Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD
Information on the triggered strips of silicon strip detectors of a MAX-lab ΔE-E CsI/SSD-telescope was used to determination the angular range of emitted reaction particles. It allowed an improvement in the energy resolution of the telescope by decreasing the kinematical broadening of the missin...
Saved in:
| Date: | 2016 |
|---|---|
| Main Authors: | , , , , , , , , , |
| Format: | Article |
| Language: | English |
| Published: |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2016
|
| Series: | Вопросы атомной науки и техники |
| Subjects: | |
| Online Access: | http://dspace.nbuv.gov.ua/handle/123456789/115398 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD / G. Brudvik, D.D. Burdeinyi, V.B. Ganenko, K. Hansen, K. Fissum, L. Isaksson,K. Livingston, M. Lundin, B. Nilsson, B. Schröder // Вопросы атомной науки и техники. — 2016. — № 3. — С. 111-115. — Бібліогр.: 10 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
irk-123456789-115398 |
|---|---|
| record_format |
dspace |
| spelling |
irk-123456789-1153982017-04-05T03:02:30Z Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD Brudvik, G. Burdeinyi, D.D. Ganenko, V.B. Hansen, K. Fissum, K. Isaksson, L. Livingston, K. Lundin, M. Nilsson, B. Schröder, B. Детекторы и детектирование ядерных излучений Information on the triggered strips of silicon strip detectors of a MAX-lab ΔE-E CsI/SSD-telescope was used to determination the angular range of emitted reaction particles. It allowed an improvement in the energy resolution of the telescope by decreasing the kinematical broadening of the missing energy spectra of ¹²C(γ,p)¹¹B reaction, and enabling more accurate separation of exited states of residual nucleus. Інформація про спрацьовані стріпи кремнієвих мікрострипових детекторів була використана для більш точного визначення кутових інтервалів детектуючих частинок ΔE-E телескопом CsI/SSD лабораторії Макс-лаб. Це дозволило поліпшити енергетичну здатність телескопа шляхом зменшення кінематичного розширення спектрів недостатньої енергії реакції ¹²C(γ,p)¹¹B і отримати більш точне розділення збуджених станів залишкового ядра. Информация о сработавших стрипах кремниевых микростриповых детекторов была использована для более точного определения угловых интервалов детектируемых частиц ΔE-E телескопом CsI/SSD лаборатории Макс-лаб. Это позволило улучшить энергетическое разрешение телескопа путѐм уменьшения кинематического уширения спектров недостающей энергии реакции ¹²C(γ,p)¹¹B и получить более точное разделение возбужденных состояний остаточного ядра. 2016 Article Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD / G. Brudvik, D.D. Burdeinyi, V.B. Ganenko, K. Hansen, K. Fissum, L. Isaksson,K. Livingston, M. Lundin, B. Nilsson, B. Schröder // Вопросы атомной науки и техники. — 2016. — № 3. — С. 111-115. — Бібліогр.: 10 назв. — англ. 1562-6016 PACS: 07.05.Kf, 24.70.+S http://dspace.nbuv.gov.ua/handle/123456789/115398 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
Детекторы и детектирование ядерных излучений Детекторы и детектирование ядерных излучений |
| spellingShingle |
Детекторы и детектирование ядерных излучений Детекторы и детектирование ядерных излучений Brudvik, G. Burdeinyi, D.D. Ganenko, V.B. Hansen, K. Fissum, K. Isaksson, L. Livingston, K. Lundin, M. Nilsson, B. Schröder, B. Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD Вопросы атомной науки и техники |
| description |
Information on the triggered strips of silicon strip detectors of a MAX-lab ΔE-E CsI/SSD-telescope was used to
determination the angular range of emitted reaction particles. It allowed an improvement in the energy resolution
of the telescope by decreasing the kinematical broadening of the missing energy spectra of ¹²C(γ,p)¹¹B reaction,
and enabling more accurate separation of exited states of residual nucleus. |
| format |
Article |
| author |
Brudvik, G. Burdeinyi, D.D. Ganenko, V.B. Hansen, K. Fissum, K. Isaksson, L. Livingston, K. Lundin, M. Nilsson, B. Schröder, B. |
| author_facet |
Brudvik, G. Burdeinyi, D.D. Ganenko, V.B. Hansen, K. Fissum, K. Isaksson, L. Livingston, K. Lundin, M. Nilsson, B. Schröder, B. |
| author_sort |
Brudvik, G. |
| title |
Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD |
| title_short |
Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD |
| title_full |
Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD |
| title_fullStr |
Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD |
| title_full_unstemmed |
Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD |
| title_sort |
improvement of energy resolution of δe-e csi/ssd telescope at measurement of (γ,p)-reactions using strip information of ssd |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2016 |
| topic_facet |
Детекторы и детектирование ядерных излучений |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/115398 |
| citation_txt |
Improvement of energy resolution of ΔE-E CsI/SSD telescope at measurement of (γ,p)-reactions using strip information of SSD / G. Brudvik, D.D. Burdeinyi, V.B. Ganenko, K. Hansen, K. Fissum, L. Isaksson,K. Livingston, M. Lundin, B. Nilsson, B. Schröder // Вопросы атомной науки и техники. — 2016. — № 3. — С. 111-115. — Бібліогр.: 10 назв. — англ. |
| series |
Вопросы атомной науки и техники |
| work_keys_str_mv |
AT brudvikg improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd AT burdeinyidd improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd AT ganenkovb improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd AT hansenk improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd AT fissumk improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd AT isakssonl improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd AT livingstonk improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd AT lundinm improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd AT nilssonb improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd AT schroderb improvementofenergyresolutionofdeecsissdtelescopeatmeasurementofgpreactionsusingstripinformationofssd |
| first_indexed |
2025-07-08T08:41:58Z |
| last_indexed |
2025-07-08T08:41:58Z |
| _version_ |
1837067528058175488 |
| fulltext |
ISSN 1562-6016. ВАНТ. 2016. №3(103) 111
IMPROVEMENT OF ENERGY RESOLUTION OF ΔE-E CsI/SSD-
TELESCOPE AT MEASUREMENT OF (γ,p)-REACTIONS USING STRIP
INFORMATION OF SSD
G. Brudvik
1
, D.D. Burdeinyi
2
, V.B. Ganenko
2
, K. Hansen
3
, K. Fissum
3
, L. Isaksson
3
,
K. Livingston
4
, M. Lundin
1
, B. Nilsson
1
, B. Schröder
1,3
1
MAX-lab, Lund University, Lund, Sweden;
2
National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine;
3
Department of Physics, Lund University, Lund, Sweden;
4
Department of Physics and Astronomy, University of Glasgow, Glasgow, Scotland, UK
Information on the triggered strips of silicon strip detectors of a MAX-lab ΔE-E CsI/SSD-telescope was used to
determination the angular range of emitted reaction particles. It allowed an improvement in the energy resolution
of the telescope by decreasing the kinematical broadening of the missing energy spectra of 12C(γ,p)11B reaction,
and enabling more accurate separation of exited states of residual nucleus.
PACS: 07.05.Kf, 24.70.+S
INTRODUCTION
In the energy range between the Giant Dipole Reso-
nance and the pion photoproduction threshold (inter-
mediate energy range) one-body and two-body effects
may play an important role in photon interaction with
nuclei. Of all possible photonuclear processes in this
energy range, the (γ,N) reactions on light nuclei (12C,
16O), with separation ground and low lying exited states
in the residual nucleus have most widely studied (see [1
- 5] and references within). One of the important re-
sults was the observation of a close similarity between
the (γ,p) and (γ,n)-reaction cross sections [1, 4], strong-
ly suggesting a two-body (quasi-deuteron (QD)) mech-
anism for photo-absorption by the nucleus, and sup-
pression of the single nucleon direct knockout (DKO).
One of the aims of the work presented here is the inves-
tigation of relative role of the DKO and OD mecha-
nisms of a photon absorption. This requires precise
experimental information on the cross section (and oth-
er experimental observables, as well) with indification
of the final state of the residual nucleus.
One of the previous measurements of the carbon
disintegration at MAX-lab [5] was in the 40…60 MeV
energy range, using a tagged bremsstrahlung photon
beam, thin carbon targets, and specially constructed
proton telescopes, consisting of thin silicon and Ge
detectors. The placement of the detectors in a vacuum
box made it possible to achieve a resolution ≤ 1 MeV in
the missing energy spectra, allowing the separation of
the ground state of 11B from the first exited state at
Eex=2.12 MeV. It also enabled the separation of the two
maxima, at Eex ~ 5 and ~ 7 MeV, resulted from unre-
solved states at Eex= 4.44 and 5.02 MeV, and at
Eex=6.74, 6.79, 7.29 MeV, respectively.
