CH A NNEL NU M BER

~

^{. a o-P 23}- - - --&>n;

~ao-a2--"""I

150

u · ::t..

0 tO

a:: w 100

a... 0

(/)

~ z

~ 0 u

50

0

260 300 340

Figure 11

Experimental set-ups used for the measurement of the Si28 + n yield curves (see figures 12-18).

Top: D(d, n)He as neutron s3 ource.

Bottom: Be 9 (a., n) as neutron source.

The data given on this figure, in conjunction with the spectra of figures 9 and 10 are used to calculate the absolute cross section for Si28

(n; a.

0)Mg25 in appendix 1 (page 81).

o+

- ->

BEAM

~ h=6.29cm---

INTEGRATOR

.l+-C:= - :>

He 4++

BEAM

Q= 27µ.C

. P=43.2mm Hg

h=

__., 2.0±0.1 ~

cm

INTEGRATOR Q= 150µ.C

DETECTOR A=0.80cm 2 V=0.275

± 0.020cm3

DETECTOR A=0.80cm2

V=0.40

±0.06cm3

Total cross section for the reaction Si28 (n, a.

0)Mg25

for 7. 2 :5 En :5 12. 0 MeV.

Table 3 is a listing of the clearly- resolvable resonances on this curve. The reaction D(d, n)He3

was used to provide neutrons and a Li-drifted silicon detector served as both target and detector. For details on how this curve was obtained and why it is

useful, see Chapter IV, section 4 (starting on page 33).

,_.

~

r..>.

-132-Figure 12

I I I I I I I I I I I I I I I I I I I I I I I I I N

r~

--

---

----

~ ----

--

I I I I I I I I I I I I I I 1!"7 l·I I I 0 I() 0 Q

(qW)..0 0 I() 0 c: w

Total cross section for the reaction Si28 (n, a.

0)Mg25

for 11. 44 :5 En

5:

16. 40 MeV.

The reaction Be9

(a., n )c12

was used to provide neutrons and a Li-drifted silicon detector

0

served as both target and detector. For details on how this curve was obtained and why

it is useful, see Chapter IV, section 4 (starting on page 33). ...

""

""

-134-Figure 13

~~.l--~~-l--~~+-~~f-o---=fL~~t-~~t-~----t~ ~

0 r<"> 0 (\J

(qw) .D 0 0 ~

c w

Total cross sections for peaks a. -a.

2 (lower curve) and a. -p

23 (upper curve) for

· the reactions Si28

(n, a.) Mg25

and

Si

²⁸

(~,

^{p)Af 28} for neutron

ene~gies

of 7. 2 to 12. 0 MeV.

The reaction D(d, n)He3

was used to provide neutrons and a Li-drifted silicon detector served as both target and detector. Figure 9 shows a typical spectrum from the data used to obtain these curves and indicates the regions summed for the different integral cross sections. The analysis, experimental techniques and possible applications of these curves are discussed in Chapter IV, section 4 (starting on page 33).

...

c,., 01

8

r<> . -136-

(qW)..0 0 0 N 0 Q Figure 14

0 > Q) ~

c w

Total cross sections for peaks a.

0-a.

2 (lower curve) and a.

0-p

23 (upper curve) for the reactions Si28

(n, a.)Mg25

and Si28

(n, p)Al28

for neutron energies of 11. 44 to 16. 40

. MeV. The reaction Be9

(a., n )c12

was used to provide neutrons and a Li-drift silicon

0

detector served as both target and detector. Figure 10 shows a typical spectrum from the data used to obtain these curves and indicates the regions summed for the different integral cross sections. The analysis, experimental techniques and possible applications of these curves are discussed in Chapter IV, section 4 (starting on page 33).

1-l

""

^-J

-138-Figure 15

~----t----'-~~~-~~~~~---j~~ .. ~l--~+-~~~~-h-'"'-~~~~y ~

(qi.u) ..D 0 Cl) 0 ~

c w

Total cross sections for peaks a

1

(lower curve) and a.

3 (upper curve) for the reaction Si28

(n, a.)Mg25

for neutron energies of 11. 44 to 16. 22 MeV. These curves were evaluated from the same data as the curves of figures 13 and 15. The reaction Be 9

(a., n )C 12

was used to provide neutrons and a Li-drifted silicon detector served

0

as both target and detector. The analysis, experimental techniques and possible applications of these curves are discussed in Chapter IV, section 4 (starting on page 33).

