1. LHCf Status Report
Measurement of Photons and Neutral Pions in the Very Forward Region of LHC
Frascati, CSN1, 18 Settembre 2007
Oscar Adriani
INFN Sezione di Firenze - Dipartimento di Fisica dell’Università degli Studi di Firenze

2. Development of atmospheric showers
Cosmic ray spectrum
Tevatron
LHC
The dominant contribution to the energy flux is in the very forward region ( 0)
In this forward region the highest energy available measurements of p0 cross section were done by UA7 (E=1014 eV, y= 5÷7)
A 100 PeV fixed-target interaction with air has the cm energy of a pp collision at the LHC
AUGER
LHCf detectors will allow to understand and model pp, (pA, A’A) interactions giving rise to air-showers in the eV range.
Correct simulation of interactions of primary cosmic rays with the atmosphere is essential to cosmic ray studies
Frascati, 18 Settembre CSN1
LHCf Status Report

3. LHCf location
INTERACTION POINT
IP1 (ATLAS)
Beam line
Detector II
Tungsten
Scintillator
Silicon mstrips
Detector I
Scintillating fibers
140 m
Detectors will be installed in the TAN region, 140 m away from the Interaction Point 1, in front of luminosity monitors
Here the beam pipe splits in 2 separate tubes.
Charged particles are swept away by magnets!!!
We will cover up to y
Frascati, 18 Settembre CSN1
LHCf Status Report

4. Detector # 2
We use LHC style
electronics and readout
2 towers 24 cm long stacked on their edges and offset from one another
Lower:2.5 cm x 2.5 cm
Upper: 3.2 cm x 3.2 cm
4 pairs of silicon microstrip layers
(6, 10, 30, 42 r.l.) for tracking purpose (X and Y)  impact point
q < 400 mrad
16 scintillator layers (3 mm thick)
Trigger and energy profile measurements
Absorber
22 tungsten layers 7mm thick  44 X0 (1.6 lI) in total
(W: X0 = 3.5mm, RM = 9mm)
Energy
Frascati, 18 Settembre CSN1
LHCf Status Report

5. Performances of the LHCf Detector
Measured at the SPS
Beam Test in 2004
Energy Resolution
SciFi Position Resolution
LHCf can measure (and provide to LHC) the center of neutral flux from the collisions
If the center of the
neutral flux hits LHCf
 << 1 mm resolution
Frascati, 18 Settembre CSN1
LHCf Status Report

6. p0 mass resolution Dm/m = 5% Arm #1 DE/E=5% 200 mm spatial resolution
2 g identified in the 2 towers
Arm #1
DE/E=5%
200 mm spatial resolution
Dm/m = 5%
Frascati, 18 Settembre CSN1
LHCf Status Report

7. Monte Carlo g ray energy spectrum
(5% Energy resolution is taken into account)
106 generated LHC interactions 
1 minute cm-2s-1 luminosity Discrimination between various models is feasible
Quantitative discrimination with the help of a properly defined c2 discriminating variable based on the spectrum shape
(see TDR for details)
Frascati, 18 Settembre CSN1
LHCf Status Report

8. Model dependence of neutron energy distribution
Original n energy
30% energy resolution
Frascati, 18 Settembre CSN1
LHCf Status Report

9. Both detectors are ready since April 2007

10. Front Counter (Both for Arm1&2)
read by a MAPMT
R7600U-00-M4
Frascati, 18 Settembre CSN1
LHCf Status Report

11. Frascati, 18 Settembre 2007 - CSN1
LHCf Status Report

12. Readout electronics LHC style electronics (Many thanks to CMS!!!!) DOH
CCU
PLL
DCU …
PACE3 chips (CMS preshower)
We have developed
Hybrid circuit (Left+Right)
Mother Board (Logic)
Adc Piggy Back board
DAQ: 100 Mbit/s optical link
VME Readout
100
Mbit
Optical
Link
Frascati, 18 Settembre CSN1
LHCf Status Report

13. Final electronics for Arm2
Power Board
Frascati, 18 Settembre CSN1
LHCf Status Report

14. Mother Board + ADC boards
Frascati, 18 Settembre CSN1
LHCf Status Report

15. The readout boards in the electronics box
Frascati, 18 Settembre CSN1
LHCf Status Report

16. Now the real installation in LHC…
The idea is that installation takes place in 2 steps:
Pre-installation
Final installation
In between the 2 installation the baking out of the beam pipe will be done (200 oC), so the detectors should be removed
Pre-Installation dates have been fixed in Fall 2006
LSS1L (Arm1)
8/01/2007 to 26/01/2007  FINISHED!
LSS1R (Arm2)
23/04/2007 to 11/05/2007  FINISHED
The dates for the final installation are still under discussion
(Decision in Fall 2007)
Frascati, 18 Settembre CSN1
LHCf Status Report

17. Transport and insertion in the TAN
Arm1 pre-installation
Transport and insertion in the TAN
Frascati, 18 Settembre CSN1
LHCf Status Report

