The ISTTOK Heavy Ion Beam Diagnostic
description
Transcript of The ISTTOK Heavy Ion Beam Diagnostic
The ISTTOK Heavy Ion Beam Diagnostic
HIBD concept
Multiple cell detector(Secondary ions)
Toroidaldirection
Primary beam detector
PlasmaBT
I+
I++
secçãodo feixe
detectorde intensidadee posição
fenda
plac
as c
ondu
ctor
as
I+++
HIBP concept
ISTTOK magnetic configuration
R
bobines toroidais
câmara
secçãocondutora
aberturainterna
Plan view
z
z
xR
RBB c
Toroidal field inside the coil aperture =
x
z
Side section
ISTTOK magnetic configuration
z
z
RR
rR
xR
RBB
ext
extc
)(
)(
int
Toroidal field outside the coil aperture (x) =
22)( yxxr c
xc
EYya
YyaK
YyaIB oy 22
222
22 )()(
)(
)()(
22
1
; ; z
BBxR
BB zx
E
Yya
YyaK
Yya
YyIB o 22
222
22 )()(
)(
)()(
)(22
1
22)( zxR
; d sin1 ; sin1
22
0
22
0 22
E
dK
1222 )()(4
Yyaa
Position coils field
Plasma current magnetic field
plasma outside 2
plasma inside 2).(2
0
r
IB
rdrrjr
B
pp
r
p
; ; r
xBB
r
yBB pypx
Asymmetric current profiles are generated
by a combination of symmetric profiles
For radial profiles
z
z
R
rrj
m
p
2
2
1)(
) sin() cos(2
)(3242
2242
tm
Ft
m
Ft
m
Ftti
m
Fiti ioioiioi
oiio
o
Beam trajectories
; ; )( ; vv2
2
22
3
3
i)1()2(0)2()1(0 Bm
qEBB
m
qBBqF iiiiiio
i x,y,z
In numerical simulation equations uses constant B and E;
B and E are updated on each iteration cycle (toroidal curvature negleted);
Electric field are modelled freely (core and edge) – normally an inverted parabola with peak eV ~ 3/2 KTe
Cs+20 keV
Cs++
plasma
coils
-32
-30
-28
-26
-24
-22
-20
5.7 6.1 6.5 6.9 7.3
z-deviation (mm)
y-de
tect
or (c
m)
Cross section front view
Detector arrangement
Detector configurations A, B, C
Beam attenuation
MOST IMPORTANT IONIZATION REACTIONS:
I+ + e- I2+ + 2e- I+ + e- I3+ + 3e- I2+ + e- I3+ + 2e-
I I
j o e e
AR
r
e j j er
Ro
n s n s ds
n r r dl n s ds
i
j
j
A
B
2
1
1 12 1 13 1
12 2 23 2
2
1
exp ( ) ( ) .
