 1. 2 -9 GHz, Diameter=500 mm，noise=2. 5 K。 • PTFE： 0. 75 mm • polyimide film： 150 MPa , 3. 5± 0. 4 , 0. 075 mm ，noise=1 K(X-band) • PMI foam： polymethacrylimide（聚甲基丙烯酰亚胺），6. 069 MPA， 1. 12 （f=10 GHz），noise＜ 2 K • Nylon材料： polyamide (聚酰胺纤维) 6

21 cm EFFelsberg 7 beam receiver 7

21 cm EFFelsberg 7 beam receiver Ceramic PTFE(teflon) 8

The requirement of vacuum window：Sealing • ALMA Band-6： 73. 7 -88. 3 GHz, WR 10($1000) • Mylar • Epoxy：Epo-Tek 301 -2 [2] epoxy, a low dielectric constant and loss 9

Sealing 10

Sealing 11

wave-transparent The Q/U Imaging Experiment (QUIET receiver) 19 beams Q-band(30 -40 GHz)，d=266. 7 mm; 90 beams W-band(4090 GHz), d=558. 8 mm • Teflon: n=1. 2, Anti-reflection Coating , loss tangent: 2. 5× 10− 4 • LDPE: low-density polyethylene(低密度聚乙烯) • UHMW-PE: ultra-high molecular-weight polyethylene（超高分子量聚乙烯）， n=1. 52，3/8”（0. 95 CM） • Polystyrene foam： 10 cm 12

wave-transparent 13

wave-transparent n（teflon）=1. 2± 0. 07 14

Resistance to pressure • VLBA, Polystyrene foam（聚苯乙烯） Emerson Eccofoam PS-1. 04+EPOXY , 40 psi, 6. 4 E-8 1. 3 -1. 8 GHz（L），thickness 2. 5”，d = 6. 3”； 3. 0 -3. 4 GHz（S），thickness 1. 0”，d = 4. 1”； polyethylene(聚乙烯)+ Eccofoam PS-1. 04 • NRAO，MYLAR 15

2000 ALMA, the dielectric constant 60 mil , 40 mil, 20 mil RA 7956 16

2000，ALMA，transmission and reflection • QMC 100 for Bands 3（84 -116 GHz）、 QMC 230 for band 6(211 -275 GHz） • quartz（0. 226”） 17

2000，ALMA，transmission and reflection 18

2001，ALMA band 3 -10 • insertion loss＜ 0. 1 d. B，reflection loss＞ 20 d. B 19

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GBT 3 mm Receiver Quartz Vacuum Window • GBT 3 mm(68 -116 GHz) , diameter=80 mm • Goretex: AR, thickness>0. 02”, adhesion epoxy(0. 0002”) • HDPE: AR layers, 1/16”, adhesion epoxy • Quartz：thickness=0. 225” 0. 57 cm， d=3. 75” (9. 525 CM) 22

the fabrication of vacuum window（3 mm） 23

the fabrication of vacuum window（3 mm） 24

the fabrication of vacuum window（3 mm） 25

the fabrication of vacuum window（3 mm） 26

the fabrication of vacuum window（3 mm） 27

the fabrication of vacuum window（3 mm） 28