...

(...:>

co

-140-

0 (\J

(qW)..0 Figure 16

0 0

Total cross sections for peaks a.

2 (lower curve) and a.

4 {upper curve) for the reaction Si28

(n, a.)Mg25

for neutron energies of 11. 44 to 16. 22 MeV. For details, see the caption of figure 16.

,_..

H:>.

,_..

0 C\J -142-

(qW)_Q Figure 17

0 0

Total cross sections for peaks p

01 (upper· curve) and p

23 (lower curve) for the reaction Si28

(n, p)A128

for neutron energies of 11. 44 to 16. 22 MeV. For details,

·see the caption of figure 16.

...

c.:> ~

-144-

0 C'J

(qW)..0 Figure 18

0 0

Cross section at 0° for the reaction Be9 (a., n

0)c12

as a function of bombarding energy. This curve was measured with a silicon semiconductor detector (see page 36) .. It agrees well, both in absolute cross section and shape, with the curve of figure 2 in the ·region of overlap (Ea.

=

5-6 MeV) and with the data of Risser, Price and Class (1957) who measured this cross section for 1. 7 ~ Ea. ~ 4. 8 MeV.

...,.

~ 01

Q co

0 C\I -146-

(JS/QW} 7jp;.op Figure 19

IO

>

'¢ © ~

Cj w

N

Q

Figure 20

Pulse-height defect of the Si28 (n, p

01) peak as determined from a calibration based on Si28

(n, a.) peaks. See page 39.

0

140

0

120

-

^{>100 0}

Q)

-

~

J-LL

-

₈₀

:r:

0

Cf) ₀

>-

<.9

a:::

w

60

w z

40

20

0 _{4 8 12 16}

NEUTRON ENE RGY(MeV)

Figure 21

Thickness measurements of a Be 9

target (top) and Fe 54 target {bottom) performed by scattering 1-MeV protons from the tungsten backing with and without penetration through the target material evaporated on one side. The two graphs show the number of scattered protons per unit incident charge vs energy of the scattered proton, the latter being given by

E (MeV) ::: 0. 3841(1 - E /(2m c2

))/ F2

p p p

where F is the magnet fluxmeter reading. The square points delineate the profile of the back side i. e. , protons scattered without penetration through the evaporated material. The scattering geometry for both measurements is indicated. Note that two measurements of the Fe 54 thickness are obtained:

the shift of the W profile and the width of the peak due to protons scattered by Fe 54 itself. These measurements were performed on the 26. 7-cm-magnetic-spectrometer station of the #1 ESG. See page 50 for further discussion of this figure.

Cl>

(.) 0 .

(/)

.ri '-

-

^Cf) 0

r-

z

::::>

0 (.)

LL

0

0:::

w CD

::::> ~

z

.660

Be9 ON W BACKING

nt=4.02 x1018atoms/cm2

Fe54 ON W BACKING

nt=6.90xlo¹⁷ atoms/cm2

.64o·

FLUXMETER READING

I

.620

Figure 22

The reaction Mg24 (He3

, n)Si26

at a bombarding energy of 11. 60 MeV as seen in a silicon semiconductor detector at

o

⁰ with respect to the beam axis. The top spectrum is the sum of several runs directly as recorded in a 400- channel analyzer. Reactions induced in the detector by the ground- state neutron are indicated by arrows. See figure 5 for the spectrum of a single monoenergetic neutron in which the peaks are correlated more clearly with the corresponding nuclear reactions in the silicon which produce them. The bottom spectrum shows the top spectrum with the best cali- bration obtained for the ground-state neutron normalized to it and subtracted out. Families of pe.aks associated with contaminants and excited states are explicitly identified.

The ordinates are true numbers of counts before and after subtraction. See page 53 for a discussion of the results obtained.

1000

500

...J

w z z <{

:c u .ol--~~---1~~~-l-~~~-l-~~~-l-~~__Jl--~~-l-~::_~-l-~~~

a: ~1000

... Cf)

z :::>

0 u

500

ois(He3,noJ

-ia1 lao

175 200

Mg24(He3 ,n) Si26

no SUBTRACTED

225 250 275

CHANNEL NUMBER

300

noao

I

t I .

325

Figure 23

Th e reac ion t . 8 .2s(H 3 )s30 ¹ e , n as seen m a s icon . n·

detector at

o

⁰ at a bombarding energy of 11. 60 MeV. In the subtraction spectrum, the large dip just in front of the n1-a.