. ( ) ( ) . exp ( ) )
v2
v.exp)v(.v
2v1
v
v).v()v,(ˆ 3
0
2
',
23
',', d
KT
m
KT
mT
e
eqq
e
e
bb
qqbeqq
0
1E-19
2E-19
3E-19
4E-19
5E-19
6E-19
7E-19
8E-19
9E-19
0 250 500 750 1000
Temperatura (eV)
eff (
m
Hg+ + e- --> Hg2+ + 2e- [46]
Cs+ + e- --> Cs2+ + 2e- [44]
Xe+ + e- --> Xe2+ + 2e- [45]
Cs2+ + e- --> Cs3+ + 2e- [44]
0.E+00
1.E-19
2.E-19
3.E-19
4.E-19
0 250 500 750 1000
Temperatura (eV)
eff (
m2)
Hg+ + e- --> Hg3+ + 3e- [48]
Xe+ + e- --> Xe3+ + 3e- [47]
Cs+ + e- --> Cs3+ + 3e- [44]
1 e 12
2
2
2m
poe
m
poe
r
rTT
r
rnn
Density and temperature profiles
dlyxTyxnIdlyxTyxnIII jjjj )),((ˆ),()),((ˆ),( 1311211
Primary beam attenuation
)),((ˆ),(2 12
22 yxTyxnI
dl
IdI j
jj
Secondary beam generation (dl is the projection of detector cell height into the primary beam path)
')),((ˆ),( 232
12
12
.)( dlyxTyxndIdIdI jjattj
Secondary beam attenuation (to integrate along secondary beam path dl’)
Espécie ne (m-3) Te (eV)
K+
(E=5 keV)~1019 (L=2 cm)
10 -1.310-4 210-3
Tl+
(E=100 keV)~1019
(L=30 cm)
1000 -0.410-4 0.810-3
21
2E
E
Plasma source (Cs+)
6.01072.1
2
27
23 d
a
V
mIP
Child-Langmuir perveance condition
in ISTTOK HIBD
sonda Langmuir
magnetefilamentode Ta
dispensadoresde césio
oríficio para extracçãodo feixe
electrodo filtro(-100 V)
electrodo de referência(0 V)
aneis de aquecimento
isoladores
Plasma source (Xe+/Hg+)
Detectorsecundário
Câmara
Plantaformasuperior do ISTTOK
Isolador
Válvula
Medidorde pressão
Pulsador
Fonte iónica
Isolador
Filtro demassa
Detector primário
Sistema dedeflecçãodo feixe
Isoladorcerâmico
Bomba Turbomolecular
FichasBNC
Célula deFaraday
Bomba turbomolecular
1122(det) )(ˆ)( 2 dsrrnABII jjeoj
Determination of
ˆ)(exp.)(ˆ)(.
.ˆ)(ˆ)(expI2I
223212
113112102
(det)
1
B
A
Rp
r ejje
r
RA
eej
j
j
i
dssndlrrn
dssnsn
Beam attenuation
Simplified
12en ̂
Simplified version
A1=0 (week primary beam attenuation due to tertiary ion production)
B=1 (weak secondary beam attenuation)
)(ˆ)(ˆ)( exp 2 11211212(det) dsrrn
I
dssnII jje
j
r
R eojj
i
dlI
Irn
j
jje
2
)(ˆ2(det)
12
The generation factor is related to the secondary currents by:
The current at the detector cell j is obtained by integration over the element dl obtained by the projection from the detector cell height length into the primary beam path.
1
0
2(det)2
10
j
LLj III
Cs+
Cs2+
detectorsecundário
detectorprimário
plasma
bobinestoroidais
a)
y
x
0
10
20
30
40
50
60
70
80
0 5 10 15 20
# cel
corr
ente
s (n
A)
Detector currents per row (linha)
Detector rows
0
1
2
3
4
5
6
-10 -5 0 5 10
raio (cm)
n x
(m
-1)
assumidorecuperado
0
0.2
0.4
0.6
0.8
1
1.2
-10 -5 0 5 10
raio (cm)
n x
(n
orm
aliz
ado)
assumidorecuperado
The beam attenuation in ISTTOK induces only first order effects to consider on the computation of the profile of
12en ̂
ne(0) = 11019 Te(0) = 200 eV Eb=22 keV I0=1 uA
Including the effect of attenuation on the secondary beams
A1=0 (week primary beam attenuation due to tertiary ion production)
B≠1 (moderate secondary beam attenuation (ISTTOK))
N
jjIII
1
2det0 2
1
The difference between injected primary beam current and detected primary beam current is equal to ½ of the all secondary beam current generated along the primary beam
N
jj
N
jjtotal IIIII
1
2(det)det0
1
3232 2
The total secondaries current lost by ionization to terciaries is given by the difference between the initial secondaries currents generated by the primary beam and the secondaries currents detected at the detector
