Differences

This shows you the differences between two versions of the page.

--- start [2013/12/13 19:26]
pereira
+++ start [2023/05/23 16:22]
swartzj
@@ Line 1: / Line 1: @@
 ====== The NSCL S800 spectrograph ======
-Welcome to the wiki page of the NSCL S800 spectrograph. The page provides technical information about the S800, as well as instructions to operate the S800 prior to and during an experiment.
+Welcome to the wiki page of the NSCL S800 Spectrograph and S3 vault. The page provides technical information about the S800, instructions to operate the S800 prior to and during an experiment, and some general maintenance information of the S800 and S3 vault. Support of the S800 is provided by Jorge Pereira ([[pereira@nscl.msu.edu]], ext. 77428) and Shumpei Noji ([[noji@frib.msu.edu]], ext. 77600). Details on the Service Level Description of the S800 can be found in [[https://www.nscl.msu.edu/users/s800_sld.pdf]]
+All users of this site are personally responsible for full compliance with the export control regulations of the United States and/or any other jurisdiction of which they may be resident.
+For questions related to this Wiki document, please contact  Jorge Pereira.
 ===== Technical Aspects of the S800 =====
@@ Line 10: / Line 12: @@
   * [[Modes of Operation]]
   * [[Determination of Angles and Momentum]]
+  * [[mapserver|Calculation of inverse map]]
   * [[Detectors]]
   * [[Electronics]]
   * [[Data Acquisition (DAQ)]]
-  * [[S800 Software]]
+  * [[S800 SpecTcl|S800 analysis software (SpecTcl)]]
+  * [[New SpecTcl in Python|New version of SpecTcl (May 2023)]]
+  * [[Preparation of S800 Experiments]]
   * Coupled Devices
   * [[Types of Experiments]]
 ===== Operation of the S800 =====
   * [[Preparation for tuning the S800]]
-  * [[Tuning the S800 (XDT: Experiment Device Tuning)]]
+  * [[Tuning the S800 (XDT)]]
   * [[During experiments]]
   * [[Division of operation responsibilities]]
+  * [[Venting/pumping vacuum sections in S800|Venting/pumping vacuum sections in S800]]
+  * [[Radiation safety in the S3 vault|Accessing and securing the S3 vault]]
+  * [[General documentation S3 vault|Documentation S3 vault]]
+  * [[Troubleshooting]]
+  * [[Shutdown S800/S3 Vault]]
-PILOT BEAM (XDT)
-Unreacted beam
-Send beam to FP
-	Ensure that crad04 is enabled with a rate limit of 20 kHz (crad04 looks at E1 up)
-	FP rate limit:  6 kHz
-	Bias S800 FP scintillators
-	Set bias to best guess based on previous experience for the fragment Z being used
-	Typical values:
-V E1 up/down
-V E2 up/down
-	Have a good expectation of rate from A1900 group information or from timing scintillators
-	remove stops to look for beam at S800 FP with scalers and adjust beam rate with attenuators
-	Look at FP scintillator scalers
-	There are typically a few scaler counts without beam
-	Ion chamber does not have scalers
-Object scintillator setup
-	Use scope to look at signal patched out to data-U6
-	This signal is a copy of what goes to cfd in vault
-	Good signal height:  400-500 mV
-	Typical bias:  1200-1800V (up to 2200 V)
-	Typical current:  _________
-	Watch for no rate change on scaler display with a bias adjustment up or down of ~50-100 V
-FP scintillator setup
-	Set trigger to “s800 trigger”
-	Start trigger GUI by clicking icon in “Operations” area
-	Under trigger tab select “s800 trigger” (which is E1 up by definition)
-	Deselect experiment trigger
-	SAVE TO FILE
-	Stop and start daq to assert new trigger condition
-	start spectcl
-	Adjust bias looking at down vs. up 2D spectra for each scintillator
-	See sketch below
-	Bias changes stretch curve (i.e. shift spot corresponding to typical unreacted beam)
-	Adjust biases so that unreacted beam are at 1/3 to ¼ of dynamic range
-	Reaction product will typically be similar enough to unreacted beam particles
-	Different particles with different e-loss will shift the curve corresponding to particles covering whole FP
-	Biases for K-48 @ ~95 MeV/u
-	E1_UP/DOWN:  1550/1500V
-	E2_UP/DOWN:  1350/1390V
-Ionization Chamber setup
-	Gas should be flowing
-	Bias detector
-	Start alarm server under “operations”
-	Start HV application under “operations”
-	Typical bias
-	Anode:  200V (should not draw current after bais reached)
-	Drift:  800V (typical current:  <80)
-	K-48 at ~95 MeV/u:  Anode/Drift:  800/200V
-	This is not a sparky detectors
-	Adjust pad gains
-	There are 16 pads each providing dE information in the Z (beam) direction
-	The idea is to make sure the dynamic range is OK so that heavy particles do not saturate the spectra; the pad gains do not have to be matched
-	Use summary 2D spectra “IC.raw”
-	Gains are controlled in “s800shpini.tcl” file in the current directory
-	This file can be edited with the bbedit editor by double clicking on the file in the browser
