Recent Radiation Monitoring Results: Expedition 10, 11 and STS-114

Transcription

1 Recent Radiation Monitoring Results: Expedition 10, 11 and STS-114 E. Semones, M. Weyland; B. Rutledge, T. Shelfer; R. Gaza; D. Zhou; A. Johnson; and N. Zapp WRMISS 10 Chiba, Japan Lyndon B. Johnson Space Center 9/7/05

2 Mission Timeline Expedition Status Launch (GMT) Landing (GMT) Duration Crew ISS-9 Flown 19-Apr :19:00 24-Oct :36: days 9 hr. 17min. Gennady Padalka, Michael Fincke ISS-10 Flown 14-Oct :06:00 24-Apr :08: days 19 hr. 2min. Leroy Chiao, Salizhan Sharipov ISS-11 In Progress 15-Apr :46:25 Estimated: 10-Oct days 23 hr. 13min. Sergei Krikalev, John Phillips Mission (Increment) Status Launch Date (GMT) Landing Date (GMT) Duration (hours) Inclination ( ) # Crew # Intl. EVA's Vehicle Crew STS-114 (LF1) Flown 26-Jul :39:01 09-Aug :11:00 13 days 21 hr. 31min Discovery

3 International Space Station As Flown Altitude Profile (Based on MCC-M/USSP Tracked SV Data) Invariant Alt. (km) - Ha, Hp, Have STS96 M-Reb STS88 M-Reb 2A Test 1A/ R Insertion STS-88 Dock 2A1 reb FGB DAM DAM (f ailed) STS96 Dock STS100 M Reb STS108 M-Reb STS-113 M Reb STS102 M-Reb STS112 M Reb STS92 M-Reb STS105 M-Reb STS111 M Reb STS106 M-Reb STS104 M-Reb STS110 M-Reb STS101 M-Reb STS98 M-Reb UF1 6P Reb 7A Inc UF1 6P Reb 9A 9P Reb 10P Stg Reb 1P Reb 7A Test UF1 Test O/ P UF2 8P Reb 10P Stg Reb 1P Test 5A1 Reb UF1 Test UF2 7P Reb 10P Stg Reb 1R Rend 5A1 Test 4R Reb/ Phs 8A Reb 11A/ 10P Reb DAM STS98 7P DAM 1P DAM DAM STS108 10P DAM 3P-M Dock 2P-M1 Dock 2R-Sz Dock 5P-M Dock 1P Dock 4P-M1 Dock 1R-SM Dock 2S-Sz Dock STS101 Dock Sz-TM M ax Rndz Alt (425 km) Sz-TM (1-4) M ax Dock/Sep (410 km) STS98 Dock STS97 Dock STS92 Dock STS106 Dock 2P Sep 1P Sep 3S-SZ Dock 4R-DC Dock 8P M-Dock 4S Dock 7P-M1 Dock 5S Dock 6P-M1 Dock 9PM1 Dock STS-113 Dock STS105 Dock STS-112 Dock STS-111 Dock STS-110 Dock STS108 Dock STS104 Dock STS100 Dock STS102 Dock 2S Sep 3P Sep DC ISM Sep 4P Sep 2R-Sz Sep 5P Sep 6S Dock 10PM Dock 7P Sep 9P Sep 3S Sep 4S Sep 6P Sep 8P Sep 5S Sep 12P M Dock 11P M1 Dock 13P M1 Dock 15P M Dock 7S Dock 14P M1 Dock 6S Sep 11P Sep 1OP Sep 13P Reb/ Inc 13P Phase-01 12P Phase 12P Phase 8S Dock 16P St g 16P Stg 15P Stg Reb 15P Phase/ Inc 15P Stg Reb 16P M Dock 9S Dock 13P Sep 15P M Sep 7S Sep 8S Sep 12P Sep 14P Sep 17P Stg Invariant Alt. (nm) - Ha, Hp, Have

4 Solar Cycle Progression

5 SRAG Operational Radiation Measurements Area monitoring devices Passive detectors: Thermoluminescence Dosimeters (TLD), Optically Stimulated Luminescence detectors (OSLDs) and Plastic Nuclear Track Detectors (PNTD) Active detectors: Tissue Equivalent Proportional Counters (TEPC) and Solid-State (Si) Detectors: IV-CPDS, EV-CPDS Personal dosimetry- Each crewmember carries a dosimeter for the duration of their mission. TLDs: LiF:Mg,Ti; CaF 2 :Tm PNTD CR-39 (USF-4, 600 mm) OSLDs: Luxel, dots and roll detectors in Lexan holder at a depth of 0.18 g/cm^2

6 Space radiation dosimetry What we want: Dose equivalent: H = å Hi = å Di i i Q ( L i ) NCRP 142, 2002 Recommendation 11, Equation 6.1: H = QD + ò OSLD / TLD Q( L) DPNTD ( L) dl LET 10 kev/mm; Q = 1 LET ³ 10 kev/mm; Q = Q(L)