32jIDetermination of the corrent lost by a single secondaries’ beam
Rp
rj ejjjjj dsnIIIII 23222
(det)232 ˆexp
1ˆ 23
p
j
R
r e dsn For ISTTOK
p
j
p
j
R
r ejR
r ejjj dsnIdsnIII 232
232232 ˆˆ1
Expanding the exponencial and taking only linear terms becomes:
N
j
pR
jr ej
pR
jr ej
total
jj
dlnI
dlnI
I
I
123
2
232
32
3232
ˆ
ˆ
So, one could find the fraction of each secondary beam current lost to terciary ionization by the ratio to the total lost current of all secondaries’ beams:
Rp
rj e dsn 23̂ Rp
rj e dln 12̂
Therefore
have similar shape to
Calculations show that:
Primary beam and secondary beams have similar radial trajectories in the plasma
Effective cross sections have similar shapes for I+I2+ and I2+I3+
0
0.5
1
1.5
2
2.5
0 0.05 0.1 0.15 0.2
percurso do feixe (m)
n x
(m
-1)
n x12
(normalizado)
Confirmed by calculations for several
ISTTOK plasma temperature and
density profiles
N
j
N
jLiiej
N
jLLLej
j
dlnI
dlnI
112
2(det)
122(det)
32
ˆ
ˆ
N
j
pR
jr ej
pR
jr ej
total
jj
dlnI
dlnI
I
I
123
2
232
32
3232
ˆ
ˆ
Experimentaly
determined
Replacing integrals by discret sums
A7
#cel = 7
dl para a célula 7
0
10
20
30
40
50
60
70
80
0 5 10 15 20
# cel
corr
ente
s (n
A)
77 7I A
I Acel celcel
# ##
0
0.5
1
1.5
2
2.5
3
3.5
4
0.79 1.28 1.31 1.28 1.25 1.23 1.21 1.19 1.16 1.15 1.12 1.11 1.08 1.08 1.06 1.03 1.09 0.54
dl (cm)
n x
m-1
)
Área sombreada = A7
A7 = LL
Le dln )ˆ(
18
712
N
jjjj IIII
1
2(det)det0
322 2
Absolute value of secondaries current at the ionization volume on the primary beam
0
1
2
3
4
5
6
-10 -5 0 5 10
raio (cm)
nex
12 (
m-1
)
recuperado
assumidoThe recovery of the absolute value of the generation factor is now more acurate
The remaining difference is due to ionization from primary to tertiary ions
Correction: see following slides
dln
I
dlnII e
j
r
R ejj
i1313120
3)31( ˆ)ˆˆ(exp3
Generation of tertiaries from the primary beam
(on the same volumes of generation of secondaries)
And the tertiaries generation factor can be given by
jj
jje
dlI
In
3
)ˆ(3
13
0.0
0.2
0.4
0.6
0.8
1.0
1.2
-10 -5 0 5 10
nx
(nor
mal
izad
o)
I + I +I 2 + I 3 +
raio (cm)
normenorme nn )ˆ()ˆ( 1213 We aproximate:
N
jej
ej
N
jj
jj
dlnI
dlnI
I
I
113
13
1
331
33131
ˆ3
ˆ3
N
jj
j
N
jej
ejj
I
I
dlnI
dlnI
1
2
2
112
1231
ˆ
ˆ
Using the aproximation
And obtain the tertiary currents at te ionization volume using:
33131331totaljj II
unknown
Experimentaly
determined
Estimation of the total current of the tertiaries: 3total
31 I
.3
2
3
22
331
1
2
1
331
te
total
totalN
jj
N
jj
CI
I
I
I
For a given temperature the ratio between production of secondaries and tertiaries is constant (only depends on the cross sections’ ratio)
In the plasma the temperature varies along the radius, but sensivity of the currents’ ratio to temperature profile changes is low
0.20
0.23
0.25
0.28
0.30
0.33
0.35
osc5
osc3 oc
o
pica
do
para
bolic
o
quad
rado
Fra
cçã
o d
e t
erc
iário
s R
100
200
300
Te(0) (eV)
(Curr
en
t ra
tio o
f te
rcia
ries
to
seco
ndari
es)
0
0.5
1
1.5
2
2.5
-10 -5 0 5 10
'assumido'
'recuperado'T e = 100 eV
n e = 5x1018 m -3
0
1
2
3
4
5
6
-10 -5 0 5 10
'assumido'
'recuperado'T e = 200 eV
n e = 1x1019 m -3
0
2
4
6
8
-10 -5 0 5 10
'assumido'
'recuperado'T e = 300 eVn e = 1.5x1019
m -3 0
2
4
6
8
-10 -5 0 5 10
'assumido'
'recuperado'
a)
b)
c)
Oco
a) Te = 100 eV e ne = 51018 m-3, b) Te = 200 eV e ne = 11019 m-3 e c) Te = 300 eV e ne =
1.51019 m-3.
