K THIET PHAN TICH DO TRO THAN

KHOA HOC VA CdNG

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THIET B ! PHAN TICH DO TRO THAN BANG KY T H U A T KICH HOAT NORON-GAMMA TU^C THOI

TS. N G U Y I N THANH TUY, TS. TRjNH V A N GIAP;

KS. KHl/ONG THANH TUAN & NNK Vi$n Khoa hgc va Ky thu$t Hat nhan

K

y thuat phan tich b l n g phipong phap kich boat notron-gamma tde thdi (PGNAA) la mpt trong nhu-ng ky thuat phan tich tien t i l n , hi^n Jai, dang ngay cang dirge dng dung rpng rai vao Dhuc vu san x u l t cdng nghiep va ddi sdng. U'u 3ilm cua phiKong phap do nay la phan tich nhanh,

<4t qua kha chinh xac, khdng phai gia cdng mau, qua trinh phan tich khdng bj anh hu-dng cua di§u

<ien mdi trirdng va phan tich diro'c h l u h i t cac nguyen td trong bang t u i n hoan Mendeleev. O cac nu'dc tien ti^n, cd th§ tim t h l y dng dung cua Dhuang phap nay trong nhilu ITnh vyc.

Tuy nhien, do viec xay dyng he do sd dung ky :huat nay ddi hoi phai cd trinh dp ky thuat-edng nghe cao , cho nen thdi gian qua, nd van chua Jirp-c dng dung nhilu d Viet Nam. M i y nam g i n Jay, da bat d l u cd nhilu ca s d cdng nghiep sd Jung thilt bj PGNAA nhirng cac thilt bj nay d l u Dhai nhap ngoai. Mpt sd vien cd d l tai nghien edu / I ky thuat PGNAA, nhirng h l u nhu* chu'a ed d l tai lao nghien CLFU c h l tao cac thilt bj do. Chinh vl uu f i l m ndi bat cua PGNAA nen c h i c c h i n cac thilt Dj sd dung ky thuat PGNAA se phat triln de dap

>ng nhu c l u ty dpng hoa trong qua trinh cdng nghiep hoa [1, 2].

Nguyen ly co ban cua PGNAA la khi tia natron : h i l u vao m l u do, trong m l u lap tde phat ra cac tia gamma (nen cd ten goi la kich boat natron gamma IPC thdi, (H.I). Gu'dng dp tia gamma phu thuoc vao nang lirgng cua natron va ham lipp-ng cac nguyen 6 cd trong mau. Khi thdng lipp-ng cua ngudn natron chong ddi (tru'dng ho-p dung ngudn ddng vj hoac /ai cac thdng sd v l ddng, ap xac djnh khi dung dng Dhdng), cu'dng dp tia gamma chf cdn phy thuoc /ao ham lu'p'ng cua cac nguyen.td ya dac tru'ng

;ho cac nguyen td cd trong mau bj ehilu.

Tuy nhien, khi bj kfch boat bdi natron, trd nguyen td Hydro chu y l u sinh ra mpt mdc nang LFO'ng 2223 keV, cac nguyen td khac se sinh ra i h i l u mdc nang lu'p'ng gamma ed cirdng dp ^hac

nhau, nhilu nguyen to lai ed nhilu mdc nang lu'p'ng dan xen nhau. Nhu- vay, moi mpt vung phd nang lu'p'ng thu nhan du'p'c (du hep) se bao gom kha nhilu nang lu'p'ng khac nhau cua nhilu nguyen td.

H. 1. Vung xay ra tuvng tac Prompt gamma xung quanh dau thu hat nhan.

N I U dijng he d l u dd ed dp phan giai cao (ehing ban h? d l u dd Ge sieu tinh khilt) ta cd t h i tach cac vach phd gamma tde thdi nay theo nang lu'p'ng, lam ca s d nhan dien va xac djnh du'O'c ham lu'p'ng cua cac nguyen td. Cdn khi dung cac he d l u dd cd dp phan giai t h l p hoac vda phai, thi ed t h i d y a vao toan hpc d l tfnh du'p'c ty le ddng gdp vao mdc nang lu'p'ng cua moi nguyen td, t d dd tfnh ra du'p'c tdng cu'dng dp cac tia gamma dac tryng sinh ra cua moi nguyen td, tren cd sd dd tfnh dyp'c ham lyp'ng cua nguyen td dd ed trong mau phan tfch.

Tfnh c h i t nay cua ky thuat PGNAA, du'gc dng dung trong c h l tao thilt bj phan tich xac djnh nhanh dp tro than; phan tfch cac nguyen td trong than, trong xi mang va trong cac vat ll^u khac.

