NA49 Beam Line 1995

Targets, counters, and other material in the H2 beam line

H. Stroebele

8 Dec 1995

C2:      Collimator 2				       -412000 mm

C3:      Collimator 3				       -412000 mm

C6:      Collimator 6				       -341000 mm

C9:      Collimator 9				       -147000 mm

S1:      50mmx30mmx0.2mm Quartz (in vac) opt. for TOF	-39772 mm
        
T0:      25mmx25mmx0.5mm Quartz (in vac) TOF and DAQ 	-39507 mm
        
BPD1:    Si strip Beam Position Detector (in vac)	-39113 mm
        
MBPL:    Bending Magnet for beam cal. alignm.(in vac)	-36907 mm
        
BPD2:    Si strip Beam Position Detector (in vac)	-16426 mm
        
S2:      20mmx20mmx5mm Scint.(in vac) not used for Pb	-15691 mm
        
V0:      80 mm diameter with 10 mm hole Scint. (in vac)	-15441 mm
        
FISC:    thin scint. wire hor. and vert. 		-14746 mm
        
Window:  vacuum 0.05 mm black Mylar 			- 6660 mm
        
V1:      large scint. covered with lead with 40 mm hole - 6630 mm
        
BPD3:    Si strip Beam Position Detector (not used)	- 6514 mm
        
Target0: 0.5 mm Ta for multi-target runs on BPD3 stage	- 6434 mm
        
Window:  Target He-bag, 0.02 mm Mylar			- 6400 mm
        
Target1: 204 mg/cm**2 Pb (main production target)	- 5801 mm
        
Window:  Target He-bag, 0.02 mm Mylar			- 5792 mm
        
VM1:     Vertex 1 Magnet and VTPC1, nominal position    - 3802 mm
        
BPD4:    Si strip Beam Position Detector (not used)	- 1895 mm
        
Target2: 0.5 mm Ta for multi-target runs on BPD4 stage	- 1815 mm
        
VM2:     Vertex 2 Magnet and VTPC2, nominal position  	     0 mm
        
Target3: 0.5 mm Ta for multi-target runs (pivoting arm)   1571 mm
        
Window:  SAC He-bag; 15 micron Al + 85 micron Mylar	  1575 mm
        
Window:  SAC He-bag; 15 micron Al + 85 micron Mylar	  3325 mm
        
Window:  MTPC He-bag; 100 micron Mylar			  3325 mm
        
Target4: 379 mg/cm**2 Pb for K0s in MTPC 		  3340 mm
        
Window:  MTPC He-bag; 100 micron Mylar			  8525 mm
        
S4:      Veto counter 20mmx20mmx1mm Quartz		  9400 mm
        
Ring:    Calorimeter front face 			 13800 mm
        
S5:      fragment counter 60mmx40mmx10mm Quartz		 19150 mm
        
Coll:    Collimator front face 				 19200 mm
        
Veto:    Calorimeter front face 			 21800 mm

Send corrections or additions to Art Poskanzer


C2: Collimator 2 -412000 mm

Hozizonal collimator for the horizontal divergence. Stardard setting is about +/-1.5 mm

Adjust the beam intensity by moving the colimators. Collimators 2, 3, and 6 should be approximately the same. If you are closing the collimator, it first opens all the way, so first put the plug (TAX) in to -100 mm. To do so on the EANORTH terminal type RUN TREE, go to TUNE, SPECIAL, TAX, 1, and set to -100. If you are opening the collimator this is not necessary. To move the collimator itself chose TUNE, SET, COLLIMATORS, 2, and type in desired value.


C3: Collimator 3 -412000 mm

Selects central momentum bite. Stardard setting is about +/-1.5 mm

Adjust the beam intensity by moving the colimators. Collimators 2, 3, and 6 should be approximately the same. If you are closing the collimator, it first opens all the way, so first put the plug (TAX) in to -100 mm. To do so on the EANORTH terminal type RUN TREE, go to TUNE, SPECIAL, TAX, 1, and set to -100. If you are opening the collimator this is not necessary. To move the collimator itself chose TUNE, SET, COLLIMATORS, 3, and type in desired value.


C6: Collimator 6 -341000 mm

Verticle collimator for verticle size. Stardard setting is about +/-1.5 mm

Adjust the beam intensity by moving the colimators. Collimators 2, 3, and 6 should be approximately the same. If you are closing the collimator, it first opens all the way, so first put the plug (TAX) in to -100 mm. To do so on the EANORTH terminal type RUN TREE, go to TUNE, SPECIAL, TAX, 1, and set to -100. If you are opening the collimator this is not necessary. To move the collimator itself chose TUNE, SET, COLLIMATORS, 6, and type in desired value.