Excellent recovery of absolute values of
12̂en
Example of effect of negleting atenuation factors
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20
#linha
corr
ente
s (
nA
)
Detected currents
0
2
4
6
8
-10 -5 0 5 10
raio (cm)
n x
(m
-1)
assumidorecuperado
versão simplificada
0
2
4
6
8
-10 -5 0 5 10
raio (cm)
n x
(m
-1)
assumidorecuperado
versão intermédia
0
2
4
6
8
-10 -5 0 5 10
'assumido'
'recuperado'
a)
b)
c)
Osc5
Using full version of algorithm
A1=0
B=1
A1=0
B≠1 A1 ≠0
B≠1
Determination of electron density and electron temperature
)3,2(13
123
2
))((3
2
)ˆ(3
)ˆ(2PT
dl
dl
dlnI
dlnI
I
Ie
m
t
s
tPP
sPP
13
12)3,2( ˆ
ˆ)(
em T
Ratio between detected currents from 2 different ionization
processes on the same volume
Table of effective cross sections
In ISTTOK two ion species are used
)2,2(122
12)(2
112)(1
22
21 ))((
)ˆ(
)ˆ(PT
nI
nI
I
Ie
mm
Pm
pm
Pm
pm
m
m
-0.4 -0.3 -0.2 -0.1 0.1 0.2 0.3
-0.2
0.2
0.4
0.6
Hg+Hg3+ and Xe+Xe2+
(E = 22 keV, Hg = 32.0º, Xe = 33.3º).
0
4
8
12
50 100 150 200 250 300 350
temperatura (eV)
Ra
cio
s (a
bs.
)
Hg
Xe
12
12
ˆ
ˆ
(a)
Hg
Xe
13
12
ˆ
ˆ
(b)
-0.4 -0.3 -0.2 -0.1 0.1 0.2 0.3
-0.2
0.2
0.4
0.6
Xe+Xe2+, Xe+Xe3+ e Xe2+Xe3+
Hg+ Hg 2+, Hg+Hg3+ , Hg2+Hg3+
Hg+ Hg 2+, Hg+Hg3+ e Hg
2+Hg3+ Ip=6 kA.