-st shaper is for ion chamber
-	typically only coarse gains are used
-FP CRDC setup
-	Bias CRDCs
-	Look at anode signal on scope while biasing drift and anode
-	Patched to data-U6 on labeled connector
-– 500 mV signals are good
-	Typical starting values:
-	Drift:  500 V (800 V used for K-48)
-	Should draw current with bias applied
-	Anode:  500-600 V (800 V used for K-48)
-	Should not draw current after set value reached
-	Watch signal as setting in 100 V steps
-	Gate: 20-40V (adjust to optimize signal height compared to noise)
-	K-48 @ 95 MeV/u
-	CRDC1 Anode/Drift:  800/800 V
-	CRDC2 Anode/Drift:  800/800 V
-	Gate:  26V
-	Not a sparky detector
-	Should see counts on scalers
-	Count rate a little higher than on scintillator due noise or thresholds
-	Check spectra
-	 “crdc1.raw” and “crdc2.raw”
-pads in dispersive direction
-	Sketch shows typical spectra
-	Width of beam peak is proportional to A1900 p-acceptance in focus optics
-	Width is narrower in match optics
-	Adjust anode to bring fuzzy maximum to around 600-700 channels
-	ADC full range for each pad is 1000
-	Can look at y vs. x 2D spectra as a sanity check
-	Remember that the y-parameter is not reliably calibrated at this point
-	“crdc1.tac” and “crdc2.tac” provide raw y-parameter (confirm these spectra titles _____________________)
-	Mask calibration
-	Unreacted beam does not provide good conditions for performing the mask calibration, but sometimes it provides the only option
-	To cover mask
-	Detune non-dispersive y quad (ratio=0.5) in spectrograph to spread beam in y
-	Sweep beam across dispersive direction using spectrograph dipole
-Timing setup
-	See http://groups.nscl.msu.edu/s800/Technical/Electronics/Electronics_frameset.htm for background information on the trigger setup
-	The TDC delays can only be changed when the run control is stopped; must SAVE settings before starting run control not to overwrite adjustments being made
-	The “S800” trigger is from E1 up signal
-	Trigger the scope with the “Live Trigger” signal patched to data-U6
-	There are 4 trigger inspect channels patched to data-U6 that can be assigned using the trigger GUI
-	Examine the timing of each of the selectable listed signals with respect to the “Live Trigger” signal
-	There are 4 TDC inspect channels patched to data-U6 that can be assigned using the trigger GUI
-	The full range of the TDC is 400 ns
-	Set each timing to 200 ns
-	TDCs of last 4 listed signals (including XF and object scintillators) are bypassed with cable delays inside the vault and thus their delays cannot be controlled with the GUI
-	They can be inspected, however using the GUI
-	Information
-	The signal delays controlled by the GUI (and not by cable delays) are not “pipelined” – i.e., any new signals that arrive during the delay time of a previous signal are lost and thus deadtime is introduced into the system.  The signals delayed passively by cables are “pipelined” and thus are not subject to deadtime losses
-	All of the trigger signals are not pipelined and are thus subject to deadtime
-Checking Particle ID and rate at S800 FP
-	Establish PID
-	Refer to information on setting from A1900 FP
-	dE-TOF
-	dE signal from Ion Chamber
-	TOF from XF or Object scintillator to S800 FP
-	Not necessary to implement dE- or TOF-based corrections
-	Document rate of fragment of interest with run to disk
-	Measure beam current with appropriate Faraday cups
-	Timed run
-Analysis line classic PPAC setup (Focus optics only)
-	“Classic” PPACs are the default detector, not TPPACs or CRDCs
-	Classic PPACs have rate limitations from pileups
-	TPPACs are not as efficient as CRDCs for low Z because it is not currently setup to set thresholds on individual pad readouts
-	Checking PPACs with beam
-	Scalers do not provide reliable diagnostic information because of noise
-	Bias PPACs while looking at patched out anode signal on scope to check for sparking
-	Typical starting value:  400V
-	K-48 @ 95 MeV/u biases:  PPAC1=580V, PPAC2=540V
-	Look at spectra of raw up, down, left, right, anode to decide on bias
-	Run with smaller p-acceptance (e.g., 0.5%)
-	Efficiency against Focal plane CRDCs should be 100%
-	Optimize bias setting based on raw signals
-	Check that position spectra look reasonable
-	Run with larger p-acceptance (e.g., 2%)
-	Efficiency against Focal plane CRDCs should be 100%
-	Record run showing tracking
-	Confirm angular dispersion: ~50 mrad/% (not an absolute measurement)
-	Confirm correlations between dispersive angle at intermediate image and p in FP (e.g., crdc1x)
-	This correlation will be somewhat washed out by straggling in the target; in principle, this should be checked without the target, but the benefit vs. cost in time to remove the target is not worth it.