18. Arm2 pre-installation
Explicit request from TS/LEA: Speed up the cabling connection time!
Some work is in progress for this (Splitter box, Distribution board)
A ‘second pre-installation’ is foreseen in Autumn
Frascati, 18 Settembre CSN1
LHCf Status Report

19. Monomode Optical Fibers
USA15
Readout and control scheme for Arm2 Silicon
TAN
Arm2
~ 240 m
VME Crate
Multimode Optical Fibers
Signal +
Control
DOH
Control PC
TSC+FEC
Monomode Optical Fibers
MB + ADC
Power
Thermistors
Thermistors
Distribution Board
Splitter Box
Power Supply
High Current Cables
Sense wires
High Voltage
High Voltage
Frascati, 18 Settembre CSN1
LHCf Status Report

20. General LHCf DAQ scheme
LHCf Rack Allocation in USA15
Frascati, 18 Settembre CSN1
LHCf Status Report

21. What do we have to do? (Slide of June 2007)
Final commissioning of the electronics (modifications to the logic, complete the PCBs, distribution board etc.) Done
Installation of the new splitter box in the tunnel  Done
Some work in USA15 and TAN region to speed up the interconnection time  Partly done
Final DAQ software common with Japan people  Well started
Monitoring program
Test beam with final apparatus (August 24, September 11)
Next part of the talk will focus on this item
Second pre-installation to test the modifications done after the first pre-installation
Final installation: schedule is under discussion (December? January 2008?)  Surely in 2008
Frascati, 18 Settembre CSN1
LHCf Status Report

22. 2007 Test Beam  3 weeks of Beam Test (24/08 – 11/09) SPS H4
Main Objectives:
Absolute energy calibration of Arm1 & Arm2 by using electrons with as many energy points as possible (50 GeV – 250 GeV)
Measurement of spatial resolution for Arm2
Energy resolution for protons
Direct identification of p0 produced in light target
Test with detectors in final configuration (Power supply, DAQ, Control system etc.)
Agilent Low Voltage Power Supply……… 
Frascati, 18 Settembre CSN1
LHCf Status Report

23. The experimental setup behind GOLIATH magnet
Frascati, 18 Settembre CSN1
LHCf Status Report

24. Arm2 Adamo tracking system Frascati, 18 Settembre 2007 - CSN1
LHCf Status Report

25. Frascati, 18 Settembre 2007 - CSN1
LHCf Status Report

26. Beam test: some general points…
11 days Arm2, 8 days Arm1
> 106 events for Arm2
Electrons: Hadrons: Muons:
50 GeV GeV GeV
100 GeV GeV
150 GeV
200 GeV
Common DAQ, between Silicon and Scintillator part
MIDAS based DAQ system (starting point for the final DAQ system)
DAQ rate was limited to 30 Hz by Adamo tracking system
Trigger from calorimeter towers has been tested
Dedicated study to optimize the PACE3 working condition (to increase the dynamic range)
TDC was used to correct for the asynchrony between particles and 40 MHz clock
Frascati, 18 Settembre CSN1
LHCf Status Report

27. Possible study of direct p0 detection?
Following the referee suggestion we tried to
directly identify the p0 produced by proton
interaction in a light target g
350 GeV Proton beam
Not in scale! g
9.15 m
Carbon target
(3 cm)
in the slot used for beam monitor
Arm1
>107 proton on target (special setting from the SPS people)
Frascati, 18 Settembre CSN1
LHCf Status Report

28. Dedicated trigger on both towers of the calorimeter has been used
Main problems:
low photon energy (≥ 20 GeV)
Direct protons in the towers
Multi hits in the same tower
 200 p0 events should be triggered (in a quite big background) Challenging!!!
Frascati, 18 Settembre CSN1
LHCf Status Report

29. Expected results for 35.106 proton on target
Simulated invariant mass
No cuts and efficiencies
applied
Expected invariant mass
by using estimated efficiencies
and standard cuts
Arm1
280 events
Arm2
540 events
Frascati, 18 Settembre CSN1
LHCf Status Report

30. p0 Like Event Calorimeters Shower Profile @ First SciFi Layer
Egamma=18GeV
20mm X
40mm Y
Egamma=46GeV
~ 250 p0 events acquired on disk
Frascati, 18 Settembre CSN1
LHCf Status Report

31. Here few plots of the PRELIMINARY results……
Here few plots of the PRELIMINARY results……. … The test is finished last Tuesday…. All results are preliminary NO TDC correction! Only silicon info is considered
Frascati, 18 Settembre CSN1
LHCf Status Report

32. PACE3 pedestals and sigma
Nominal Pace3 parameters … Not so good…
X view
y view 1 2 3 4
Frascati, 18 Settembre CSN1
LHCf Status Report

33. PACE3 sigma after parameters tuning
Low Gain
High Gain
Good channel uniformity!!!!!
Frascati, 18 Settembre CSN1
LHCf Status Report

34. Pedestal for various PACE3 parameters
1 ‘defective’ chip has been recovered!
Frascati, 18 Settembre CSN1
LHCf Status Report

35. 50 GeV e- 200 GeV e- Very clear peaks!!!!!!
Frascati, 18 Settembre CSN1
LHCf Status Report