-0.4 -0.3 -0.2 -0.1 0.1 0.2 0.3
-0.2
0.2
0.4
0.6
-40
-36
-32
-28
-24
-20
-5 0 5 10 15 20
z (mm)
y (
cm
)
Hg2+
Hg3+
iões Hg3+
provenientesda ionização dos iões Hg2+
coluna de célulasdo detector secundário
-0.4 -0.3 -0.2 -0.1 0.1 0.2 0.3
-0.2
0.2
0.4
0.6
0
25
50
75
100
-6 -4 -2 0 2 4 6
raio (cm)
corr
ente
s (n
A)
Xe 2+
Hg 3+
P 1P 2P 3P 4
50
90
130
170
210
0.00 0.02 0.04 0.06 0.08 0.10 0.12
percurso L (m)
tem
pera
tura
(eV
)
The two beams have overlaped trajectories
Detector currents
The Hg2+ currents are not detected, they can be estimated from the Xe2+ currents using the average
of the ionization ratio between the limits of temperature of ISTTOK (quasi constant function with
temperature)
)2,2(XeHg
22
1212
ˆˆ
XeHg
XeHg n
n
Therefore the generation of Hg2+ can now be estimated from
1
0
1
0
3(det)3
1120 )ˆ(
j
L
j
LLL
HgLj IdlnIII
And the Hg+ primary beam current at each ionization point given by
100
150
200
250
300
-6 -4 -2 0 2 4 6
Raio (cm)
Tem
pera
tura
(eV
) assumidos
recuperados
6.0
7.5
9.0
10.5
-6 -4 -2 0 2 4 6
Raio (cm)
De
nsi
da
de
(x1
018
m-3
)
b)
100
150
200
250
300
-6 -4 -2 0 2 4 6
Raio (cm)
Tem
pera
tura
(eV
) assumidos
recuperados
a)
6.0
7.5
9.0
10.5
-6 -4 -2 0 2 4 6
Raio (cm)
Den
sida
de (
x10
18 m
-3)
b)
50
100
150
200
250
300
350
-6 -4 -2 0 2 4 6
Raio (cm)
Tem
pera
tura
(eV
)
0
5
10
15
20
Den
sida
de (
x101
8 m
-3)densidade
temperatura
50
100
150
200
250
300
350
-6 -4 -2 0 2 4 6
Raio (cm)
Tem
pera
tura
(eV
)
0
5
10
15
20
Den
sida
de (
x10
18 m
-3)
densidade
temperatura
()TOF = TOF(t2) - TOF(t1) =
½(v0)-1{e{(ltr,t2) - (ltr,t1)}/E0} dltr + add Accounts for shifts on
trajectories due to external and internal
magnetic field changes
PULSER
SLIT
PLASMACHAMBER
BEAM POSITIONCONTROL
DETECTOR
Cs+ BEAM20 s
~250 ns
HI PASSFILTER
EARTHBREAK START
~6sDELAY
STOP TAC
FAST POWER SUPPLY
SHAPINGAMPLIFIER
FAST CHARGEPRE-AMP.
CONSTANTFRACTIONDISCRIM.
Distinguishing 2 ns delay
resolution (/)TOF ~310-4 for =7.2 s of time-of-flight of the beam pulse
from modulator to detector.
Plasma potential measurements using the primary beam
MCAD
Cs+
Stop Start
Modulator
Cs2+
Primary detector
Sample volumes Plasma
Average plasma potential
measurements
Absolute plasma potential measurements
Plasma potential measuremenst using the secondaries
K1F + eVF = K1P + eVP
K2P + 2eVP = K2D + 2eVD VP = (K2D - K1F) + (2VD - VF)
1
e
Energy conservation
x
y
zCh1
Ch2
Ch3
Ch4
MCAD
“Start” “Stop”Control module
Cylindrical plates
XY-alignment plates
Z-plates
620 mm
TOF-path module
Plasma Poloidal Field Measurements
Important: In ISTTOK all ion trajectories are very close to