-Setup beamline
-	Object and XF scintillators and intermediate image PPACs inserted if they will be used
-	If Object scintillator will not be used, there is no reason to look at beam on it unless to debug a problem with the transmission
-	Set spectrograph Brho for unreacted fragment
-Start scalers
-	Use s800 account
-	Make sure experiment daq is:
-	Stopped
-	Gone
-	Open terminal window (from bottom of mac)
-	ssh to spdaq20
-	ps auw | grep Readout
-	Does not get restarted
-	Under operations folder on mac
-	scalers (gives error if no bridge)
-Setting Optimization
-	Focused optics
-	Expectations for A1900 FP to S800 FP transmission
-% or better for mid-Z fragments
-	>60% for low-Z fragments with large angles
-% transmission might be a cause for concern for high-Z beam with charge state losses in detectors/targets depending on the charge state distribution and how many charge states reach the S800 FP
-	Strategy for optimizing transmission
-	Want to balance losses between S800 analysis line and Transfer Hall (the S800 analysis line is typically slightly worse)
-	Best diagnostic is scalers from S800 FP, object scintillator and XF scintillator
-	Tweak y-quads (while watching scalers) in front of dipole gaps (this works both for Transfer Hall and analysis line); choose elements that have biggest effect with smallest ratio change
-	Matched optics
-	Typically much more time is invested for optimizing optics for matched optics than for focused optics
-	One input is optimizing for transmission
-	For tritons a scintillator is required at the pivot position since fragments at 5 Tm will not reach S800 FP
-	The last two analysis line triplets are used to tweak for the desired optical properties
-Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP
-Reaction Settings and Coincidences
-Setting up Reaction Settings
-	Calculating reaction setting
-	Center unreacted beam at S800 FP
-	Adjust spectrograph Brho to center beam at S800 FP
-	Requirements for a beam to be “Centered”
-	Spectrograph dipoles matched
-	Beam position within about 1 cm of center as judges by 0 point on crdc1x spectrum or on track.xfp spectrum
-	Record run to disk to document centered unreacted beam setting
-	Calculate reaction setting using “effective” beam energy and the nominal target thickness
-	Ideally, experimenters should be the ones making this calculation
-	This approach assumes that the target thickness is known
-	Reaction setting to FP
-	Start with Attenuator setting of unreacted beam and step up in intensity
-	Set up beam blocker, if necessary
-	Expect to see unreacted beam if reaction setting is within +/- 3% of unreacted beam setting
-	Should have to move only one of the two blockers unless charge states are present
-	A graphic tool is available to help (not yet calibrated)
-	Try to cut only as much as necessary; depends on
-	What rate limits allow
-	What experimenters want (e.g., if they want singles, the cut has to be more restrictive to limit acquisition deadtime)
-	Move blocker, decrease attenuator, repeat
-Coincidences
-	Overview
-	Most experiments at the S800 involve setting up an auxiliary detector system (e.g. SeGA, HiRA, etc) to be used in coincidence with the standard detectors of the S800.