0 peak arises in the same way as the dip in the Si26 spectrum (see figure 22 and the discussion of artificial dips on page 53). This spectrum, which was taken at

o

^{0, does}

not show n

1 very clearly, particularly when artifically- produced dips and rises of comparable magnitude are present. However, in spectra taken at other angles, n

1 shows up clearly even before subtraction. In fact, at 30°, the n

1 cross section is about three times that of n

0• (See the n0 and n

1 angular distributions of figure 30.) For notation see figure 22 and for a discussion of the results see page 55.

500

__J w

z z

<(

::r:

0 et: w a..

CJ)

I-z

~

0 ₅₀₀ 0

·OO

0

@:)')

0 0

0

0 ^c:B>

0c£ .

-~

0

0

0

150 175 200

ao

5;28(He3,n) 530 no SUBTRACTED

Cl2 (He3,nol

Po1 a2 01 ao

0

J0

₈

0 0 0:;)~ ₀

0 0 0

~

225• 250 275

CHANNEL NUMBER

noao I I t

00Y 0

300 325

Figure 24

The reaction

s

^{32(He3,n)Ar34 as seen in a silicon}

detector at

o

⁰ at a bombarding energy of 10. 81 MeV. For notation, see figure 22 and, for a discussion of the results, see page 55.

_J

w z z <!

I

(..)

0:: w a..

en 400

200

..._ 400

:J z

0 (..)

200 0

0

016lHe3 ,nol

· la

¹

la

⁰

125 150

s32(He3 ,n)Ar 34 532(He3 ,nol

532 (He 3 ,n) Ar 34

no SUBTRACTED

C12 lHe3 ,nol

175 200 225

CHANN~L NUMBER

250

Figure 25

The reaction Ca 40 (He3

, n)Ti42

at a bombarding energy of 11. 60 MeV as seen in a silicon detector. The upper spectrum shows the peaks produced by neutrons leading to the ground states of 0 14

, Ti42

and Ne18 with the detector at 0°. The lower spectrum shows the same peaks with the center of the detector at 45°, its face subtending an angle of 10°. The kinematic shift of the Si28

(n, a.

0) peaks is

· indicated by ~Ek'. There was about four times more carbon

· on the target when the lower spectrum was taken. See page 56 for a discussion of the results obtained and figure 22 for notation.

w _J

z z

<(

600

400

0

²⁰⁰

er w

Q_

(/)

1-z

:::>

0 0

100

ca⁴⁰ (He3, n0l

cl2(He3 n₀l

Ca 40(He3 ,n) Ti 4 2 6=0°

Ca40(He3,n )Tj42 9=45°

0 '

. 00 0_JP01 la2 {a1

ao}---

^.6Ek

---J

.00000~··

0%_ .· . .

. .

.. ·.

· .... 0 . . ·.· ~-

.__

__

^__._

____

^{...____ ...}

200 250 300 350

CHANNEL NUMBER

Figure 26

The reaction Ti 46

( He~,

n)C r 48

at a bombarding energy of 11. 00 MeV. Note that the ground-state neutron subtraction cannot be extended below channel 255 because of the presence of groups from Be9

(a., n

1) in the calibration reaction. For notation see figure 22 and for a discussion of the results see page 57.

100

0

...J

w z z <(

:c (.)

a:: ⁵⁰

w Q_

(/)

I-z

:::i 0 (.)

0

50

0 0 0 0

0(,) _~

0if' . ^{0 00 n0 SUBTRACTED}

6> 0

0 00

0 0

46 3

Ti (He ,n1l

0 0 0

0 0

0

0 0 n₁ SUBTRACTED

®

~

0

0 0

0 0

0 T1 .46(H e3 , n₂ )

0 0

ct?

0

250 275 300 325 350

CHANNEL NUMBER

0 0

375

100

50

Figure 27

The reaction Fe 54 (He 3

, n)Ni 56

at a bombarding energy of 11. 51 MeV. The middle spectrum was obtained after two subtractions and the bottom after three more. Three excited states of Ni 56

are definitely seen and there is weak evidence for two more. The a.

0 peaks of these latter two are indicated in the top spectrum between channels 200 and 225. The

subtractions and the results obtained are discussed starting on page 59. For notation, see figure 22.