7 Schematic of Passive Dosimeters

8 New NASA-SRAG Passive Radiation Detector used for STS-114 and Expedition 12 TLD-100 (8 samples) TLD-300 (6 samples) TLD-600 (2 samples) TLD-700 (2 samples) OSLD/Luxel (2 samples; 6 samples future flights) CR-39 (2 samples)

9 Detector Stack Lexan Cover: 0.15 cm Label (White Paper) CR-39 (1 Sheet, Bare) 600 mm Polycarbonate Film (1 Sheet) CR-39 (1 Sheet, Bare) 600 mm Polycarbonate Film (2 Sheets) TLDs/OSLD in Lexan Holder: 0.45 cm

10 Service Module Monitoring Locations US Destiny Lab to Zvezda SM = 44.5 meters

11 US LAB Monitoring Locations

12 Overall View of Monitoring Locations

13 Node Dosimeter Location 2

14 SM-P327 (R16) Location

15

16 ISS RAM monitoring Periods for Expedition 1-10 Start Date 5/20/1999 5/19/2000 9/8/ /1/2000 4/19/2001 7/12/2001 8/10/ /5/2001 4/8/2002 6/5/ /24/ /18/2003 4/19/ /14/2004 End Date 5/29/2000 9/20/ /11/2000 5/1/2001 7/24/2001 8/22/ /17/2001 4/19/2002 6/19/ /7/2002 5/4/2003 4/30/ /24/2004 4/24/2005 Exposure Duration (days)

17 Passive Monitoring Summary Since launch of ISS in 1998 there have been 14 separate passive monitoring periods The average length of monitoring periods is 152 days. ~2100 days of continuous monitoring. There are 17 permanent monitoring locations covering 30 meters of habitable volume Monitoring locations are only separated by a few meters

18 ISS Dose Rate Summary: TLD Unity Node Location 2 SM-P442 SM-P327 US LAB Location 1 mgy/day TEPC locations /1/00 1/1/01 1/1/02 1/1/03 1/1/04 1/1/05 1/1/06 Monitoring Period Ending Date

19 Airlock U.S. Node 1 U.S. Lab Service Module Entire Vehicle 2.1 ISS Radiation Area Monitors MAx Dose Rate/Min Dose Rate May May May Sep Sep Dec Dec May Apr Jul Jul Aug Aug Dec Dec Apr Apr Jun Jun Dec Nov May Oct Apr-2004

20 Horizontal Alignment: SMP442

21 Vertical Alignment: SMP442

22 Node 1 - No Cyclic Data TEPC Dose SM 30 +XVV +ZLV (LVLH) -XPH+ZNN (XPOP) Detector Horizontal +XVV +ZLV (LVLH) -YVV +ZLV Detector Vertical +XVV +ZLV millirad NODE SM STBD CQ SM P TEPC/R /15/05 3/1/05 3/15/05 3/29/05 4/12/05 4/26/05 5/10/05 5/24/05 6/7/05 UT Daily TEPC values > 97 % Daily R-16 Values Attitude Shift or TEPC Movement TEPC Interval Averages by Attitude R-16 Averages By Attitude Alt (Km)

23 TEPC Ratio Current average /previous TEPC Daily Dose (> 97% coverage cyclic data) (inverse) (1.24) XVV +ZLV LVLH -YVV +ZLV LVLH +XVV +ZLV LVLH -XPH +ZNN XPOP STS-114 Docked millirads Note: Previous TEPC -YVV/+XVV = 1.27 (SM CQ Detector Horizontal) 1.30 (SM CQ Detector Vertical) SM STBD CQ SM P TEPC/R /30/2005 6/19/2005 7/9/2005 7/29/2005 8/18/2005 9/7/2005 9/27/2005 Daily TEPC values > 98 % TEPC Interval GMTAverages by Attitude R-16 R-16 Averages By Attitude Attitude Shift STS-114 Alt (Km)

24 ICCHIBAN 3 Neon 400 MeV Neon - 90 Degrees - No Absorber Differential Flux (Number/cm 2 sr day kev/mm) x10 2 6x10 2 4x10 2 2x Lineal Energy (kev/mm)

25 ICCHIBAN 3 Neon 400 MeV Neon - 0 Degrees - No Absorber Differential Flux (Number/cm 2 sr day kev/mm) Lineal Energy (kev/mm)

26 Trapped Differential Flux Directional Comparison of Iss-Tepc 5x10 3 April 30 - May 3 April Differential Flux (Number/cm 2 sr kev/mm) 4x10 3 3x10 3 2x Lineal Energy (Tissue, kev/mm)

27 GCR Differential Flux Directional Comparison of Iss-Tepc 2.0x10 3 April 30-May 3 1.8x10 3 April Differential Flux (Number/cm 2 sr kev/mm) 1.6x x x x x x x Lineal Energy (Tissue, kev/mm)

28 Expedition 10 Combined Integral Flux 10 6 Lab S Lab S1 SM-P327 Node SM STB CQ Total Dose (mgy) Total Dose Equiv. (msv) Q 2.82 Integral Flux (Number/cm 2 sr) Lineal Energy (Tissue, kev/mm)