Recent measurements of the cross section asym-
metry, have also been made at MAX-lab, using a
tagged linearly polarized photon beam [6, 7] and
available
ΔE-E CsI/SSD-telescope. The telescope consisted of
two silicon strip detectors (SSDs) and a CsI(Tl) coun-
ter, and was not optimized for high energy resolution at
the 12C(γ,p)11B measurements. Hence it was not possi-
ble to resolve the ground and first exited states, and the
peaks near 5 and 7 MeV. The poorer energy resolution
was manly due to the fluctuation of ionization losses of
the protons on their way from the target to the tele-
scope, the intrinsic resolution of the CsI-detector, and
kinematical broadening due to large angular capture
An improvement in the energy resolution in this case
can be achieved by decreasing the kinematical broaden-
ing, using coordinate information of the detected events
from SSDs.
The telescope characteristics and method of the
(γ,p)-reactions identification were described in [8] in
detail.
1. EXPERIMENTAL APPARATUS
AND DATA ANALYSIS
The measurements were made at the MAX-lab nu-
clear physics facility, described in detail in [9] and
summarised hear. Electrons with energy
E0=192.7 MeV were extracted from the MAX-I ring,
which operated a stretcher mode and delivered beam
into experimental hall. A schematic of the MAX-lab
beam line is shown in [7, 9]. Then electrons are di-
rected towards photon bremsstrahlung radiators, 50 µm
Al or 100 µm diamond, fixed in the target holder of a
goniometer. A photon collimator with 12 mm opening
was used for the photon beam formation on the target.
The focal plane (FP) hodoscope of tagging system con-
sisted of two rows of overlapping (50%) scintillators
25 mm wide and 3.2 mm thick. The coincidence re-
quirement to overlapping scintillators resulted in 62
channels covering an energy range of
Eγ=21.9…78.8 MeV. The resolution of the tagger sys-
tem calculated for 50% overlap and normal incident of
the scattered electrons to the MT focal plane was
ΔEγ≈0.8 MeV for the high end of the tagged range, and
smoothly increased to ΔEγ≈1 MeV at Eγ≈38 MeV.
The measurements were made on a CD2 and CH2
targets. The CD2 target had a disc shape, of 75 mm in
diameter, 1 mm thick, and density ρ=1.026 g/cm3. The
CH2 target had square form, 150.2 150.2 mm and
ISSN 1562-6016. ВАНТ. 2016. №3(103) 112
1.1 mm thick, and the ρ=0.937 g/cm3. The targets were
positioned on distance of ≈ 2 m from the photon colli-
mator at an angle of θm=600 to the photon beam direc-
tion.
1.1. CsI/SSD-TELESCOPE
The emitted protons were detected by a CsI/SSD-
telescope, schematically shown in Fig. 1. The telescope
consists of two identical single-sided silicon strip detec-
tors (SSDs) and a CsI(Tl)-counter. The SSD-detectors
(ΔE) are of octagonal shape, have an active area of
3300 mm2, and a thickness of 0.5 mm. They have 64
strips, each with a width of 1 mm. The strips are paral-
leled in groups of two for the read-out, thus yielding an
effective strip width of 2 mm. The active aria of the
detectors was wrapped Al foil 15 μk thick. The CsI(Tl)-
detector (E) is a cylinder 12.5 cm in diameter and 10
cm long, placed in Al container. The thickness of the
front wall of the container is 0.5 mm. The telescope
was placed at angle of θp=900 to the beam axis. The
distance between the first SSD and center of the photon
beam sport on the target was equal 98.5 mm, the dis-
tance between the SSDs was equal 15 mm, the distance
between the second SSD and the CsI was equal 10 mm.
Fig. 1. Scheme of the SSD/CsI-telescope
1.2. DATA ANALYSIS
The data analysis was described in [8] in detail. It
included three stages: proton identification, selection of
prompt events, and reaction separation.
The proton identification were performed by stand-
ard ΔE-E method, based on relationship between the
particles with different masses. ADC signals from the
SSDs (ΔE) and CsI (E) detectors were presented as
two-dimensional -E plot, in which the proton signals
were separated from other particles signals (electrons,
deuterons, etc.) into clear band. The background parti-
cles were removed by a soft cut on the plot.