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1. Thilt bj phfin tfch d^ tro than bSng k9 DT.03/09.NLNT, cac can bO nghidn edu cua V\^

thugt PGNAA [1] Khoa hpc va K9 thu^t Hat nhan da c h l tao thSnIi Du-gc BO KH&CN giao thyc hi$n d l t l i : "Nghidn cdng h$ thilt bi phSn tfch nhanh dd tro sd dyng kj edu xay dyng h$ thilt bj phSn tich dO tro sd dyng thu$t PGNAA. Sa d l khii ehde nang cua h$ thill ky thuat PGNAA vdi nguIn phat natron", mS s6 bj md t l trfin H.2.

D«y tin hidu 6ng chi>a det

Dau thu Hop (Jien tCr

(Khiuech d^i, MCA, nguon nuoi va gh^p noi USB)

May finh

(xCr ly s6 deu, bieu dien pho, on clinh pho va ti'nh toan do tro,. )

H.2. Sa do ktioi he phan tich do tro than bSng phuvng phap PGNAA.

Bang 1. Lieu buc xa gay bdi natron va gamma a ben ngoai hop chua nguon (khi tie khong lam viec) va ben ngoai tliung do (khi dang phan tich mau) tai vi tri each tam 1 m va 2 m.

Khoang each (m) Lieu bdc xa natron (pSv/h)

Hop chira ngudn

Lieu bdc xa gamma (|jSv/h)

Thung do Lieu bdc xa natron

(pSv/h)

Lieu bdc xa ^ gamma (pSv/hlJ 1

2

0,40 0,15

2,1 1,50

0,97 0,33

3,50 1,80 Nguyen ly chung cua h0 thilt bj phan tich d0 tro

than blng ky thuat PGNAA nay la sd dyng tia natron phat ra td ngudn ddng vj Cf-252 ehilu vao ddng than. Mlu than bj kfch boat bdi natron va phat ra cac tia gamma, cac tia gamma nay tan xa trong mau than va di tdi d l u thu. Olu thu thu bdc xa gamma chuyin d l i thanh tin hidu dldn va truyin v l hop xd ly tin hi^u roi truyin sang may tfnh va du;gc bilu diln du'di dang phi nang lygng. Phln mim phan tfch phd cd nhi^m vy xy ly, tfnh toan tren phln phd cua tia gamma tde thdi va tinh ra gia tri dp tro than cua mau phan tich. H.3 la hinh anh phd nang lu-gng cua m0t mlu than (toan p h i va phln nang lirgng cao)

Thilt bj phan tfch theo ky thuat PGNAA la mOt trong nhdng loai thilt bj phSn tfch nhanh (thdi gian khdng qua 15 phut/lln), k i t qua kha chinh x l c va

dac bidt la khdng phai gia cdng m l u . phan tich dQ tro khdng bj anh hydng bdi thanh phln kim lo?i nang, dO I m trong than va cac dilu ki^n moi trydng khac,... H$ thilt bj c h l tao, sd dyng ngiift Cf-252 c6 thdng lygng 0,85x10^ n/s, lygng mlu cln cho mOt l l n phan tfch v l o khoang 650-750 kg.

Dilu quan trpng khi c h l tao thilt bj hat nhan la ySu t l dam bao an toan bdc xa cho ngydi sd dung va mdi trydng (Bang 1).

Lilu dygc phdp d l i vdi ngu'di lam vi§c trong mdi trydng phdng xa la 5 pSv/h.

00 tro cua m l u phan tfch dygc xac djnh bing cdng thyc:

Apt (%)=42.564 * (RAT OF 570-1570 BY 260- 340)+(-42.758) [1]

(RAT OF 570-1570 BY 260-340) la ty sd gida hai

s6 dim. s6 dim vung nSng lygng cao, td k§nh 570

CONG NGHIEP MO SO 2 - 2 0 1 2

KHOA HOC VA

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NGHE MO CNM

lln kenh 1570 va s i dim vung nang lirgng thlp td :enh 260 din kenh 340; He sd a=42,564 va b=- 12,758 dipgc xac djnh blng thyc nghiem tr§n cac nlu than khu vyc Ha Tu. Do thyc nghiem xac djnh 16 tro cua 4 mau than, vai 52 Ian 6o, co 3 Ian co sai

;6 tuyet ddi >1 % nhyng <1,2 %, cac phep do con lai Jeu CO sai so <1 %. Vol k4t qua do do tro va sai so nhu vay la hoan toan co th§ chap nhan duoc.

a)

I ]j>^*3Lfw^jy^.>,v.J^*aa^ft^ msmt I.I

b)

fiTx: g:'iiifHillf»milJM ULXJ

1-1.3. Pho nang Iwang PGNAA phan tich than:

Toan phd va phin NL cao (hinh b).