1000-

500

0

500

I N.56•

I I

'ao

250 300

CHANNEL NUMBER

200

:14 3 56

Fe (He ,n01Ni

100

350

All the data used for one determination of the Ni58 (He3

,n)zn60

Q value. See the next figure for the subtraction spectra. Left: The reaction Ni 58

(He 3

, n) Zn 60 at a bombarding energy of 11. 60 MeV. Top right: Spectrum obtained by bombarding the target backing. The Si28

(n, a.) peaks of (He3,n) reactions on Mg24

, Si28

0 and C 12

are identified both here and on the Zn 60

spectrum. The magnesium and silicon accumulated on the target during the run. Bottom right: One of the Be 9

(a., n ) spectra used to calibrate the neutron group leading to the ground state of Zn

BU

See page 63 for a discussion of the results obtained.

>-4 O')

~

_J w

400

z ³⁰⁰ z

<!

I

(.) Cl:'.

a.. w

Cf)

1-z

::> 200 0 (.)

100

225

~

B

~

x 1/5

250 275

EHe3 = 11.600 MeV A

~

58 3

Ni (He, nol

ao

•

• •

•

•

•• ••

~

c

•

B

EHe3 = 11.600 MeV

A

II ,,

~

•

~

c ^{A Mg B} C12(He3,n)O ^{Si2824 (He~n)s(He,n)S1 3 .26 30}

A .. _l,J ^{A .} _{l,·~~~ ~}

e I -

CALIBRATION SPECTRUM En = 12.300 MeV

P23 !a4 1°3 !Poi 1°2 1°1

•

300 325 225 250 275 300 325

CHANNEL NUMBER

75

50

.25

200

100

,_.

I 0)

~ I

":rj ...

°2

1-"j (!)

~ ():)

The first excited state of zn60

. See the preceding figure for the raw data.

Left: Peaks remaining after subtracting the ground-state calibration spectrum.

Right: Peaks remaining after subtracting the target- backing spectrum attributed to Mg and Si contaminants. The first three peaks of the Si28

(n, a.) spectrum produced by the neutron group to the first excited state of Zn 60

are clearly revealed. See page 63 for a discussion of the results obtained.

.-

en

CJ!

n₀ SUBTRACT.ED

1

^{n0 A}ND BACKGROUND SUBTRACTED

EHe3 = 11.600 MeV EHe3 = 11.600 MeV

B A

300

ll li

--' A Mg²4cHe~ n) Si ²⁶

t ^l

w z _{B Si}²⁸_(He~n)S³₀

z

A

<{ ~

I 0

5

²⁰⁰

PU ^j ₁ ^t _I

a.. ... ^I

(f)

~

^Q)

I- ~

z ^I

::>

0

0 "oao

l

^fQ f. ^I•

JOO \-- I I I ^I

I

• f. I

•

f ^•

• ^•

t

^•

₁

^~

•-'

^.., ... ^{. . ..} I ^•• ·

^•

^'

^•

^{. r .}

^{~ ...}

0 I-

• •

• • •••

. ..,_ ... , . . .

>i

• • • • • • CD

• • • •

•

• ^1:1.?

• ^c:.o

•

225 250 275 300 325 225 250 275 300 325

CHANNEL NUMBER

Figure 30

Angular distribution of neutrons from Si28

(He 3, n)s30 to the ground and first- excited states of

s

³⁰ measured in a

semiconductor detector at a bombarding energy of 11. 60 Me V.

The vertical error bars are largely from uncertainty in the relative variation of the Si28

(n, a.

0) cross section but also include statistical uncertainty. The horizontal lines on each point indicate the total angle subtended by the detector face.

The error on the absolute cross section is 30% and the error on the relative magnitude of the ground and first-excited- state neutron yields is 20%. The solid lines are theoretical fits which assume a stripping process and use the plane-wave Born approximation with R ::: 5. 0 fermis. See page 65.

---,,---- r-- .

4

3

Figure 31

~ 54 3 56

The proton spectrum from the reaction Fe (He , p)Co at a bombarding energy of 11. 50 MeV and laboratory angle of 15°. Peaks C and E and the small peak at about 41. 5 Mc did not appear at other angles. They are probably spurious peaks produced by bursts of noise in the array detectors.

The remaining peaks correspond to levels in Co 56

, except perhaps J which was not seen with certainty at other angles.

See page 70 and table 9.

. 2500 .

~000

u ::t.

0 ~ 1~00

a: w a.

"'

>-

z R Q P 0 N M

:>

l I I ^{j j} I

0 u 1000

500

J I H G c

j j j I I

+.