The prompt events were obtained by selection of a
time coincidence between the FP-detectors and the
CsI/SSD-telescope signals. The coincidence searching
technique was described in [8]. Having performed the
procedure, the coincidence prompt peak appeared in the
individual FPtdc spectra on top of random background.
There are two types of events in the prompt peak re-
gion: true coincidence events from various channels of
carbon and deuteron disintegration, an electromagnetic
background, and random events. For separation yields
of the d(γ,p)n and the 12C(γ,p)11B reactions, a missing
energy (Emis) method was applied. It assumes of miss-
ing energy spectra construction of the reactions under
study. The missing energy is given by relation,
Em = Eγ – Tp – Tr,
where Eγ is the photon energy, Tp is the proton kinetic
energy, measured by the CsI detector and corrected for
energy losses of the proton on its way from the origin
point to the detector. Tr is the energy of a recoil nucleus
(neutron or 11B), which is calculated using the reaction
kinematics and the proton emission angle value θp=900.
-40 -36 -32 -28 -24 -20 -16 -12 -8 -4 0 4 8 12
-20
0
20
40
60
80
100
120
140
C
o
u
n
ts
Emis, MeV a
-40 -36 -32 -28 -24 -20 -16 -12 -8 -4 0 4 8 12
-20
0
20
40
60
80
100
120
C
o
u
n
ts
Emis, MeV b
-40 -36 -32 -28 -24 -20 -16 -12 -8 -4 0 4 8 12
-40
-20
0
20
40
60
80
100
120
140
C
o
u
n
ts
Emis, MeV c
Fig. 2. Missing energy spectra of the protons from
the CD2 (a) and CH2 (b) targets. (c) the d(γ,p)n
missing energy spectrum after the CD2 and CH2 spec-
tra subtraction. Photon energy is Eγ=(49.0±2.0) MeV
After the random background subtraction (the proce-
dure is descried in [8]) the final missing energy spectra are
obtained. In order to increase statistics, summation of the
ISSN 1562-6016. ВАНТ. 2016. №3(103) 113
Emis spectra for four physically adjacent tagger channels
was produced. As a result, the Emis spectra were obtained
for eleven energy bins, with the width ΔEγ ≈ 4 MeV. In
Fig. 2 [8] the spectra for CD2 and CH2 targets at photon
energy bin Eγ = (49 2.0) MeV are shown. According to
choice Tr=Tn, the events corresponding to reaction of
the deuteron disintegration are located in a peak, whose
position is equal to the deuteron binding energy,
Emis ≈ 2.2 MeV (see Fig. 2,a). To the left side from this
peak, there is a big maximum at Emis ≈ -4 MeV, corre-
sponding to reaction of the carbon disintegration,
12C(γ,p)11B, when the recoil nucleus 11B is in the ground
state or in the first exited state with excitation energy
Eex = 2.12 MeV. These states are not separated owing to
insufficient energy resolution. There is also a weaker peak
in the missing energy range Emis ≈ 0…4 MeV (see
Fig. 2,b), corresponding to the carbon disintegration, when
the 11B is in one of the excited states, Eex ~ 4.44, 5.02,
6.74, 6.79 or 7.29 MeV, which are also not separated.
The energy resolution can be more accurate esti-
mated from the spectrum of the d(γ,p)n-reaction, pre-
sented in Fig. 2,c. As can be seen, it is ~ 3.5 MeV
(FWHM). As was stated the above, such energy resolu-
tion results from the telescope construction, in which
too much matter was on the proton way (thick SSDs,
targets, foils, air, etc.). That results in large ionization
losses of the protons and their fluctuations, especially at
small energies, and as a result, decreasing accuracy of
the proton energy determination. Secondly, there is
kinematical broadening of the peaks due to large angu-
lar acceptance of the telescope, in the case of standard
procedure of the data taking, when only ΔE infor-
mation is taken from the SSDs.
2. THE TELESCOPE ANGULAR
ACCEPTANCE
The angular aperture of the CsI/SSD-telescope is
determined by the sizes of the target active volume, the
second SSD active aria, and the distance of the second
SSD from the target. It was calculated by Monte Carlo
simulation, using the GEANT-4 software package [10].
