Multi-channel electronics for secondary emission grid profile monitor of TTF linac
According to theTTF beam experimental program, a measurement of the time dependence of the energy spread
 within the bunch train should be done by means of a standard device for profile measurements, that is Secondary
 Emission Grid (SEMG). SEMG on the high-energy TTF beam is placed...
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| Published in: | Вопросы атомной науки и техники |
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| Date: | 2004 |
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| Format: | Article |
| Language: | English |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2004
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| Cite this: | Multi-channel electronics for secondary emission grid profile monitor of TTF linac / P. Reingardt-Nikoulin, V. Gaidash, A. Mirzojan, A. Novikov-Borodin // Вопросы атомной науки и техники. — 2004. — № 1. — С. 97-100. — Бібліогр.: 2 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860246470595182592 |
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| author | Reingardt-Nikoulin, P. Gaidash, V. Mirzojan, A. Novikov-Borodin, A. |
| author_facet | Reingardt-Nikoulin, P. Gaidash, V. Mirzojan, A. Novikov-Borodin, A. |
| citation_txt | Multi-channel electronics for secondary emission grid profile monitor of TTF linac / P. Reingardt-Nikoulin, V. Gaidash, A. Mirzojan, A. Novikov-Borodin // Вопросы атомной науки и техники. — 2004. — № 1. — С. 97-100. — Бібліогр.: 2 назв. — англ. |
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| container_title | Вопросы атомной науки и техники |
| description | According to theTTF beam experimental program, a measurement of the time dependence of the energy spread
within the bunch train should be done by means of a standard device for profile measurements, that is Secondary
Emission Grid (SEMG). SEMG on the high-energy TTF beam is placed in the focal plane of the magnet spectrometer. It should measure the total energy spread in the range from 0.1% up to a few percents for any single or any
group of electron bunches in the bunch train of TTF Linac. SEMG Profile measurements with new high sensitive
electronics are described. Beam results of SEMG Monitor test are given for two modifications of an electronic
preamplifier.
Відповідно до експериментальної програми тестового лінійного прискорювача TTF вимір часової
залежності енергетичного розкиду прискорених електронів уздовж макроімпульсу буде зроблено за
допомогою стандартного приладу для виміру профілю пучка – багатодротової повторно-емісійної камери
(ВЕММ). ВЕММ на пучку високої енергії прискорювача TTF розташований у фокальній площині
магнітного спектрометра і буде вимірювати енергетичний розкид прискорених електронів у діапазоні від
0,1% до декількох відсотків. У роботі викладаються виміри профілю пучка повторно-емісійної
багатодротовой камерою з новою високочутливою електронікою. Результати іспитів ВЕММ на пучку
прискорювача TTF і їхнє обговорення дано для двох модифікацій електронних передпідсилювачів.
В соответствии с экспериментальной программой тестового линейного ускорителя TTF измерение временной зависимости энергетического разброса ускоренных электронов вдоль макроимпульса должно производиться с помощью стандартного прибора для измерения профиля пучка – многопроволочной вторичноэмиссионной камеры (ВЭММ). ВЭММ на пучке высокой энергии ускорителя TTF расположен в фокальной
плоскости магнитного спектрометра и должен измерять энергетический разброс ускоренных электронов в
диапазоне от 0,1% до нескольких процентов. В работе излагаются измерения профиля пучка вторично-эмиссионной многопроволочной камерой с новой высокочувствительной электроникой. Результаты испытаний
ВЭММ на пучке ускорителя TTF и их обсуждение приводятся для двух модификаций электронных предусилителей.
|
| first_indexed | 2025-12-07T18:36:49Z |
| format | Article |
| fulltext |
MULTI-CHANNEL ELECTRONICS FOR SECONDARY EMISSION GRID
PROFILE MONITOR OF TTF LINAC
P. Reingardt-Nikoulin, V. Gaidash, A. Mirzojan, A. Novikov-Borodin
Institute for Nuclear Research of RAS
60-th October Anniversary prospect, 7a, 117312, Moscow, Russia;
petrrein@al20.inr.troitsk.ru;
V. Kocharyan, D. Noelle, H. Weise
DESY
Notkestrasse 85, Hamburg, Germany
Hans.weise@desy.de
According to theTTF beam experimental program, a measurement of the time dependence of the energy spread
within the bunch train should be done by means of a standard device for profile measurements, that is Secondary
Emission Grid (SEMG). SEMG on the high-energy TTF beam is placed in the focal plane of the magnet spectrome-
ter. It should measure the total energy spread in the range from 0.1% up to a few percents for any single or any
group of electron bunches in the bunch train of TTF Linac. SEMG Profile measurements with new high sensitive
electronics are described. Beam results of SEMG Monitor test are given for two modifications of an electronic
preamplifier.
PACS:29.27.Fh
1. INTRODUCTION
According to the TTF beam experimental program
[1], a measurement of the time dependence of the
energy spread within the bunch train should be done by
means of a standard device for profile measurements,
that is Secondary Emission Grid (SEMG).
The SEMG Monitor on high-energy TTF beam is
placed in focal planes of magnet spectrometers. It
should measure total energy spread in the range from
0.1% (σx =1 mm) up to a few percents [2].
SEMG Monitor was tested to measure profiles of
any single bunch or any group of electron bunches in
the bunch train for TTF beam with the next parameters:
a) Repetition frequency of bunch trains – 1 Hz.
b) Repetition frequency of bunches within bunch
trains - 1 MHz.
c) Bunch charge – (0,5...5) nC per bunch.
In contents of this paper SEM Grid electronics are
described. Results of SEMG Monitor test on TTF beam
are given for two modifications of the electronic
preamplifier. Some discussion of results is given too.
2. SEMG ELECTRONICS
The schematic diagram of the tested electronics is
shown in Fig.1. The electronics consists of the internal
(right near the SEMG) front-end and external (outside
the TTF linac tunnel) parts.
The front-end part is made in the Eurocard crate and
has three 16-channel preamplifier modules and one
Multiplexing module. The Multiplexing module
(MPLX) includes an analog 48-channel multiplexing
circuit and an controlled calibrator to test the electron-
ics. The external part is made in the VME crate and con-
sists of a Control Unit (CU) module. The ADC and Out-
put Register were installed in this crate also. CU in-
cludes the External Amplifier (AMP) with an Oscillo-
scope and ADC outputs, the Timing and Control Cir-
cuits (CC).
Fig.1. The diagram of INR electronics
CC organizes MPLX operation for the beam profile
output to the Oscilloscope and ADC inputs. Also the CC
transmits the digital signals from the Output Register
through MPLX to the preamplifier to change the gain of
the amplification and the level of the calibration signal
on the entrance of the preamplifier. The input perma-
nent pulses 1 MHz are used for the channel switching of
the multiplexing circuit and to create a set of 48 syn-
chronizing signals.
The schematic circuits of two possible modifications
of tested front-end electronic channels for profile mea-
surements are shown in Fig. 2.
___________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.97—100. 97
Fig.2. SEMG electronics: a - the channel with two
switch integrator at the input, b - the channel with oper-
ational amplifier at the input
3. DETAILED TIME DIAGRAM
OF PREAMPLIFIERS
The integration time interval T1 (Fig.3) defines the
time position and the duration of charge accumulating
for the investigated group of bunches within the bunch
train the profile of which should be measured. Two
switches (or keys) are installed at every preamplifier
current integrator for organizing of the time diagram:
input key and feedback key. The keys in feedback nets
of all integrators are opened during T3 interval and
areclosed during the whole interval between bunches
being investigated or bunch groups in the bunch trains.
Fig.3. Detailed time diagram of preamplifier switches
The keys in input nets of integrators are opened
during the T2 (T2=T3-T1) interval and are closed
during the whole interval between bunch groups. Then
the integrators in both channels have to store charges
from wires during T1 and keep stored potentials during
the time T2 needed for reading values of these
potentials by means of 1 channel VME ADC through
the multiplexing module. Hence, the closing of the input
key in the whole interval between the measurements
prevents storing of charges on the input cable
capacitance from previous bunches of the train before
T1 for the scheme with an input integrator (Fig. 2,a).
But some distortions of measurements are possible due
to charge accumulating on the cable capacitance from
last bunches of the train during T2 interval after T1.
However there are not these distortions with charge
storing on the cable capacitance for the scheme with the
input preamplifier and the integrator as an analog
memory (Fig. 2,b).
4. RESOLUTION OF PREAMPLIFIER
CHANNELS
In Fig. 4 shown are both circuit modifications of
electronic preamplifier channels for the signal/noise ra-
tio analysis, where
Is – current source i.e. a wire in a beam, that emitted
secondary electrons,
dQ/dt – charge injection current source due to elec-
tronic switches of integrator circuit
Ccab – input cable capacitance,
Cfb, Rfb – feedback capacitance and resistance of
preamplifiers with the gain coefficient K0,
Cw - wire capacitance,
Rini Rino – resistors at the inputs of preamplifier cir-
cuits,
Rkey – resistance of the electronic key at the input of
the integrator circuit,
Rfb key – resistance of the electronic key in the feed-
back circuit of integrator,
Uint – interference source in the ground wire.
Fig.4. Front-end channel schematics
4.1. SIGNALS OF SEMG PREAMPLIFIER
CHANNELS
The signal charge qs from the SEMG wire is trans-
mitted to the input of the preamplifier by wire pair,
loaded by Rino for resistive amplifier or Rini+Rkey for inte-
grator. TTF bunch has duration a few ps. And we shall
take it as δ-function. The wire charge will be trans-
formed on the wire capacitance to the potential Us. If
Rino or (Rini+Rkey) is the same as Rwv – wave impedance
of wire pair, then the signal on Cw will go to 0 with time
constant of τ wv=CwRwv. That is with very short time
constant because Cw≈ 3...5 pF and Rwv ≈ 100Ω (τ
wv=5·10-10s).
For the resistive preamplifier some part of charge
can be lost for this very short input signal, therefore the
value Rino is taken as 11Rwv to prevent charge losses.
Then whole charge of secondary bunch will flow
through Rfb/K0 without losses. The shape of the output
pulse is defined by the time constant of an input net of
the resistive preamplifier CcabRino=150 pF·1.1k=1.5·10-7s,
and this pulse transformed into the current will be inte-
grated in the integrator. Thus very short input pulse is
transformed into the pulse with the front defined by the
bandwidth of the resistive preamplifier and the edge de-
fined by the input net. That is the resulting pulse is short
enough for measurements of the single bunch profile at
a bunch frequency of 1 MHz. The integrator used as an
analog memory device at the output of this preamplifier
stores the larger charge proportional to the bunch charge
98
on the detector wire. In this case the influence of the
charge injection source dQ/dt due to switch operation is
in many times smaller than for the integrator at the input
of the preamplifier because the signal charges on the
current integrator inputs is in ~102 times more. The out-
put signals for both types of channels in Fig.2 are
a) Uoi = (qs/Cfb)*Rfb/Rino – for the current integrator
preamplifier stage with the resistive operational
amplifier after it.
b) Uoo ≅ (qs/Cfb)*Rfb/Rwv – for the resistive opera-
tional preamplifier stage with the integrator as
an analog memory, if the time constant τi=RwvCf-
biK0>>T2.
4.2. NOISE
The total noise of equivalent sources is the noise
sum of all ones: the stationary noises as a thermal noise
of resistance and not stationary noises as some interfer-
ence Uint at the input circuits. Measurements of the noise
level of SEMG preamplifiers had showed that noises of
stationary sources are smaller than the low frequency
noise of input interference. It was checked with con-
nected and disconnected input cables. That is, it was ob-
served that the nonstationary source of interference is
the main source of noises in SEMG Monitor.
The interference signal for both types of
preamplifiers is defined by the transmission coefficient
for Uint at the output of these channels. As can be seen
(Fig.2 and 4) the signals of the interference ratio are the
same for both channels approximately without taking
into account the input switch charge injection.
5. RESULTS
5.1. BEAM PROFILE ALONG THEBUNCH
TRAIN
In this test we checked a possibility to observe time
dependence of transverse beam profile along bunch
train by means of SEMG with current integrator pream-
plifier channels (Time dependence of bunch profile be-
hind spectrometer dipole is the dependence of energy
spread along the train, if the beam optics and a beam
will be adjusted for this parameter observation.) In Fig.5
(A,B,C,D) the group profiles within the bunch train of
30 bunches are shown. Bunches have charges from 2 to
3 nC and approximately 200 MeV average energy.
Fig.5. SEMG Profiles of bunch groups within the bunch
train of 30 bunches
Bunches were focused on the SEM grid behind the
spectrometer dipole. In Fig.5 the profiles are shown on
the panels of MATLAB application after subtracting of
pedestals and with Gauss fitting in applications. Group
profile time positions were moved along 30 µs bunch
trains from beginning to the end of the bunch train.
Integrator preamplifier channels permit to investi-
gate profiles along the bunch train by groups contained
7 bunches or more.
5.2. SINGLE BUNCH PROFILE MEASURE-
MENTS
The preamplifier in fig. 2,b was tested on a single
bunch with result resolution in ~10 times better of the
current integrator with switches. In fig. 6 the profile of a
single bunch in the bunch train is shown. This applica-
tion picture shows row profile with pedestal after digi-
tizing in ADC without MATLAB fitting for more sensi-
tive resistive preamplifier channels. That is, only resis-
tive operational preamplifiers added before the current
integrators permit to observe TTF beam single bunch
profiles, and all preamplifier channels should be modi-
fied in this way for investigations of long bunch train
energy spread in the bunch by a bunch manner.
___________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.97—100. 99
Fig.6. Single bunch profiles on resistive preamplifier
channels
6. CONCLUSION
Now the SEMG Monitor with current integrator
preamplifiers can be used for bunch group profile
measurements on TTF beam with bunch charge from
0.5 nC at a 1 MHz bunch repetition rate.
For single bunch profile measurement in the bunch
by a bunch manner the front-end channels with resistive
preamplifiers at the channel inputs are effective.
7. ACNOWLEDGMENTS
Great thanks to B. Faatz, A. Fateev, O. Hensler,
K. Rehlich, E. Schneidmiller and S. Schreiber for
fruitful discussion and help in this work.
REFERENCES
1. TTF LINAC - Design Report // TESLA 95-01,
March 1995, item B1, p.15 and p.394.
2. M. Bernard, R. Chehab, T. Garvey, et al. Secondary
Emission Grids for Low- and High-Energy Electron
Beams // Proc. Fifth EPAC’96, Sitges (Barcelona),
10-14 June 1996, p. 1680.
МНОГОКАНАЛЬНАЯ ЭЛЕКТРОНИКА ДЛЯ ВТОРИЧНО-ЭМИССИОННОГО МНОГОПРОВО-
ЛОЧНОГО МОНИТОРА ПРОФИЛЯ ПУЧКА ЛИНЕЙНОГО УСКОРИТЕЛЯ TTF
П. Рейнгардт-Никулин, В. Гайдаш, А. Мирзоян, А. Новиков-Бородин, В. Кочарян, Д. Ноелле, Х. Вайзе
В соответствии с экспериментальной программой тестового линейного ускорителя TTF измерение вре-
менной зависимости энергетического разброса ускоренных электронов вдоль макроимпульса должно произ-
водиться с помощью стандартного прибора для измерения профиля пучка – многопроволочной вторично-
эмиссионной камеры (ВЭММ). ВЭММ на пучке высокой энергии ускорителя TTF расположен в фокальной
плоскости магнитного спектрометра и должен измерять энергетический разброс ускоренных электронов в
диапазоне от 0,1% до нескольких процентов. В работе излагаются измерения профиля пучка вторично-эмис-
сионной многопроволочной камерой с новой высокочувствительной электроникой. Результаты испытаний
ВЭММ на пучке ускорителя TTF и их обсуждение приводятся для двух модификаций электронных предуси-
лителей.
БАГАТОКАНАЛЬНА ЕЛЕКТРОНІКА ДЛЯ ПОВТОРНО-ЕМІСІЙНОГО БАГАТОДРОТОВОГО
МОНІТОРА ПРОФІЛЮ ПУЧКА ЛІНІЙНОГО ПРИСКОРЮВАЧА TTF
П. Рейнгардт-Никулин, В. Гайдаш, А. Мирзоян, А. Новиков-Бородін, В. Кочарян, Д. Ноелле, Х. Вайзе
Відповідно до експериментальної програми тестового лінійного прискорювача TTF вимір часової
залежності енергетичного розкиду прискорених електронів уздовж макроімпульсу буде зроблено за
допомогою стандартного приладу для виміру профілю пучка – багатодротової повторно-емісійної камери
(ВЕММ). ВЕММ на пучку високої енергії прискорювача TTF розташований у фокальній площині
магнітного спектрометра і буде вимірювати енергетичний розкид прискорених електронів у діапазоні від
0,1% до декількох відсотків. У роботі викладаються виміри профілю пучка повторно-емісійної
багатодротовой камерою з новою високочутливою електронікою. Результати іспитів ВЕММ на пучку
прискорювача TTF і їхнє обговорення дано для двох модифікацій електронних передпідсилювачів.