radial
r
IB po
p 2
Poloidal magnetic field outside the plasma:
1
2)1(
2)1()1(21
211
2)1( 2
1
s
TaTvzzz pd
Primary beam initial
position
secondary beam increment from plasma bondary
to detector position
Velocity of primary beam at ionization
point X secondary time of flight
Secondary ions average
acceleration from ionization point
to plasma perifery
Secondary beam position
at cell (1)
dtT
TvdtTvzzzdv
j
jpjjjjjjdjj
21
)1(2
)(2
)(21
)1(2)()(2
)1(2
)1()1,(
dtdvdtvzz jjjjj
)1,()()()1( 2
1
)1,()()1( jjjj dvvv
dtdvTvTv jjjpjjpj
)1,()(
2)()1(
2)1( 2
2
1
2
1
2
1
Recursive calculation allows to determine the accelerations at ionization point
vdt
dv
e
mBp
1poloidal field module can
be obtained from
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
-10 -5 0 5 10
raio (cm)
j (
MA
/m2 )
j plano
j parabolóico
j picado
-31
-28
-25
-22
-5.5 -5.1 -4.7 -4.3 -3.9 -3.5 -3.1 -2.7
z (mm)
y (c
m)
plano
parabolóico picado
0
5
10
15
20
25
30
-10 -5 0 5 10
raio (cm)
Bp
(mT
)
o B p+ recuperado B p+ assumido - B p totalj picado
j parabolóico
j plano
0.0
0.1
0.2
0.3
0.4
0.5
0.6
-10 -5 0 5 10
raio (cm)
j (
MA
/m2 )
oco
0
5
10
15
20
25
-10 -5 0 5 10
Raio (cm)
Bp
(mT
)
o B p+ recuperado B p+ assumido - B p total
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
-10 -5 0 5 10
raio (cm)
j (
MA
/m2 )
perturbaçãolocalizada
0
5
10
15
20
25
-10 -5 0 5 10
Raio (cm)
Bp (
mT
)
o B p+ recuperado B p+ assumido - B p total
-31
-28
-25
-22
-5.3 -4.9 -4.5 -4.1 -3.7 -3.3
z (mm)
y (
cm)perturbaçãomagnética
parabolóico
DETECTOR RESOLUTION (mm)
Border Center
A 0.3 0.2
C 0.6 0.3
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
-10 -5 0 5 10
raio (cm)
j ( M
A/m
2 )
pedestral
-31
-28
-25
-22
-5.5 -5.1 -4.7 -4.3 -3.9 -3.5 -3.1
z (mm)
y (c
m) pedestral
parabolóico
0
5
10
15
20
25
30
-10 -5 0 5 10
Raio (cm)
Bp
(mT
)
o B p+ recuperado B p+ assumido - B p total
0.0
0.2
0.4
0.6
0.8
1.0
1.2
-10 -5 0 5 10
raio (cm)
j (M
A/m
2 )assimétrico
-31
-28
-25
-22
-5.5 -5.1 -4.7 -4.3 -3.9 -3.5 -3.1 -2.7
z (mm)
y (
cm)
picado
assimétrico
0
5
10
15
20
25
30
-10 -5 0 5 10
Raio (cm)
Bp (
mT
)
o B p+ recuperado B p+ assumido - B p total
EXPERIMENTAL RESULTS
4.5
1.4
-1.6
-4.4
3.55
.57.59
.511.513.515.517.519.521.523.525.527.529.5
0
1
2
3
4
5
ne
(m
-1)
4.5
2.4
0.4
-1.6
-3.5
3.5
5.5
7.5
9.5
11.5
13.5
15.5
17.5
19.5
21.5
23.5
25.5
27.5
29.5
raio (cm)
tem
po
(m
s)
Plasma current
Average density - comparison with interferometer
00.2
0.40.60.8
11.2
3 6 9 12 15 18 21 24 27 30
tempo (ms)
u. a
.
HIBD
Beam off
12̂en
4.7
-2.4
1622
2834
4046
5258
32.8
0
0.01
0.02
0.03
0.04
0.05
ne
x
(u
.a.)