Three associated blocks of the experiment modeling
were developed, described in [8] in detail. The first
block includes simulation of the electron beam interac-
tion with a photon radiator and passing of the brems-
stahlung photon through the photon collimator on the
target. As a result, the target active volume was deter-
mined. Its projection on the target plane, presented in
[8], has an elliptic shape of ~14 mm (FWHM) in verti-
cal, and ~ 28 mm in horizontal planes. The photon
beam intensity distribution within this aria was ob-
tained.
The second block simulated the passage of the pro-
tons produced in the target active volume from the re-
actions of the carbon and deuteron disintegration, trac-
ing them through the telescope to the CsI. The proton
energy losses were calculated, and the CsI detector en-
ergy calibration was produced.
The telescope angular acceptance was investigated
in the third block. Using the accumulated data base,
trajectories of the protons were constructed and their
distributions over polar angle were calculated. Having
the trajectories, the related SSDs strip numbers (the
“triggered strips”) were determined. It was found from
the experimental data analysis [8] (and confirmed by
the simulation results) that difference between the trig-
gered strips of the first and the second SSDs, Δ=n2-n1,
was within |Δ|≤3 for all detected protons. n1 and n2 are
the numbers of triggered strips in the first and the se-
cond silicon strip detectors, respectively, counted from
the left to the right.
a
b
c
d
Fig. 3. Calculated angular capture of the SSD/CsI-
telescope at the particle selection conditions: | Δ|≤3
and |Δ|=0 (a); Δ=±1 (b); Δ=±2 (c); Δ=±3(d)
The simulated trajectories of the protons were sepa-
rated into seven groups determined under the triggered
strips conditions: Δ=0, ±1, ±2, ±3, and the polar angle
distributions of the proton emission for every group
were calculated. Results of the simulation for the
ISSN 1562-6016. ВАНТ. 2016. №3(103) 114
12C(γ,p0)
11B-reaction, taking into account angular de-
pendence of the corresponding cross sections from [5],
are presented in Fig. 3. They show that in the case of
detection of all particles, passing through the active
aria of the SSDs (|Δ|≤3), the telescope angular ac-
ceptance is Δθp≈300 (FWHM). However, for the first
group (Δ=0), using events with identical triggered strip
numbers in the first and the second SSDs, the angular
capture is less, Δθp≈120 (FWHM). In this case the de-
tected particles are emitted from the whole active vol-
ume of the target, and pass predominantly within the
central part of both SSD- detectors.
The trajectories selected into the next two groups
(Δ = ±1) correspond to the proton, emitted within angu-
lar intervals θp ≈ (83±7)0 and 970±70 (FWHM) for
Δ=+1 and Δ= -1, respectively. The further two groups
(Δ = ±2) include trajectories of the protons, emitted
within the angular intervals θp≈800±70 and θp≈1030±70
(FWHM) for the Δ=+2 and Δ = -2 selection conditions,
respectively, and from different parts of the target ac-
tive aria. In the last groups (Δ=±3) there are trajectories
corresponding to the protons, emitted within angular
intervals θp ≈ (73…82)0 and θp ≈ (100…107)0 for selec-
tion conditions Δ=+3 and Δ=–3, from small part of the
active target aria, being in opposite ends of the target.
For test of the simulation the calculated triggered
strip number distributions in the first SSD were com-
pared with the experiment data in the case of
12C(γ,p)11B-reaction. The results of the simulation are
in a reasonable agreement with the experiment. Fig. 4
shows distributions for two groups, Δ = 0 and Δ = ±2.
a
b
Fig. 4. Experimental (solid lines) and simulated (dotted
lines) distributions of the triggered strip numbers in the
first SSD for the particle selection conditions Δ=0 (a)
and Δ=±2 (b). The distributions are summarized over
odd and even strip numbers
Table 1
The effective angles of the proton emission, obtained
from simulation <θp>m and experiment <θp>e
Group (Δ) -3 -2 -1 0
<θp>m,deg 101.2 100.2 96.0 89.8
<θp>e, deg 100.1±0.7 95.4±0.7 90.0±0.4
Group (Δ) +1 +2 +3 –
<θp>m,deg 85.0 80.9 77.9 –
<θp>e, deg 83.8±0.6 80.7±0.4 – –
The simulation demonstrates that the triggered strip
information allows separation of the detected protons
into seven groups with determination of an effective
proton emission angle <θp>m for each group, Table 1.