He PGNAA phan tich do tro than co cac thong s6 ky thuat chinh sau day;

•:• Sd dung ngudn natron Cf-252 co cuang do (6/2011) la 0,85 X 10^ n/s.

•:• Thiet bi do sd dung d§u thu hat nhan BGO kich thuo'c 51x51 mm do hang REXON c h l tao, ADC CO do phan giai 2000 keph.

•:• "^hiet bj CO ch§ do ty 6n dinh phd, gio-i han troi kerih tdi da la 4 kenh.

•:• Tho-i gian phan tich m l u than cho k i t qua tin .cay tu 600-1000 s.

• Khoi lu'gng mlu than phan tich la 700 kg.

• H0 do kit nli vdi may tinh qua cong USB, chay tran mdi tru'dng Windown XP

• Khoang each td thung do tdi hOp dien td (phdng do) la 30 m6t.

•:• Co khoa d l bao v0 nguIn phdng xa khi he do khdng lam viec.

2 Phat trien ung dung cua cua ky thuat PGNAA Thiet b! sd dyng ky thuat PGNAA da thanh cdng trong viec xac djnh nhanh d0 tro than, dang tilp tyc nghien cuu hoan thi0n them cac ehde nang sau day:

V Hoan thi§n ky thu$t phan tich: Tr6n ca sd cdng su^ty thdng lygng nguIn phat natron xac djnh clu hinh do tdi U'U d l giam khii lugng mau than, tim thdi gian do hgp ly va xay dyng du'dng ehuln cho thidt bi vol tung vung than khac nhau d Viet Nam 6k tang dd chinh xac phdp do, sai s i tuyet ddi <1% [3, 5].

V Chuyen thiet bj phan tich trong phdng thi nghiem thanh thiet bi phan tich hien truvng. Vdi clu hinh Inien tai cua thilt ijj viec phan tich du'gc thyc hien tai mot vj tri cd dinh (phdng thf nghiem). Mau phan tich lay vd phdng thi nghiem se gay ra nhilu khd khan cho ngudi sd dung: Lugng mau phai Idn; qua trinh thay mau se mat nhilu thdi gian va cdng sdc, gay byi binjam nnlt ve sinh mdi trudng;... Viec phan tich nhilu mau nhlm danh gia tot han chit lugng dong than cung_nhu xac dinh chat lygng md than se khd thyc hien, mau Idn se lam tang gia thanh lly mlu, tang gia thanh van chuyin tu kho/ bai tap kit ttian v l nai phan tich, do dd se gay tam ly khdng mudn su dung thilt bj dli vdi ngudi van hanh va khach hang. D l khlc phuc tinh trang nay, cac tac gia dua ra y tudng dat toan bd clu hinh thung do va hop chua nguon len tren xe tai nhe hoac xe ban tai (H.4).

Tren cac khe tru'dng hoac tai cac bai than cua nha may sang tuyIn than, than cd thi rdt true tilp tu bang chuyin, tu gdu tai hoac tu may xuc vao thung do, sau khi kit thuc qua trinh do, ngudi van hanh thyc hien md cua xa d duai day thung la cd thi dd hit than ra khdi thung do, thay miu mo'i va qua trinh do lai tilp tyc. Viec ca dpng din vj tri khac cung rlt de nhd sy di chuyin cua xe.

•:• M& rgng chipc nang phan tich nguyen to.

Phat triln tu mpt ehde nang phan tich dp tro them cac chuc nang khac nhu phan tich ham lugng nguyen to hoac tfnh ham lugng cac dxit trong miu phan tich [3], [4], [5]. Tu pho nang lugng cao cua mau phan tich thu dugc (H.3), ed thi thly mpt so vung dinh nang lugng xult hien kha rd rang. Blng toan hoc, cd t h i phan tich cac vijng phd theo sy ddng gdp cac vach phd cua cac nguyen td d l tinh dugc ty le % cua nguyen t l dd trong mau phan tfch.

Mat khac, n l u sd dyng ngudn natron vdi thdng lugng cao han cung lam tang kha nang nhan dien va dp chinh xac cua phep phan tich nguyen t l .

CdriG NGHIEP MO SO 2 - 2 0 1 2

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H.4. Md hinh h$ phSn tich PGNAA th^nh h$ do hi$n tmung nho st> dijng xe tii nh^ (hinh minh haa).

V Phan tich do am. Thilt bi PGNAA phan tich dp tro than, ngoai kha nang cd thi xac djnh ham lugng cac dxit cdn cd t h i c h l tao md ring th6m Chile nang xac djnh dd I m trong than.

•:• Md rgng them doi twqmg do. Tu phan tich than, xay dyng quy trinh phan tich cho cac loai d l i tugng khac nhu dat, da, quang bdxit,... Thilt bj nay ung dung kilm tra chit lugng nguySn vat li|u dlu vao va san phIm dlu ra trong tung cdng doan cdng nghe san xult xi mang va ung dyng d l xac djnh thanh phln kim loai trong tham dd, khai thac khoang san [4, 6].