100
Fig.3. Detailed time diagram of preamplifier switches
REFERENCES
|
| id | nasplib_isofts_kiev_ua-123456789-78954 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T18:36:49Z |
| publishDate | 2004 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Reingardt-Nikoulin, P. Gaidash, V. Mirzojan, A. Novikov-Borodin, A. 2015-03-24T11:15:20Z 2015-03-24T11:15:20Z 2004 Multi-channel electronics for secondary emission grid profile monitor of TTF linac / P. Reingardt-Nikoulin, V. Gaidash, A. Mirzojan, A. Novikov-Borodin // Вопросы атомной науки и техники. — 2004. — № 1. — С. 97-100. — Бібліогр.: 2 назв. — англ. 1562-6016 PACS:29.27.Fh https://nasplib.isofts.kiev.ua/handle/123456789/78954 According to theTTF beam experimental program, a measurement of the time dependence of the energy spread
 within the bunch train should be done by means of a standard device for profile measurements, that is Secondary
 Emission Grid (SEMG). SEMG on the high-energy TTF beam is placed in the focal plane of the magnet spectrometer. It should measure the total energy spread in the range from 0.1% up to a few percents for any single or any
 group of electron bunches in the bunch train of TTF Linac. SEMG Profile measurements with new high sensitive
 electronics are described. Beam results of SEMG Monitor test are given for two modifications of an electronic
 preamplifier. Відповідно до експериментальної програми тестового лінійного прискорювача TTF вимір часової
 залежності енергетичного розкиду прискорених електронів уздовж макроімпульсу буде зроблено за
 допомогою стандартного приладу для виміру профілю пучка – багатодротової повторно-емісійної камери
 (ВЕММ). ВЕММ на пучку високої енергії прискорювача TTF розташований у фокальній площині
 магнітного спектрометра і буде вимірювати енергетичний розкид прискорених електронів у діапазоні від
 0,1% до декількох відсотків. У роботі викладаються виміри профілю пучка повторно-емісійної
 багатодротовой камерою з новою високочутливою електронікою. Результати іспитів ВЕММ на пучку
 прискорювача TTF і їхнє обговорення дано для двох модифікацій електронних передпідсилювачів. В соответствии с экспериментальной программой тестового линейного ускорителя TTF измерение временной зависимости энергетического разброса ускоренных электронов вдоль макроимпульса должно производиться с помощью стандартного прибора для измерения профиля пучка – многопроволочной вторичноэмиссионной камеры (ВЭММ). ВЭММ на пучке высокой энергии ускорителя TTF расположен в фокальной
 плоскости магнитного спектрометра и должен измерять энергетический разброс ускоренных электронов в
 диапазоне от 0,1% до нескольких процентов. В работе излагаются измерения профиля пучка вторично-эмиссионной многопроволочной камерой с новой высокочувствительной электроникой. Результаты испытаний
 ВЭММ на пучке ускорителя TTF и их обсуждение приводятся для двух модификаций электронных предусилителей. Great thanks to B. Faatz, A. Fateev, O. Hensler, K. Rehlich, E. Schneidmiller and S. Schreiber for fruitful discussion and help in this work. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Элементы ускорителей Multi-channel electronics for secondary emission grid profile monitor of TTF linac Багатоканальна електроніка для повторно-емісійного багатодротового монітора профілю пучка лінійного прискорювача TTF Многоканальная электроника для вторично-эмиссионного многопроволочного монитора профиля пучка линейного ускорителя TTF Article published earlier |
| spellingShingle | Multi-channel electronics for secondary emission grid profile monitor of TTF linac Reingardt-Nikoulin, P. Gaidash, V. Mirzojan, A. Novikov-Borodin, A. Элементы ускорителей |
| title | Multi-channel electronics for secondary emission grid profile monitor of TTF linac |
| title_alt | Багатоканальна електроніка для повторно-емісійного багатодротового монітора профілю пучка лінійного прискорювача TTF Многоканальная электроника для вторично-эмиссионного многопроволочного монитора профиля пучка линейного ускорителя TTF |
| title_full | Multi-channel electronics for secondary emission grid profile monitor of TTF linac |
| title_fullStr | Multi-channel electronics for secondary emission grid profile monitor of TTF linac |
| title_full_unstemmed | Multi-channel electronics for secondary emission grid profile monitor of TTF linac |
| title_short | Multi-channel electronics for secondary emission grid profile monitor of TTF linac |
| title_sort | multi-channel electronics for secondary emission grid profile monitor of ttf linac |
| topic | Элементы ускорителей |
| topic_facet | Элементы ускорителей |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/78954 |
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