Nghiên cứu chế tạo khuếch đại phổ kế SA-694: Chi tiết và chuyên sâu

Thong beo khoa hoc 2001

,," DJ)..IPHO

,,' ESA-69

NGH EN cuu C ETJ).O KHUEC

NgUY~ll Due Hoa - Djllh Sy Hiell

Bai bdo dua ra mot thitt kt cht tao khuech dai pho' kt hat nhdn vai muc dich ruing cao cdc dijt trung cua no ciing nhu cho phep loai bi) duac hi~u ling chong chdp xung bdng cdc mach ht5i phuc duang khong BLR va hieu ling tich tu di~n tich bdng phuang phdp hinn thanh xung tich phtin c6'ng GL.

I. nAT VAN BE:

Trong toan bQ h~ thong ph6 ke' hat nhan, khuech dai ph6 ke' (KBPK) conhiern vu khuech dai va xii'I9 tin hieu Ia'y ra tir ti~n khuech dai (P.Amp) d6 dira tdi cac bQ bien d6i nrong nr thanh so' (ADC) hoac ca thie't bi di~n tii' khac a sau d6. KBPK Ia mot kh6i dien tii' chirc nang quan trong, c6 anh huang mang tinh quyet dinh tdi dQ chinh xac ciia phep do birc xa. VI. vay, van d~ nang cao cac d?c tnrng ciia KBPK luon dU<;1C d?t ra d6i voi cac nha thiet ke' che' tao, va cang tro nen birc thiet han khi cong nghe detector ban d~n dli tro nen hoan thien vdi loai sieu tinh khiet, dung tich ldn, hieu sua't cao.

B6 nang cao cac d?c tnmg ciia KBPK, hien nay tren the' gidi dli che' tao theo hai

xu hirdng nhir sau:

Thu nhdt la, tang dQ van nang Wi mire t6i da va dira ra cac so d6 phtrc tap d6 dat dU<;1C cac d?c tnrng cao.

(j Viet Nam, trong nhtrng nam g~n day, tai Vien Nghien Ciru Hat Nhan Ba Lat (VNCHN) dil b~t d~u nghien ctiu che' tao cac kh6i di~n tii' chirc nang cha't IU<;1ng cao, thong qua d~ tai ca'p nha mrdc KC-09-14B.

Vdi bai bao nay chung toi nham nghien cuu che' tg.o KBPK SA-694 vdi tinh vg.n . nang va d~c trung cao thea xu hudng thu nha't, vdi ml,lc dich Ia nang cao kha nang tai t~n so', dQ tuye'n tinh cao, tg.p am vao be va cho kha nang phan giai nang IU<;1ng cao, cl1ng nhu Iog.i bo dU<;1C hi~u ung ch6n ch~p xung va tich tl,l di~n tich.

II. N(H DUNG - PHUONG PHAP:

MOt each t6ng quat KBPK c6 ca'u truc nhu hlnh 1 [I] Tin hi~u tu ti~n khuech d~i (P.Amp) oU9C olta qua m~ch rut ngan xung vdi hang so thai gian cho phep va clUC,1c be)

Thu hai la, dii' dung mot hang so' thai gian c6d!nh, hie nay dn phai chap nhan hy sinh mot d~c tnrng nao d6, vi du nhtr tap am I6i vao d6 nhan dU<;1C mot d~c tnmg khac cao han chang han nhir kha nang tai t~n so'.

Tho ng fP O k /1Oa hoc 200 1

clunh Ulf('Jng khong, sa u do JU(.1c duu V£lO mach khuech da i nhanh va t(3i mach hlnh tha nh xung chua n ch o xung ra thong qua ma ch u~ m IC;i ra. Bao qu anh giua h"{i ra V£I IC;i V£lO ciia ma ch hinh tha nh xung CPS) lam mach hoi phuc ulfl1ng khong loa i thUi gian thay ul1i (BLR - Base Line Rirec tor) no uU<;Jc heat

Tren co sa do, khuech dai ph6 ke SA-694

A~lP

RC Pole- zero

Hinh 1: So 06 khoi ciia khuech dai ph6 ke.