Fc54 ( Hc3, p) Co56

e • 1s⁰

B A

I I

250

200

5C

100

Figure 32

The proton spectrum from the reaction Ni 58

(He 3, p)Cu 60 at a bombarding energy of 11. 50 MeV and laboratory angle of 15°. Peaks J and Z are proton groups from the reaction c 12

(He3, p)N14; peak Q is a proton group from a light target contaminant with A > 16. The remaining peaks correspond · to levels in cu60

. Peaks FF' are a closely-spaced doublet and peaks Wmay be up to 4 levels. See page 70 and table 10.

800

(.)

:::i..600

~ (\J

a: . w CL

~ 3 ⁴⁰⁰ 8

200

34.0

ZYXW VUT S

11 I I II I

34.5 35.0 35.5

R OP ON ML K J

I I I l I I l l

36.0 36.5 37.0 37.5

FREQUENCY (Mc)

Ni58(He3, p) Cu60

e: 15•

HGF'FEDC BA

I I ll I I I I l

38.0 39.0 39.5

Figure 33

Summary of Q-value measurements for the mass-56 system. See pages 59-62 (Ni56

) and 70-71 (Co56

). All numbers are in MeV.

7.410± 0.010 Fe 54 +He3 -p

2.381 2 312-

2.225 2.087- 1.934

I. 723 1.

592_ 1.445

1.246 I.Il l 0978- 0.832 .

0.576

0.166

. Co56

5.35

- - - -

4.98

- - - -

3.95

2.69

4.513 ± 0.014 Fe54

+He3 -n

Figure 34

Summary of Q-value measurements for the mass-60 system. See pages 63 (Zn60

) and 70-72 (Cu60

). All numbers are in MeV.

5.770 ± 0.012 Ni⁵⁸ + He3-p

3.6023477- 3.361 .

3.157 30 8

~3.000. 7 2.762

2.547

2.196

2.007 1.917- I. 783 1.673- 1.428

0.9400796- Q§§Jo.6060 568 0.465 0 375·-

0.298 .

0.072 cu60

. 1.02

I I

Zn

6 0 I

I I I I I I I I

4.170 ±0.022 MeV

I

I I I I I I I I I

0.818 ±0.018 Ni58 + He3 -n

Figure 35

Gamma rays seen in the first two seconds after the bombardment of Sb

2S

3 with 10-MeV He3

summed over approximately 1000 bombardment cycles. The top curve is the total yield in the first two seconds; the bottom, the yield in the first minus the yield in the second. The following gamma rays (energies in MeV) are seen: 0. 51 annihilation radiation; 1. 17, 2. 13, 3. 30 and 4. 11 all produced in 834 following the decay of

c1

³⁴ m; 1. 46 and 2. 62 from the decay of K40

and RdTh in the concrete walls of the target room;

and 1. 77 which may be due to the 1. 77-MeV gamma ray which

28 .28

follows the beta decay of Al (T_₁₁₂ = 2. 28 m) to 81 . The

28 . Z7 28

Al is presumably made by Al (n, Y )Al . See Chapter VII, section 2 (page 74) for a discussion of the results obtained from this spectrum.

CJ) w

_J

~

0 0 Q 10⁵

0:: w

Cl..

~ z ::>

0 (.)

o.51c134

tor

XIOO

534 2.13-0:51 2.13

~ l

Ar40

1.46 ^Si28(?)

lBKGNDlr

105

2.13+0.51

lCOINC.

534

13.30-0.51

A

3.30 3.30+0.51'

i l ^l

^{COINC. 104}

ThC,..

2.62

l

^BKGND.

534 4.11

l

103...._~~'--~--''---'---'~~--'-~~.-J..~~-L..~_...__....~~..._..._·_~_·~~--'·~10

0 40 80 120 160 . 200

CHANNEL NUMBER

Figure 36

The mass-34 system showing only those levels of interest to the work described here, which chiefly concerned Ar34

made via

s

³²(He3

, n)Ar34

. See page 55 for a description of the Q-value measurements of the ground and first-excited states of Ar 34 , and pages 74-77 for the measurement of the positron branch to the 0. 67-MeV level of

c1

³⁴ and the relative intensities of the gamma rays following the beta decay of c134 m(O. 143).