• Chuyen doi thiet bi tif phan tich dong (bulk analyser) thanh thiet bi phan tich online.

Sau khi hoan thien cac ky thuat tren, md rpng ehde nang phan tich online, tuc la phan tich vat lieu tren cac bang tai dang chay,

• SIP dung 6ng phat/may phat natron thay the nguon dong vi phdng xa phat natron. Hien nay. do cdng nghe chl tao cac loai may phat/ ong phat natron cdn d mdc dp ban c h l nhu tudi thp ngln, dp bin thlp, gia thanh c h l tao cdn cao, cd it cdng ty tham gia c h l tao, ban nu'a thj trudng su dung loai linh kien nay chua thyc sy nhilu cho nen gia tinanh chl tao thilt bj PGNAA su dyng may phat/dng phat natron cao ban nhilu loai thilt bj PGNAA su dung ngudn dong vj.

3. K i t luan

D l tai da xay dyng thanh cdng he thilt bj phan tich dp tro than su dyng ky thuat PGNAA vdi ngudn phat natron la ngudn ddng vj Cf-252. Vi^n Khoa hpc va Ky thuat Hat nhan, Trung tam trinh dien Vung (TDC-Ha Npi) da cd them mOt thilt bj phan tich hat nhan hien dai phyc vy cho cdng tac dao tao chuyen sau, chuyin giao cdng nghd va tiln hanh cac nghien cuu khoa hpc cd lien quan d i n ky thuat phan tich PGNAA. Tilp tyc nghien cuu holn thien chuc nang 6k phat triln ung dyng cua ky thu$t PGNAA, thdi gian tdi, Vien Khoa hpc va Ky thuat Hat nhan se nghien cuu chl tao thilt bj phan tich dudi dang cac san phIm thuang mai phyc vy tot cho cdng tac tham dd, khai thac, chl biln than va khoang san d

Vi$t Nam. cac thilt bj dugc c h l tao trong nudci lam cho gia thanh thilt bj thlp ban rlt nhilu so v nhap khIu, hoan toan chu ddng trong vi^c chuyi giao cdng ngh$, bio tri, sda chda va md rpng clii;

nang do cho thilt bj d l phyc vy san xult-kinh doanh Chung tdi by vpng nhan dugc sy quan tam tig tac dlu ty, ty vln nhlm tli uu ehde nang cua thiet va ung dyng thilt bj cua cac dgn vj trong nganh Tha va Khoang sin Vi$t Nam d l vi$c ung dung nSn lugng nguyin tu vi myc dich hda blnh trd ngn d dang va thanh cdng trong nganh cdng nghiep qua trpng cua Vidt Nam, phyc vy die lye cho qua trin cdng nghiep hda-hi$n dai hda dit nude.n

TAI LIEU THAM KHAO

1. Bao cao ting kit d l tai "Nghi§n edu xSy di/n h$ thilt bj phan tich dd tro su dyng ky thuat PGNA vdi nguIn phat natron", ma s i DT.03/09.NLNT, 200£

2011, BO Khoa hpc va Cdng nghd.

2. Technical data on Nucleonie Gauges, lAB TECHDOC-1469, IAEA, July 2005

3. J. Charbucinski, S. F Youl, P L. Eisler, am M. Borsaru, Prompt neutron-gamma logging fo coal ash in water-filled boreholes. Geophysics; Ma 1986; V. 51; no. 5; p. 1110-1118; DOI 10.1190/1.1442165.

4. J. Charbucinski, J. males. A. Rojc, C.Smitli Prompt gamma neutron activation analysis methoi and instrumentation for cooper grade estimattion ii large diameter blast holes. Applied Radiation an(

Isotopes 59 (2003) 197-203. Available online a www.seiencedirecLcom

5. M. Bosaru, Z. Jeeny, Application of PGNA/

for bulk coal samples in 4n geometry, Applie(

Radiation and Isotopes 54 (2001) 519-526 Available at www.elsevier.com/locate/apradiso.

6. M. Bosaru, M. Biggs. W. Nichols. F Bos, Thi application of prompt gamma neutron activatioi analysis to borehole logging for coal, Appli©

Radiation and Isotopes 54 (2001) 335-343 Available at www.elsevier.com/locate/apradiso.

Ngudi bien t$p: Dao Die T90

SUMMARY

Institute for Nuclear Science and Technolog belong to VAEI has successfully studied coal as analyzer by Prompt gamma neutron activatio.

analysis method. The article presents this devic and its potential application in Vietnam coal an mineral industry.

CdN6NGHliPM0Sd2 2012