KT2Lab@PSI KT2Lab@PSI
Lea Caminada,
Lea Caminada, Stefanos Leontsinis, Stefanos Leontsinis, Olaf Steinkamp
Olaf Steinkamp
lea.caminada@physik.uzh.ch
FS 2020 FS 2020
olafs@physik.uzh.ch steleo@physik.uzh.ch
29 May 2020
Schedule 2020
Filled in request for 7 days, July 16 – 22
→ approval by PSI pending
→ dates may change by a few days,
depending on Covid19 situation and progress at PSI
Schedule 2020
Each of you comes to PSI for two full days (9h – 17h) Every day, there are two of you at PSI
→ up to you to decide who comes on which days
( but suggest you wait with this until the dates are confirmed )
Paul Scherrer Institute
Paul Scherrer Institute
“Experimentierhalle”
Cockcroft-Walton→Injector →Cyclotron:
→ accelerate protons to p = 590 MeV Proton beam hits two targets:
M (“Mince”) and E (“Epais”)
→ secondary beams
( mostly pions, muons, protons ) to seven experiment areas:
πM1, πM3,
πE1, πE3, πE5, μE1, μE4 ( also neutrons: UCN, SINQ )
“Experimentierhalle”
Cockcroft-Walton→ Injector→Cyclotron:
→ accelerate protons to p = 590 MeV Proton beam hits two targets:
M (“Mince”) and E (“Epais”)
→ secondary beams
( mostly pions, muons, protons ) to seven experiment areas:
πM1, πM3,
πE1, πE3, πE5, μE1, μE4 ( also neutrons: UCN, SINQ )
PiM1 Beamline
Dipole magnets to select beam momentum p [MeV] = 300 × B [T] × r [m]
and steer beam direction
Quadrupole magnet to focus beam Collimators to reduce beam intensity
PiM1 Beamline
magnet QTA11 -87.1427 "A" 0.8 { {scalevalue "100%"} } magnet QTB11 -113.17 "A" 1.5 { {scalevalue "100%"} } magnet QTB12 160.648 "A" 2.5 { {scalevalue "100%"} } magnet SSB11Y 0.558 "A" 0.2
slit FS11-L 500 "Steps" 1 slit FS11-R 500 "Steps" 1 slit FS11-O 500 "Steps" 1 slit FS11-U 500 "Steps" 1 magnet ASM11 226.784 "A" 1
magnet TS11 150.408 "A" 1 { {scalevalue "100%"} } magnet TS12 -192.026 "A" 1 { {scalevalue "100%"} } shutter KSD11
magnet QSL11 -103.529 "A" 1 { {scalevalue "100%"} } magnet QSL12 89.0151 "A" 1 { {scalevalue "100%"} } magnet QSL13 78.7203 "A" 1 { {scalevalue "100%"} } magnet QSL14 -110.835 "A" 2 { {scalevalue "100%"} } slit FS12-L 620 "Steps" 1
slit FS12-R 620 "Steps" 1 slit FS12-O 620 "Steps" 1 slit FS12-U 620 "Steps" 1 magnet ASM12 225.511 "A" 1
magnet TS21 -273.395 "A" 1 { {scalevalue "100%"} } magnet TS22 217.657 "A" 1 { {scalevalue "100%"} } magnet QSL15 -47.285 "A" 1 { {scalevalue "100%"} } magnet QSL16 63.6361 "A" 1 { {scalevalue "100%"} } magnet QSL17 131.201 "A" 1 { {scalevalue "100%"} } magnet QSL18 -133.582 "A" 1 { {scalevalue "100%"} }
Experiment Area
“Control room”
Experim ent
Goal of the Measurement
Measure decays of charged pions π
+→ μ
+ν
μ
μ
+→ e
+ν
eν
μStop π+ in a scintillator (→ signal starts clock)
Measure e+ in a second scintillator (→ signal stops clock)
Measure time spectrum (→ Time-to-Digital Converter) Determine π+ and μ+ lifetimes
from a fit to the histogram
Goal of the Measurement
Also: π
+→ e
+ν
e( but strongly suppressed by … what ?!? )
Measure e+ energy spectrum ( using a calorimeter ),
estimate ratio of branching ratios:
π+ → e+ νe is a two-body decay
→ fixed e+ energy
μ+ → e+ νe νμ is a three-body decay
→ wide e+ energy spectrum
Setup
Beam particles pass through SC1 and SC2 (and are slowed down in plastic moderators)
π+ are stopped and decay in SC3 (→ no signal in SC4)
Positrons are detected in SC6 (→ time measurement)
and Calorimeter
(→ energy measurement)
Scintillators and Calorimeter read out by photo-multipliers
Setup
Calorimeter Scintillators
Programme at PSI
1. Test scintillators / photomultipliers
→ connect High Voltage, check currents
→ look at noise signal
→ look at signal with radioactive source 2. Mechanical setup
→ connect cables to control room
3. Setup electronics for scintillator readout
→ amplify and discriminate
→ form coincidences
4. Optimize beam parameters
→ direction
→ momentum
Programme at PSI
1. Test scintillators / photomultipliers
→ connect High Voltage, check currents
→ look at noise signal
→ look at signal with radioactive source 2. Mechanical setup
→ setup detectors in the area
→ connect cables to control room
3. Setup scintillator readout & logic
→ amplify and discriminate
→ form coincidences
4. Optimize beam parameters
→ direction and momentum SC1&SC2&SC3&!SC4
stopping μ+ in SC3
stopping π+ in SC3
Programme at PSI
5. Setup electronics for time measurement
→ Time-to-Analog Converter
→ Analog-to-Digital Converter
→ Histogram
6. Measure decay-time spectrum
→ take data over night
→ time calibration
7. “Calibrate” calorimeter
→ e+ energy spectrum from each PMT
→ adjust HV to make spectra look similar 8. Measure energy spectrum
→ sum signals of all PMTs
→ take data over night
“Maestro”
(KT1 lab)
Data Analysis
True time distribution described by
Try adding components to describe
→ background from random coincidences
→ background from hadronic interactions
→ “smearing” due to measurement resolution Analysis of energy spectrum
more “qualitative”
→ no proper energy calibration
→ no theoretical model
Report
One common report by the whole team
→ physics, motivation
→ description of setup
→ relevant parameters
( beam settings, discriminator thresholds, etc )
→ auxilliary measurements
( beam optimisation, time calibration, … )
→ data
( list of files with short description, histograms )
→ fits to data
→ results ( with uncertainties ! )
→ discussion
Before we go to PSI
Discuss how you want to communicate with each other
→ need to pass important information from one team to the next Discuss how you want to keep a logbook
→ paper? electronic?
→ will be crucial for writing the report
It might be a good idea to do a first rough analysis already while you are taking the data
→ helps you see immediately if things go badly wrong, if things are missing
→ means you need to prepare some basic analysis tools beforehand (read in and plot histograms, do a basic fit)
→ maybe generate simulated decay-time spectrum ???