36. Good double particle identification!
100 GeV e GeV e-
Good double particle identification!
Frascati, 18 Settembre CSN1
LHCf Status Report

37. m 200 GeV Hadron 200 GeV We can see MIP! (First time with PACE3?)
Frascati, 18 Settembre CSN1
LHCf Status Report

38. 200 GeV e-: Many superimposed events Low Gain High Gain
Clear saturation in High Gain
Frascati, 18 Settembre CSN1
LHCf Status Report

39. Energy correlation on the x-y layers Low Gain High Gain
Frascati, 18 Settembre CSN1
LHCf Status Report

40. Total measured energy in silicon
50 GeV
100 GeV
No TDC correction!!!!!
200 GeV
150 GeV
Frascati, 18 Settembre CSN1
LHCf Status Report

41. Spatial resolution
ADAMO tracking system is used to track particles towards ARM2
~ few mm spatial resolution for ADAMO
The expected impact point on the ARM2 silicon planes is evaluated
Peak search is performed on the ARM2 silicon data
Lorentzian fit to reconstruct the impact point on ARM2
Difference between ADAMO extrapolated point and ARM2 reconstructed point is used as estimator of the ARM2 spatial resolution
Very preliminary results!
No optimal impact point reconstruction
No relative alignment between ADAMO and ARM2
Frascati, 18 Settembre CSN1
LHCf Status Report

42. Spatial resolution for 200 GeV electron
Y projection
~ 75 mm
YAdamo – YArm2
XAdamo – XArm2
X projection
s ~ 50 mm
Frascati, 18 Settembre CSN1
LHCf Status Report

43. Spatial resolution vs Electron energy
Frascati, 18 Settembre CSN1
LHCf Status Report

44. LHCf proposed running scenario
Phase-I
Run since the very beginning of LHC operations (Stage 1, 43 bunches)
Remove the detector for radiation issues when the luminosity reaches 1031cm-2s-1
Phase-II
Re-install the detector at the next opportunity of low luminosity run (Totem dedicated runs? Possible LHCf dedicated runs?)
Phase-III
Future extension for p-A, A-A run with upgraded detectors?
We are continously in touch with Machine and ATLAS peoples
to agree on detailed running and installation scenario
We had a dedicated Meeting with Atlas Management
(Peter Jenn, Per Grafstrom, Marzio Nessi, ZDC groups etc.)
at beginning of September
Frascati, 18 Settembre CSN1
LHCf Status Report

45. LHCf Optimal Running Conditions
From Helmut Burkhardt
Frascati, 18 Settembre CSN1
LHCf Status Report

46. Summary Detectors are ready Pre-Installation completed
Very long test beam finished
Second pre-installation this year
Final installation next year
Waiting for LHC Beam!!!!!
Frascati, 18 Settembre CSN1
LHCf Status Report

47. Back up Slides

48. Milestones dei preventivi 2008
Installazione definitiva di Arm1 e Arm2 (se compatibile con la macchina)
Inizio presa dati (compatibilmente con il funzionamento della macchina)  
(Milestone aggiuntiva)
Risultati preliminari da calibrazione/allineamento (compatibilmente con il funzionamento della macchina)
Frascati, 18 Settembre CSN1
LHCf Status Report

49. Detector #1 Impact point (h) Energy
2 towers ~24 cm long stacked vertically with 5 mm gap
Lower:2 cm x 2 cm area
Upper: 4 cm x 4 cm area
4 pairs of scintillating fiber layers for tracking purpose (6, 10, 30, 42 r.l.)
Absorber
22 tungsten layers 7mm thick  44 X0 (1.6 lI) in total
(W: X0 = 3.5mm, RM = 9mm)
q < 300 mrad
16 scintillator layers (3 mm thick)
Trigger and energy profile measurements
Energy
Frascati, 18 Settembre CSN1
LHCf Status Report

50. Energy spectrum of π0 expected from different models (Typical energy resolution of g is 3 % at 1TeV)
Frascati, 18 Settembre CSN1
LHCf Status Report

51. Clear CR signal separation (20ADC by 2249W ~ 5pC)
Frascati, 18 Settembre CSN1
LHCf Status Report

52. Installation of the detectors in the TAN absorbers at 140m from IP1
LHCf
96 mm
Frascati, 18 Settembre CSN1
LHCf Status Report

53. The LHCf operation in LHC

54. Optimal LHCf run conditions
Beam parameter
Value
# of bunches
≤ 43
Bunch separation
> 2 msec
Crossing angle
0 rad
140 mrad downward
Luminosity per bunch
< 2 x 1028 cm-2s-1
Luminosity
≤ ~1030 cm-2s-1
Bunch intensity
4x1010 ppb (b*=18 m)
1x1010 ppb (b*= 1 m)
Beam parameters used for commissioning are good for LHCf!!!
No radiation problem for 10kGy by a “year” operation with this luminosity
Frascati, 18 Settembre CSN1
LHCf Status Report

55. From R. Bailey presentation at January 2007 TAN workshop
Optimal conditions for LHCf running!
Stage 1
Frascati, 18 Settembre CSN1
LHCf Status Report