29 Expedition 10 CR-39 Simulation D(TLD-300) is 38.9 mgy in days, TEPC was operated for days D(TLD 300) for days = x (38.9/192.79) = 3.28 mgy D(TLD-100) for days = x (34.92/192.79) = 2.95 mgy

30 Heavy Ion Efficiency Measured (Cs Equivalent) Dose/Delivered Dose TLD A TLD-100 slow cool TLD100-2 hour TLD B LET in Wate r

31 Comparison of TLD-TEPC combination TLD Average D(total)/ D (TEPC) D H Q efficiency D(low) (Total) (Total) (mgy) (mgy) (mgy) (msv) / / TEPC

32 ISS/Shuttle TEPC Comparison-GCR GCR Differential Flux 10 5 ISS-TEPC Differential Flux (Number/cm 2 sr day kev/mm) Shuttle TEPC Lineal Energy (Tissue, kev/mm)

33 Expedition 10 Example NCRP 142, 2002 Equation 6.2 Q derived from Tissue Equivalent Proportional Counter (TEPC) if PNTD not utilized: SM-P327 Dose = mgy Q measured by TEPC = 2.82 H» QD TLD e H = 108 msv for 193 day mission Factors to consider: Depth Dose Quality Factors/Neutrons

34 Risø TL/OSL-DA-15C/D Reader OSL stimulation module: 49 Nichia Green Diodes (525 nm) Power at the sample of ~ 43mW/cm 2 Emission filter Hoya U-340 (7.5 mm thick)

35 Preliminary STS-114 Results: CPD Cumulative Gamma Dose (mgy) Luxel (Int. OSL) Luxel (Aver. OSL Int) TLD-100 (MP) TLD-300 (HTP) arm leg Crew Passive Dosimeter (CPD) # Simplicity of OSL dot readout

36 STS-114 Luxel Results OSL Ratio R Luxel 1 H 4 He 12 C 28 Si 40 Ar 20 Ne -----CPD# CPD# CPD# CPD# CPD#5 (arm) -----CPD#5 (leg) -----CPD#6 56 Fe 84 Kr LET (kev/mm in water)

37 The bulk etch B* the thickness removed by etching for one surface of the CR-39 plate, can be calculated by formula where m 1 is the detector mass before etching, m 2, the mass after etching, T 2 is the detector thickness after etching, p is the detector perimeter and A is the detector surface area.. The etch rate ratio S is calculated by Somogyi s formula (Somogyi, 1977). where a and b are the major and minor axes respectively. ) 2 (1 2 ) ( A pt m T m m B - - = / ú ú û ù ê ê ë é ø ö ç è æ - ø ö ç è æ + = B b B a S *Etching: NaOH (6.25 N, 60oC) for 48 hours, B = 27 mm

38 LET calibration exposures for CR-39 (2004 July 2005) Institute Ion Energy LET (MeV/n) (kev/μm CR-39) NSRL (BNL) (Sept. 04) Proton O Fe HIMAC (March 05) O Ne Ar Fe Xe He TAMU (March 05) Proton 14, 10, 8, 6, , 3.43, 4.14, 5.25, 9.50 (Gev/n) BNL (July 05) Si 0.3, 1, 3, 5, , 28.76, 25.73, 26.67, Fe 3, 5, , 92.01,

39

40 STS-114 TEPC Location Results C R d e t e c t o r s w e r e u s e d f o r S T S m i s s i o n, s o m e p r e l i m i n a r y r e s u l t s w e r e o b t a i n e d u s i n g J S C C R L E T c a l i b r a t i o n a n d i s l i s t e d b e l o w : Results Measured by TEPC and CR-39 Location: Dose Rate Dose Equivalent Rate Quality JSC-TEPC ( 10 kev/μm water) ( 10 kev/μm water) Factor (ICRP 60) (μgy/day) (μsv/day) TEPC CR

41 Integral spectra of dose equivalent measured by TEPC and CR-39

42 STS-114 TEPC Results, full LET spectrum Dose Rate (mgy/day) GCR Trapped Total Dose Dose Dose Quality Equivalent Quality Rate Rate Factor Rate Factor (mgy/day) (mgy/day) (msv/day) Dose Equivalent Rate (msv/day) Dose Equivalent Rate (msv/day) Quality Factor ICRP

43 Shuttle TEPC/Crewmember CR-39 Results Preliminary Results of STS-114 from CR-39 Plates ( 10 kev/μm water, ICRP 60) CR-39 Dose Dose Dose Dose Equivalent Q Plate Rate Equivalent Rate (mgy) (μgy/day) (msv) (μsv/day) Near TEPC Collins

44 Future Work Continued investigation of Optically Stimulated Luminescence (OSL) of Al2O3:C detectors, leading to use as primary low LET dosimeter Operational Use of Plastic Nuclear Track Detectors CR-39 to determine dose equivalent at surface of the astronaut directly STS-114 is first mission to have full complement of TLD/OSL/CR-39, analysis of track detectors, OSLD, and TLD underway