For the reactions under study this separation results in
different energies of the protons (the recoil nuclei, as
well) for the selected groups at the given photon ener-
gies. So, Fig. 5 shows position of the ADC peak of the
CsI signals resulted from the protons of the Δ=±2 and
Δ=0 (shown by solid line) groups, as a function of the
photon energy. One can see that protons from these
groups at the same photon energy produce different
signals in the CsI, resulted from the difference of the
proton energies. This difference should be taken into
account at the Emis spectra construction.
Fig. 5. ADC peak positions of the signals, detected by
the CsI, from the protons of the Δ=±2 and Δ=0 (shown
by solid line) groups for the 12C(γ,p0)
11B-reaction,
as a function of the photon energy
Fig. 6. Calculated effective angles of the proton emission
for Δ=±2 groups, as a function of the photon energy
Using of the ADC peak positions and results of the
CsI detector energy calibration [8], one can get the av-
erage energy of the detected protons from each group,
and to calculate the proton emission angles from the
kinematics. The angles were calculated by such a way
for all groups (besides Δ=±3 due to poor statistics) as a
function of the photon energy, as shown in Fig. 6. The
angle’s values for the given selected groups do not de-
pend on the photon energy, fluctuating near effective
values <θp>e, obtained by averaging the angles over
ISSN 1562-6016. ВАНТ. 2016. №3(103) 115
photon energy interval. The effective angles values,
obtained by two methods well agree within the experi-
mental errors and are presented in the Table 1.
Taking into account the effective proton emission
angle values at the missing energy calculation, the
missing energy spectra were obtained for the 12C(γ,p0)-
and the d(γ,p)-reactions for each from the seven groups,
as a function of the photon energy, and positions of the
peaks, corresponding to the d(γ,p) and 12C(γ,p0)
11B-
reactions were determined. Within the data accuracy,
they coincide with the Q-values of the both reactions
for all photon energies, ≈2.2 MeV for d(γ,p) and the
≈16 MeV for the 12C(γ,p0)
11B-reactions, for all selected
groups. The values averaged over photon energy inter-
val are presented in the Table 2.
Table 2
Q-values of the 12C(γ,p0) and the d(γ,p) reactions
for selected groups averaged over photon energy bins
Group (Δ) -3 -2 -1 0
Q, MeV,
12C(γ,p)
15.92
±0.38
15.89
±0.41
15.94
±0.32
15.97
±0.06
Q, MeV,
d(γ,p)
2.26
±0.41
2.12
±0.33
2.26
±0.35
2.20
±0.06
Group (Δ) +1 +2 +3 –
Q, MeV,
12C(γ,p)
15.90
±0.32
15.98
±0.32
16.01
±0.32
–
Q, MeV,
d(γ,p)
2.09
±0.32
2.27
±0.32
2.29
±0.45
–
-40 -36 -32 -28 -24 -20 -16 -12 -8 -4 0 4 8 12 16 20
-20
0
20
40
60
80
100
120
140
160
180
200
C
o
u
n
ts
Emis, MeV a
-40 -36 -32 -28 -24 -20 -16 -12 -8 -4 0 4 8 12 16 20
-20
0
20
40
60
80
100
120
140
160
C
o
u
n
ts
Emis, MeV b
-40 -36 -32 -28 -24 -20 -16 -12 -8 -4 0 4 8 12 16 20
-20
0
20
40
60
80
100
120
140
160
C
o
u
n
ts
Emis, MeV c
Fig. 7. The same missing energy spectra as in Fig. 2
after the kinematical broadening decreasing (see text)
The missing energy spectra taking into account in-
formation from SSDs triggered strips for calculation
the energy of the recoil nucleus, are shown in Fig. 7,
for the same experimental conditions, as in Fig. 2. The
figures demonstrate more distinct peaks for both reac-
tions, and the clear separation the ground and first exit-
ed states from the group of states at Eex≈7 MeV. The
energy resolution estimated from the peak of the d(γ,p)-
reaction is ~2.2…2.5 MeV (FWHM). So, decreasing of
the kinematical broadening allowed one to get more
accurate missing energy spectra.
REFERENCES
1. P.D. Harty, M.N. Thompson, et al. 12C(γ,n) cross
section from 30 to 100 MeV // Phys. Rev. 1988,
v. 37, p. 13.
