Home Page of HIT experiment (Feb 2014)

Aim

From the approved project

• A first "Catania/GSI" like measurement: the full fighting power of a combined StartCounter /Two LYSO/Collimator + DCH/Two NaI setup.
• A second "GSI" like fragmentation measurement with movable LYSO crystals: StartCounter /Two LYSO/ Two plastic scintillator.

The measurement planning is being discussed in this document, linked here

Other measurements

• Gunzert-Marx et al measurement is linked here.
• Measurement on water (haettner): here
  
• Sommerer thesis on beta + linked here
  

Measurements

Available beams: For ^16 O the full beam library is available all the time, ^4 He is presently being tuned (should be ready till the end of the year, though).

• A: Please note, that for switching the source from carbon to oxygen and vice versa we need something like 1 h , hence we prefer to have oxygen beam times only over the week end.

• A: Although the intensity settings for therapy are somewhat higher, there is not problem in bringing them as low as you want (can be done in interaction between you and the accelerator crew).

Beam

• If you are only concerned with the question of range of a pencil beam, all planning can be performed rather quickly (actually on sight), since we have detailed tables relating the energy of the beam to the residual range achieved after a given thickness of water in front. Hence, all you would need to tell us would be the total (if possible water equivalent) thickness of the material in front of the interaction point. By choosing the adequate energy from our beam library we could than "tailor" the beam to stop right there (with a precision of ≈1 mm).
• If you would need 2D (or even 3D) beam plans, we would like to have a preparation time of about 1 day before the measurement.
• Beam size: Pencil beams are available with the standard settings from our beam library (labeled "LIBC"), which I attach as ASCII documents to this e-mail for the individual ion types. Smallest beam spots (FWHM) at highest energy are for carbon 3.4 mm, for protons 8.1 mm, for oxygen 2.7 mm and for helium 4.9 mm at the iso-centre. - Please, be aware that the sizes of individual pencil beams are determined

1. 1. By energy (as you can see from the attached lists).
   2. By scattering in air: This is particularly true for lighter ions (p and ⁴He), hence moving closer to the beam pipe will, in general, significantly reduce the beam size.
   3. By beam optics: For almost all entries of our beam library the pencil beams are set up such, that the focussing point is located near the exit window of the beam pipe, hence the beam extend will in general become smaller when moving closer to the beam pipe and larger when moving away from it.

• Bragg Peak He
• bragg peak vs energy , oxigen

MC simulation

Angle distributions can be found here

When

The assigned shifts are in

• 22 feb (2300 -> 600): (chance to have Oxy)
• 23 feb (2300 -> 500): (chance to have Oxy)
• 24 feb (2300 -> 500): Only He
• 25 feb (2300 -> 500): Only He

Schedule

• Is possible to start to mount the setup ~12 hours (the longer the better) before the beam time ?
  • In principle, yes, although the answer to this question depends a little bit on the details of the schedule. - Ideally, you would leave an area of about 1 m^2 free at the iso-centre, to allow other small experiments (typically bio-irradations) to use the beam in the little slots around your beam time.

1. Upon arrival
2. Night 1
3. Night 2
4. Night 3

A first schedule attempt, covering a full 6h shift including mounting/dismounting and positioning of different detectors is attached in the table.

1. The 10 cm lenght of the basic reference measurement for the Fragmentation is taken as "mean half-head dimension", interesting for head tumor hadrontherapy applications.
2. The 2.5 h data taking for Fragmentation have been computed in order to have "enoug" N fragment from the oxigen beam at small (5 deg) angle.
3. The 2.5 h will be divided in 2 samples in which we want to move the chamber + LYSO setup at 60deg
4. The chamber/LYSO (monitoring) measurements will be performed in 4 different PMMA configurations keeping the BP position fixed.

Preparation

• Detectors
  • GAS: Verify that all the pieces needed for the Gas system are available
  • All Detectors: should be re-checked/ defined an operating voltage
  • Drift Chamber: cabling is main issue. Calibration has to be done for follwoing pourposes AT LAB
  • Telescope: PRE test with the Cosmics AT LAB
  • PET heads --> measurement of beta+
• Electronics
  • Attenuatori!!
  • Trigger Logic: All modules entering the trigger logic have to be tested: dual timers/coincidence units/splitters. all discriminators should be checked as well.
  • NIM/VME modules: verify scaler + TDC modules (strongly push for havin multihit ones!

Experimental Details

Setup

Experimental setup updated to end of Genuary 2014: Gennaio2014_knote.key, Gennaio2014_pdf.pdf.

1. Vetos are all of the same widht: 2 mm
2. BGOs (Davide) to be checked
3. The tree angle configurations are acquired at the same time
4. super super pencil beam (that is not going to be that super)
5. modular target.
6. "Intruso": new Veto for particle exit point identification

Mechanics

Large room is available. Beam is at 120 cm from ground.