Thanh xung chuan tren ba mach tich phan Salenky ICS,9,lD voi xung chuan Gauss Ifty tnrc tiep tir IC 10 va xung chudn tam giac diroc Ifty ra qua mach cong IC 11 cua cac tin hi~u Ity tit loi ra ICS,9,1O. Mach BLR loai thai gian khong 06i thirc hien tren IC5,6,7. . Mach BLR loai thai gian thay 06i thirc hien tren ICI2,13,14, no hoat dong nho vao mach di~u khien logic nharn .loa i be hieu ling chong chap xung. Khi xay ra hieu ling chong ch?p xung, tren loi ra ciia ngudng nhanh se xuftt hien so xung nrcng ling vci so xung chong chap, cling voi xung tir ngirong cham cho ta mot xung ra tren loi fa cua mach Pll...E UP la mach phat hien va loai be chong chap, xung nay se di~u khien rCl3 oe eho phep tu nhd ClD phong dien nhanh qua no, dam bao mire kh6ng cho tin hieu ra. Nhu vay, khi co hieu ling xay ra mach BLR se dam baa rmrc khong tren loi ra nrc drr IOC;li be diroc cac xung chong chap,

~ : . xu .g : a tre n c d

rhl5i gran ~:c ::

Doi vd i cac detector ban dfrn co dung tich Ion luon xay ra cac hie u ling tich tu dien rich la m t6i di khd nang phan gidi nang Iirong ( FWHM - Full width at Ha ft maximum) a de h5ng so tho i gian hlnh tha nh xung be. De loa i 06 hieu ling nay trong KDPK drr dira ra mach hlnh tha nh xung bhng rich pha n eQng rre n IC 16. Xung chuan Gau ss orr dira td i IC 16 qua c.ic e6ng tuy en :fnh LG uti n~lp eh o rl,l C 12, duci ' t! ki€m soat eu a xlIng i~u khi ~n Ifty qua kho a K ue hInh rhanh xung tu m ~.t ' h Pile - up , khi ;'e'r rhu c xung na y tl,l C 12 ~ <1 n..a j ~r '< y b:' ng ph (ung phip .~~ p pho ng c: u -~ an kh6 ng con ph l;! ra . " th£. h xu ng . ! 'gh!" a rh Ll) . v"

ic;n (feh ' u;-- ;; :1'

~ :.J .g ~() :hi i gia hlJ '

a ng S:'\ -60..1

Vei khoi lr ~ :: tll hue

t U I C L:e'( :· "· lf p rLi p ho ~ n chI nh . ch ung ro i orr

t j ~

ttr V" v~} r l y J~ :-: ~m tr:: v} t: n gia 'h ung.

siJ .Jl.. ng ph Mng p h ~i t-'

Thong baa khaa hoc 2001

rt ~ ;"

' A

•

...-) t •

t

I

, ~ I t .1TU ~ c u t i- 'J' ''

....... , , '

l·h ,4" C.. ..-t a ut " . , 1

I-n U!12:

I ' . ,,/ .'\. .

- ' 1 "" 11", 41/," '" •' , ( u v UU 6 - ~ " '- ''''

Thong bflO khoa hQc 2001

La cac d~c tnrng diroc rut ra viec

kiEm tra danh gia bang phucng phap dira

a. Phuong phdp l1i~n tic:

IpULSE' GEN

vao cac dung cu do di~n til goi Ia phircng

So 06 do d?e tnrng nhu hlnh 3

Hinh3: So d6 do d?e tnrng ella KBPK.

phap dii;n ttl'.

v - VN .o1l1 N. in - 6 x k

thea con g thirc [2]:

Vdi phuong phap nay ta co th6 ki6m tra va rut ra cac dZie tnrn g co ban sau: 1. Tap am vao: B~t h~ng so thai gian ella KBPK t - 2j.lS, h~ so khuech dai K= 1000, tin hieu ra Vo = lOv, sau do tin hieu VaG VI = 0, do diroc di~n the' tap ra VN.out. the' tap am vao diroc tinh

phu thuoc ella tap am vao hang so thai gian.

TfJS)

POS

V N.o u t (mV) V N.in (;.J.S )

GAUSS

V N.o Ul (mV)

NEG

V N.in (LlV )

POS

KE>PK SA694 se dung OP-37

V N.OUI (mV) VN.in (uV)

TRI

NEG

V N.o u t (m V ) VN.in (j1V)

0,5 110 17,8 120 20 90 14 95 15,8

1 66 11 96 14,7 43 7,1 60 9,2

2 41 6,8 38 8,8 27 4,5 30 5,5

4 22 3,6 24 4,0 18 3,0 20 3,3

6 12 2,0 18 3,0 13 2,1 14 2,3

10 11 1,8 15 2,5 6 1,6 12 2

Bang phep do eho ta ke't qua nhu tren bang 1, va tren hlnh 4 Ia d6 thi bieu di~n su

2. Khd nan g tdi ttin sf;:'

So d6 do nhu hlnh 3 va gian 06 xung tre n hlnh 5. T~n so eire da i rna kh uec h da i ph6 ke co kha nan g tai dUc;1e. la gia tri khi tang tfr n so xung phat rna ha i diem a va b va n khorig thay (1c1i va (j mile OV.

Ket qua 00 nhir tre n bang 2 va ttl da y cho th.Iy kha na ng rai tfrn 56 ella SA-694 Ia

KHz CJ hang so tha i gian 2PS .

1 n

Hlnh 4: Stf phu thtuoc tap am vao hang so thoo i gian hlnh th a nh xung CJ ra TAM GIAC: 1) Ioi ra pas; 2) Ioi ra NEG ella KPBK SA-694

D~l l he Dj Let

Thong beio khoa ho c 200._1

- -_

.-'-.

- - - -

ffinh 5: Gian d6 xung dien dci xac dinh khd nang tai tfin s6

Bang 2: Ke't qua do kha nang tai tfin s6

1 .

SA694

0,5 · 92 92

92 92

2 70,5 72

LOIRA ' Gauss Gl

4 28,4 30

6 20,8 21

10 12,7 l·t2

3. BQ phi tuytn tich phiin:

So d6 do nhu hlnh 6a va gidn d6 xung tren hlnh 6b

SP.AMP

PULSE GEN

A.TTANOR

IV I

- r l - - A

1-0-

t/;JS) Fmax(KHz) FmaxCKHz)

0

OSC

()

.011

1 .JL/

-L_I

Hlnh 6: a) So d,) do dO phi tuyen rich ph:1n

b) Gian doxung cua so dj do dO phi ttuyen rich phan

,r.

Thong beo khoa bee 2001

Tre n OSC ta 00 diroc oQ le ch 2 SV = 4m V. Vo = l OY, oQ phi tu yen tich phan ttinh th eo co ng thirc [4]:

DP7TP = - - x 100% = '

x l 00 % = 0 04%

4 10-3 V 10V

- Ket qua OQ phi tuyen phan tich ciia SA-694 1a 0,04%

2SV

La ca c o~c tnrng ciia KDPK diroc rut ra tit phep 00 tnrc tiep vo i ngucn chua n ph6ng xa beji h~ thong ph6 ke nang hrong goi 1a phucng phap V?t 1Y. eoay ngudn chuan sii' dung la 60 Co va 57CO, vdi so 06 00 kha nang phan giai nang hrcng nhir hmh 7:

~ DET H SA H ADC H MCA I

Hlnh 7 :Kha nang phan gidi nang hrong.

Birc xa dang khong oi~n tit ngudn ph6ng xa S diroc detector ( DET) bien thanh da ng oi~n dira tdi P.Amp va tin ra cua P.Amp OU<;1c dira toi KDPK dn ki€m tra da nh gia, sa u 06 oU<;1C noi vdi ADC nharn bien tin hieu nrong tlf th anh tin hieu so o€ dtra vao m ay tinh nho khoi giao dien MCA. Tren may tinh cho ta dang ph6 va so oem nrcng iing ej ca c kenh. Phep 00 diroc thirc hien tai phong thi nghiern heat oQ thap - trung tam ph an tich tnrong VNCHN Da lat, voi muc dich so sanh SA-694 off OU<;1C che ta o vci KDPK m oi Silena off c6 cac o~t tnrng dat tieu chuan quae teo H~ thong sii' dung Detector ban dffn loai sieu tinh khiet GeHP e6 dung tich 90 crrr'.

- Ket qua 00 ph6 voi nguon 60C O nhir ej tren bang 3:

Bang 3: Ket qua 00 FWHM cua SA-694 57CO va 60C O

NGUON

LOIRA O.5/lS 8KeY

5.2 KeY

2/lS 3.31 KeY 2.7 KeY

6uS 2.6 KeY

lOuS 2.56 KeY

6OCo

3.72 KeY 3.28 KeY 3.08 KeY 3.02 KeY 2.98 KeY 2.89 KeY

57C O

2.8 KeY

Gauss GI Gauss

T a c6 <.16 thi bi liu dilin slf phu thuoc cua FWHM vao han g sc> th ('1i g ia n nhu tren

hi nh 8.

b. Phuong phdp Vij.t iy:

Thong beo khoa hoc 2001

D:;i hQc Da L? t

KHA NANG PHAN GIA.r CVA SA-694

-+ - Scrics I

o +---,--,;"",,---,;=-,.--,-";"""..,.--..;

0.5

Hhng so' thoi zian -

Hlnh 10: Su phu thuoc FWHM VaG hang s6 thai gian

1)-LtJi ra Gauss

2)- LiIi ra tich phdn c6ng GI

Tir ket qua cho thay FWHM ciia SA-694 tren 16i ra GI cho gia tri nho hen cd hai l~n so voi tren 16i ra Gauss la 8KeV d hang s6 thai gian la 0,5/lS, nrc mach da cho phep loai trir diroc hieu irng tich tl;I dien tich luon xay ra trong cac detector ban dftn dung tich IOn. Tren hlnh 9 la dang ph6 thu diroc ciia SA-694 do voi 57CO va 6()Co.

IV. KET LuAN:

KBPK SA-694 da ducc che tao co 16i ra cho dang xung chuan Gauss, tam giac va .

tich ph an c6ng GI, vdi cac d?c tnrng nhu sau:

Hc$ s6 KB eire dai 1500 l~n

• Thai gian hlnh thanh xung: 0,5.._._...10/lS

• Dien trd VaG: IKn

E>Q phi tuyen tich phan: 0,04%

• • Trd khang ra: son •

Phan cue xung ra: dirong

• Tap am VaG vdi t = 2/lS nho hon 4/lV

• Bien do xung ra eire da i: lOY

• Phan eire xung VaG: ba't ky

Mach duoc l~p ra p thea chudn NIM tren khung 2M. Vdi nhirng ket qua dar dUQC trong nghien ciiu cht' ta o KBP K SA-694 un cho cac (i~ t [rung t6t hen nhung KBP K da san xuat tnrdc day (j Vi TCHN Da lat va hien tai a mot s6 trung tam khac trong nude . Bdi trong thiet k~' arr dira Ul (C/C d e hua ng gidi quyet phu hop nhu de giarn tap am vao trong so LIo LIIT sit dung lui mi c vi sai ij ma ch VaG eho phep gi ~ m [~. p J.m.f2 l~n, cfing nhu tang d6 tuye n tinh betng c.ich sl'r dung OP-37 a loi vao

Thong baa khaa hoc 2001

kha nang chong tich tu dien tich ciia mach, Nguyen nhan la, cl€ giarn th€

TAl LI~U THAM KHAO

1. AKIMOV.YU.K -: DINH SY HIEN - KALININ, Spectroscopy Amplifier, Preprint

kh uech dai nhanh rna kh6ng sii' du ng HA-2525 nhu tru yen thong. KDPK con co kha na ng loa i bo diroc hieu irng ch ong ch a p nho ca c mach BLR va hie u irng tich tu cli~n tich ba ng phirong ph ap hinh tha nh xung tich ph a n cang, cung nhir cho phe p nang kh ii na ng ta i tfi n so len rmrc toi da la 70 KH z IOn han cac KBPK clrr san xu at trong mroc lau nay la 35.. 45KHz. Chinh VI v? y rna kh d nan g ph an giai nang IUQng cua SA-694 clrr diro c nang cao (j gia tri 3,3 1 KeV voi thai gian hlnh thanh xung la 2flS. Tuy vay, tren loi ra GI cho FWHM ban g 3,72 Ke V (j h~ng so thai gian hlnh thanh xung 0,5 flS la mQt gia con kha IOn so vdi 19 thuyet v€ tich cho khoi dien tii' buoc phai sii' dung cang tuyen tinh tren IC loai HI-201 la loai co clap irng t~n so trung binh, mac du trong so cl6 nguyen 19 cla dira ra cac mach ba chinh cl€ nang cao t~n so, nhirng v£n chua da t cluQC nhu mong muon.

JINR, 13-84-227; Dubna -1984 (chii' Nga)

2. CANBERRA NUCLEAR CA TALOG - Mod - 2025, Spectroscopy Amplifier

Intruction Manual -1987.

3. DINH SY HrEN - NGUYEN DUC HOA, Khuech dai pho ke' vdi hinh thanh xung chua n Gauss. , Bao cao tong hop cl~ tai cap nha nude KC-09-14B: "Che'-t?o cac khoi cli~n tit clnrc nang chat IUQng cao " Da Lat -1995; trang 11

4. ORTEC NUCLEAR CATALOG - Mod - 673, Spectroscopy Amplifier and Gate

SUMMARY

THE STUDY OF MAKING SPECTROSCOPY AMPLIFIER SA- 694

Nguyen Due Boa

Intergrator Operating and Service Manual

This paper is about the design of a nuclear spectroscopy amplifier in order to improve its characteristics as well as to give off the Pile - Up effects by Ba se Line Restore circuits - BLR and the accumula ted electric charge effects by method of shaping the pul se of integr at ed gate - GI