-	The auxiliary detector provides a secondary trigger that is fed into the S800 trigger system
-	A key part of setting up the S800 for such experiments is getting proper timing setup between the S800 and any auxiliary detectors
-	For cases where the Secondary detector has a slow response relative to the S800, the coincidence timing must be reset to the S800 timing by delaying the S800 trigger using the third gate and delay generator on the trigger GUI
-	A typical S800 delay for SeGA is 450 ns
-	Probably smaller typical S800 delay needed for HiRA
-	An example of experiments where auxiliary detectors are not used and, thus, setting up coincidence timing is not an issue are the experiments with tritons run by the charge exchange group
-	It is not clear whether coincidence setup gets logged as “XDT” or “EXR”
-	Choice of setting to be used for coincidence timing setup
-	The reaction of interest for the experiment can be used to setup coincidences only if the rate of coincidences is high enough
-	Sometime the pilot beam is used for setting up the coincidence timing in cases where the intensity of the secondary beam is too small
-	Example:  Reaction of interest 2p knockout to make Mg-36 from Si-38 (Si-38 rate was 1000 pps)
-	Setup
-	Coincidence signals are usually visible on scope without running scope in acquire mode
-	Adjust the width of the early signal (S800 or secondary) should be wide enough to catch coincidences with the late signal (width of late signal is not critical)
-	Readjust TDC delays based on changes made to S800 trigger delay
-	Experimenters will need to adjust their delays based on delay made to S800 trigger
-	Have experimenters record a run with coincidences on their account
-	S800 trigger TDC channel should show a peak (which corresponds to coincidences)
-	“secondary” TDC channel should have a peak
-	This check is required for verification in cases of low beam intensity (e.g. 1000 pps)
-	Length of run required is typically about 10-15 minutes
-	To be resolved:  whether or not to this run copied from experiment account for documentation of device tuning
-	Sample timing for running S800 with SeGA
-	SeGA trigger is late with respect to S800 trigger
-	Timing schematic to show how to
-	Setup of the S800 trigger to recover timing needed for proper functioning of S800 FP detectors
-	Set up the coincidence trigger
-	See:  http://groups.nscl.msu.edu/s800/Technical/Electronics/Electronics_frameset.htm
-	A double peak structure will appear in the TDC for the S800 trigger between the coincidence events and the singles events; the groups are separated by 25 ns because of the delay introduced by the downscaler used for the singles
-Followup
-	Before leaving beam with experimenters
-	Set up current trip points on Linux HV controls
-	Values used for K-48
-for CRDC and Ion Chamber anodes and intermediate image ppacs
-for CRDC drifts
-for IC drift
-	Ensure alarms are running
-	Make sure Linux HV GUI alarms are enabled
-	Make sure threshold on isobutane level is set up (not currently connected to alarms because they give too many false alarms when communication is lost)
-	All logs are being recorded
-	There is no log file for biases controlled by Labview
-	Linux HV
-	LabView gas handling system
-	Note in logbook
-	Scintillator biases
-	IC gate biases
-	Post reference printouts for experimenters
-	HV status:  a snapshot of HV GUI
-	Gas handling system status:  a snapshot of LabView window
-	Create window configuration with summing regions to make it easier for experimenters to track efficiency/performance of all detectors
-	Setting up coincidences for additional reaction settings in an experiment
-	Do not need to redo coincidence settup if secondary beam does not change
-	Might need to redo coincidence setup if secondary beam changes drastically
-	To watch during experiment
-	Look for isobutene running out – messes up data over several hours
-Experimenters responsibilities
-	Implementing dE- or TOF-based corrections is part of EXR
-More detail needed
-	Minimum rates required for coincidence setup
-	Selection of appropriate substitute reactions for coincidence setup
-	How to feel comfortable that there will not be a problem with FP detector gases running out
-	Starting alarms
-	Starting logging
-Not covered
-	Details of mask calibration
-	Details on implementing dE- and TOF-based corrections
@@ Line 377: / Line 43: @@
-	Index
-	Introduction
-	Experiment Types
-	Experiment planning
-	NMR
-	Operations software (Barney, QTChan, BLkq...)
-	Tracking setup
-	Device Tunning  Process (Focus mode, Dispersion-matching mode, Reaction setting, Unreacted beam)
-	Mask calibration
-	Beam blocker use
-	Setting optimization (tweaks)
-	Electronics
-	DAQ
-	Analysis
-	Operation Environment System Overview
-	Dump Switches
-	Experiment preparation (S800 checklist prior to experiment)
-	Login strategy
-	Detectors (TPPACs, CRDCs, IC, OBJ_SCI, S800_SCI, Hodoscope)
-	Overview
-	HV
-	Gas Handling system
-	Vacuum control
-	Special considerations for each detector
-	Shimming OBJ
-	Replacing OBJ
-Advance preparations

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