4.11

2.129

32.40m

47 1.2

100 34

c2+

2.16

0.67 0.143

..___.., l _

__.__..__-=-..J - 5. 5 2 534

2.06

L----0--- - - 0..;..+__, 6. 06

(2+) (T=I)

c134 l.59s

Ar34 l.2s

13+>0.012.e6

-0.76

s

^32+He3-n

Figure 37

Gamma- ray spectrum observed in coincidence with neutrons from the reaction Fe54

(He3

, nY)Ni56

. Peaks are seen corresponding to gamma rays of energy 1. 28 ± 0. 06 MeV and 2. 66 ± 0. 10 MeV. The apparent peak in channel 46 (EY

=

3. 47 ± 0. 13 MeV) is not statistically significant and, if it exists, does not correspond to a transition between known levels of Ni 56 . See page 77.

80

_J

w

!

z

₆₀

z i

<[

I u

0:::

w

Q...

40

(/)

I-

z

:::::>

0

u

20

0

25 50 75 100

CHANNEL NUMBER

Figure 38

Known levels of Ni 56

separated into a vibrational band built on the ground state and a vibrational or rotational band built on the state at 3. 95 MeV. Evidence in favor of this interpretation is given on pages 78 and 79.

4.513 ± 0.014 Fe54 + He3-n

~16.3 j

5.35 ± 0.05 4.97 ± 0.05

Ni55 + n 8.015 Fe52 +a

7.193_

1 c₀55+ P

6.60 + 0. 03 {2+)

3.950±0.025 {O+)

L _ _ _ _ _ _ _ 0+

l

Nj56

Figure 39

Left: Energy levels of Ca 40 below 8. 6 MeV.

Center: Levels in the proposed rotational band with their energies redefined with respect to the

o+,

3. 38 MeV level (see page 79). Experimental errors are given. The error on the 7. 12-MeV state is an estimate of the error in the data of Bauer et al. (1965); the remaining errors are those quoted by Braams (1956).

Right: The rotational spectrum calculated from E(J) = 0. 092 J(J + 1) MeV.

8.38 (4+,5 )

8.11 2+

7 92 4+

- - - -

7.5

7.12 >6+ 3.77 ~6+ 3.864 s+

6.94 2+,3 ±0.02

6.58 3-

6.28 3-

6·029

5.901 3- 5.606 5.621 4+

5.202 5.2415.272 1.854 1.840 4+

±0.009

4.483 5-

3.900 2+ 0.552 2+ 0.552 2+

3.730 3 ±0.006

3.348 o+ o+ o+

o+

ca4o

Negative ion current at the LET vs 20° magnet current measured with a mixture of 93% H2 and 7%

o

₂ ⁱⁿ the source, and H

2 in the exchange canal. The ion .source controls were adjusted to maximize the beam labelled 0 +

;0-.

Useful oxygen beams · have been obtained from the three broad peaks explicitly identified as being oxygen.

Each peak is seen to have considerable fine structure, probably due to different combinations of oxygen and hydrogen. The maximum probable range for such structure is indicated for

o

⁰

/o-

and

o+ /0-

peaks. See page 86.

The energies indicated on the graph were measured with an electrostatic analyzer.

The dotted curves are helium peaks found with a 00- 50 mixture of He and 0

2 in the source and H2 in the exchange canal.

,_,.

CX>

-.:i

10-1

0

-

::l I- 10-2

z w

0::

0::

:::>

(.)

1-w

_J

10-3

10-4

H3+/H- (53.3 keV)

H2+/H- (60 keV)

H+/H- (80 keV)

iHe°/He-

iHe+/He-

(\

II 11 I I I I

I I I \ I \ I I I I I \ ,, I ,; I

'' I \

I \

^{I \}

I \ I I

I I I I

I I I I

I I I I

I I I \

I \ 1 I

40keV

!0°;0-

i

^H20/H20-

o + ; o - n

67.7keV H20°?'H20- (?)

io3++;0-

I

^{I I I}

10-~ I ^{I .,} ,J I, I 1 ^{I I} t i ' ' I ^{I • , , I} I ^{I \ I I} I ^I I ^{I I I I} I ^{I I I I} I '. I I I I I I I I

·-- 200 250 300 350 400

100 150

MAGNET CURRENT (ma)

I I-A 00 00

I

"Ij

...

(]~

(t) 1-i

~ 0

Figure 41

Energy spectrum of particles scattered through 30°

from a gold foil as seen in a semiconductor detector. The tandem was regulating on the S 7+ beam and the terminal voltage was 5. 30 MeV. See text (page 88) for explanation of the remaining peaks.