C9: Collimator 9 -147000 mm

Cleaning collimator. Be sure not to scrape the beam. Stardard setting is about +/-5 mm

On the EANORTH terminal type RUN TREE. To move the collimator chose TUNE, SET, COLLIMATORS, 9, and type in desired value.


S1: 50 mm x 30 mm x 0.2 mm Quartz (in vac) opt. for TOF -39772 mm

This counter is mounted on a vertical stage, which can be controlled from inside the counting house in Rack 17. If not needed by TOF this counter should be in the out-position, because it will produce unwanted fragments.

For the above 3 values also check the logbook!

The HV has to bet set to zero before the vacuum in the beam pipe is either broken or reestablished!

Responsible for this Detector: Marburg group


T0: 25 mm x 25 mm x 0.5 mm Quartz (in vac) TOF and DAQ -39597 mm

This counter is used as the positive beam defining counter for ions and, in addition, as time=0 for TOF.

This counter is mounted on a vertical stage, which can be controlled from inside the counting house in Rack 17.

For the above 3 values also check the logbook!

The HV has to bet set to zero before the vacuum in the beam pipe is either broken or reestablished!

Responsible for this Detector: Marburg group


BPD1: Si strip Beam Position Detector (in vac) -39113 mm

This detector measures the beam position in x- and y- directions perpendicular to the beam with twice 192 Si strips. Each strip is 200 microns wide.

The nominal x- and y-coordinates of its center are

Remove bias voltage before changing the pressure in the beam pipe!

Responsible for this detector: P. Freund, MPI Muenchen


MBPL: Bending Magnet for beam cal. alignm. (in vac) -36907 mm

This bending magnet (2 m long) can be used to deflect the beam for TPC alignment measurements. It is controlled by the beam control console (TREE: magnet name is Bend8).

Its maximum bending power for a 400 GeV/c particle (corresponding to 160 GeV/c Pb beam) is appr. 10 cm at VTPC1. Either spectator protons or secondary hadrons have to be used.


BPD2: Si strip Beam Position Detector (in vac) -16426 mm

This detector measures the beam position in x- and y- directions perpendicular to the beam with twice 192 Si strips. Each strip is 200 microns wide.

The nominal x- and y-coordinates of its center are

Remove bias voltage before changing the pressure in the beam pipe!

Responsible for this detector: P. Freund, MPI Muenchen


S2: 20 mm x 20 mm x 5 mm Scint. (in vac) not used for Pb -15691 mm

This counter is not used for normal Pb running; however, it can be used to tune the beam.

This counter is mounted on a vertical stage, which can be controlled from inside the counting house in Rack 17.

For the above 3 values also check the logbook!

The HV has to bet set to zero before the vacuum in the beam pipe is either broken or reestablished!

Responsible for this Detector: D. Vranic, CERN


V0: 80 mm diameter with 10 mm hole Scint. (in vac) -15441 mm

This counter is essential for the clean-up of the beam; it vetoes charged particles and fragments which are produced upstream.

This counter is mounted on a vertical stage, which can be controlled from inside the counting house in Rack 17.

For the above 3 values also check the logbook!

The HV has to bet set to zero before the vacuum in the beam pipe is either broken or reestablished!

Responsible for this Detector: D. Vranic, CERN


FISC: thin scint. wire hor. and vert. -14746 mm

This detector, FISC 11/12, belongs to the external beams group (N. Doble) and is controled by the TREE program. It consists of two perpendicular thin wires which are read out by two PM tubes each. The wires are movable under beam console control.

The detector is used to scan the profile of the beam in the plane perpendicular to the beam. Also, the wires can be positioned in the center and scanned with TRIM5 and TRIM6 to fine tune the beam position.

Normally the FISC is aligned such that the reading 0.0 gives the center of the nominal beam. At present (27 Nov 95) X = -4 mm and Y = 0 mm.

Responsible for this detector is the external beam group.


Window: vacuum 0.05 mm black Mylar - 6660 mm


V1: large scint. covered with lead with 40 mm hole - 6630 mm

This large area counter provides additional clean-up of the beam; it vetoes charged particles and fragments which are produced upstream. It is mounted in the gap between the vacuum pipe and Target0. For beam calibration operation it has to be removed.