2. S.V. Springham, D. Branford, T. Davidson, et al. A
high-resolution study of the 12C(γ,p)-reaction with
49-78.5 MeV tagged photons // Nuclear Physics.
1990, v. A517, p. 93.
3. D.G. Ireland, D. Branford, T. Davinson, et al. The
(γ,p)-reaction at Eγ~60 MeV // Nuclear Physics.
1993, v. A554, p. 173.
4. J.R.M. Annand, G.I. Crawford, P.D. Harty, et al.
High resolution measurements of 12C(γ,n) and the
implications for the (γ,N)-reaction mechanism at in-
termediate energy // Phys. Rev. Lett. 1993, v. 71,
p. 2703.
5. H. Ruijter, J-O. Adler, B-E. Andersson, et al. Angu-
lar distributions for the 12C(γ,p)11B-reaction // Phys.
Rev. 1996, v. C54, p. 3076.
6. V. Ganenko, K. Fissum, K. Hansen, et al. Produc-
tion of linearly polarized photon beam at MAX-lab
// Problems of Atomic Science and Technology. Se-
ries “Nuclear Physics Investigations”. 2009, № 3,
p. 95-102.
7. V. Ganenko, J. Brudvik, D. Burdeinyi, et al. Linear-
ly polarized photon beam at MAX-lab // NIM. 2014,
v. A 763, p. 137.
8. D. Burdeinyi, J. Brudvik, V. Ganenko, et al. Meas-
urement of (γ,p)-reactions with ΔE-E telescope at
MAX-lab facility // Problems of Atomic Science and
Technology. Series “Nuclear Physics Investiga-
tions”. 2015, № 3, p. 49-64.
9. J.-O. Adler et al. The upgraded photon tagging fa-
cility at MAX-lab // NIM. 2013, v. A715, р. 1-10.
10. http://geant4.cern.ch.
Article received 30.03.2016
http://geant4.cern.ch/
ISSN 1562-6016. ВАНТ. 2016. №3(103) 2
УЛУЧШЕНИЕ ЭНЕРГЕТИЧЕСКОГО РАЗРЕШЕНИЯ ∆E-Е CsI/SSD-ТЕЛЕСКОПА ПРИ ИЗМЕРЕНИИ (γ,р)-
РЕАКЦИИ С ИСПОЛЬЗОВАНИЕМ ИНФОРМАЦИИ О СРАБОТАВШИХ СТРИПАХ МИКРОСТРИПОВЫХ
ДЕТЕКТОРОВ
G. Brudvik, Д.Д. Бурдейный, В.Б. Ганенко, K. Hansen, K. Fissum, L. Isaksson, K. Livingston, M. Lundin, B. Nilsson,
B. Schröder
Информация о сработавших стрипах кремниевых микростриповых детекторов была использована для более точного
определения угловых интервалов детектируемых частиц ΔE-E телескопом CsI/SSD лаборатории Макс-лаб. Это позво-
лило улучшить энергетическое разрешение телескопа путѐм уменьшения кинематического уширения спектров недоста-
ющей энергии реакции 12C(γ,p)11B и получить более точное разделение возбужденных состояний остаточного ядра.
ПОКРАЩЕННЯ ЕНЕРГЕТИЧНОЇ ЗДАТНОСТІ ∆Е-Е CsI/SSD-ТЕЛЕСКОПУ ПРИ ВИМІРЮВАННІ (γ,р)-РЕАКЦІЇ
З ВИКОРИСТАННЯМ ІНФОРМАЦІЇ ПРО СПРАЦЬОВАНІ СТРІПИ МІКРОСТРІПОВИХ ДЕТЕКТОРІВ
G. Brudvik, Д.Д. Бурдейний, В.Б. Ганенко, K. Hansen, K. Fissum, L. Isaksson, K. Livingston, M. Lundin,
B. Nilsson, B. Schröder
Інформація про спрацьовані стріпи кремнієвих мікрострипових детекторів була використана для більш точного ви-
значення кутових інтервалів детектуючих частинок ΔE-E телескопом CsI/SSD лабораторії Макс-лаб. Це дозволило по-
ліпшити енергетичну здатність телескопа шляхом зменшення кінематичного розширення спектрів недостатньої енергії
реакції 12C(γ,p)11B і отримати більш точне розділення збуджених станів залишкового ядра.
|