4.7
1.1
-2.4
13
16
19
22
25
28
31
34
37
40
43
46
49
52
55
58
61
raio (cm)
tem
po (m
s)
12̂en
Te , ne
Plasma current for 2 discharges Radial average density for two discharges
-20
213
19
25
31
0
70
140
210
T e (
eV)
R (cm)
t (ms)
-20
213
19
25
31
4
6
8
10
12
ne
(10
18 m
-3)
R (cm)
t (ms)
interferometer
HIBD
The change in average
plasma potential is -450 V,
Vp
0
1000
2000
3000
4000
5000
6000
7000
8000
0.00 10.00 20.00 30.00
TIME (ms)
P L A
S M
A C
U R
R E
N T
( A
)
#2939
#2940
T1 T2 T3 T4
Bp
1.2
1.6
2.0
2.4
2.8
3 4 5 6 7
Row Number
( y
) ( m
m )
T
T
T
T
-1
0
1
2
3 4 5 6 7
Row Number
P o l o
i d a l F
i e l d
N o r m
a l i s
e d t o P
l a s m
a
C
u r r
e n t (
a . u
. )
T
T
T
T
A1 A2
A3
A4
1
2
3
4
references
33. ”Time–of-flight energy analyser for the plasma potential measurements by a heavy ion beam diagnostic”S. Nedzelskiy, A. Malaquias, B. Gonçalves, C. Silva, C. A. F. Varandas, and J. A. C. Cabral,REVIEW OF SCIENTIFIC INSTRUMENTS VOLUME 75, NUMBER 10 OCTOBER 2004, pp. 3514-3516in Proceedings of 15th Topical Conference High-Temperature Plasma Diagnostics, San Diego, California, April 19-22,2004
1."Developement of a new type of Cs Plasma Ion Gun for application in a heavy ion beam tokamak diagnostic" J.A.C. Cabral, O.J. Hancock, A.J.T. Holmes, M. Inman, C.M.D. Mahony, A. Malaquias, A. Praxedes, W. van Toledo and C.A.F. Varandas. Plasma Sources Science and Technology, 3, 1994, pp. 1-9.
2."The Heavy Ion Beam Diagnostic for the Tokamak ISTTOK" J.A.C. Cabral, A. Malaquias, A. Praxedes, W. van Toledo, and C.A.F. Varandas. IEEE Transations on Plasma Science, vol 22 nº4, August 1994.
3."The Control and Data Acquisition System for the ISTTOK Heavy Ion Beam Diagnostic" C.A.F. Varandas, A.J. Baptista, C. Coreia, A. Malaquias, J. C. Mata, A Praxedes, A. P. Rodrigues, J. Sousa, W. Toledo and J.A.C. Cabral Meas. Sci. Technol. 6 (1995) 1588-1597.
5."Analysis of the ISTTOK plasma density profile evolution in sawtooth discharges by heavy-ion beam probing" J.A.C. Cabral, C.A.F. Varandas, A. Malaquias , A. Praxedes, M. P. Alonso, P. Belo, R. Canário, H. Fernandes, J. Ferreira, C. J. Freitas, R. Gomes, J. Pires, C. Silva, A. Soares, J. Sousa and P.H.M. Vassen Plasma Phys. Control. Fusion 38 (1996) 51-70
6.“Engineering Aspects of an Advanced Heavy Ion Beam Diagnostic for the TJ-II Stellarator” A. Malaquias, C. Varandas, J.A.C. Cabral, L.I. Krupnik, S.M. Khrebtov, I.S. Nedzelskij, Yu. V. Trofimenko, A. Melnikov, C. Hidalgo, I. Garcia-Cortes Fusion Technology V.1 pp. 869, 1996
8."Evolution of the poloidal magnetic field profile of the ISTTOK plasma by heavy ion beam probing" A. Malaquias, J. A. C. Cabral, C.A.F. Varandas and R. Canário Fusion Engineering and Design, 34-35 (1997) 671-674
10.“Evolution of the tokamak ISTTOK plasma density and electron temperature radial profiles determined by heavy ion beam probing” A. Malaquias, I.S. Nedzelskii, C.A.F. Varandas, and J.A.C. Cabral Review of Scientific Instruments, V70, N1, Jan 1999, Part II. Pp. 947-950