Responsible for this Detector: D. Vranic, CERN


BPD3: Si strip Beam Position Detector (not used) - 6514 mm

This detector measures the beam position in x- and y- directions perpendicular to the beam with twice 48 Si strips. Each strip is 200 microns wide.

It is mounted on a stage movable horizontally remotely from the counting house. To operate the stage go to the Laser Macintosh and open the desktop item GPIB. Then open SMK Control 2.2. To activate, click on the upper left arrow. This window allows one to move the stage. BPD3 is axis "Z". The direction of motion is positive towards Saleve and negative towards Jura, thus opposite to the standard NA49 coordinate system definition. Step size is 17 microns.

The stage can also be moved locally by activating one of the limit switches; the stage will then move away from that switch.

Responsible for this detector: P. Freund, MPI Muenchen and H. Stroebele Univ. Frankfurt


Target0: 0.5 mm Ta for multi-target runs on BPD3 stage - 6434 mm

This target is mounted on the BPD3 shielding box on the downstream and Jura side. The box is mounted on a stage which is movable horizontally remotely from the counting house. To operate the stage make sure that the control unit ("upstream") in rack 21 lowest row is switched to remote control and then go to the Laser Macintosh and open the desktop the item GPIB. Then open SMK Control 2.2. To activate, click on the upper left arrow. This window allows one to move the stage. BPD3 is axis "Z". The direction of motion is positive towards Saleve and negative towards Jura, thus opposite to the standard NA49 coordinate system definition. Step size is 17 microns. Target position in the beam should normally be 00000. This can be checked at the stage: there are vertical marks on paper stickers at the upper and lower end of the vertical L-beam. These define the horizontal position of the stage.

CAUTION: "target in beam position" is very close to V1!!!!!!

Switch back control unit to local for safety reasons. The stage can also be moved locally by activating one of the limit switches; the stage will then move away from that switch.

Responsible for this item: H. Stroebele Univ. Frankfurt


Window: He-bag, 0.02 mm Mylar - 6400 mm

To inflate the target He bag open the valve labelled TARGET on the He distribution line in the gas cave. Adjust the flux to about 7 l/hr. on the scale on the corresponding flow meter. Make sure that the valve mounted on the lower left front of VTX1 is open. The valve next to the He inlet to the He bag just above the green gate valve on the target mount must be closed. The exhaust of the He bag is a pigtail inside the magnet compartment.


Target1: 204 mg/cm**2 Pb (main prod. target; in He-Bag) - 5801 mm

The target is mounted on the axis of a pneumatic cylinder which can be moved up and down remotely from the counting house. The corresponding buttons and indicators are mounted in the very top row of rack 15. The nitrogen supply labelled "LASER" in the gas cave has to be open for operation. Also, the pressure reducing valve on top has to be open. One of the two indicators will be lit, if there is pressure in the corresponding line to the cylinder. There are additional valves after the sensors in these lines which have to be open! They are mounted on the front face of VTX1 at the very lower left side.

The target is in He atmosphere. It can be changed without opening the He bag:

  1. move the target into the "out" position
  2. close the green gate valve
  3. open the lower vacuum clamping connection
  4. remove cylinder with target
  5. exchange the target (other targets are in Stroebele's tool box in the cage; key is in the beam console drawer).
  6. for reinstallation use reverse procedure


Window: He-bag, 0.02 mm Mylar - 5792 mm


VM1: Vertex 1 Magnet and VTPC1, nominal position - 3802 mm

For VTPC1 see elsewhere.

For Magnet operation press the buttons in the following order:

  1. rearmement
  2. commande marche
  3. contacteur CT4 (red LED => green LED)
  4. set dial 00000
  5. press "SET" next to dial
  6. puissance marche
Now set new dial values (choose steps smaller than 500 from what you have) and press "set" button until you arrive at the nominal setting.

After current becomes stable verify field strength by looking at the hall probes read-out on slow control (terminal in rack 24): select E+B field; select hall probes; choose uppermost readings only. Also check the magnet current reading and compare it the logbook value.

If the field changes by more than 100 Gauss (30 Amps) call an expert.

In case of trouble with the power supply contact

In case of trouble with Cryogeny call their control room 6877 or D. Delikaris 8276 <5025>.


BPD4: Si strip Beam Position Detector (not used) - 1895 mm

This detector measures the beam position in x- and y- directions perpendicular to the beam with twice 48 Si strips. Each strip is 200microns wide.

It is mounted on a stage movable horizontally remotely from the counting house. To operate the stage go to the Laser Macintosh and open on the desk top item GPIB. Then open SMK Control 2.2. To activate, click on the upper left arrow. This window allows one to move the stage. BPD4 is axis "R". The direction of motion is positive towards Saleve and negative towards Jura, thus opposite to the standard NA49 coordinate system definition. Step size is 17 microns.

The stage can also be moved locally by activating one of the limit switches; the stage will then move away from that switch.

Responsible for this detector are P. Freund, MPI Muenchen and H. Stroebele Univ. Frankfurt


Target2: 0.5 mm Ta for multi-target runs on BPD4 stage - 1815 mm

This target is mounted on the BPD4 shielding box on the downstream and Jura side. The box is mounted on a stage movable horizontally remotely from the counting house. To operate the stage make sure that the control unit ("downstream") in rack 21 lowest row is switched to remote control. If you do it remotely make sure that someone is at the target watching the action. Then go to the Laser Macintosh and open on the desk top item GPIB. Then open SMK Control 2.2. To activate, click on the upper left arrow. This window allows one to move the stage. BPD4 is axis "R". The direction of motion is positive towards Saleve and negative towards Jura, thus opposite to the standard NA49 coordinate system definition. Step size is 17 microns. Target position in the beam should normally be 00000. This can be checked at the stage: there are vertical marks on paper stickers at the upper and lower end of the vertical L-beam. These define the horizontal position of the stage.

Switch back control unit to local for safety reasons! The stage can also be moved locally by activating one of the limit switches; the stage will then move away from that switch.

Responsible for this item: H. Stroebele Univ. Frankfurt


VM2: Vertex 2 Magnet and VTPC2, nominal position 0 mm

For VTPC2 see elsewhere.

For Magnet operation press the buttons in the following order:

  1. rearmement
  2. commande marche
  3. contactor CT4 (red LED => green LED)
  4. set dial 00000
  5. press "SET" next to dial
  6. puissance marche
Now set new dial after currents has nearly stabilised (choose steps smaller than 500 from what you have) and press "set" button until you arrive at nominal setting.

After current becomes stable verify field strength by looking at the hall probes read-out in slow control (terminal in rack 24): select E+B field; select hall probes; choose uppermost readings only. Also check the magnet current reading and compare it the logbook value.

If the field changes by more than 100 Gauss (30 Amps) call an expert.

For technical help see VM1.


Target3: 0.5 mm Ta for multi-target runs (on pivoting arm) 1571 mm

The target is mounted on a pivoting arm which can be moved up and down remotely from the counting house. The corresponding buttons and indicators are mounted in the very top row of rack 15. Always make a visual inspection of what happened.

The nitrogen supply labelled "LASER" in the gas cave has to be open for operation. Also, the pressure reducing valve on top has to be open. One of the two indicators will be lit, if there is pressure in the corresponding line to the cylinder. There are additional valves after the sensors in these lines which have to be open! They are mounted on the front face of VTX1 at the very lower left side. The indicators light up, if the corresponding limit positions are reached. Thus the target may be in the beam if the "target out" light is not lit.


Window: SAC He-bag; 15 micron Al + 85 micron Mylar 1575 mm

The beam passes through the normal He bag walls. The material is foil A30 from NAWROT GmbH, D-51688 Wipperfeld, Fax 02268 2701.


Window: SAC He-bag; 15 micron Al + 85 micron Mylar 3325 mm

The beam passes through the normal He bag walls. The material is foil A30 from NAWROT GmbH, D-51688 Wipperfeld, Fax 02268 2701.


Window: MTPC He-bag; 100 micron Mylar 3325 mm


Target4: 379 mg/cm**2 Pb for K0s in MTPC 3340 mm

This target is hanging from an aluminium plate above the He bag. It can be pulled out or dropped into the beam from inside the MTPC hut.


Window: MTPC He-bag; 100 micron Mylar 8525 mm


S4: Veto counter 20 mm x 20 mm x 1 mm Quartz 9400 mm

This counter is mounted on a stage movable in the plane perpendicular to the beam, which is remotely controlled from the counting house in Rack 17.

The present (22 Dec 95) nominal positions are

Always verify in the logbook!


Ring: Calorimeter front face 13800 mm


S5: fragment counter 60 mm x 40 mm x 10 mm Quartz 19150 mm


Coll: Collimator front face 19200 mm

The verticle opening is +/-50 mm. In the STD+ configuration the horizontal opening goes from -50 mm to +380 mm.


Veto: Calorimeter front face 21800 mm


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