• There is a way to take electronic rack (on wheel) in the experimental room?
  • Yes, no problem. If you prefer to transport individual crates, we also have an (empty) rack (standard dimensions) in our cave.
• Are lead (or iron) bricks available for the shielding of the detectors.
  • Usually we use lead bricks (10 kg each) for that purpose.
• Is possible to take an aluminum plate 1x1 m2 with all the setup mounted and laid down the plate on the moving table?
  • Should be possible, provided we remove the conveyer belt which is presently mounted on one edge of the experimental table. - Note, however, that we would prefer not to have the table blocked during several days by the plate, in the case that other researchers would like to use the the small beam time slots around your core beam time (see 8.).
  • Please, be aware that the aperture of the entering couloir is not larger than 120 cm at its narrowest point (actually only near the floor up to a height of 50 cm), hence any trolley supposed to enter the cave must not have a wheel distance larger than that.
  • Concerning the possibility to mount a detector at small angles behind the interaction point , I do not see any principal problem, provided you bring along some small platform (or tripod) to mount the detector at the height of the beam (120 cm above ground). The distance from the rear wall to the iso-centre is about 210 cm.
  • • The 220 cm from the rear wall (actually 210 cm, we remeasured them today) are the distance from the wall to the iso-centre. I.e. the total distance from the real wall to the beam nozzle (see below) is 310 cm rather than the 220 cm mentioned in your e-mail.
    • The distance from the beam exit window to the iso-centre is 145 cm, however the housing of the beam extends another 45 cm towards the iso-centre, comprising the control chambers and the ridge filter used by our scanning system. I.e. the net distance between the nozzle and the iso-centre is 100 cm.
    • The "thing" that looks like a beam dump on the photographs is indeed a hole in the rear wall used as a beam dump. To prevent long term activation of the iron shielding in the wall we usually prefer to put some water vessels in there, since the decay time of the activity induced in water is much shorter than in iron. - However, these vessels may be remove on request, if you need this room for support of primary beam detectors.

• Few images of the cave/setup

Electronics

• Is possible to have an electronic signal from the machine to signal the change in position of the Bragg peak, whenever the energy changes?
  • Routinely you can have trigger signals (TTL standard) of the machine cycles, which you may use as a gate. If you need information on the EFI (energy, focus, intensity level) of each cycle, we have to think how to get it over to your electronics from our DAQ (/EtherCAT/-system).
• Splitter/Attenuator
  • ADB: 2*6
• Simple Splitter
  • 13: 8*1/2 + 8*1/3
• Delays
  • We have 35 channels to delay

Detectors

The detectors status is constantly updated here

Drift chamber

• It is possible to use non flammable gas bottles in the experimental room, provided the bottles are attached safely. We would be glad, if you could live with the standard gas mixture used by the MWPCs of our control system (80% Ar / 20% CO_2 ), otherwise I don't see any principal problem in ordering a special gas mixture for your experiment with our local gas distributor (takes about 1 week).
• The used gas of our control chambers (7x2 l/h) is exhausted to air, hence the same should be allowed for you.

Start counter

The SC used in the data taking is the FIRST one (margherita). This paper documents the expected performances.

Software

The software has been setup under svn. To get the repositories please use:

• Acquisition: svn co svn+ssh://sarti@arpg-serv.ing2.uniroma1.it/Users/Shared/SvnRepos/TestBeamCode/Hit_2014_Bridge
  • To compile: make acquire
  • To run: ./acquire -f #output_file_name -p #check_for_stop_any_p_events -n #number_of_events
• Decoder/Tupler : svn co svn+ssh://sarti@arpg-serv.ing2.uniroma1.it/Users/Shared/SvnRepos/TestBeamCode/Hit_2014_BridgeDecode
  • To compile: make Analizer
  • To run: ./Analizer -in #dat_file -out #root_file -nev #nevents -con #config_file -pla (to produce the ntuple)
• Analysis: in order to run the different analysis please follow the instructions and details in the Analysis Page
• Simulation: svn co svn+ssh://username@arpg-serv.ing2.uniroma1.it/Users/Shared/SvnRepos/TestBeamCode/Hit_2014_Sim

Dead time measurement

Inside RateMonitor the methods for rate and deat time monitoring have been setup.

• The rate is monitored using the Scaler
• The dead time can be mesured
  • Using the scaler (MEga OR no DT should be acquired)
  • Using the rate measurements themselves: 10�s have to be subtracted since the daq reset involves 2 calls to V513 modules, while the read trigger only 1.
  • Both methods have been tested with a pulser.

Detector Calibration

Are radioactive sources available for on site energy calibration purpose. If yes, which ones?

We have some radioactive sources available at HIT, most of them for PET-calibration: In particular 2 extended ^68 Ge-sources and one point source of ^22 Na (MBq activity). Other (mostly shielded) sources from the medical physics group are made with ^90 Sr. In addition there are two (rather bulky) ^137 Cs-sources and one ^241 Am-source from the accelerator group.

Bureocracy and Connectivity

We need to know the radioprotection procedure to have access to the Center 30 days in advance the data taking.

From our side, the needed formalities are not very complicated, since you will be accompanied all the time by a local scientist who is supposed to know about the radiation- and security-related risks at our facility, hence from a legal point of view you are considered as his "guests". Guests are requested at our site to wear electronic dosimeters (provided by us) showing at every moment the accumulated dose, and they should be under radio-protection surveillance at their home institution. On request, our radio-protection officer will document the dose accumulated during the stay at HIT in your radio-protection passports.

Connectivity.

The present architecture of HIT computing network (as from the hospital computing centre) is as follows:

1. Measurement Net: Completely contained, i.e. no direct data transfer to the outside wold possible.
2. Scientific Net: Restricted communication to the outside world possible through a firewall (i.e. internet access through a proxy-filter, limited ssh-connections on request).
3. University Net: (Almost) unrestricted data exchange with the outside world. At present, access to this net is not possible at HIT on a regular basis.

ELOG

The experiment elog can be found here

A scanned version of the paper logbook can be found here

Calibration Analysis

Notes

Birk's law

Documentation:

Scintillation Efficiency of Inorganic Scintillators for Intermediate-Energy Charged Particles ,

The Proton Energy Response of a LYSO Crystal ,

Light Output Response of LYSO(Ce) Crystal to Relativistic Helium and Carbon Ions

PET HEADS Analysis

Notes

LYSO resolution in literature (5mm thickness) ~9% @511 keV

Documentation:

Papers on previous LYSO resolution studies

-- AlessioSarti - 2013-11-28

• Art_-_Compact_Readout_Electronics_for_Position_Sensitive_Photomultiplier_Tubes.pdf: