Target Monitoring System

Charge Integrators Si- telescopes Si-Pad detectors SVD-tracking Beam position monitor

The main task for the Target Monitoring System(TMS)(see V.Pugatch,Multi-Target Equalization Steering) is to monitor Target-Beam Interactions and to provide data to the steering code for an equal distribution of the Interaction Rate (IR) over all inserted targets.

One has to built the IR monitoring system operating at 40 MHz Interaction Rate equally distributed over eight interaction points created by eight targets moving in the close vicinity (2-3 mm) to the core of the proton beam to keep IR constant at progressively (or occasionally) changing parameters of the proton and/or positron beams as well as of the targets.

The Target Monitoring System components are based on the counters with comparatively small acceptances (Si-telescopes and Si-pad detectors), while Charge Integrators provide data which do not depend upon any acceptance.

18 of April 1999 multiwires Run #110 was successfully realized. Two, three and four wires were operated simultaneously. Target Steering System provide an equal contribution of all the working targets. TMS shows a perfect agreement between Charge Integrators measurements (blue markers + on the lower histogram) and hodoscopes( red markers + on the upper histogram) data.

Charge Integrators

In order to get a principal scheme of the charge integrator, click here.

Charge Integrators are connected to the electrically isolated targets by means of high vacuum feedthroughs and ~3 m long cables.
There is 1.5 nA calibrating current permanently flowing at their inputs from 'long live' batteries through the targets. The ChI output frequency for that current is around 500 Hz ( ~ 5 times higher than in 1998).
Thus, till the target is alive one has to see this frequency (which is stable within 1 % level) without any p-beam.

The Target-Beam-Interaction borned current has to bring an additional frequency at the rate of 10-30 Hz per Interaction Rate of 1 MHz.

Connections and some useful relations (last update Run 101) are as follows:

Target/Material BNC Scaler input ChI # Baseline offset ChI/IRate(Hz/Mhz) IR=A*ChI+BRemarks
hb-vme03 hb-vme01
Below 1 / Ti 58 0 0 1 365 6.9 +/- 0.61.4E5 -52.7 no
Outer 1 / Al 59 1 1 2 0 -- Target broke off
Above 1 / Al 60 2 2 3 466 11.5 +/- 1.08.7E4 -40.5 no
Inner 1 / Al 61 3 3 4 366 33.6 +/- 1.23.0E4 -10.9 no
Below 2 / Al 63 4 4 6 502 18.5 +/- 1.25.4E4 -27.1 45 degree target
Outer 2 / Ti 64 5 5 7 443 7.9 +/- 0.31.3E5 -56.4 no
Above 2 / Fe 65 6 6 8 532 8.3 +/- 0.81.2E5 -64.8 45 degree target
Inner 2 / C 66 7 7 9 0 --Target shortened
Control 62 10 8 5 577 -- no
Control 67 8 9 10 604 -- no

Remarks:
A. hb-vme03 computer runs Target DAQ (data acquisition system).
B. hb-vme01 computer runs TaCoS (Target Steering System).

Previous tables Run 009, Run 032, could be seen.

Si-telescopes

Si- telescopes are installed at the Target tubes.
Coincident rates are to be observed at the CAMAC 12 channel Scaler (CAMAC station No. 14) corresponding to the following connections:

Target/Si-tel. BNC Scaler input Remarks
(CAMAC Station # 14)
B1.1
B1.2
42
43
0
no
O1.1
O1.2
44
45
2
no
A1.1
A1.2
46
47
4
no
I1.1
I1.2
48
49
6
no
B2.1
B2.2
50
51
1
no
O2.1
O2.2
52
53
3
no
A2.1
A2.2
54
55
5
no
I2.1
I2.2
56
57
7
no

Remarks:

1. High Voltage cable for all 16 Si-tel. detectors is No.2.
2. One has to check the discriminator thresholds (ones have to be at 30 mV).
3. Coincident rates are expected to be in the range of few kHz per 10 MHz Interaction Rate.

Si-Pad detectors

Si-pad detectors are installed at the VDS exit window.
Connections are as follows:

Si-pad. BNC Scaler input Remarks
CAMAC Station # 16
C1
C3
34
36
0
no
C2
C4
35
23
1
no
D1
D3
38
40
2
no
D2
D4
39
41
3
no
A1
A3
26
28
4
no
A2
A4
27
29
5
no
B1
B3
30
32
6
no
B2
B4
31
33
7
no

Remarks:

1. High Voltage cable
"Target HV3" - detectors C
"Target HV4" - detectors B
"Target HV5" - detectors D
"Target HV6" - detectors A

2. One has to expect ~ 50 kHz coincident rate at 10 MHz
Interaction rate (discriminator thresholds : 30 mV).

SVD-tracking

Silicon Vertex Detector (SVD) can provide data for an additional control of the each target contributions. Number of the tracks come out from the targets in the same time bin should be equal.

Beam position monitor

Center of the beam was located most of the time (runs 001 to 074) inside the yellow rectangle with co-ordinates:
(-2.4, 0) - upper left and (-1.4, -1.0) - lower right.
Starting from Run 75 beam position has been shifted down ~ 1mm, as you can see on the figure:
and began to be located inside rectangle with co-ordinates: (-2.4, -1.0) - upper left and (-1.9, -1.5) - lower right.


TMS-team:Valeriy Pugatch ,Iouri Vassiliev andVladimir Aushev

Last modified: Thu Apr 15 16:40:19 MET DST 1999